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I've been an owner of a miata for over 10 years and am well versed in modifications and adding lightness to that car. What I am curious is there any good sights on how to mod and add lightness to the 2006 Honda Insight?

I just picked mine up with under 14k miles on it and managed to get 63.9mpg on the way to work today. Before you all down me, I was averaging 42mpg just 1 week ago, so I am learning. I was extremely excited to see what I could do already. To me a 22mpg increase with not much effort was huge! Now to get it higher than that!

I have some ideas on what I am thinking of doing to it to help the MPG.

GOAL: I want to remove over 200lbs from the car or more!

1. I only inflated my tires to about 40psi... I have read in other threads I should go 45 plus

2. Checking out the spark plugs to make sure the dealer didn't fudge them up

3. Considering removing the side mirrors and putting in blanks with the addition of a nascar 360 type rearview mirror.

4. Converting to LEDs through out the car

5. Replacing the seats with Race seats and 5 point harnesses and removing the seat belts mechanism. I've seen seats that are sub 9 lbs, so I'm going to rip out the seat and weight it for comparison

6. Replacing the battery in the engine compartment with a light weight 4.5lb battery if it is not already a light weight version. I had one in my miata and shaved over 10lbs.

I've already done the following:

1. Removed the spare and all hardware and added a can of fix-a-flat. My insurance has road side assistance so a major blow out would be covered. Also at the PSIs we run these things at I think any flat we get mandates a tire be replaced as I question if a plug would hold up to the pressure.

2. Removed the cargo/cooler box and the trunk mat and net (My goal is to weigh the stuff this weekend)

3. Losing weight. I've dropped from 185 to 165 (hey this is an easy mod!)

So other suggestions. I saw the Scanguage thing to help me ID when I'm in lean burn. I'm open for some good feedback and any websites that help detail out my passion that is now getting this insight to avg 100mpg.

Sunin

Welcome, Sunin!! You have a fantastic vehicle to work with. :D

I understand your enthusiasm with lightening the load but honestly, it won't help you as much as you think. 200lbs is worth maybe another 7mpg in your car with the same driving habits.

As a contrast, click on the green banner in my signature to see the mileage logs for my stock 2002. I'm 6'5" and weigh in at about 248lbs. My tire pressures are considerably higher than yours but other than that my results are strictly driving technique based. My highest tank was right around 120mpg for most of the distance but winter knocked me down to 115mpg in the last 300mi or so (out of 1567.4mi total).

We can teach you how to turn your car into a consistent 100mpg+ vehicle but you have to be willing to change the way you drive. You're doing great right now but there is a lot to know about the car's subtleties.

Where are you located? What is your local terrain like and what temperatures are you dealing with? Long or short trips?

I am in Sioux City Iowa. I have some mild terrain, a bridge that elevates probably a couple of hundred feet and i live about 500 feet or more up on a hill side. Weather is similar to chicago, we get very cold in the winter and 80's in the summer. The big difference here is we get a lot of wind. No buildings to block airflow. So on most days I am fighting a 30mph wind. Some days it gets to 50 plus.

I am eager to learn techniques. I have no set style. I have a highly modified 10AE 1999 Miata with 400RWHP that I use for spirited driving so this is my commuter vehicle.

The thing I have noticed the most is I can not maintain speed on the highway. I took a 300 mile round trip this weekend and avg'd 47.8 before learning something new on Monday that obviously has helped. But I want to learn even more. I am reading the Beating the EPA article now and am eager to get into that 100mpg range.

I appreciate any and all help! Oh and somewhat short trips. Generally 10miles or under.

tire plugs will hold the pressure fine.

only problem should come from bad angle of puncture or sidewall damage where the plug won't work. If they work, they should hold. The sidewalls would blow out hundreds of psi before the plug got blown out, and even sean doesn't use that much psi.

check out aerocivic.com about our own basjoos. I think at highway speeds the cd reduction will gain you more than weight savings. And driving technique is always the biggest factor.

Another note on tire pressure. I had a puncture in one of mine a while back. The plug has been holding for 6+ months at 60 psi. No trouble there at all.

