PDA

View Full Version : Better mpg on Chevy 350 TBI


zz4guy
05-01-2007, 11:34 AM
I've got a 92 K2500 with the 350 and TBI injection. Right now I get about 10mpg in the city and 13mpg if I'm lucky on the highway.

Is there a way to improve the mileage at ALL? I've heard of people advancing the timing on these motors to improve mileage. Does that work? I can already tell the motor has lazy timing. Any other ideas? THanks.

grassmanak
05-01-2007, 11:37 AM
not to many things you can do on a gas engine, make sure your oil and tranny fluids are fresh, clean air filter also.

zz4guy
05-01-2007, 11:40 AM
The thing is I get 20mpg in my camaro on the highway with the same motor and gearing with a carburetor. I'm not worried about city miles- I know they will suck. But why cant I get good highway mpgs? It's a real downer when I see something I want 300 miles away and figure I have to shell out $200 in gas :confused:

grassmanak
05-01-2007, 11:44 AM
buy a 02-04 diesel if you want 20+ mpg

Eclipse
05-01-2007, 02:28 PM
The thing is I get 20mpg in my camaro on the highway with the same motor and gearing with a carburetor. I'm not worried about city miles- I know they will suck. But why cant I get good highway mpgs? It's a real downer when I see something I want 300 miles away and figure I have to shell out $200 in gas :confused:

Aerodynamics, 4x4, and level of fueling.

hosejockey2002
05-02-2007, 01:32 AM
Aerodynamics, 4x4, and level of fueling.

What he said. Your 2500 probably outweighs your Camaro by 2500 lbs. or more, and comparably has the aerodynamics of a brick. Is that mileage towing or solo? Also, big tires or a heavy foot will kill mileage.

Sydenstricker Landscaping
05-02-2007, 07:56 AM
On my 94 GMC 2500 with the 350 V8 TBI, I got really bad gas milage as well. I put a k&n air filter on it, complete tune-up, ran some injector cleaner through it, and a flowmaster dual exhaust. The stock system chokes back that 350 so much that you need to open it up. I got about 12-13 in the city and 16-18 on the highway after that. And it was 4x4, 3 inch body lift, and 33 inch BFG all terrains!!!

lawnboy dan
05-02-2007, 09:35 AM
dont feel bad -i get 10 mpg from my 93 1500 with 305 while towing and its bone stock. my neighbor has 88 1500 w/350 with all the mods-no cats-flomaster -k/n he gets 12 mpg not towing anything- mpg isnt these trucks strong suite!

mcwlandscaping
05-02-2007, 11:21 AM
Ive got a 97 k2500 and have come to accept the lousy gas mileage as it makes me money. I will soon be doing some work like Tom described above to improve mine.

General Landscaping
05-02-2007, 10:24 PM
From years as a mechanic, I can tell you there are good ones and bad ones.
Two vehicles with the same everything can be very different in the power & mileage department. It's not always a trade off.... some of them have economy and power.
It seems to be something in the engine machining/measurements/setup..... hard parts.
I've tried to swap over bolt-on parts to try to change things, but it seems to be something it's "born with".
A friend of mine has a Tahoe, 4X4, 5.7L with Buckshot Mudders that can pull a trailer and get better mileage than I can get bobtail in my Dakota 4.7 4WD.

zz4guy
05-02-2007, 11:21 PM
On my 94 GMC 2500 with the 350 V8 TBI, I got really bad gas milage as well. I put a k&n air filter on it, complete tune-up, ran some injector cleaner through it, and a flowmaster dual exhaust. The stock system chokes back that 350 so much that you need to open it up. I got about 12-13 in the city and 16-18 on the highway after that. And it was 4x4, 3 inch body lift, and 33 inch BFG all terrains!!!

Thanks - the only USEFUL info posted yet on this thread :rolleyes:

I'm going to order some shorty headers and put in a K/N and see how that does. Also going to up the timing about 3 degrees until the terrible laziness goes away. When I rev my motor now it takes about a minute before the engine decides to rev. Wayyyyyy ******ed timing.

If anybody else has any suggestions how to increase the MPGs please let us all know. Thanks guys.

FERRISBUEHLER
05-03-2007, 01:02 PM
Funny, I bought an F-250 with a 5.8L and it got 15-16 mpg city from the get-go, little did I know it had a cracked exhaust before the cat. One day my son was driving it and the exhaust DROPPED. Well I put it back together and MIG welded the pipes together, Damn it if my mileage dropped to 12mpg!!! Stock truck exhausts are restrictive, and I also noticed, I lost power! I'm hollowing out my cat this Summer, in my county in VA, no emissions testing!

John