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Hey, all!

I've been surfing the site for several months, working on my technique, and decided to join so I could take it to the next level.

I'm basically a cyclist on sabbatical with some exposure to automotive engineering (My dad recently retired from GM, and I spent a summer in Corvette Engineering before graduating from MIT in `92), so I'm aware of a lot of the physics and mechanics of what's going on even though I haven't tinkered with engines much. Between commuting and ultramarathon riding, I've put in about 100,000 miles on the bike. I bought a car in July to alleviate some chronic health issues; I expect to be back on the bike within a year or so, but I expect to keep the car.

My car is a `99 Chevy Prizm, a Corolla clone for less money. I bought it for its low overall cost (purchase, maintenance, gas cost), high reliability and good safety record. I figured the majority of my driving would be just back and forth to work, so a small vehicle made sense despite the allure of a wagon for ride support during cycling events (wagon selection in my price range was limited anyway; there were a lot fewer models a few years ago than there are now). I expected that some of my driving would be for solo checks of bike routes, so I bought an automatic (4-sp, locking TC) so I could drive while taking notes. Unfortunately, the auto will hurt optimizing FE with my particular commute; even though the auto has a taller final ratio than the manual, at the lower speeds I'm driving the TCC is unlocked most of the time. I didn't know I'd be interested in hypermiling when I bought the car; if I had, I probably would've given stronger consideration to a Metro with a stick.

So far, I haven't made many modifications. I've blocked most to all of the intake depending on temperatures, unplugged the AC clutch (it was running all the time) changed to 3 quarts 5-30/1 quart 5-20, all synthetic, installed a SG II and am gradually raising the tire pressures. I'd been running 40/38 F/R based on a 35 PSI max sidewall, but I found last night that only one tire (new tires were installed by the dealer) was rated for 35 PSI max; the other three are rated for 44. They're all the same model (Radial LL650 M+S) but different makes (35 is Segura and 44s are Pro Meter). As of this morning, I'm using 44 in all and will probably bring it up to 50 in the Pro Meters tomorrow. Fortunately, the 35 PSI tire is already on the rear where it belongs. :)

The car appears to have its best cruising FE in the 40-45 MPH range with constant throttle after locking up the TCC in fourth gear (>43-44 MPH), as you'd expect. Next best is around 30 MPH in fourth gear, TCC unlocked. Many of the speed limits are 35, in which case I'll accelerate to 44 on a downhill and gradually drift down to 40 without unlocking the TCC. The TCC unlocks if I coast, so the TPS on the Scangauge helps a lot when trying to find out how much further I can let off the gas without unlocking.

I've already modified my former commute and found a route that is shorter, faster and has fewer stops (all a plus). My current commute is 16 miles of fairly shallow rolling hills, with speed limits ranging from 20 to 55 and an average speed around 30-35. The route to work has a stop, four yields and two lights; the route home has three lights and six yields. The five miles at the work end are expressway. On nights that I've worked late, I've occasionally been able to DWB from a stoplight a couple of blocks from work until I stop to back into my driveway. Most afternoons, there's relatively heavy stop-and-go going home, and traffic backs up at the lights. I was driving much more efficiently when I was working 12-hour days in October, but I wasn't able to do much else. :(

FASing on hills doesn't appear to make much difference because I have an automatic (no bump starting = less efficient start) and most of the hills are short enough that I can't coast very long. FASing to red/stale green lights is a no-brainer, especially where light cycle lengths are known to be long.

I coast in neutral where I'd come out ahead doing it, and leave it neutral at short lights. I'm pretty used to using neutral at stops, since it's a good practice for driving on ice anyway.

It's tough to come out ahead P&Ging with the automatic, since I can't have a mostly-open throttle and low RPMs at the same time to reduce pumping losses, and a FAS glide doesn't last long enough to make the startup hit worthwhile.

DWL seems to help but is hard to do on rolling hills at low speeds without ticking off other motorists because the speed variation is so huge. I'm guessing that the best compromise may be to maintain speed for the bottom part of the hill, then let it run out near the top. I do my best to delay acceleration until the downhill parts of a staircase descent, or the flat parts of a staircase ascent, figuring that this minimizes the fluid shear (and energy loss) in the torque converter at lower speeds.

I've generally been trying to use more throttle on downhills than on uphills at low speeds where the TCC is unlocked, a constant 40 MPH with the TCC locked when the speed limit is 35, and constant throttle at higher speeds. I'm able to keep in the 50-55 MPH range on the expressway without getting raged by others.

I practice face-out/PP parking and smart braking where possible, draft trucks on the expressway when there's a good opportunity, and do my best to keep my momentum on turns when the roads are dry. I've cleaned out the garage and am keeping the car inside to minimize the FE hit from warming up.

I haven't yet figured out the optimum way to accelerate. My best guess has been a brisk acceleration to 30, let off to shift to 4th, more gradual acceleration to 45 to keep it in 4th, let off to lock the TCC, then a bit harder if more speed is needed. I should probably do some experiments at some point to find the optimum rate.

It's only a 25 minute commute in the morning, so I probably won't be able to wring out huge mileages. OTOH, I'm not using much gas, either -- less than a gallon per day. :) I've been able to hold about 34-35 MPG tanks so far despite the decreases in temperature; EPA mixed is 31 and most users get around 30. I'd like to keep it around 35 MPG the rest of the winter, after which it should rise naturally during the summer.

Any thoughts?

Welcome! That's one of the better intros we've had I think. Your choice of car was a good one IMO and it sounds like you have a really good handle on what you are doing behind the wheel. You should be pleasantly surprised come spring if you can maintain 35mpg in freezing or near-freezing weather.

Hi Bruce:

___Great intro and thanks for posting the details for us to try and help. I looked your Prizm up and it was rated at 28/36 w/ the 4 speed Auto. Not a bad choice for a 99 in fact!

___You have the oil type sorted out but I assume you are using a 5-30 mix because of the manuals recommendation. Nothing wrong with that but I would be using 5W-20 all around myself? Those tires … I have no idea what kind they are or their RRC but I bet your Prizm would receive a little boost the next time they are in need of a change with a name brand LRR tire and w/ Max sidewall’s of 44 all around. That one tire w/ a 35 Max sidewall in the rear bothers me a little is all? 50 #’s will give you another little push to what appears to be a 40-mpg tank goal this early on?

___And to the heart of my reply.

“Many of the speed limits are 35” AND “my current commute is 16 miles of fairly shallow rolling hills, with speed limits ranging from 20 to 55 and an average speed around 30-35.”