Mirror delete is good if you can legally and safely do it.

LED's are good, and absolutely essential if you're downsizing the battery. I personally would keep the battery as it's already tiny.

Honestly, I think Honda already did most of the easy stuff in lightening this car. It's built from aluminum, after all.

Another note on tire pressure. I had a puncture in one of mine a while back. The plug has been holding for 6+ months at 60 psi. No trouble there at all.

Cool good info I will use my road side assitance and ditch the fix o flat!

Now it is learning technique!

Another note on tire pressure. I had a puncture in one of mine a while back. The plug has been holding for 6+ months at 60 psi. No trouble there at all.

Mirror delete is good if you can legally and safely do it.

LED's are good, and absolutely essential if you're downsizing the battery. I personally would keep the battery as it's already tiny.

Honestly, I think Honda already did most of the easy stuff in lightening this car. It's built from aluminum, after all.

Who said I was downsizing. The battery is about the same amperage, but a dry cell battery versus lead and acid. They are called Odyssey Drycell Batteries. In general they weigh about 10-20lbs less than oem. I'll do a touch of research and remove the battery over the weekend and weigh it :)

The ODY is a good battery with savings in weight. I even removed the passenger seat. That saves several pounds and you can haul bigger cargo (2x4x8's)

NO ONE will diss you here for 63MPG. That's great for a step in the learning curve! I'm sure Sean will give you some great tips.

Sunin, do you have a CVT? It will be more difficult to hit high numbers with that but you can do it with some work. The wind is another matter...

Those short trips are going to be tough to get around. Does your car have a block heater? That can help quite a bit with short trips by enabling the car to warm up more quickly.

Are you avoiding the highway? If not, you'll want to. :)

I do have a CVT. I only hit the Highway for 2miles. I needed it to be automatic because the GF doesn't know stick and she is hesitant to learn.

So the CVT is part of the why I feel like I can't get it over about 55-60mpg on the highway at speeds of 55+. I could peak at about 70mpg on the high way if I drafted someone like a semi, but too often they would reduce speed if they saw me staying about 3 car lengths off their bumpers.

I guess that is why I was heading toward the lightness. I also want to figure out how to get the IMA to kick on quicker. Right now I have to get it to nearly 25mpg for the assist to kick in and I'd like that to be around 40mpg. Any ideas on how? My battery stays within 3 bars of full all the time and to me that is not making the best use of it. Thoughts?

Keep in mind my prior car was a 2000 malibu that on a good day got 25mpg, so I am happy with anything 50mpg or higher, but I do want to get it up higher and higher!

Hi, Sunin -- you've got some new concepts coming your way. :)

First off, your car does not have lean burn. You won't be able to get your car up to the heights that a MT equipped version (which does have lean burn) will reach, but you can definitely get her up over 80mpg in the right circumstances.

The thing that isn't going to make sense to you right away is that you want to stay away from using the battery. I know this sounds counter-intuitive, but the simple fact is that you will use more fuel if you use the battery than if you do not. The reason is that the only way the battery will charge is if you first burn fuel to generate momentum, which is then inefficiently converted into electricity to charge the battery (slowing you down in the process). Avoiding this lossy conversion from gas to electricity you will get better fuel economy. In other words, using assist will get you better mileage in the short term but regen will pull it back down past where you would have been had you not used the assist in the first place.

The first thing you want to do is practice a light touch on the accelerator. The CVT will adjust ratios to the most efficient RPM for a given speed -- you can encourage this once up to speed by backing off the pedal gently, then reapplying pressure. Use the lightest pressure you can to maintain speed and you'll see your instantaneous FE go up.

Ah, the hybrid conundrum: buy it for the battery, then avoid using the battery for max FE.

Ah, the hybrid conundrum: buy it for the battery, then avoid using the battery for max FE.
Not exactly. More like "buy it for the small ICE optimized for MPG rather than HP, use the battery only when needed when the ICE doesn't have enough oomph, such as brief accelerations or uphills".

