StrokerTA

Ok, so let me preface this by saying no one is buying these cars because they are the most economical and I know this. However I do think it's pretty awesome just how good they can be on fuel if we want them to be.

So my question is this, how far can you push a turbo street car and still maintain it's ability to get over 20mpg on the highway?

So for those of you who have actually still calculated fuel mileage on a road strip, or driving to work, what do you get, and how much power are you putting down?

necrocannibal

iTrader: (5)

I haven't checked the mileage on mine, actually scared to, but my mpg was terrible on my twin turbo build. I'm switching over to a single 7675 right now but I bet the mpg will still be bad.

StrokerTA

Was it bad because it was always in boost? Rich tune?
Here is my comparison, WhiteLTone has a 8000 Chevy 2500.. With his big tune, it gets 26mpg on the highway if he keeps the RPM low enough to keep it out of boost..

Why can't a turbo LS1 do the same thing, obviously the fuel is a little different.

silver_82

Runs mid 8s and i got 15mpg on dragweek. It gets about 20 if i keep the revs down and go 50mph instead of 65.
This is on e85 so it would get a bit more on gas. I don't have overdrive, so with one i think i could get 20 still on the E

StrokerTA

See that's what I was looking for! I heard rumors of the big HP guys getting 20mpg on dragweek.
what trans and rear gear do you run?

necrocannibal

iTrader: (5)

Honestly I think the tune on it was pretty rich. I'm hoping this new set up will be better.

stevieturbo

There is no reason whatsoever for a well built and tuned turbo engine not to achieve near stock mpg figures, or pretty damn close.

When cruising or town driving, you are never in boost, and mixtures will or should always be close to stioch anyway.

Now maybe peoples choice of trans etc is having a negative effect on fuel economy, or if people choose silly camshafts.

But silly camshafts arent needed to make lots of power with turbos.

HexenLord

The turbo has little to do with it. On a big turbo app, the gas mileage is often the mileage of the motor if it was N/A. You aren't building boost in town or on the highway with normal driving. Small turbos effect mileage much more.

Superchqrewrs get slightly worse mileage because they are constantly being driven, but they shouldn't be producing boost at cruise either so that aspect is out too.

StrokerTA

I totally agree with you guys.. You can make silly power with a turbo engine with a 224 cam, no need for anything crazy. Especially if your goal is just to have a nice powerful street car.

00Wildcat

Keep the cam timing under 230@.050" and overlap to a min, combined with injectors designed for Gasoline (not white top 160's) with a manual Trans or lockup converter.

My buddy built a customers 6-speed, twin 60mm 408 car that got 28mpg on power tour with a 860rwhp pump gas tune.

StrokerTA

Very good advice, same type of cam specs I would implement for a healthy turbo street car.. That 408 sounds like a bad *** machine.

Tally TransAm

iTrader: (17)

Ive calculated 24-26 mpg cruising on the interest at 80 mph during the past few trips ive taken. Gotta love 1800 rpms @ 80.

Start messing around on the hwy and that number drops with a quickness though

silver_82

Glide with 3.50 gears 30" tire
This is with bosch white top 160s. I run stoich or a touch leaner while crusing.

I-H8-RICE

man ill just be happy to get 15, my SBC 327 Th400 4.11 car SUCKS like 5-7 MPG maybe lol terrible driveability and only runs 11.9's lol ill be so stoked to be low 10's getting 15+ mpg

NV Z 28

iTrader: (14)

On average I get 16-18 combined mpgs. I have a our Speed Inc twin turbo set up with a full exhaust and a 3400 converter. I'm also running a th400 and a 3.25 gear.

StrokerTA

Not bad Nick. You normally have a short tire on the car too right? 26?

westtexasbuff

iTrader: (40)

I got about 18 on the highway... Twin turbo, with AC

It'll be about 10-12 soon, switching to e85 lol.

StrokerTA

^^^ I might have to drive to Texas and "borrow" your car! Looks awesome man!

Chicago TDP

iTrader: (3)

Can you clarify this? A full size 3/4 ton truck getting 26 MPG? How?

"WhiteLTone has a 8000 Chevy 2500.. With his big tune, it gets 26mpg on the highway if he keeps the RPM low enough"


Also, my 69 nova with 3.55 gears, 6 speed and PT7675 got 18 MPG with a rich tune and heavy foot.
My '03 silverado 6.0 HD2500 gets 10 MPG no matter what basically....

StrokerTA

haha, yes he has a Chevy 2500 crew cab short bed duramax... It has 35" tires, and a 3" body lift.. Has EGR delete, CAI, and a full turbo back exhaust, and a custom tune..
He averages between 22-26 on the highway... That's not uncommon at all...
Heck my F350, long bed, crew cab, dually, 4.30 gear, Powerstroke get's 18 on the highway.