___Oh my god what 95% of us would do for that kind of speed limit and terrain on our daily grinds! All that is needed is for you to take advantage of those speeds and terrain given this is primo P&G territory for a non-hybrid w/ an automatic or any other vehicle known to man imho ;) Do not worry so much about TC lock up but if you truly understand the many safety and HW based limitations of a FAS (it sounds like you already know about your Prizm’s Brake and PS limitations) it is time to start taking advantage of those limits and that terrain. Since you are already SG-II equipped, when and where applicable, why not consider a load of maybe 70 - 90% on your pulse w/ a range of maybe 25 - 45 mph. The low end would be dictated by traffic of course but with traffic, maybe a 33 mph low w/ a 45 mph top end in the 35 mph limited roadways. Depending on the delta and stop lights/signs just after the top of those elevations, I would recommend trying to peak at an absolute minimum speed if the slope is steep enough to allow a terminal velocity of traffic around you on the down slope afterwards. If it is not steep enough for a slight acceleration to the limits, and there are no traffic lights/signs ahead, accelerate down the previous slope and maybe ¾ the way up into the climb with a terminal above the current limit of 5 - 10 mph. Start your FAS before the crest so that you are just a touch above the limits (as you crest) and then let the glide go for as long as traffic will allow as your speed bleeds away on the back side(s). Forget about a NICE-On’s unless able to ride Fuel Cut while in gear allowing for traffic, obstacles or conditions to slow your progress riding Engine braking down to 1,000 RPM or so and FAS from there.

___The above is a very generic blueprint for what I imagine you are facing - hill crest after hill crest but as always, you will come up with a better overall solution of your own once you start your own analysis of the FE achieved through a given section of roadway/commute.

___I do not know how fast your SG-II responds to a FAS in your Prism (recent gen Honda’s, Acura’s, and non-hybrid Toyota’s have an almost 5 second lag before the data stream begins to update) but jump on a real P&G routine w/ rhythm and your numbers will get stupid high real fast.

___Lastly, keep an eye on that 12V in one of your SG-II’s readouts as all us Auto drivers have to for obvious reasons ;)

___Good Luck and hopefully Tim and I have helped!

___Wayne

Welcome Bruce!

That was a good intro.

It reminded me of a story of a high school class around 1980 disassembled a Trans AM, When they put if back together - it's fuel economy doubled, telling you they would have made darn good employees....or maybe the QA needed upgrading.

Thanks for the compliments on the car. Yes, I've been using 5-30 mix because of the manual's recommendation.

The oddball tire is a bit disconcerting, but there's no point in dumping new tires for several hundred dollars to save a few bucks' worth of gas...I may as well wear them out first. Given my history with my last car (a `78 Malibu I owned from `85 to `99), they'll probably fall apart from rot before I wear them out if I'm back on the bike within the next year, so it's probably just as well if they're high RR...they won't waste as much gas over their life on my car as they would on someone else's. :)

I'm having some difficulty deciphering your paragraph about the commute.

Are you advocating a pulse that's a large percentage of full throttle? That seems to run counter to the notion of avoiding jackrabbit starts.

There's some amount of variation but most of the hills are minor undulations in terrain, maybe 10-30 feet of elevation -- just enough to keep the road from being a pancake in most places. The undulations are short enough that a FAS would only last a couple of seconds, so most are not worth it. I can coast down in neutral with the ICE on, but coasting down runs counter to my understanding of DWL. My understanding of DWL is to use more throttle going down a hill than going up to maintain a set MPG. If I ICE-on coast down a gentle descent, I'll necessarily need to use more throttle on the ascent to maintain speed, especially if I've lost speed while coasting. So where is it best to apply throttle? Or are you talking about alternating DWL and FAS?

I've set the SG-II's engine type to Hybrid, and it appears to read okay (9999 MPG) during a FAS. I've been keeping an eye on the voltage, have been keeping it above 11.6 and won't FAS when it gets too low. I'll generally shut the headlights off but leave the marker lights on after I've stopped at a light to save some juice. Unfortunately, I bought a new battery last fall and didn't read about the Optima until just recently.

After reviewing the paragraph on the commute several times, I think I've figured it out...FAS just before a crest and hit just above nothing at the crest if I'll gain speed or just above the limit if I'll lose it or stay the same. I'm doing that now.

There are only a half-dozen places on the commute that are really ripe for a FAS, but I may be able to work in some more if I'm really aggressive about it and I only need a seven second minimum to come out ahead. I still need to figure out about the acceleration rate. Also, if you FAS over most of a roller, you'll need to accelerate up part of the next one, and I was under the impression that accelerating up a hill is one of the worst things you can do for FE.

Hi Bruce:

___The tires are a problem but you should only replace them when they are ready. Sorry that there was a mismatch from the dealership :(

___70 - 90% load is not full throttle in the least so do not think of it in those terms. You have a data display with LD (load) vs. the rest. Just swap one of your current data points for it and you will see what we are talking about. If you were without an SG-II, I would say keep your machine less than 2K during accel’s and let it climb in speed normally.

http://www.cleanmpg.com/photos/data/523/SG-II_Review_ICE_Load_-_Current_Manifold_Pressure_-_Open-closed_Loop_-_iFCD.jpg
Upper left data point in your SG-II gauge display is your “Load” readout.

___10 - 30’ hills is what I drive on a daily basis. If you don’t want to FAS for any reason except FE, I would not ask you to ever use it but from your intro and commute, yes, it will bump you up by more then just a few mpg’s when used appropriately. You are going to run a FAS far longer then a few seconds and it doesn’t matter if you are in a bumper to bumper Stop and Crawl or out on the highway heading into an exit ¾ + miles ahead form 60 +. You have to judge traffic flow so that you are moving in on it before the FAS and are slowly falling back in place by the time you are ready to either pulse back up, exit the roadway, or come to a stop. Timing is critical for safety reasons of course so be very very careful but when you are ready, busting the EPA in your Prizm will be child’s play. You have to trust me as I have used the gamut of techniques in everything from 4WD SUV’s to B-Class sized coupes and using the proper tool(s) at the appropriate times allows numbers you are not going to believe! When you get a handle on all of this, you will be busting out tanks that will make a non-trained driver of any type wonder how in the heck does Bruce do that :) Your commute description just sounds absolutely too juicy to throw it away. Ask any Prius II driver here what they think about your commutes and they too will say, “Let me at it” :D

___DWL. If you are not HS (High Speed) or MS (Mid-speed) P&G’ing, you want to DWL over all those 10 - 30’ rises and falls. Let us say you are in a 50 mph limited section of your commute. Enter the trough at 51 and slowly bleed off speed while maintaining your iFCD at a given FE (50 mpg for example). By the time you reach the peak of the overpass or hill, you should be down to let us say 48 mph with the iFCD still holding 50 mpg. On the back side, you will more then likely see your iFCD bump way up as you are re-accelerating back to your initial target of 53 mph and by the flat, you are right back to the same speed you entered. I ma guessing on those numbers but I have to believe the 1.8 in your Prizm acts very similar to the 1.8 in a well setup Corolla w/ Auto (EPA rated 29/38) and in the summer months, 50 - 55 mpg at those speeds is almost a guarantee.

___Lastly, I want you to get those tires pressed up to 50, drive down a flat section of roadway at 45 and back of to 40 so your TC is locked up and watch your iFCD. Do the same for 50, and 60 mph. If you are running relatively steady state with a well setup Prizm, that 40 - 50 mph range should also shock you. I know the 03 – 07 Corolla’s will camp at 50 - 55 mpg at those speeds and I bet yours will too. Now all you need to do is try and maintain a steady state speed while DWL using anticipatory focus for timing through the lights and you have all the basics figured out.