The first thing you want to do is practice a light touch on the accelerator. The CVT will adjust ratios to the most efficient RPM for a given speed -- you can encourage this once up to speed by backing off the pedal gently, then reapplying pressure. Use the lightest pressure you can to maintain speed and you'll see your instantaneous FE go up.

I figured that out quickly, but what i have noticed is if I don't use the IMA to get up to speed it takes too long and I drag out the 25-30mpg time for too long. Now I get up to speed quicker and am in the 60-70mpg range longer.

I've already dropped 30 lbs from the car, I have plans to remove the multi-cd pack in the trunk and some of the excess sheet metal.

I'll figure out battery and seat issues this weekend.

You should be aware that the spare tire is actually considered part of the crumple zone in the back of the Insight -- yes, they really did configure it to absorb part of an impact! There really isn't much "excess sheet metal" back there.

The trade off for battery usage is still there. As a rule of thumb, it will take twice as long to regen back the charge you use during assist.

What "battery and seat issues" are you referring to?

Might want to consider a hot air intake while it's still cold.

On battery usage: only about 30% of wasted kinetic energy is recovered by regenitive braking, so it's better not to waste it to begin with.

So the CVT is part of the why I feel like I can't get it over about 55-60mpg on the highway at speeds of 55+. I could peak at about 70mpg on the high way if I drafted someone like a semi, but too often they would reduce speed if they saw me staying about 3 car lengths off their bumpers.


The mileage you get while drafting is the mileage improvement that your car could potentially get via air drag reduction mods since drafting has the effect of reducing your car's aero drag. I've gotten the Cd so low on my car that drafting produces so little mileage benefit that it is not even worth consideration.

You should be aware that the spare tire is actually considered part of the crumple zone in the back of the Insight -- yes, they really did configure it to absorb part of an impact! There really isn't much "excess sheet metal" back there.

The trade off for battery usage is still there. As a rule of thumb, it will take twice as long to regen back the charge you use during assist.

What "battery and seat issues" are you referring to?

Interesting design.

The issue is just figuring out if I will replace them both for lighter weight. With the CVT limitations I feel the only way to get to the 100mpg will be to lose a good 300lbs.

I was fishing around in the mod section and saw about the windshield wipers both front and rear. I have yet to use the rear wiper and it got nasty the other day. I also saw about a top air damn for the front bumper. I've got the wheels working on that already. I want to put something together that looks OEM.

Last night I pumped up the tire pressure to 55lbs, from 42 in the front and 40 in the rear. I'm very curious to see what impact that has. Hoping it gets me closer to 70mpg.

I agree with the using the battery. What I've noticed so far is the only regenerative parts happen when I used the brakes. Like I said on my normal commute I used less than 3 bars and it regens by breaking for 2 stop light and 1 stop sign I have on the way.

Also just curious, and not suggesting others do this, but do you all do rolling stops. I've gotten in the habit of checking for cops and rolling through the stop sign if it is clear. Obviously I'm only going 5-10mph, but again that is 5-10mph that my ICE does not have to work for!

You're going to have a tough time finding 300lbs to remove in the car! Search for Blake's posts and you'll see what he did to his '06 (MT). He hasn't been around for a while but did really nice work -- including the LED swap you are thinking about. He posted lots of pictures.

55psi is good, but I run higher than that. ;) The car should coast very well at moderate (>30mph) speeds if the alignment is good. The ride can get a little rough because of the stiff suspension and short wheelbase but frankly I don't care when I can get stupid high numbers.

Don't draft! It is way too dangerous to be worth the risk. :(

Rolling through stop signs isn't condoned here -- we advocate following traffic laws. I can't claim that no one here does rolling stops, though.

One easy target for weight reduction is the passenger seat -- it isn't hard to remove and if you never have a passenger it will not be missed. I'm not willing to remove mine but I know that billy did in his show Insight (which did have the mirror deletion mod, by the way -- replaced by a camera mounted in the driver's side tail light!) when he did mileage competitions.

