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Today on my way to work, I tried some P&Ging. Just want to bounce this off others and see if I am getting it right. I performed all P&Gs with the engine on; don't want to overwhelm myself as I start out.

As I travelled on the interstate, I gently accelerated to 60MPH, the shifted to N, and when I got down to 50MPH, I re-engaged the tranny, matched speed and started again. As I matched speed, (I was watching this on the Garmin to get as accuarate numbers as I could), I noticed I always got down to 48 before starting back up in speed. As I did this I counted the cycles for a 10-mile stretch, and did 15 P&G cycles. Does this sound in-line, or no?

I still need to inflate my tires to 44MPG (MAX sidewall pressure). I am guessing this will help some when I get them up to pressure.

I kept the accelerations gentle, staying around 2000-2200RPM; should I be accelerating more quickly? I am spending more time getting up to 60 than I am gliding down to 50. I wasn't able to time it, but it felt along the lines of 75% accel/25% glide.

I utilized a few FAS's also. I was happy to see my mileage increase over my 42 mile trip from 29.8 to 30.1; I can not recall ever seeing it climb .3MPG over a trip to work.

You want your glides to be longer than your pulses, but you are limited by your automatic transmission. Basically accelerate as fast as you can without your transmission downshifting. I use 75% load (on the SG) during my pulses and it ends up being about a 3:1 glide-pulse ratio.

Make sure you are shifting to neutral for the glide, and don't push the button in when you shift (you should be able to nudge it between N and D). Since it's an automatic, ensure that is flat towable before doing any more FAS's.

Kirk

I agree - harder, shorter pulses and longer glides. Find the throttle point where the transmission will downshift, and aim for just slightly below that.

OK not having a SG, I guess I will need to work on this.

So accerate faster, as long as she does not downshift?

Yes, the HHR is flat-towable; I believe they were trying to cater to RV'ers.

Alright folks, here is what I had happen on my way home from a grueling day of police dispatching.....ugh.

Tried a quicker pulse and longer glide. Counted out as I did it, approx 12 second pulse to 62MPH, then approx 20 second glide to 50, back in gear, repeat. Did this on the interstate for 12 miles, then on the 2 lane. 62-50 for rural highway driving, then a 10MPH delta for in town.

Here is where I bring my latest questions. Please remember I do not have a SGII, and have no idea when I will be able to get one (unless someone has one they wanna gift to me :rolleyes: but I am not expecting many takers there).

1. I tried accelerating faster; I think I was not in top gear sometimes, as I was watching the tach and it would suddenly drop from ~2800 to ~2200, but I can't feel a shift. :confused: I kept my tach under 3K at all times.

2. How much can I trust the Driver Information Center (I hesitate to refer to it as a DIC.....LOL)? I watch the trip meter and the remaining miles like a hawk; today I saw the remaining miles range from as low as 380 miles to 535 miles. (I was FAS'ing a lot, does that confuse/reset/alter those readings?)

I am rather astonished; I have never had a total trip (combination of elapsed miles and miles remaining) exceed 530; today I had it as high as 625! I also increased my average MPG on the way home from 30.1 to 30.5; I can not remember when I have seen such increases.

Also, I forgot; ran the A/C for a short period (it was quite uncomfortable), then decided to put my big boy pants on and cracked the windows (driver's and rear passenger) 2 inches with the fan on a medium setting. While a little warm, I was able to drive without any real discomfort. I tried to FAS as often as I could as I approached red lights and stop signs.


As an afterthought, if I am FAS'ing to a stop sign, is it unusual to have your speed bleed way off, say to 20MPH or below? There was no one behind me, so I was not impeding anyone's flow. Just felt like I was crawling, but I was thinking of the gas I was saving. :D

Down to about 20 is good, any slower than 15 and it's probably not worth the added time. The amount of kinetic energy you are wasting during braking is proportional to the square of your speed, so at 20 mph you have half the kinetic energy of what you had at 30 mph.

A max speed of 55 with the same speed delta would extend your glides, anything over 55 starts really hurting (in general). I use 45-55 or a 40-55 P&G most of the time on the highway.

I'm not sure whether the DIC would be confused if you FAS, but it's quite possible. Maybe use neutral gliding for a while (a tank or two) until you find out what acceleration works best, and then transition to FASes later on.

If you see a 2800 to 2200 drop, it's up-shifting, which means you were in a lower gear. Try and keep the tach under 2500.