___Good Luck

___Wayne

Hi Bruce:

___Whoops, we crossed paths on my reply above.

___You don’t normally want to accel on an uphill as the FE is atrocious but if you are P&G’ing or pushing a FAS for the furthest glides, sometimes it has to be done. What you really want in a semi-hilly area is to pull 2 or 3 crests in a FAS for the price of one pulse as this is where the really crazy 90 + mpg like numbers from your Prizm can come from.

___Good Luck

___Wayne

Okay. I'll try to FAS a bit more on the way home, keep the engine load to 70-90% on pulses and inflate to 50 PSI in the morning.

90+ sounds very improbable, but we'll see. Best I've seen on a commute so far is a tad over 40, and that was when it was still warm.

I have noticed the FE at 40 with the TCC locked up, so I try to keep it there when practical.

90+ sounds very improbable, but we'll see. Best I've seen on a commute so far is a tad over 40, and that was when it was still warm.


He used to tell me that 60-70 mpg segments were possible in my Saturn when it was warm and I thought he was crazy. :D Now, I just got back from taking my daughter to youth group and pulled a 63.3 in 20F temps.

Obviously, Wayne can get really good mileage, but how is still a mystery to me. I'm using most of the tools and am only doing about 115% of EPA.

I tried FASing a bit more on the way home and pulsing at 70-90 LOD. It's roughly the same acceleration I normally use, perhaps slightly more aggressive. Mileage was 32.6 MPG for the trip, down from 36.0 this morning...although this start was from 15°F outside instead of 45°F in the garage (followed by 10°F outside).

I must be doing something wrong. In order to double my mileage with frequent FASs, I'd need to have the engine off something like 2/3 of the time. I have no idea how I can pull that off in traffic at speed, let alone keep the battery charged -- AFAIK, the battery can only charge at about 1/10 the rate it's being used, so I'd only be able to coast about 1/10 of the time steady state. I put the battery on a charger to make sure it'll start in the morning, because the voltage was pretty low by the time I got home.

I forgot to shift to neutral on one of the glides, keyed back to IG-I and back to IG-II; the engine kept running. Any idea if my car cuts fuel completely when coasting in gear at speed? The SG-II indicates the same FE numbers at a given speed with ICE-on coasting, regardless if the shifter is in N or D.

Hi Bruce:

___Let us start with some basics as to the how’s and why’s P&G works in the P&G plus Warp Stealth in the Prius II for maximum Fuel Economy … (http://www.cleanmpg.com/forums/articles/t-pulse-and-glide-plus-warp-stealth-in-the-prius-ii-for-maximum-fe--1224.html) article and then move on to the Beating the EPA - The Why’s and how to Hypermile. (http://www.cleanmpg.com/forums/articles/t-beating-the-epa-the-whys-and-how-to-hypermile-1510.html)

___I would like you to pay close attention the pulse rates/glide distances description in the first and the actual EPA City test cycle in the second. All we are doing is taking the EPA’s test cycles and smoothing them out with better technique and better setup. I also want you to pay close attention to “Speed Kills FE” section in Sect. II of the second article. Just because a hybrid is shown does not mean your car has any less of an increase in FE above the EPA combined on a percentage basis at those speeds then a Hybrid does. I recently tested a Toyota Corolla w/ Auto and at 50 mph, she was showing 50 - 55 mpg in 40 degree temps. I am almost positive your Prizm will show a similar number at those speeds because even on the EPA in a non-setup Prizm, it punched out 36 mpg on the highway test cycle.

___Please do not get discouraged as we will help you every step of the way. Just take small steps and it will get better very soon.

___About your 12V. You are assuming you are riding it down during a FAS and you are not. Just watch the voltage on the SG-II. I am assuming you are practicing the techniques in the daylight without lights? I hope so anyway ;) With your headlights on, you will never be able to FAS “At Will” due to the OEM 12V not having the CAP to take any kind of distant ICE-Off glides. You are only using current to keep the electronics booted up during the day and in a 99 Prizm, there will be a minimal draw. You are using the 12V basically for starting and you have quite a bit of CAP without any charging whatsoever. Think of going out to your car, pulling the plug wires and start turning it over on the starter. How long would it turn over? Maybe 1.5 minutes before it grinds to a halt? You are using maybe 3 - 4 seconds worth of that after every FAS and you are charging on every pulse. Except with a smallish cap OEM battery, you can even FAS at night without issue but there are always limits. Just watch the 12V signal in your SG-II and it will tell you that below 11.7 V (as a guesstimate) you had better begin a pulse to bring the 12V back up or you will be below the current capability needed to spin her over to re-ignite the ICE.

___About Fuel Cut. I cannot say for sure that your 99 goes into Fuel Cut but I bet it does. You will feel engine braking in Gear while slowing and this is when fuel cut happens. The problem with fuel cut under engine braking is that you are throwing away that glide distance (momentum) to compressing air and throwing it back out the tailpipe. A NICE-ON vs. ICE-Off FAS is worth about 20% less from 50 down to about 10 mph in the Accord. It is the difference between a 40 mpg segment including a pulse to a 50 mpg one w/ a 75’ climb included which is a huge number in my book.

___Good Luck

___Wayne

I've seen the first article but wasn't sure what I'm supposed to get out of it, since it's Prius-specific. There's no way I can do a 50 MPG pulse, since the best the car will do when cruising at 40 with the TCC locked up was 46 MPG or so this morning. While I'm accelerating at a slow rate, the SG-II usually shows about 15-20 MPG.

The second article got me interested in the site a few months ago, and I review it weekly to see if there's anything else I can put into my routine.

If I'm lucky and get out of work on time in the afternoon (I had to stay late last night) I can usually get home by the time it's getting dark. Otherwise, all my driving is at night, so I'm draining the battery during a glide. The car also has automatic headlights and DRLs, which complicates battery management somewhat.

Most of my ride is in heavy traffic on a 2-lane road with only two passing zones. My conclusion about speeds relative to the limit is this:

10 MPH over: you'll get a ticket.
5 MPH over: no problem.
at the limit: no problem.
5 MPH under: the guy behind you will flash his lights, start honking and then pass over a double yellow line if you don't respond.

The situation is so crazy but well known that one local town uses advisory speed limits that are strictly enforced but 5 MPH _over_ the former posted limit, with the understanding that all the traffic should move at exactly the advisory limit -- no more, no less. As a cyclist, I was rather amused by it, because not even Lance could've gone at the limit up the hills on the road. (This is one example, but it is not the situation on the roads I use for my driving commute.)

I P&Gd a bit less this morning -- maybe 2-3 times over the ride, and my mileage was 34.7 MPG at a 10°F ambient, coming from a 40°F garage. Historically, my experience has been that the more I P&G, the worse the mileage. I wasn't able to get much out of a glide this morning because the car wouldn't glide very far in the low temps.

Perhaps I need to give a much more detailed description of my commute route, but I'd need to do it on the weekend so I'd have more time to find all the distances.

The example in the last four paragraphs of page 3 of this article http://nbtsc.org/~ryland/RoadAndTrackArticle/ demonstrated that P&G didn't yield a significant advantage over just cruising unless bump starting is used. How does what you are doing differ from this example? How does a Corolla/Prizm with pull a 90 MPG segment when these guys are only getting a little more at very low speeds with cars that have a 60% better EPA FE?