What is the speed limit on the highway you have to drive on? Your best mileage is going to come from speeds around 50mph. That may not be feasible for your location. If not, are there alternate routes that are lower speed? Sometimes the shortest route is not the one that will use the least fuel -- likewise the one with the highest fuel economy average isn't always the one that uses the least fuel. Try alternates and calculate your usage (distance divided by mpg). I actually drive a 3.5mi longer route each way for work because the numbers are so much higher that I use less fuel over all.

You should get regen anytime you induce an engine braking situation. The brake pedal will intensify the amount, but it can be triggered without the brakes. You might need to shift to "S" to get it to do that for you. If you can accomplish this you'll have better control of regen and use less of your brake pads.

What is the speed limit on the highway you have to drive on? Your best mileage is going to come from speeds around 50mph. That may not be feasible for your location. If not, are there alternate routes that are lower speed? Sometimes the shortest route is not the one that will use the least fuel -- likewise the one with the highest fuel economy average isn't always the one that uses the least fuel. Try alternates and calculate your usage (distance divided by mpg). I actually drive a 3.5mi longer route each way for work because the numbers are so much higher that I use less fuel over all.

You should get regen anytime you induce an engine braking situation. The brake pedal will intensify the amount, but it can be triggered without the brakes. You might need to shift to "S" to get it to do that for you. If you can accomplish this you'll have better control of regen and use less of your brake pads.

The highway is 65mph. I tend to do about 55-60 as the end of it goes down to 55 anyways so I waste less energy getting up an additional 5-10mph.

My only alternate route takes me over some very hilly terrain. I know my MPG on that 30mph road is less than that of the 55-60mph stretch. There are two large hills that just eat my MPG.

I will have to check the alignment and the spark plugs.

Oh and I noticed some goof ball overfilled the engine with oil so I need to get that fixed this weekend!

Sigh... uneducated people assuming 4quarters no matter the car...

I travel very often with a passenger thus the desire to go to full on race seats that weight around 9lbs versus what I expect is a 35lb seat in the car now. I will look for blake's posts and see if I can gleem some Insight. Oh man that was a really bad joke!

Too bad about the alternates. :(

Something else that you should consider is time of day for your routes. Finding the right time for a route is important -- sometimes a section that is nearly impassable at one time is the perfect hypermiling route at a different time.

Traffic overall is very light here in Siouxland. The only slow downs I generally have are traffic lights which appear to be on no set pattern, and cars occassionally cutting me off.

Even at 60mpg I am very happy with the car. Will I keep trying yes. I bet my malibu gets avg 20mpg between the city / highway mileage, so 1/3 the fuel cost and pollution!

Light traffic is a good thing!

Lights can be dealt with. You may need to hang back a little so that other cars trigger them for you. Keep watching the traffic at the lights and you should be able to determine a ballpark change interval when a car arrives at a red. I use this quite often on the lights along my routes and can generally figure out about how long the light will still be red (or will stay green if cross traffic appears). It may take some time to get a good handle on it.

Out of curiousity what do you all think losing 300 lbs of weight would do to my MPG?

I was thinking 15%. I just want to know how aggressive I should get. This will be a several year project, but I have the following already in sight:

1. Seats
2. Battery
3. Remove side mirrors (Checked laws and it is allowed) Install Nascar style 180 mirror
4. Remove sun visors - Keep sun glasses in car
5. Remove carpet
6. Remove CD Changer in Trunk
7. Considering removing rear speakers
8. Begin Aero mods - Goal is to not alter the look of the car
9. I run without an antennae - I'm thinking of integrating a jack for my iphone.
10. Remove the rear winshield washer - motor and all - Plus wiring harness

I hope to be about 35-40lbs lighter by the end of the weekend.

Thank you all for the help! :)

A kill switch would be up there

So you kill the car while you do the glide phase?

Yes, and it is doable in a CVT (in Neutral!!) as well.

I rode along with someone in an '06 CVT Insight the last time I was in Milwaukee to give instructions. In traffic and over reasonably hilly terrain he managed upper 80's -- and that was the first time he'd ever done that sort of driving. I had him coasting with the engine off in several places. The temperature was in the 50s and honestly, he wasn't paying as much attention to what he was doing as I would have liked. That car could have been in the upper 90's with just a little more work, and that was with the two of us in it (stock with the exception of the aftermarket stereo he'd installed).

