My 40 MPG Corvette is going well but I need help

[Ecky]

Originally Posted by Fat Charlie

OE cluster MPG displays are about as accurate as a presidential hurricane forecast.



Get a ScanGauge or UltraGauge, spend some time getting it calibrated, and then use the short trip measurement to ABA test your mods.

If OP is running anything but stoichiometric, a Scangauge or Ultraguage will be really inaccurate too, as they don't use air-fuel ratio in their calculation. The way to get accurate numbers in a lean burn vehicle is with an MPGuino.

[slowmover]

The display number is relative. As a value. Mines off 11% at 60-mph. A glance tells me how I’m doing after correction. The main value is in checking against current road conditions. As a tank for me is in excess of 700-miles, the display rarely is left alone.

As to mpg:

A fuel stop 50-60 miles out from home. Warmup (including tires) is done. Fill to first auto shutoff. Then, a drive of 100 or more miles. Make the midway turnaround at a deserted crossover to avoid stopping.

Run about 62-64/mph. Keeps you under commercial traffic, but not so they jam up behind you. 100% cruise control use. No lane changes. Cancel cruise to get groups around you (drift down to 55; use terrain to re-engage cruise: let the computer handle the drivetrain). No accel or decel. Note exceptions.

Back to same pump and refill same way.

A baseline which anyone can copy. This is the most important consideration.

.

[mikeyjd]

Corvette For Prius Fuel Economy & Z06 Power With LEAN BURN MODE! Project 40 MPG EcoVette!

https://www.youtube.com/watch?v=keGz...UpVH02it16%3A6

[Hersbird]

https://m.youtube.com/watch?v=vNIZ25eBMco

[hayden55]

I find it hilarious that this guy was a lurker on the forum already and we had no idea. He even had a thread going back in March about it. lol
At least he's going in the right direction now. Turning an LS motor into an Atkinson cycle mimicking motor was pretty lame.
He's not wrong though. I've always dreamed about the 40mpg C5 starting from when I joined this forum around 13-14.
Those cars were doing 300hp and 30mpg way before the v6 muscle cars!

[ksa8907]

To be as accurate as possible you will need to measure the fuel flow (hopefully returnless?) Or maybe have a separate fuel source/tank that is easier and more accurate to track usage?

[Tahoe_Hybrid]

Originally Posted by 2016 Versa

As it's already been stated most MPG displays are very optimistic. The one in my Nissan Versa is consistently off by 5-10%. Probably your best bet is to get a Scan Gauge or Ultra Gauge calibrate it as close as possible over a few tanks then start your mods and testing. Even with the calibrations there may be some error but will probably be minimal.

my average is off mine says 23.2mpg but pump calculation say 25.5 to 26.9mpg...Highway


my best for the 6.0L v8 was 31MPG in the city at a steady 43mph hit almost every single green light (CVT mode runs at 1,050RPM at 42MPH)

it's really hard but you can get it running in lean mode it's very hard to keep it in lean mode slightest hill or bump in the road kicks it out




Best combined was 28.7MPG


I think a new HV ⚡ �� battery will get me to 40MPG+ on this V8...




11 years old yep toast...

I fill up at the same pump everytime from now on i think i was getting scammed at a mobil station they were cheating me upwards of a gallon of gas.. for the first 2-4$ it's "Slow"



If I turn off Hybrid mode it only gets 12.8MPG City



You should swap out for a taller gear ratio like 2.93 or taller tires.....be sure to get the speedo programmed.... this will lower the RPM of the engine.... there for save gas at highway speeds

[Mustang Dave]

Without actually logging miles and gallons at fill-ups, his numbers are meaningless. I filled my Mustang on my way home one evening, and my MPG average display showed 45.x MPG when I got home. (The trip was all downhill) I log EVERY fill-up. My numbers are legitimate.

[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...

[Fat Charlie]

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.

What it guarantees is that you're limiting your variables down to one piece of equipment and spreading its flaws over the widest number of miles possible.

OE displays are feel-good instruments. SGs and UGs need to be calibrated. The best independent measurement we have is a gas pump. It's regulated, inspected and certified for accuracy and you can maximize consistency by using the same one under as similar conditions as you can.

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.