Hi Bruce:

___The Prius article is for explaining why P&G works. You cannot Pulse at 50 mpg’s but you can pulse at 16 and that is the point I want you to consider and understand. You do not need the TC to be locked up for great FE. P&G works no matter if it’s a hybrid or non although the benefit decreases quickly with increasing speeds and tighter ranges. You do need to allow an appropriate Glide distance however or it is not worth performing. When coming into any light or sign, you should consider a FAS other then the Fuel Cut situation but if you are relying on Fuel cut w/ ICE-breaking, you are coming in far to hot in the first place.

___Yes, DRL’s can be problematic. Fortunately, longer days are already heading our way by a minute or two daily and after DST, you should have day light hours both too and from depending on your work schedule. Use the 12V display and it will tell you when its time to light her up and maybe perform some NICE-On’s but a NICE-On will not help you move up to what you will soon be capable of.

___5 mph under … You should be building a buffer behind when you pulse but best of all is that both lanes will not be filled bumper to bumper at most times of the day or night. Anyone behind will not be pulsing with you so if you are P&G’ing between 30 and 40 in a 35 zone, no problems. You will become much more aware of what is ahead and behind when you start pushing as you simply have too …

___Just keep working it and don’t give up … You will find whatever balance you need while also receiving exceptional FE. We can also perform a case study on your route once you post that detail later this week if you think you need some more help.

___Good Luck

___Wayne

10 MPH over: you'll get a ticket.
5 MPH over: no problem.
at the limit: no problem.
5 MPH under: the guy behind you will flash his lights, start honking and then pass over a double yellow line if you don't respond.



This is the same thing I'm up against most days, except that around here I'll get tailgated, honked at, flashed, and passed for driving at the limit. Even yesterday I had a guy behind me making hand gestures and tailgating while I was 5-under but within 300ft of the next stop sign. That morning I was passed illegally because, apparently, I wasn't accelerating fast enough from a stop sign in a residential neighborhood. I have decided to live with it and no longer even acknowledge that the idiots exist. The only notable exception was when I rolled up behind a repeat offender at a light (read: passed me every day in his rice rocket doing 10-15 over the limit) and made a big production out of pulling out pen & paper to write down his plate numbers while he watched in his rear view. He had to recognize me from our daily encounter and was paying attention. Anyway I used to see him every day and since then I haven't seen him even once. In short, we have to be courteous to other traffic for their sake and ours but there are limits (usually written on signs in big numbers) to what they can expect.

As for P&G, my experience is that it's a touchy art. I have had the same experience of going overboard and realizing at the end of a segment that my mileage is in the toilet. What seems to work in my case (and particularly this morning) is to let go of P&G when terrain is sub-optimal and take the good opportunities when they arise. It sounds like you have learned that for yourself, but don't think it's just you having trouble.

I don't really understand how the folks like Wayne, Larry, and Chris can be so consistent with numbers that far above the EPA, either. Those guys are blessed with the right touch, the right attitude, and at least sometimes the right driving environment to make magic happen. However don't feel that you have to compete against them or feel bad if your numbers aren't as good because, in the end, every situation is different and there's only one person you can really compete against: yourself. Just don't even worry about it as long as you are doing the best you can within watever limits are comfortable for you.

___5 mph under … You should be building a buffer behind when you pulse but best of all is that both lanes will not be filled bumper to bumper at most times of the day or night. Anyone behind will not be pulsing with you so if you are P&G’ing between 30 and 40 in a 35 zone, no problems.


Not to hijack the thread but I have tried that and it just doesn't seem to work. If the zone is 35mph and I'm P&Ging between 30 and 40, traffic DOES inevitably catch up. Once that happens they DO pulse with me and automatically ride my bumper all the way down to 35 at which point I give up. Is there some other variable that puts it all together?

I think brick has a better handle on what I'm up against, since he's from the Northeast as well. The roads out here are improved cowpaths with lots of hills and turns and short sight distances. Passing zones are rare to nonexistent. Many hills are substantial enough that at residential speed limits, you only have enough momentum from a glide to make it down one hill and partway up the next before the car stops completely, and the hills vary widely in profile and elevation. It's very different from most of the rest of the country, where the roads are on the grid system and have passing zones with long sight distances. If you pull up a Google map of the Boston area and compare it to, say, Oklahoma or Michigan, you'll see what I mean. My wife and I administer cycling events on these roads and it's often challenging to pass riders safely.

On the medium-speed roads, there's enough traffic that >10MPH variation generally isn't tolerated well unless there's a decreasing speed limit during the glide (I only have two of these going to work, for example). It sounds like a glide needs to cover a substantially greater speed range than 10 MPH if it is to help rather than hurt FE for the trip.

- Bruce

Hi Bruce:

___Tim made a very good point. Tarabell’s article on External Factors Affecting Mileage, or why “YMMV” (http://www.cleanmpg.com/forums/articles/t-external-factors-affecting-mileage-or-why-ymmv-3168.html) would be an appropriate one to read at this point. Don’t worry about the busting the EPA in the teeth just yet but it is waiting for you. Just begin with the basics and it will come to you like a bolt of lightning out of the blue very soon :D

___Tim, in some instances, I will pull into the left lane, let a tailgater pass, and move right back into the right when driving around locally on four lane roads with 30 - 45 mph limits. I have actually had to do this on the Interstates when driving the limit because some SOB wants to drive 10 + over in the far right lane but will not pull around when traffic is completely clear in the center and lanes further to the left. Just the way some people view the roadway I guess? The OTR (Over the Road) drivers always catch a RR from way back and pull around usually ¼ mile or more behind but the cel phone talking, paper reading, make up applying types just don’t get it sometimes :( As I am sure you are, I am driving from my rear view as much as my windscreen so as to time the lane to lane dances if needed just right. Hopefully you can make it out to HF2007 and we can do some Chicago style hypermiling in the Accord in heavy traffic so you can see how I am swinging that beast around. I would love to see you swinging your Prius around as I know you will be when the warmer temps arrive and a Glide is a Glide each time you throw her into one :)

___If I am within a band of 30 - 40 on a two lane - 35 mph limited roadway and 2 lanes of traffic are starting to crowd, I can pick it up to 35 - 45 as I am already 10 over on the pulse. This is one of those rare instances when I can out hybrid a hybrid but I really do not see this that much given I am usually out the door by 04:00 AM (little to no traffic) and coming home in the heat of Rush (things are bumper to bumper and moving decently but not crazily) or battling the stop and crawls in the early afternoons out on the Interstate. I like driving the Ranger in the city/towns because I can swing it from a Pulse to Glides so much faster then with the Accord with its Auto. What I will never do is accelerate into a red light even with traffic behind. I arrive to the bumper in front of me just as fast as everyone else would and they will have to follow at a coast down speed since I am not impeding anyone’s progress through the light. I have had some flashing lights and honks with this (daahhh ;)) and then arrive at the bumper in front of me just as they are moving away and I see the guy/gal behind with a big bright light bulb lit up on top of their head as I wave and they sometimes even wave back. “Oh, that is what he was doing”. Remember that I am a very passive/aggressive driver and if I see a P&G opportunity with a lane change and to come back into the right while passing in a FAS, I will take it. Most wouldn’t think that far ahead nor would they want to in most instances as it is a lot of calculating?

