gas mileage

kb426 · June 28, 2009, 10:34:05 PM

Those of you that followed the buildup of my 32 truck might remember that I installed a 5.0 Ford and eec iv efi. This weekend is the first time in 3000 miles that I went more than 100 miles. I drove to Pueblo and back for the NSRA meet. I left friday mid morning and had about 30 mph crosswinds for 125 miles. After the first 50 miles I tried the ac for the first time. It worked but I had air leaks around the lower door hinges that were making it less than wonderful. I pulled into the station at Pueblo and filled up. 223 miles and 23.3 mpg. Running around town this thing is regularly 12 mpg. Coming home this morning with almost no wind and no ac, I went 173 miles and filled up at the last stop for cheaper gas before home. (2.49 versus 2.79 here) 26 mpg! There's room for that to be a one time affair but my goal was 24 mpg and I think I'm there. Pueblo is 4800' in elevation and it was 98 degrees friday when I got there. You can tell right away which cars are efi and which have a carb that aren't perfect. The most I had gotten on short trips was 20 mpg so I was pleasantly surprised. I hope you guys are having a good summer. I remember a few years ago that several of us had some sadness in our lifes and I hope that this is a better year for all. Ps. I went to Home depot in Pueblo and got some stick on weather stripping and fixed the door leaks. Ac is way better now.

enjenjo · June 29, 2009, 01:30:52 AM

I am only hoping for 20 MPG with my EFI setup.

C9 · June 29, 2009, 08:21:05 AM

I need to do some more running/testing with the 32.
(Carbureted, mildly cammed, 9.0/1 CR, 462" Buick engined 32 roadster.)

It got 16 mpg on mostly highway with the 3.70 gears and 30" tall tires.

Stuck in a set of 3.00's and mpg seems to have gone up 1 mpg in town and the same on highway running.

I think I should be able to hit 18 mpg during highway running if I stick to the flatter areas.
Doesn't help that the previous checking mileage with the 3.00's had the steep 12 mile 5% many places between Laughlin and Kinglam as part of the mix.

Gonna try dialing in a coujple degrees of advance as well.

My thinking is that with the roadster having all the aerodynamic qualities of a brick, it may be a tough go.

Although I do see and hear guys talking 27 mpg in these cars when they run an EFI equipped SBC.

A couple of times when improving - trying to anyway - I'd be improving and the state would allow the gas formula to be altered and you'd lose 10% mpg.
Happened with California's MTBE, it killed mileage 10% on my EFI V6 Ranger and 5.0 liter EFI Mustang - both stockers.

Got to Arizona and they started or increased the amount of methanol in the mix and mileage there dropped about 10% a few weeks after the move.

Enjenjo's hopes for 20 mpg looks to be a reasonable one....

phat rat · June 29, 2009, 08:55:28 AM

I've pulled as high as 19.6 with my cpe running 454/700R w/3.73's

rumrumm · June 29, 2009, 09:22:55 AM

I can get 20 mpg on the open road if I use a light foot.

phat rat · June 29, 2009, 11:24:51 AM

Correction 454/700R w/3.42's

papastoyss · June 29, 2009, 12:11:38 PM

In the mid 90's I built a Minotti 37 3 w w/ a 93 lt1 350 ,700r4, 3:70 rear. It would get 20 -21 mpg at 70mph any day. The best I've ever done with a carb 350/350 is 16-17 mpg

Learpilot · June 29, 2009, 08:11:50 PM

I think the key to great gas milage is to match the rpm for a cruise speed.
My SBC EFI 700r4 got 17 mph with a 3.00 gear at 65 mph and then put a 3.55 gear I got 23 mpg at 65 mph. This the best I got on the interstate between gas stations with a/c on.
Just my 2 cents worth.

C9 · June 30, 2009, 08:56:04 AM

Quote from: "Learpilot"I think the key to great gas milage is to match the rpm for a cruise speed.
My SBC EFI 700r4 got 17 mph with a 3.00 gear at 65 mph and then put a 3.55 gear I got 23 mpg at 65 mph. This the best I got on the interstate between gas stations with a/c on.
Just my 2 cents worth.

That's an on the money comment.

When we bought our 88 Mustang GT (1st new car) and drove it to Idaho from SoCal I found that it would pull more vacuum in 4th than it did in 5th on the long desert uphill grades.
Running fourth gear at times like that the mileage improved 1 mpg.
24 to 25 mpg.

I pull a pretty good vacuum in the 23 on the flats and also on the steep grades.
Aside from the previously mentioned aero capabilities of the brick-shaped roadster I'm beginning to think I need a little more time timing.

Gonna try a couple degrees more initial and see what happens.

It has 8* initial and 32 * all-in by 2800 rpm.

Have to keep an ear open for the ol devil, detonation, I run 87 octane summer and winter righ now.