New Insight Owner... Am I hearing you all Correctly? Only at 58mpg

[ronandjess2010]

I've spent a lot of times pouring over all of these threads on driving techniques to learn as much as I can before posting any kind of ignorant or exhausted questions. Now that I've done my homework I'm hoping for feedback as to why I am stuck at 58mpg. I think I know the factors but would greatly appreciate feedback. It seems many people can comfortably be in the 75 mpg range, unfortunately I am not. I was told that the previous owner was a traveling salesman so I can assume he accumulated mostly highway miles. I would have expected to see the cars lifetime average higher than 55.4mpg(unless he was a lead foot). Please read my stats, then my thoughts and post your feedback. Thank you for your time.


About the Car:
Year: 2001
Transmission: Manual
Mileage: 117,000
Cars Lifetime MPG: 55.4mpg
Front Tires: Michelin Harmony Tires
Rear: (Forgot Name) but noticed size 175/65-14
Battery Pack: Original
Spark Plug Changed: Unknown but seem perfect
Other: Everything is stock and all body panels including undercarriage is present.

About My Driving:

Location: SE Wisconsin(Flat) 50/50 hwy and city
Speed: Everybody passes me(55-60hwy).
Mileage Driven since purchase: 700 miles
Coasting: I coast every chance I get in neutral to maximize distance if the battery is over 75% charged.
Acceleration: Slow
Shifting: I tend to use the 1-2-5 meathod I read about
Lean Burn: I have a good grasp on this, can readily identify it and hold it.
My MPG Average: 58.6mpg over 400 miles
Other: Plan for every uphill approaching, take advantage of every down hill.


My first thought is on the tires, I understand the fact that they are not stock is a big factor. After looking over my stats, other than environmental, is anything else jumping out at anyone? Thanks again.

[rhall]

Your mileage isn't terrible but I would focus on those tires. You didn't say what pressure you were running. There are many things that make the Gen 1 Insight such a mileage champ but lean burn might be the main one. But to keep the car in lean burn mode you need the other factors working at least close to design spec. Wrong tires or pressures combined with underbody aero problems, poor tuning or other factors work to bring the car below the lean burn threshold. It's not incremental. If it won't stay in lean burn you won't get the stellar mileage.

Rick Hall

[kennysmith]

Most cars for sale have lifetime mileage similar to yours. I don't think you are doing that bad. I'm not sure coasting in neutral is a good idea since the car will be idling whereas if coasting in gear the fuel is cut off completely. Try not to use assist. I wonder if 1-2-5 is a good idea for that reason. Replace the tires and pump them up! I run 50lbs.

[Jivko57]

I woulds clean the EGR plate, probably is clogged by now
and would switch off the a/c and roll the windows down.

[MN Driver]

You are better off holding a constant load versus idling in neutral, unless the engine is off while in neutral or if you are in neutral coming to a stop where auto-stop will occur. If the load is light enough to where you can be in neutral, that is prime territory to be in lean-burn or if your speed is under about 35, doing a pulse and glide may be more beneficial but lean-burn gets close even at low speeds and always better than idling in neutral.

Your biggest problem are the tires, you need a set of Bridgestone Potenza RE92 165/65/14 tires. It doesn't make sense to swap the tires until they are worn out though due to the large expense it takes to swap tires of any brand, you might need to live with roughly 60MPG until they have worn out. If they are brand new, you might be living with them for awhile, but if they aren't than it isn't too long that you'll need to worry about it. If you aren't running at least sidewall max when cold on the tires you already have, you should raise the pressure to get better rolling resistance.

[racer26]

The problems I see in your post:

The obvious elephant in the room, your tires. Anything other than Bridgestone Potenza RE92 in the 165/65R14 size results in a ~10-15% mileage hit. Period.

I'm unconvinced on the 1-2-5 shift method. I tried it for a while, and it works, but I've migrated to a more traditional 1-2-3-5 or 1-2-3-4-5 approach, and get better mileage. The trick is in using little-to-no assist.

Coasting in neutral: don't do this; its more efficient to coast in 5th. The engine's deceleration fuel cut off mode means that when its in gear and coasting, the engine uses no fuel. You can see this on your dash much better if you flip the display to metric, and watch the difference between coasting in neutral vs coasting in gear. (they both look like 150MPG in US units)

LMPG's of 55 are not uncommon. When I bought my car back in May, its LMPG was 4.6L/100km (51MPG), and its taken me about 12,000km (7500mi) to get it up to 4.5L/100km (52MPG). My car's total mileage is 167,000km (a little over 100,000 mi). I have been consistently turning out tanks in the mid-to-high 60's. I don't understand what the previous owners were doing. My worst tank so far was 4.0L/100km, and that was with alot of aggressive driving and A/C usage.

Its taken me 2 months and nearly 15,000km (9500mi) to reach a point where on my current tank, which I'm halfway through, I am sitting at 3.3L/100km (71MPG). Forum member Eli said it took him 2 years before his first 70MPG+ tank. You simply haven't gone far enough to get really in tune with your car.

Remember: the EPA rating on these cars according to EPA's new counting method (more realistic than their old method), is 48MPG City, 60MPG Hwy, 53MPG Combined.

[racer26]

Also:

with 175/65R14 tires, you're travelling 2.2% farther than your dashboard says you are, and therefore, you can multiply your mileage by 1.022.

[ronandjess2010]

Thank you all for your input. I never use the A/C and my tires are at 45psi. I'll jump it up to 50 and replace with oem when the time comes. I love this car and look forward to becoming one with her. I came from a 300hp car and I have much more fun with this and the science behind high mpg driving.

[Eli]

I'd say you're doing pretty good with only 700 miles under your belt.

It looks like everything has pretty much been covered. I encourage you to keep experimenting with the car, to see what works best for you and your driving conditions. The worst that will happen is you'll find your new technique hinders MPG. But it may help MPG, so it's worth trying.

And yeah, 55MPG is fairly standard for a lifetime MPG.

[racer26]

Also, switching back to other vehicles, even for a day at a time hurts.

I'm driving my Dad's Toyota T100 today because I'm using it to haul a dead prelude back to our shop for conversion to a race car after work. Round trip to work in my insight yesterday, I pulled 3.0L/100km on my 150km round trip. (Fuel is about $1.29/L here right now). Dad put $30 in the truck the day before yesterday, its nearly empty with only 180km on the meter.