___Good Luck

___Wayne

Drivers in the NE have some of the shortest fuses in the country. Locals have called it the "New York effect". Several years ago, I was waiting for traffic to clear to make a left turn out of a McDonald's onto a busy roadway; in less than a minute, two cars from behind went around my left side to turn right rather than wait.

There are lots of dashboard videos on Youtube of people doing illegal top-speed runs, commutes of 16 miles in 3 minutes, etc.

Somebody needs to post a dashboard video with a scangauge showing a fuel-efficient commute.

Somebody needs to post a dashboard video with a scangauge showing a fuel-efficient commute.

I agree. It would be fun to share videos of our daily grinds w/ a little commentary and FE feedback goodness. There are obvious privacy concerns ("This is me leaving my house" etc.) but that could be dealt with in post-production if it's an issue. I bet there's a lot to be learned from that, as it's not every day you get to ride along with someone else who drives with fuel efficiency in mind, let alone for maximum efficiency. There is a limit to how much understanding can be gained from the written word vs. a real demonstration.

I agree. It would be fun to share videos of our daily grinds w/ a little commentary and FE feedback goodness.

This is an awesome idea. I nominate Wayne to post the first video. ;)

It sounds like you guys in the NE have it pretty bad w/regard to clueless driver impatience and RR, but I can vouch that the midwestern "nice" has yet to extend to driving. Coasting to a stop sign/light is the worst, followed by P&G on 30 MPH roads with some tailgater who wants to do 40 just to get to the next stop sign. The speed variation inherent in a "full" P&G doesn't work so well.


and I see the guy/gal behind with a big bright light bulb lit up on top of their head as I wave and they sometimes even wave back. “Oh, that is what he was doing”.


...but this makes it all worth it.

I agree that videos demonstrate some of this stuff in a way nothing else (short of being there) will do.

I know there’s already a couple of Wayne illustrating diagrams of drafting techniques somewhere and I think some driving videos made by him and some other hypermilers, but it takes a while to find them. Some might need reformatting to be directly viewable though? There’s also Psy’s infamous Okie FAS.

Tom/Wayne, we have a Multi-Media category in the Gallery, would it be possible to collect stuff like this here? They would be a big help to everyone, especially new folks.

tarabell

I think there is some concerns about video's and such. Take mine for example. I do alot of high speed fas'ing. Also fas in the city alot. Hard to get video of city fas'ing. It can get real busy,, real fast... :)

For me its not a problem. I have enough strenght and raw power to stop my cars with or without power brakes, steer it and pretty much anything else that can happen with ice off. I would hate to see somebody have a wreck because they didnt know the car's limits or there's.

I think some detailed videos of load driving. Engine shut off at lights. and other simple tatctics would be great!

Ive done my vid's mainly for wayne and others that drive alot of hwy. I would hate for a noob to get hurt doing the same thing and not understanding fully how or whats at stake.

psy

I know as a newbie, it took a bit of digging before I figured out what "re-engagement of the Tranny with rev match" in the P&G description really meant. I originally interpreted it as starting the engine, then giving the gas a tap as you're putting it in gear. I later found out that it meant putting it in gear as soon as the engine lights up. Who knows what else I'm doing wrong? All I know at this point is that P&G doubles Wayne's mileage and makes mine worse.

I would hate for a noob to get hurt doing the same thing and not understanding fully how or whats at stake.

If you post on Youtube, there's probably about as much risk from that as there is a video of somebody doing 150 or sliding sideways, and there are plenty of the latter.

Hi Bruce:

___Hobbit lives up in Boston and I think maybe you need a first hand clinic with him as he throws his Prius II into a Pulse and a Glide scenario on whatever no-traffic back road is available.

___I know you do not drive a Prius but Carl Hurschik’s and Dan Kroushl's Prius opened up a ton of possibilities for me and I know it will for you once you see both the results and how the Prius can do it so seamlessly vs. our swinging everything but the kitchen sink at our non-hybrids vehicles by comparison.

___Would you be interested, as I will PM Hobbit when I hear the word go. We will have to pull him away from all the tech talk and get him honed in on just Pulse and Glide and maybe a touch warp stealth but that is beyond your cars abilities. We can FAS and he can’t ;) I think it will help you once you see it in person …

___Tarabell, I guess we had better get on it then. I will do some vids when it warms up as I am not going to do a FE technique vid w/ a subpar effort in these lousy temps ;)

___Good Luck

___Wayne

I don't really understand how the folks like Wayne, Larry, and Chris can be so consistent with numbers that far above the EPA, either. Those guys are blessed with the right touch, the right attitude, and at least sometimes the right driving environment to make magic happen. However don't feel that you have to compete against them or feel bad if your numbers aren't as good because, in the end, every situation is different and there's only one person you can really compete against: yourself. Just don't even worry about it as long as you are doing the best you can within watever limits are comfortable for you.

I would say that the biggest key to my success is my driving environment. I live in an area where the roads are relatively straight and most of the hills(if there are any)are fairly gentle. The roads are generally 1 mile apart and stops are anywhere from 1-3 miles apart. Also, my driving is probably 80-90% on rural county roads. I usually chose my route based on which one is the least travelled and that can vary at different times of the day and on different days.


However don't feel that you have to compete against them or feel bad if your numbers aren't as good because, in the end, every situation is different and there's only one person you can really compete against: yourself. Just don't even worry about it as long as you are doing the best you can within watever limits are comfortable for you.

The above is VERY important. Tim said it so well that I won't comment further.

Sorry to be late for the party. I had emailed Delta Flyer an idea a week or so ago. I have been really busy at work.

I have a miniDV recorder that has four video inputs; I believe. I was going to position a video recorder on the four following positions for my entire commute to work.

1. Speedometer / Trip meter
2. Energy Screen / Consumption Screen
3. Front Windshield
4. Rear Windshield.

The beauty of this is that one will be able to see all four video inputs at once and they are all synched (sp?) with each other. I can email a DVD of the movie or with someone's help upload it to the web.

Brick,

I post consistent numbers by driving slowly all the time. Some days I really want to punch it, but I don't. I am obsessing too much about my mpg. I am trying to top the 71.8 mpg average at greenhybrid.com. Only if someone would update the database, I might be able to sleep. :D I think it will take me until mid summer to do it. I need to let it go. The 25F am weather is killing me. Luckily, the temperatures are still positive and there are only a few weeks until spring.

I am only showing 71.5 mpg over 320 miles on the MFD. :p As I said before, this tank will calculate a little higher than normal since I gave my car the gas washdown at the last fillup.:mad:

It was at 77.4 mpg at 226 miles before the weather changed from 74F to 25F.

I'd be interested in a ride-along with Hobbit, perhaps next weekend or around dinnertime Mon, Wed or Fri next week. I'm not sure I'd learn as much from a hybrid hypermiler, but it's certainly worth a try.

