My 40 MPG Corvette is going well but I need help

[Big Dave]

I never trusted one-tank fill-ups for accuracy. I used four fill-ups. In my case that was about 1,600 miles.

But then, I had a long commute.

[Mustang Dave]

Originally Posted by Big Dave

I never trusted one-tank fill-ups for accuracy. I used four fill-ups. ...

I agree. A single fill-up over 33 MPG may be due to exceptional circumstances; or it may be due to a short fill. It doesn't establish a trend.
6 consecutive fill-ups over 33 MPG could possibly indicate a trend.
(Then cold weather and Winter fuel arrived.)

[talonts]

Originally Posted by Fat Charlie

Nothing's perfect, but pointing that out and then claiming that onboard measurements covering a gallon or two are somehow more valid is acting like our politicians.

Yeah, well, lying about what I said is definitely "acting like our politicians", so...

[Fat Charlie]

I'm sorry I associated you with our politicians. I zigged when I should have zagged, and you weren't calling onboard measurements more accurate (except for a physically full measurement, which you weren't recommending).

That's the fun thing about multiple threads spanning time, things can get confused. I screwed up and acted like our politicians. Sorry.

[MeteorGray]

I don't judge a car until I've got a number of fill-ups under the cap. The more evidence added to the pool, the more confidence in the conclusions.

For instance, now that I've got 100 refills on my 2015 Mazda3 2.0L automatic, I can confidently say I've got a car that is delivering over 44 mpgs achieved mostly on the highway for a lifetime-so-far fuel cost-per-mile of 4.6 cents.

I consider each refill as the latest iteration of a track record that becomes more valid every time I fill the car. Any significant deviation from that track record at a refill means that I start looking for reasons: A strong headwind? A brake dragging? A malfunctioning engine computer?

I do use a ScanGauge, but only as an interesting indication of fuel mileage under varying conditions. My gauge is usually within about 2% of actual accuracy, which is good but not as good as counting gallons at the station.

[Hersbird]

I think his test was long enough to reasonably claim he got 40 mpg out of his Corvette. If you watch the video you see he could have done much better. I'd say he should repeat in the summer on a more deserted road, run lower speed with more tire pressure and go for 50 mpg.

[diesel_john]

I go to lean-burn by reducing the voltage to injector power. I put a 0-100 ohm 100 watt rheostat in series. ( Grainger). Use 0 ohms to start.(choke). lol. When warmed up dial up the ohms till the power drops off, then dial down the ohms if I need more power. Add kill a switch to engine brake or coast.
Of course, this makes any data based on pulse width useless.
This works well on throttle body injection. Dont mind error codes as long as the processor dont mess with the ignition timing on the newer systems. {knock}
I have tried fuel flow meters to a small reservoir by the engine but fuel temperature changes have to be controlled or compensated for. Many gas stations dont compensate for temperature.
Fuel consistency is a problem now days I dont even know what Blend I am buying today. It changes every day with the price of crude.
So the fuel mileage is useless on the E85 systems. A gallon of what per mile?
Strain gages on a drive shaft would be good for ABA tests. Read torque directly.

Lingenfelter did some mods to reduce drag. splitters, skirts, dams, etc.

Keep in mind the exhaust system is air cooled.

[hayden55]

Plus he did the test while it was 20F outside. That's a big difference in highway mileage with the Prius. I bet if you convert the math to 70F and 70mph he's almost at 37 ish mpg driving like a normal person.

[Hersbird]

Originally Posted by hayden55

Plus he did the test while it was 20F outside. That's a big difference in highway mileage with the Prius. I bet if you convert the math to 70F and 70mph he's almost at 37 ish mpg driving like a normal person.

The cold makes it worse and he was going 70 mph for a bunch of the loop when he wasn't stuck in stop and go traffic, and got 40. That's why I say lean without even more, slow it down, and do it again in the middle of summer on an open back road and go for 50 mpg

[hayden55]

Originally Posted by Hersbird

The cold makes it worse and he was going 70 mph for a bunch of the loop when he wasn't stuck in stop and go traffic, and got 40. That's why I say lean without even more, slow it down, and do it again in the middle of summer on an open back road and go for 50 mpg

Ah okay. I skim a lot of tech videos. I saw him going 60 at the beginning and also in the last video so I assumed he did it the whole video. Oops lol