This is something that requires a lot of experience to do safely -- you have to know how your vehicle reacts and how long it takes to get the engine started again. If you decide to try this, do it in an empty parking lot and test how many full presses of the brake pedal it takes to deplete the vacuum power assist. It should take in the 3-5 press range. You can still use the brakes after this but there won't be any assist and you should be prepared for the extra pressure that requires. You'll still have power steering because that is electric, but you have to remember that everything is running on the small 12V instead of the large 144V battery behind your seat. This can be an issue if you have your headlights on.

So 300 lbs later: I used Miata weights, but reduced them a bit.

Spare Tire 15.5 Lbs
Storage Box 4.5 Lbs
Owner's Manuals 1.5 Lbs
Rear Cargo Mat and Net 7.5 Lbs
Rear Carpet 4.5 Lbs
Full Carpet Rip Out & Polish 40 Lbs
Seats 52 Lbs
Remove A/C 20 Lbs
Remove Rear Speakers 10 Lbs
Remove Rear Wiper blade and motor 5 Lbs
Remove CD Juke Box 5 Lbs
Remove Airbags 15 Lbs
Remove Visors 5 Lbs
Upgrade Brakes 10 Lbs
Remove floor mats 5 Lbs
Remove tie-down hooks 8 Lbs
Remove excess metal in trunk 2 Lbs
Remove Excess Bolt Lengths 20 Lbs
Remove Door Panels 20 Lbs
Remove Dash 40 Lbs
Remove Center Console 5 Lbs
Remove Antifreeze overflow bottle 5 Lbs
Battery Swap 10 Lbs

Adds up to 310lbs. Now what was the curb weight of the 2006 CVT?

Add in another 10lbs of me losing weight... hehehehe :) Crap forgot remove side mirrors and related wiring 10 Lbs.

Also looking at the engine there are excess plastics and crud I can remove. That could be a few more Lbs.

Umm...I'm not so sure about removing those airbags, I would not recommend it.

Do you really think there is 20lbs of excess bolt lengths??

Do you have a rear defrost?

The door problems probably wont weight that much.

Other than that, good luck with the weight reduction.

I agree on the airbags -- not worth it at all.

Are you seriously wanting to drive something showing bare (and sometimes sharp!) metal inside?

Umm...I'm not so sure about removing those airbags, I would not recommend it.

Do you really think there is 20lbs of excess bolt lengths??

Do you have a rear defrost?

The door problems probably wont weight that much.

Other than that, good luck with the weight reduction.

I will only remove air bags if I put in race seats + 5 point harness. The airbags will not reach you if you have 5 point harnesses generally.

Yes I do have rear defrost, thus the wiper blade is a bit useless.

Door panels may not weight that much, but those are Miata weights, so as I do removals I'll weight them. All of the weights are estimates at this point, besides the wheel, cargo mats, and owner's manual etc. I removed and weighed those last night.

Still no guesses on what 300 lbs of weight reduction will mean in MPG savings?

I agree on the airbags -- not worth it at all.

Are you seriously wanting to drive something showing bare (and sometimes sharp!) metal inside?

I will dremel/sand smooth all bare metal to ensure smooth. I've seen a miata with it, it gave it an industrial look. Something I am still rolling around in my head. I'm not 100% sure yet. I figured start with Seats and Battery, Visor, Mirrors and see what impact that has.

That would probably give you a 10-15% increase depending on the torque produced at the various rpms.

I will only remove air bags if I put in race seats + 5 point harness.

You might want to consider how that would look to a police officer...I car nearly stripped on the inside with a racing seat & 5 point harness, but being driven like the last thing you want is a speeding ticket....think they might be asking you questions for quite a while.

You might consider option 2....get a motorbike, everything you mentioned is stripped along with 2 wheels, and entire exterior and quite a bit more.

Well, stock your car weighs 1975lbs. Mine weighs in at 1881lbs. (Both are equipped with AC). The non-AC MT version tips the scales at 1850lbs, though most of the FE gains attributable to that deletion have to do with losing the belt.