The Prizm has a fairly low idle fuel consumption when warm (~1-1.1 l/hr = .28 GPH) and I average about .9-1 GPH on a drive, so it appears that ICE-off glides only have a significant, positive impact if they're for a really long time -- on the order of 30-60 seconds. They seem to work best for downhills with a decreasing speed limit; downhills where speed is maintained or gained while coasting; coasting to a stop at lights or signs; exiting an expressway and level low-speed or slightly downhill residential streets with zero traffic.

My trips have been in the 37-38 MPG range the last day or so. This morning's commute was in sandy slush. In general, trips have been 35-40 MPG range lately with the occasional short jaunt that only pulls 30 or so because of the warm-up hit. I have yet to see P&G come near the efficiency of cruising on the expressway at 50-55 MPH (~42 MPG) in my situation, let alone surpass it as others have reported.

I'm finding that I'm better able to plan for the terrain on roads other than expressways, since I'm familiar with them from cycling. I still haven't memorized most of the terrain on the expressway that I use.

Perhaps I need to try driving my cycling route home, since it's specifically designed to avoid traffic as much as possible and I'm already familiar with the terrain. However, there are a lot of stops and hills, since it uses mostly residential streets. Unfortunately, a lot of the stops are at the bottom of hills. :(

I finally figured out this morning that I could FAS for the last block into my parking space at work merely by using a parking space closer to the entrance. :) A blinding flash of the obvious, as it were.

MetroMPG posted a video of basic FE techniques at http://metrompg.com/posts/online-video.htm; I watched it a few months ago.

Hi Bruce:

___That vid was cool! DWL, DWB, Anticipatory focus and Rabbit timing, superior setup and even a bit on FCD’s. I wonder if MetroMPG was the guy in it or somebody else?

___Thanks for the link. I hope MetroMPG stops by and gives us the scoop ;)

___I will try and get a hold of Hobbit tonight to see when he is available.

___Chris, wait until warmer temps when you can throw up a 100 mpg segment to really shock them :D

___Good Luck

___Wayne

Yep, I was the guy in it, lo those many (14?) years ago. Back in the day... before the techniques had acronyms. :D

Hi Bruce:

___I PM’d Hobbit so hopefully you can see what is possible in a hybrid and then use the same techniques in your non-hybrid although forced.

___Darin, excellent job on the vid. I wish even more where aware of it!

___Good Luck

___Wayne

Wow, okay, I just managed to catch up on this thread and the
PMs. Sorry, been WAY busy with Arisia (http://2007.arisia.org/forum) and this training thing (http://www.cleanmpg.com/forums/showthread.php?t=2945).
.
Some ride-around and testing could certainly be done, although
I suspect the Prius will differ fairly radically in some ways
from a non-hybrid machine. Overall traffic-management technique
would be the same, of course, as Wayne says. One thing I'd
immediately advocate for anyone serious about this in a non-hybrid
is a "FAS switch" or injector power cutoff, for killing the
engine without having to key-off and reboot everything. This
would probably be a fairly simple mod but one would want to
consult the vehicle's wiring diagram to make sure it's done right.

Still, if you're into the idea of watching my extra gauges
swingin' around and generally getting into some possibilities,
I might be able to make some time for you and anyone else local
who thinks my input would have value...
.
Oh, right, and there are some cool traffic-flow animations up
under http://amasci.com/amateur/traffic/traffic1.html that show
how things work a lot better when larger spacing is maintained.
.
_H*

BTW, how do users put their mileage into their signature? I haven't been able to figure this out from the FAQs.

Try entering this exact text in your sig:

(img)http://www.cleanmpg.com/garage/images/308.png(/img)

... then change the parentheses to square brackets.

If you paste it, it might include "url" in square brackets too. Delete those. The message editor thinks it's smarter than me and that I'm trying to paste a link here. I'm not smart enough to figure out how to make it do otherwise.

This is for your car, BTW. 308 is what identifies it as such. If you want it to show recent history (like mine), add "his" (without quotes) as a prefix to 308.

To the mods: I had a little trouble figuring it out at first too. How about a sticky?

Thanks!

I'd suggest putting it in the FAQ, since that's where I looked for it...but I'm still figuring out the website. :Banane10:

thanks, Bruce

We can also perform a case study on your route once you post that detail later this week if you think you need some more help.

Okay, let's give it a try...here's my morning commute and the way I'm currently driving it:

Get in, open the garage door, Key to IG-II, put in N and release handbrake, push car with
foot out door to get rolling, then close car door quickly before it hits the garage door frame.
Halfway down driveway, turn car lights on and check that street is clear. Turn
onto street, hit garage remote and fasten seatbelt. If car coasts to end of street, start
it there, if not, start, briefly put in drive then NICE-on coast to end of street.

Stop, turn right, accelerate slowly up hill and hold speed once in second gear. At crest,
allow speed to reach 23 MPH, then FAS to end of street. If street is clear (T with
cul-de-sac to left, so it's technically a yield) relight, turn and put in gear to hold
speed up hill. At top of hill, the road flattens out. I'll usually keep it at 25-30
through a couple of left turns, usually NICE-on coasting in between because the distances
to the turns are short.

After the second left, accelerate to about 30 and FAS down a gradual downhill to the corner,
after which it goes up again. When speed is down to about 15, relight and accelerate
uphill to about 23 at the peak, then FAS to a stop. All the speed limits up to this point
have been 20-30 MPH.

Turn left onto a very slightly downhill road with a speed limit of 35 MPH. I'll usually
accelerate to 30 and hold it there, since the car won't coast very long unless there's
a significant downhill. Near the end of the street, it starts going downhill quicker,
followed by a sharp rise to an overpass, followed by a downhill to a yield sign. I'll
usually accelerate to 40 on the downhill, crest the top barely moving, then accelerate
into the turn if traffic is clear.

At that point, I'm on a busy 2-lane US highway with limited passing zones; if I travel
substantially below the speed limit, traffic will accumulate behind me. The speed limit
is 30, soon increasing to 40 and then 45, which works well because there's a very mild
downhill staircase at the same time to help with acceleration. The 45 MPH zone starts
at the base of a steep hill, where traffic is often turning left halfway up. If things
are clear, I'll try to accelerate to 45 by the base of the hill to lock up the TCC, bleed
off to 40 during the climb, keep the same pedal position until it hits 45 on the other
side, then start a FAS.

The steep downhill is followed by a ~1/4-mile stretch followed by a 35 MPH zone and a
short staircase climb. I'm usually down to about 30 in the FAS at this point, so I'll
relight, accelerate to hit 40 by the top of the climb, then FAS again.

A short downhill, followed by another ~1/4 mile stretch to the first traffic light,
during which the speed limit drops to 25 MPH. The light has an extremely short,
traffic-controlled cycle with a short yellow. I'll often relight to try to make a
green, only to have it turn before I get there. Usually I'll have the best luck if
I just let it glide through the intersection, traffic permitting.

