straight pipe exhaust

[916drifter]

I have a straight pipe w/ a custom exhaust and i was wondering if thats the reason my gas milage would suck. Someone told me if i run a straight pipe it would cause loss of gas mileage. so is this the problem or should i rplace my 02 sensor. Cuz i get about 18 miles the gallon and 16 on the freeway.

[bcuz]

yah thats pretty mad mileage... I think mine is bad too... but Im missfiring in alteast one cylinder... Im gonna see what mines at then get new sparkplugs and whires and then see again..

[Phax]

If you think about it, anything that allows the engine to breath more is going to use more gas. Does it use more like increasing the fuel injector size uses more... no, not really. There is certainly an effect on it though.

Is your car a turbo? If so, then an exhaust can make a world of difference in gas mileage. When I had the stock exhaust on my current engine, I got about 400 miles to a 14 gallon tank. With the 3 inch exhaust that allows the turbo to spool sooner (read, start sucking more gas), I get 350 if I'm lucky.

[916drifter]

I get have a 2.25" inch pipe and my car isnt turbo. i get 244 miles on my tank. so i ont know what the problem is.

[lbrowne]

With a super leaking exhaust, excessive blowby in the crank case, and also what i think is a worn ring i get 260-270 miles to a tank in my 89 240, all city driving and thats not driving like grandma.