We can't compare directly because your vehicle doesn't have lean burn, but I can tell you what adding weight to my car did on a highway trip. Last summer I drove from Coon Rapids (just north of Minneapolis) to Elkhart IN with a passenger and a full hatch. I averaged 52mph and went through a couple of traffic jams as well as some city congestion along the way. My average over that distance was 100.1mpg and I estimate I had about 250lbs of extra weight (besides the driver) in the car.

The last time I drove to the cabin north of my residence (130mi one way) I had my wife in the car and easily over 150lbs in the hatch (so something close to 300lbs total). That was mostly highway with some city congestion, same average speed, and I averaged 98.3mpg for the round trip. The temp was in the high 50's.

By myself, both of those would have been in the low 100 range (105mpg or so?). That should give you some idea what the weight difference will do on the highway in terms of percentages. Do remember that weight hurts you worse around town because there are a lot more momentum changes than out on the highway.

Welcome from a former Siouxlander.

I'm originally from LaCrosse WI, but I lived at 2310 S. Clinton in Morningside from 1989-1997, working for "The Beef".

Have a couple Cheese Charlies at the Miles for me.:D

Out of curiousity what do you all think losing 300 lbs of weight would do to my MPG?

I was thinking 15%. I just want to know how aggressive I should get. This will be a several year project, but I have the following already in sight:

1. Seats
2. Battery
3. Remove side mirrors (Checked laws and it is allowed) Install Nascar style 180 mirror
4. Remove sun visors - Keep sun glasses in car
5. Remove carpet
6. Remove CD Changer in Trunk
7. Considering removing rear speakers
8. Begin Aero mods - Goal is to not alter the look of the car
9. I run without an antennae - I'm thinking of integrating a jack for my iphone.
10. Remove the rear winshield washer - motor and all - Plus wiring harness

I hope to be about 35-40lbs lighter by the end of the weekend.

Thank you all for the help! :)

Glass is heavy. Maybe remove the side and rear glass and replace it with plastic sheeting held on with duct tape?

Or remove the rear hatch altogether and cover the opening with plastic sheeting?

If you are going that far, yank the AC off too! I think I remember somebody saying there was 30 to 40lbs with it.

Imagine the weight saved by removing the REAR HATCH! Glass is heavy!

Out of curiousity what do you all think losing 300 lbs of weight would do to my MPG?

I was thinking 15%. I just want to know how aggressive I should get. This will be a several year project, but I have the following already in sight:

1. Seats
2. Battery
3. Remove side mirrors (Checked laws and it is allowed) Install Nascar style 180 mirror
4. Remove sun visors - Keep sun glasses in car
5. Remove carpet
6. Remove CD Changer in Trunk
7. Considering removing rear speakers
8. Begin Aero mods - Goal is to not alter the look of the car
9. I run without an antennae - I'm thinking of integrating a jack for my iphone.
10. Remove the rear winshield washer - motor and all - Plus wiring harness

I hope to be about 35-40lbs lighter by the end of the weekend.

Thank you all for the help! :)

I can't help thinking about:
(1) Sealing up all the openings, filling the cabin with helium, and breathing through a mask and tube going to the outside. Problem is when you open the door you'd lose all the helium, and how to refill without carrying along a heavy tank?
(2) Removing the body entirely, but unfortunately too many things are bolted to it.

Maybe some sort of inflatable aero body, inflated with helium?

Yeah, reading this I thought - pull carpet, sound deadening, heat shields, replace glass with plexi (but no duct tape... do it right). If you can live without roll down windows, pull the power window innards. Pull glove box, rear trim, stick to light weight LRR tires, light weight wheels. Replace wiper fluid resi with smaller one. Pull out all dash plastic. Pull out door cards. Pull headliner and roof card. Replace that sunroof with plexi and pull out workings.

By the time you're done, you'll be left with a car that weighs - and is worth - much, much less!

If you can find lighter rims than the factory ones, use them. Trouble is, they're already among the best available. Same with the tires - this is a specific model in only this size, with the best RR of any tire available.