On the far side of the intersection, a short flat section is followed by a steep hill
and a 35 MPH speed limit. I usually accelerate to 40 in the flat section and allow
my speed to bleed off to 30 during the climb. On the backside, I'll back off the
accelerator and allow the speed to climb to 45 by the bottom so the TCC will lock up
for the next climb -- a long, steady grade followed by a flat section through a
business district. If traffic ahead permits, I'll hold it at exactly 40 through
all of this.

Just after the business district, the speed limit increases to 40; I'll increase the
throttle position slightly and DWL in a 40-45 MPH range with the TCC locked through
a flat section with a short dip in the road. After about a mile, the speed limit
increases again to 45 on a very slight downhill, followed by a long flat section of
about 1/2 mile. I'll continue to DWL, trying to stay in a 40-45 range and keeping
the TCC locked up.

If the traffic light ahead is red, FAS to a stop; if not, continue to travel at 40-45.
The speed limit changes to 40 MPH.

Start down a staircase descent, hit 45 by the end of the first flat, then start a
FAS. Continue to FAS over a couple of stairs, during which the speed limit decreases
to 35 MPH. At the start of the last descent before the bottom, relight and accelerate
from 35 to 40, then DWL up a steep hill toward the expressway interchange, hitting the
exit at about 25 MPH.

Accelerate quickly through a dip in the short on-ramp to 45 MPH, and merge onto
the expressway. The expressway is 4 lanes each direction, with short, steep hills,
short sight distances, and about 10 interchanges and a rest area during the 6 miles
I'm on it. The speed limit is 55 MPH, 45 minimum; very heavy traffic fills the roadway
at speeds ranging between about 80 for the left lane to about 55 for the right. I'll
usually take the right lane and DWL with a constant throttle position unless a good
draft target passes by at a comparable speed. A TPS of 17 generally keeps me in
the 50-60 MPH range, unless it's cold and/or windy.

Near the end of the stretch, 4 lanes become three partway up a steep rise. I'll
usually change the TPS to 18 in advance of this to keep my speed at 45 by the crest
of the hill. On the back side, I'll continue to hold the constant throttle to 60
MPH, then FAS to my exit.

I usually hit the cloverleaf ramp at about 45, quickly declerate to 30 on the
incline and relight the engine to maintain speed and merge with traffic. Once
safely positioned in traffic, FAS again down a slight grade to a hairpin turn
on a side street, braking as necessary.

Relight, accelerate to 30 and slowly bleed off speed to the next intersection, turning
left onto a side street and accelerating to 30 again. FAS down the street, braking
slightly for the turn into the company parking lot, and coast to a stop into a
parking space.

Any suggestions?

I'd love to see the analysis on this. It'll help me a whole lot with my own drive.

Hi Bruce:

___Wow, that was some detail! I will try and add my thoughts later tonight or by the weekend unless Larry or Psy beat me to it :)

___Good Luck

___Wayne

Wow, that was some detail!

Thanks!

For reference, the segments I posted this morning:

Segment A: 1.7 miles, 27.9 MPG
Segment B: 5.3 miles, 35.6 MPG
Segment C: 8.4 miles, 48.0 MPG
Total: 15.4 miles, 39.7 MPG

Segment A ended and B started at the start of paragraph 4 ("Turn left onto a very slightly downhill road...");
Segment B ended and C started on "a long flat section of about 1/2 mile" in paragraph 9. There's a police station on that stretch, which makes a good landmark.

Thanks again -

Bruce

That is some great detail. The detail to you driving your daily grind is awsome!!! And I mean it!!! Very good work on your part. Class A...

You keep mentioning TCC. I would think your working with torque converter lock up correct? If so the speeds sure indicate it. This is a problem with the I4 5AT Accords. Basic rule of thumb for me in our Accord is if Im not going to beable to get up to 44 to 47 mph and get lock up. Then keep a very light foot. If 45 mph or better is in the near future then Im abit heavy on the gas to get it up to speed,,, and locked up. Then I can bleed speed if needed pretty well in ours. I dont think xcels responds quite as good as ours doing the bleed down in lock up.

One thing that kept leaping out at me reading your report was how hard you are working FAS. This is good. And ice on coasting if I read it right. It would be nice to see in some of your higher speed area's of the drive. Some up hill coasting or FAS'ing. This goes against convention. But it can be very useful. maybe bust into a FAS or ice on coast just before you crest a hill. Then work it alittle father back if possible. Im going to be working on this a bit harder this spring and summer,, and in low wind conditions.

I would think your Yota clone would truly be a bit more thrifty. It will be intresting to see what your spring and summer numbers are like.

With 53f this morning and a new ECU in my Civic I did a 48 mpg segment into work this morning. I was running late so I didnt push it hard. Hope it goes that well this evening....

Good Job
psy

Hi Bruce:

___Wow, that was some detail! I will try and add my thoughts later tonight or by the weekend unless Larry or Psy beat me to it :)

___Good Luck

___Wayne

Wayne, It probably won't be me anytime soon. All I can come up with is:WOW! That is some great detail. It kind of inspires me to go back through my route and see if there are any areas I can improve in.

Bruce, If you don't mind, I think I may adapt your method of reporting segments ie, A,B,C, etc. Much less typing. :)

Thanks for the comments and compliments, all.

psy - yeah, there appears to be a no-man's land for steady state between 4th
unlocked (~27-30) and 4th locked (~44 MPH), FE-wise. It seems better to
hang out at one or the other but not in between, at least when cruising
without FASing. 4th locked appears to have a slight edge, at least on the
iFCD (50-60 MPG vs 40-50).

I was struck by your comment in one of your Okie FAS videos that the
Civic wouldn't FAS quite as far as the Accord, which makes sense...the
Accord weighs about 500-800 lb more and probably has comparable
rolling/aero resistance, and coastdown times would be a function of the
weight per total friction. It goes against all recommendations for
maximizing FE, but I'm tempted to try adding 500 lbs just to see what it
does for glides and DWL. I know my wife's Saturn LW300 sure keeps its
momentum a lot better over small hills. Of course, all this goes up in smoke if
I use the brakes at all, but I can DWB nearly all of my commute.

At this point, I'm still in the other direction -- nothing in the car, and I
pulled the rear seat to knock off another 50-100 lb.

If I could increase the glide times, I'd be more likely to use them on
flats or uphills. Right now, I can't get a glide long enough to be
worth a FAS unless it's on a downhill. Warm weather will help this
somewhat, since it'll reduce rolling and aero losses, so I expect I'll
be able to FAS in a lot more places once the temperatures warm up.

Thanks for the comments and compliments, all.

psy - yeah, there appears to be a no-man's land for steady state between 4th
unlocked (~27-30) and 4th locked (~44 MPH), FE-wise. It seems better to
hang out at one or the other but not in between, at least when cruising
without FASing. 4th locked appears to have a slight edge, at least on the
iFCD (50-60 MPG vs 40-50).

I was struck by your comment in one of your Okie FAS videos that the
Civic wouldn't FAS quite as far as the Accord, which makes sense...the
Accord weighs about 500-800 lb more and probably has comparable
rolling/aero resistance, and coastdown times would be a function of the
weight per total friction. It goes against all recommendations for
maximizing FE, but I'm tempted to try adding 500 lbs just to see what it
does for glides and DWL. I know my wife's Saturn LW300 sure keeps its
momentum a lot better over small hills. Of course, all this goes up in smoke if
I use the brakes at all, but I can DWB nearly all of my commute.

