ykp53

is it possible? if so what would it take to do this?
just wondering...

gerry72

Sure. You build the engine for VE at a very low rpm and gear accordingly. If you want more than that, visit http://www.feuling.com/ and read some of the engine tech he was working on before he went HOG wild.

A 25 pound monkey can get 20mpg from a BB 'Vette as long as that's really what you're trying to do.

PRNDL

around town would be tough but on the highway an O/D trans + a little tuning might do the trick. :)

verskel

Highway - 20 mpg is possible with a 5-speed tranny with a final drive of 0.68:1 :yesnod:

Otherwise, you'll need to convert from carb. to EFI....... ;)

turtlevette

(Scotty's voice) "Captain, I can't change the laws of physics"

American Boy

If you take the famous 100 mpg carburator and combine it with a BB, you will acheive close to 20 mpg... :jester :lol:

mrvette

Well, as ever I suspect any reasonable tuner will reply, 'it depends on where the power curve is'.....

so given that on any level....the most efficient engine will sport a DPFI closed loop system on top....nuff said.....

IMO tune carbs all day long, and rebuild to any standard...but nothing beats that computer.....not with an O2 sensor input anyway....

GENE

zwede

I should be able to tell you in late may. Going on a road trip to the forum cruise in (about 800 miles each way). I have a 454 with EFI and 5-speed with 0.68 OD. We'll see what kind of mileage it'll crank out.

mrvette

ZW, please do, for sure ....as I would love a BB vette, but the thing is the total cost of a conversion....accessories and DPFI, and the aluminum heads and so forth....freaking thing would have to get some decent MPG for that kind of price.....

GENE

Chuck Harmon

I took my L88 on a run up to San Franciso and back one night last year, about 150 miles total. Cruising between 70 and 80 mph depending on traffic, but being very gentle with the throttle (no secondaries), I averaged 15mpg. This is with a factory spec L88, Richmond 6 speed with a 2.54:1 overall gear ratio.

I am hoping that with the new roller cam and some jetting changes, numerous fuel ionizers and other gadgets from JC Whitney & Co. that I can win some "beer bets" with over 20mpg's.

I do believe that a more modestly cammed BB than mine with a well tuned carb and ignition system would easily get 20mpg's on the highway with gearing in the high 2's, maybe even with 3.08's and 27" original diameter tires. I have found that high compression engines, i.e. 11:1, deliver much better mileage than engines with only 8.5:1, everything else being equal. I think I recall reading that the difference can be as much as 20%.

Chuck

69stingray

Sure, I do not think it is impossible. Like it has been mentioned, an efficeint engine, fuel injection and good driving habits (probably the most important), you should be able to get 20 MPG once.

gdh

did it in a Cutlass 442 vert in the early 70's - does getting towed for 75% of the way count though?

'79ProwlerOrange

you could.... but why? you dont get a BB for fuel efficiency. :confused:

ZL1powr

On my last road trip to Indiana and back (about 1000 miles total) I averaged 19.6 mpg. I attribute the milage to the .6 ratio of the Richmond transmision and the tune of my 850 DP carb. The carb was tuned using an Inovate Motorsports wide band o2 sensor. I run a 15.4 a/f at cruise a 12.6 a/f at full throtle and a 14.7 a/f at idle.

ykp53

Zl1Powr do you have a oxygen sensor mounted to the side pipes? if so where? and how? i know its a big block its not supposed to get good gas milage, but hearing the wife complain about $35 a week in gas is gettign old.

norvalwilhelm

I am regularly pulling down 15 mpg on mostly open roads with a little city driving thrown in. I would like to take a trip with strickly open roads to find out how good it gets. I do run extremely lean at cruise, over 15 to 1 and drop to 13-1 on hills and passing. I do have an oxygen sensor.
This is with 2 850 double pumpers and a blower

isosceles

anyone remember those ads in the Sunday paper in "Today" section that would turn your V8 into a V6? :lolg:
I think it kept the valves shut on 2 cylinders.

Rowdy Rat

ykp53,

You might want to check out back issues of Super Chevy from the early 1980s I believe. They had a project Monte Carlo with a 454 that was getting around 26 mpg in real life driving.

That's 26 mpg with no fuel injection and no overdrive transmission...

Regards,

mrvette

RR, frankly that mag is crazy.....no way in hell getting 26 mpg without DPFI and o/drive......not in a 3800 lbs monte anyway....

ZL1powr

I have an o2 bung welded to the driver side collector at about the 4:00 position so that the sensor just clears the frame. You are not suppose to mount them below 3:00 because of suseptability to damage by moisture but I have not had any issues and i didn't have to bugger the frame.