Sunin,

Wayne took a CVT Insight just like yours to 146mpg on the 2007 MPG Challenge.

Lightening up any vehicle is a good idea but you are considering weight reduction on the Lance Armstrong of vehicles. ;)

The CVT Insight is still on par with the Prius I, casual Prius II driver, and Insight II.

The mods that might give significant improvement: CalPod switch, FAS switch, hot air intake. They are all relatively simple.

I'll look into those. I have no idea what a calpod switch is... search is your friend. Calpod is for clutches only right? There might be something similar in the Automatic housing.. i can look.

I think it's manual only. :(

I want to see if I can make a push button to fake the trans into thinking I shifted to neutral. In order to avoid actually shifting it. I know the cable won't take that repetitive abuse. Back in the day an old dodge omni and an auto where you used the automatic to rev it higher. about 3 months of that and the cable gave way.

I don't think you need to worry too much about that with this car. There are many of us here who have shifted AT vehicles to neutral and back to drive several thousand times without any problems at all.

Try xcel's 2005 accord, for one.

Weight and speed have a linear relationship with rolling resistance.

Keep in mind that rolling resistance is not the only force that acts on a car... but it is a big one.... rolling resistance is the reason higher PSI in tires gives better MPG, but in that case it is reducing the coefficient of rolling resistance.

For a CVT insight with AC + driver + fuel + etc... you probably started out close to or over a combined weight of about ~2,150 Pounds... of course you could go to a scale and get a direct measurement if you like.

The % lowering of rolling resistance is directly , linearly related to the % decrease in weight.

If you started at 2,150 and lost 300 pounds that would be ~13.9% weight reduction... which would yield a ~13.9% decrease in rolling resistance.

Sense rolling resistance is not the only thing effecting MPG you will get less than this % increase in MPG.... exactly what % of your MPG comes from rolling resistance will vary depending on many variables including: speed, temperature , tire pressure, etc....

Depending on the specifics you will be a above or bellow ... but ... in general I would expect that about 1/2 of the decrease in rolling resistance will yield MPG improvement.

So a ~13.9% decrease in rolling resistance I would expect to yield a ~7% increase in MPG under the same conditions / skills / etc....

So that would take a 60 MPG average to a 64 MPG average... or a 70 MPG average to a 75 MPG average.

As it has been said above... driving skills can net you much better results... although the driving skills can be combined with the decreased weight.

Then if you do mostly shorter trips ... add PHEV power and you will do even better.

Sunin:

after much though, I think you should actually ditch the modification idea completely.

Work on your driving skills and I'm sure you could get up to 80+. If you can bring your skill level somewhere in the vicinity of Sean's, All those modifications will be put to shame as far as mpg increases.

Besides that fact, you wont be able to quantify what these mods really do until you reach a skill level where you plateau. If you are dissatisfied at the plateu, which can take a while, then modify your Insight.

Until then, Time your lights and get to know your car better.

I agree with Ricardo, enjoy your Insight as is! Good discussions thou. Hal

Sunin:

after much though, I think you should actually ditch the modification idea completely.

Work on your driving skills and I'm sure you could get up to 80+. If you can bring your skill level somewhere in the vicinity of Sean's, All those modifications will be put to shame as far as mpg increases.

Besides that fact, you wont be able to quantify what these mods really do until you reach a skill level where you plateau. If you are dissatisfied at the plateu, which can take a while, then modify your Insight.

Until then, Time your lights and get to know your car better.

I am in agreement, but I need help. I'm Now averaging even with big hills 55mpg, upwards of 70mpg when I'm running on flat.

So any hypermilers near Sioux City? hehehe

I am totally happy with 55mpg average, but I've always been one to push for more. From my computer overclocks, to my miata, to my career. So that is where the urge comes from. Although that is probably TMI..

Sounds like you are improving nicely! Do remember that winter temps are going to keep you down significantly from what you can achieve in summer.

Are you using DWL (Driving With Load) yet?