At this point, I'm still in the other direction -- nothing in the car, and I
pulled the rear seat to knock off another 50-100 lb.

If I could increase the glide times, I'd be more likely to use them on
flats or uphills. Right now, I can't get a glide long enough to be
worth a FAS unless it's on a downhill. Warm weather will help this
somewhat, since it'll reduce rolling and aero losses, so I expect I'll
be able to FAS in a lot more places once the temperatures warm up.

Bruce

Don't add weight to the car. Maybe just use the dainty wife and children for a test. ;) The Accord is a coasting machine. I don't think Ive ever seen a car that coast as good as the Accord. Now the Civic on the other hand is awful. Throw in a head wind,, and your wasting time and effort. ( for me anyway )

As a motorcycle rider at times. Ive become very aware of road surface's. There is a campaign in Oklahoma to build the cheapest uneven roads that can be had. Then if its concrete. They come back over it and grind it level and leave these tiny little grooves that run with the direction of the road. Make the ride smooth but increases rolling restence like a mofo. Its truly awful. This has ruined alot of my FAS'ing on some of the hwys. If its not a concrete road and asphalt. They use the course's cheapest stuff they can find. The effect is the same if not worse. I cant change my route much. Get very far off the beaten path on my daily grind and travel times double. And I'm not xcel.... LOLOLOLOLOL.

Maybe load driving will be your savior?

Good work

psy

Maybe load driving will be your savior?

After a few days of expressway driving this week, I tend to think you're right. It certainly works a lot better on unfamiliar roads.

On Tuesday, I was driving between facilities on an expressway that was mostly flat except for long notches where it crossed under cross streets. I'd accelerate to 60 by the edge of the downhill, FAS down the hill to 50 by the time I hit the bridge, hold speed up the hill until I hit 55 again, then go to a constant TPS. With all the extra pulsing that was required, I have a hard time believing I came out ahead over just holding constant throttle through the dip.

After some more time on the expressway, I concluded a FAS wasn't worth the bother unless I was on a downhill steep enough that I was getting up to 60-65 MPH at very light throttle, in which case I wouldn't mind bleeding off some speed anyway.

In another thread, Wayne wrote:

___I have driven the MASS Pike in the Insight while in the climbing lanes and slowly bled off until I was near 20 - 25 mph in second just below VTEC and above Assist. She sat there again and again during those climbs.

Which raises an interesting question: how did you determine that this speed and gear would maximize fuel efficiency on an extended climb, and how can I do the same in my car? In other words, is it possible to use the iFCD information to maximize fuel efficiency in real time on an extended climb, and if so, how?

Hi Bruce:

___You have been doing some research, haven’t you ;) One of my own personal unwritten rules when driving an IMA equipped Honda hybrid is to stay out of assist at all costs. This is not so much a FE issue but a pack longevity issue. If there was a pack that was going to last 15 + years, the Little Red Beauty’s was the one. A side effect is the FE got stupid quick … I would also never run one so high so as to engage VTEC up or around 3,000 - 3,250 + RPM’s either as that was not only a waste of an ICE, it was a waste of fuel.

___Since this was my first and last real climbing experience in her, I was going to do my darndest to maintain her current 104 mpg average while crossing the country for my last drive and was working out these things in my head with the iFCD feedback guiding/leading the way. In the manner described, she would hold 50 + mpg during the climb while I could double that by FAS’ing a similar distance down the backsides of each of those monsters out east. As long as there was a truck lane, I was repeating this over and over until I finally reached my destination about 40 miles from the coast. IIRC, I increased her FE from 103.8 to 104.x when I arrived using the method as described through those mountains?

___Good Luck

___Wayne

One other question...I've been told that acceleration to a steady state speed and acceleration in a pulse require different rates for optimum FE; slower is better for steady state, whereas an engine load of 70-90% is optimum for a pulse.

Why is that? The engine consumes the same amount of fuel for a given acceleration rate, so why wouldn't a single acceleration rate consume the least amount of fuel, regardless of application?

Hi Bruce:
One other question...I've been told that acceleration to a steady state speed and acceleration in a pulse require different rates for optimum FE; slower is better for steady state, whereas an engine load of 70-90% is optimum for a pulse.

Why is that? The engine consumes the same amount of fuel for a given acceleration rate, so why wouldn't a single acceleration rate consume the least amount of fuel, regardless of application?___You have been told this? Where did you read that ;)

___Three things … Remember a P&G releases the ICE from any duty as well as any fuel consumption on the back side in a FAS/EV-Glide/Glide but it is absolutely imperative you receive the maximum glide distance w/ no fuel consumption to make it work properly. Accel fast into a back up and you just accelerated at 2 - 10 mpg and then threw it all away while hitting the brakes to come back down. The slow and steady would have yielded a much larger buffer in which to FAS or slow in fuel cut back down … Second item. A slow increase keeps FE at a higher rate until the slower speed steady state speed is reached. A higher load pulse is burning fuel like mad but you are burning fuel during the steady state cruise also which is completely different then a P&G. See Tarabell’s HCH-II article for proof of concept. There is no non-fuel consumption portion and the high load/extremely poor fuel consumption just never gets made up. Third item. ICE and drivetrain wear. Accelerating with a higher load pulse is putting the colas to the fire so to speak. There are high forces seen throughout the drivetrain and those forces are not kind to any of the components that see the higher loads. Think an all-city taxi cab vs. an all highway delivery service driver. Which vehicle would you like to purchase used with 100K on the ticker? The all-highway miler of course just do to the fact it was mostly steady state highway cruise vs. the continuous cycle of an all-city like daily grind. I HS P&G the Accord but my accel’s are usually in the 2,100 RPM range (sometimes a bit more but not much) with glide distances that can be scary long. For longevity, take it easy and she will pay you back in dividends time and time again.

___Finally, with your SG-II, go do the test runs similar to those designed for Tarabell. P&G is just a completely different animal then accel’s to a steady state cruise. In your Prism it may work out differently but it doesn’t in the non-hybrid Accord, Ranger or HCH-II.

___Good Luck

___Wayne

Hi Bruce:
___You have been told this? Where did you read that ;)

:) I was too lazy to hunt down the quote, but I'm sure you can guess. :)

I agree that lower accelerations have a better chance of success and have been using the lowest throttle settings that will get me to a target speed lately (7% to 30 MPH, 9% to 45 MPH); max RPM's have been under 2100-2200 for most rides. I still haven't had a chance to do any acceleration testing.

One other question...at the last oil change, I put in a quart of 5-20 and three of 5-30 (all Mobil 1 synthetic) because that's what I could get locally. The manual recommends 10-30, 5-30 or 0-30 depending on weather conditions. I've mail-ordered a bunch of 0-20 and 0-30 Mobil 1 for the next change, and am considering a 50-50 mix. I'm a bit concerned that I'd have insufficient journal pressure and some blowby (the engine's at 112K) if I threw in straight 0-20. Any thoughts, recommendations or experience with a similar setup?