what kind of gas mileage can you expect from a 5.7 tpi? An almost totally stock one. im not a tpi guy but i know they all came with 700r4's and like, 3.23's i think? thanks for the info

 

no answers for such a simple question?

 

Well, gas milage reports very from what I've seen over the past years. Around 20 sounds right, depending on driving habits and condition of the engine. And no, not all TPI's had the 700r4 behind it, they also came with a 5 speed in thirdgens... And they also ranged in rear end gear ratio's depending on year and options on the car.

 

I get about 14 around town (read "on it all the time"), and about 20 on the freeway.

5.0L TPI with 700r4 and 3.08 posi rear. It does however have almost 180k miles on the engine.

I have to check mileage again soon, since I did a bit of work which should make it more efficient.

 

Stock I got about 20 mpg. Now I get 21 to 22 mpg on the highway. In town, doesn't count, I'm always playing! Haven't checked it with the new 30# injectors but I think it might have improved due to the matched injectors, based on gas used to go to a couple of meetings about an hour each way.

 

with the combo in the sig, i get 18 city, and 24 hwy. some guys with custom chips have gotten as good as 30mpg.

 

I get about 13mpg in city and it's all stop and go. red lights, stop-signs, Brooklyn.
On the other hand I was surprised to get 24-26mpg at 65mph on the highway, in 5th. My fifth is taller due to the fact it's an aftermarket tranny, but I do have 4.11s, though.

 

Maybe if I slow down on the highway it would really help my gas mileage. 75 to 80 is my cruising speed on the Highway when I check the MPG. But then again, NAH!

 

wow jeez...
im really starting to hate TBI......

 

I just got back from a trip last weekend to the closest track. I came home with a 12.8@106 and 27MPG to boot. When the car was stock I could still get 23MPG with a really worn but tuned stock engine.

 

I have a 87 TA with a 93 vortec short block with l98 heads. It is running the stock Vortec cam (very mild, almost no overlap) with 1.6:1 rockers, and a speed density tpi with a custom chip. The gears are 3.23s. I'm averaging 22 on the highway & 16-18 in mixed driving. I don't use it as a daily driver and don't do daily driving around town 100% anyway, so I can't say what it would do just driving around town. On the highway I generally try to stay around 75 mph sometimes 80. I forgot to mention, mine has a t-5. An automatic probably comes up a couple of mpg worse.

 

thanks for the replies. i guess im sorry i didnt make it clearer that im intersested in numbers for the l98's that are mostly stock. reason being that my 5.0 tbi gets 20 and if i can afford to im going to look for an iroc or z28 with a 5.7 TPI and i need to know if i can afford the gas. and since im looking at 350's without major modifications they would ALL have auto's in them. less i could get real lucky and find one with a t56....

 

lot of L98s get 16mpg in the city and 24mpg on the Highway. Those Are my #s

 

12-16mpg in town, 23 highway...... L98 100% stock.

Edit: 3.23:1 gears

 

305's out the window. i swear im taking an ax to that thing......
what gears are you running?

 

Hey now 305s arent all that bad!

 

if you're only getting 20 with the stock L03, something is wrong. or you need to stop driving everywhere in 2nd.

try some distributer timing, and see if you're still getting 20 mpg.

i don't really like the L03 either, but you should be pulling a LOT higher than 20mpg......you should be getting close to 30mpg. and if you are running super rich, it's also going to make that car run really really slow. set your timing to 4* advanced, and that will wake up that motor quite a bit, and will help more than a little with fuel economy.

 

I always got 12-14 in town 22-24 highway 350 stock tpi