Yep I am, I don't have cruise on the car and rely on the display to lock in my mpg I want. Sometimes due to the hills it is just not feasible to keep it at 75mpg without going under 5 mph of the speed limit. I do not feel safe going much less than 35 on a 40mph road. I am looking forward to the summer. If I can achieve 55-65mpg rather easily now, I am going to guess that will be +10mpg in the summer :)

I am working the rollercoaster method of hills atm it is hard to resist adjusting the throttle and actually letting up a bit as you go up the hill and then gently increasing on the way down. I do not lock the rpm, but I do try to lock the mpg display. You really do get a feel for how slightly you need to adjust the gas.

Good approach. Use the downhill gravity assist to build momentum so that you can hold a higher average up the next hill. Keep in mind that law enforcement likes to lurk at the bottom of hills and also that many drivers have the inexplicable habit of slowing on the down hill and accelerating on the uphill (the most fuel INefficient approach :confused:) so they will tend to blast over the crest of a hill at something over the the limit... and they can't see you on the other side before they get over the hill.

This means that you should look far back in your rearview mirror and take note of cross streets other vehicles can pull out of after you've passed them. If all is clear, your most efficient way over the hill is a drop off in speed so that you just barely get over the top (preferably just coasting), but do adjust for traffic and road conditions.

What is your average temperature this time of year? 10mpg improvement might even be on the low end of what you can expect if you keep working on your technique and the temps are extra low right now.

What is your average temperature this time of year? 10mpg improvement might even be on the low end of what you can expect if you keep working on your technique and the temps are extra low right now.

Avg now is about 25-30F. Sometimes lower. Plus it is very windy here. I would say avg day is 20-25mph winds. I do not know if that goes away in the summer or not... Will find out this year :)

I saw some posts about a hot air intake. Might be something that I can do pretty easily.

Okay -- you've got a lot of upside ahead of you. :) We've had similar temps here and I've been stuck in the 70's and low 80's for FE. With no wind and good traffic patterns I can top 100mpg around freezing. Put me in 60F+ and I'll be over 100mpg for pretty much any trip I take. That's a pretty big difference. ;)

The hot air intake can definitely help. I've not got a specific hot air intake installed but I do have the lower grill blocked and half of the top grill blocked. Facing the car from the front, the air intake horn opens on the left. I've got that side completely blocked and do see a nice increase in intake temperature because it is forced to pull air over the warm engine. The classic way to do this is to reroute the intake to pull air from around the catalytic converter.

Out of curiousity why does hot air improve fuel mileage? Wouldn't the ECU compensate for the hot air and lean the mixture, thus produce less power, thus you have to step on the gas more to maintain speed?

Its somewhat confusing to me. I know how to add power to a car, I am foggy on how to add FE.

You do end up with less power but better fuel economy. The mixture isn't "leaned," though. Think of this way: do you get better mileage in the summer or the winter? There are a lot of variables but the density of air in the combustion chamber has a fairly large impact on fuel economy. The air/fuel ratio will stay the same but the denser air will require more fuel to keep the ratio up.

This works for any vehicle but don't try it in the summer -- you'll end up with very little power indeed! The object is to get the combustion parameters closer to what you experience in summer.

Out of curiousity why does hot air improve fuel mileage? Wouldn't the ECU compensate for the hot air and lean the mixture, thus produce less power, thus you have to step on the gas more to maintain speed?

Its somewhat confusing to me. I know how to add power to a car, I am foggy on how to add FE.

Another effect that the warm air intake helps with is cutting down the warm-up time for the engine (it makes more difference than you would think).

Out of curiousity I was wondering what effect humidity has on FE. The other day it was heavy fog and pretty much pea soup and I felt my mpg drop off more than just wet roads. I assume it has to do with the air being less oxygen rich and thus resulting in

LOL on a side note, I had the worst ride home. I hit every single light on the way home, I had people cut me off etc. I averaged at one point (early in the drive) at 32.8mpg. UGH that was frustrating knowing how easy it has been to get a 55mpg avg. I ended the run at 52.8mpg, so I recouped alot, but damn that still took a hardy toll on my MPG...