Kirk

OK in working to keep the tach under 2500 when I re-engage the AT, I found this morning that if I feather the accelerator for approx. 1 second, it engages around 2000, then drops. If I get back in the gas right after I engage the AT, it seems to be 1 gear under top gear. But if I wait a moment with a slight pressure on the pedal, it downshifts (from ~2000 to ~1800), then when I accelerate in the pulse, I can get to 60MPH and it never gets above ~2100-2200.

MPG on the dash upon arrival at work is 30.8.

So if I understand correctly, a ScanGauge would help me find the points in my accelration curves when the engine is about to shift? (Meaning, I will learn what RPM's the engine will shift at)

In relation to my above post and confusing the MPG computer, I noticed when I FAS and restart the engine, if my car is angled and alters the fuel tank gauge level, also altered (greatly, I might add) is my Remaining Tank Miles. On flats, when the fuel gauge is more "accurate", it seems the computer stays a little more consistent. As it is, I am looking at a 600 mile tank according to my dash.

Excellent, keeping it under 2200 is much better.

There are a lot of factors considered when the auto shifts, almost all newer cars have adaptive transmission control, which means they actually remember your driving 'profile' and shift accordingly. What a ScanGauge will add is the ability to watch throttle position or engine load which is one of the critical factors for gear selection. It will let you know how much throttle you can give it before it down-shifts, and when you should be letting off the throttle (as you approach a shift point) to coax a shift.

Remaining tank miles will not mean much during P&G the trip MPG is what you want to watch.

Kirk

Kev, you are doing quite well!

The scangauge will help by giving you moment by moment info -- you could get similar results by resetting your built in computer regularly but then you'd lose your tank numbers.

When you see the RPM drop the car is actually shifting UP to a higher gear. That's what you want. If you see the RPM jump suddenly, that's a downshift and you want to avoid that.

Your experience with holding steady on the pedal to get it to upshift is consistent with the description I've seen from Andrew when driving his minivan.

I run into the fuel left thing as well -- I can see it very easily in the Insight because of the lit bars. There is one corner I take in a FAS and if I'm at 2 bars, when I bump start it comes up with no bars. :p They come back later but then the low fuel light is on and won't go off again (I think it is a latch and doesn't reset until it has at least 4 bars).

Kev, you are doing quite well!

Your experience with holding steady on the pedal to get it to upshift is consistent with the description I've seen from Andrew when driving his minivan.

Yup, until your transmission "learns" your new habits, you can coax it to upshift with a little feathering. On the Montero Sport auto, I'm training it to shift before 2K RPM every time, but, if for whatever reason or road conditions it gets up to 2K, I just let off the gas slightly until it upshifts for me.

With respect to P&G on the highway and backroads, remember that you are driving a big box around. While a tiny aerodynamic car might be able to get away with P&G at higher speeds, you'll probably see much better results at lower speeds. And inflating those tires is going to make a big difference on the glides.

You're doing well. That drop from 2000 to 1800 is a great find. :)

My minivan is not a learning transmission. It has the same shift points all the time. I know exactly when it will shift, if I let up on the gas. I do like this: medium throttle... let up for a shift, back to medium...........let up.... etc. I do a slightly longer "let up" at 45 where it goes into top gear, and it locks into gear.

When I do a glide, and then transition back to a pulse, I do like what you were describing. I rev just a touch over the target rpm, then shift into D. It's a lot happier to drop into top gear that way. If I just drop into D from idle, it'll shift down, then up (rpm up, then down). That's about a second of higher fuel usage I don't want. Hold for a moment while it locks in on top gear, and then I can use up to about 85% throttle without a downshift.

The fuel readings will be affected by all kinds of things. How long a reading does it use, and does that include just this pulse, or just this glide, or both? What slope are you on? Are you accelerating or decelerating? Just eyeball it and try to see an average. Or do like you have been, and try to keep bumping the tank average up.

You might start resetting it to get a trip average instead, and then calculating the tank total. If you record every trip's miles and mpg, you can do it. Miles / MPG = gallons. Divide tank total miles by tank total gallons and you've got tank mpg.

Is it my imagination, or does P&G work better at lower speeds? It seems at the higher speeds, when I glide, I bleed off speed much quicker than at lower speeds.

Aero drag increases with the square of your speed, so at 60 mph you have 4x the drag that you did at 30 mph. So yes, lower speeds are better for P&G. I wouldn't use anything above 60 mph, and I'm normally under 55, but you would get better results keeping it under 45-50. The main thing is that highway P&G is good compared to steady state highway driving, but city P&G blows steady state city driving out of the water.

Kirk