My 40 MPG Corvette is going well but I need help

[slowmover]

As noted above, consistency matters, not perfection.

MPG isn't really a goal. It’s in knowing the fuel cost expressed as cents per mile.

Cars are about practicality. More than one per household is where it gets out of hand. There’s not even a reasonable attempt to try this, yet it was the norm right into the 1960s.

There are minimums to meet in re safety (design + size) which happily correspond with what’s needed for a household.

Specification, matters most. Past that is the detail of circumstance: climate, terrain and driver motivation. These are fixed, for the most part.

Fuel burn is just a trend. How it’s monitored doesn’t mean much. It’s less than half the cost of a vehicle, on average (any type). The trend is about VEHICLE USE as to what matters.

That’s the other part ignored. There are a dead-minimum number of places to stop for which one requires a car. That’s the MPG loop that counts as the car will be in constant service to & from those locations. Highway trips are a laughable “worry”.

It’s not just avoiding cold starts. It’s avoiding the use of an empty vehicle altogether.

How accurate a fuel pump is or isn’t , as FC notes above, relevant to the trend itself. Especially on a car that couldn’t be any more impractical.

1). Where’s the annual miles reduction from Square One? (the decision to emphasize economy)?

2). Where’s the upgrade to vehicle weather-proof storage?

3). Where’s the savings account to cover ALL TRANSPORTATION EXPENSES as a car is only one category. The weekly family expense over a years time?

4). What’s the expected increase in vehicle component life? Tires, brakes, steering, etc? What’s the projected life extension at a lower vehicle expense (but temporarily increased by expense of a garage) to lower THE LIFETIME EXPENSE?

5). What’s the projected increase to Net Income as a percentage once analysis & remedy are implemented?

Buying gas is just use Fuelly. Be consistent as with all else. But it’s the “all else” as above that matters. On a car that’s ridiculous, the whole exercise is pointless.

“Claims” are trends. Consistent use. So long as the owner isn’t disciplined enough to take the driver out of the equation (anyone can replicate it in his car), any claims he makes can’t be backed.

As MG notes, it’s A LOT of fill-ups to make an accurate trend. It’s at least a year to cancel weather effects. Afterwards, anyone should be able to match it with minimal rules to follow.

Has the Corvette owner — after 50-miles of warmup — scaled the car with full fuel (dialed in tires based that data) and then made a 2-300/mile Interstate
roundtrip at 58-mph on cruise control? No acceleration, braking or lane-changes except as the law requires. Zeroed-out driver inputs.

He hasn’t? Then there’s not even a baseline against which to work. Much less make claims which aren’t suspect. (Good intentions ain’t the thing).

.

[Hersbird]

Well he sold the car now for $8800 so there will be no more tests. Pretty good deal for a clean C5. Maybe the next owner will end up here.

[talonts]

Originally Posted by 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.

No worries, and thanks for the reply.

[Tahoe_Hybrid]

Originally Posted by talonts

Honestly, without a separate tank, your (and others') "solution" of filling to the first click, even at the same pump, is generally useless.

I can watch the pulsing of the fuel in the hoses to the fillers on cars and see that the more cars there are filling at once, the more sensitive the shutoff valves are. They can also be temperature sensitive. You'd have to hit a pump when the station is deserted, run your tests, hit it again when deserted, and have the outside temps the same. Even then, there is ZERO guarantee that "first click" will lead to the same fuel level both times.

You either fill the tank ALL the way up, possibly destroying your vapor recovery system (depending on design), or you get a separate calibrated tank/pump to run your tests from.

Edit: Todd Day and I played around with fuel maps on our 90 Talons in the late 90s/early aughts, and while lean burn obviously helps a lot, the fastest gains were from extending the closed loop tables as far as possible, as that helped in all upper rpm situations. Which was very difficult on the stock ECU, as making room for those extended tables required removing other code, that chip was PACKED full for the 90-94s.

I do love your setup though, best of both worlds. I'd love to do the same with an LS/LT motor in the future in a transplant.

You want to basically add any power mod you can that involves volumetric efficiency, as that will boost power AND mpg. Long tube headers probably aren't going to help much at 1-2K, though...

i use the same pump it's pretty accurate since in California it has a return vapor line so all the vapor gets sucked out of the tank

[Tahoe_Hybrid]

Originally Posted by talonts

Honestly, without a separate tank, your (and others') "solution" of filling to the first click, even at the same pump, is generally useless.

I can watch the pulsing of the fuel in the hoses to the fillers on cars and see that the more cars there are filling at once, the more sensitive the shutoff valves are. They can also be temperature sensitive. You'd have to hit a pump when the station is deserted, run your tests, hit it again when deserted, and have the outside temps the same. Even then, there is ZERO guarantee that "first click" will lead to the same fuel level both times.

You either fill the tank ALL the way up, possibly destroying your vapor recovery system (depending on design), or you get a separate calibrated tank/pump to run your tests from.

Edit: Todd Day and I played around with fuel maps on our 90 Talons in the late 90s/early aughts, and while lean burn obviously helps a lot, the fastest gains were from extending the closed loop tables as far as possible, as that helped in all upper rpm situations. Which was very difficult on the stock ECU, as making room for those extended tables required removing other code, that chip was PACKED full for the 90-94s.

I do love your setup though, best of both worlds. I'd love to do the same with an LS/LT motor in the future in a transplant.

You want to basically add any power mod you can that involves volumetric efficiency, as that will boost power AND mpg. Long tube headers probably aren't going to help much at 1-2K, though...

i use the same pump it's pretty accurate since in California it has a return vapor line so all the vapor gets sucked out of the tank... I also make sure it's seated correctly other wise it will shut off prematurely.. and put way over the amount, to make sure it does not enter slow mode...

[Big Dave]

Hey, Legit. Can you re-tune a Ford 4.6 in a similar manner to what you did in the 40 MPG Vette? Or are you a strictly Chevy man?

I live in Indianapolis so a trip to Chicago would be easily possible.

[Hersbird]

Originally Posted by Big Dave

Hey, Legit. Can you re-tune a Ford 4.6 in a similar manner to what you did in the 40 MPG Vette? Or are you a strictly Chevy man?

I live in Indianapolis so a trip to Chicago would be easily possible.

He's a YouTube guy more than a make money as a mechanic guy. So what you need is a project that will generate views. Like cutting the roof off a Tesla. A 40 MPG Corvette raises some eyebrows but 10 sec 1/4 mile vettes are a dime a dozen on YouTube. A 40 mpg taxicab probably doesn't get views, but a 10 sec 1/4 mile Taxi might.