hey just wondering if anyone can tell me how much fuel mileage i should expect to lose by getting rid of the 3 cats and putting on a straight down pipe to a muffler.

 

My GXL's freeway cruise went from 22-24mpg to 24-27mpg when I replaced my exhaust. I don't think you'll lose mileage unless the newfound power and noise have you leaving the throttle on the floor all the time.

 

You should not loose any gas mileage you shoudl actually get better gas mileage. At least thats what I have noticed on every car I have owned. especially if you drive ont he highway a lot.

 

getting rid of stock exhaust is worth 2-4 mpg depending on driving style

pat

 

thanks me having a TII i should loss some for the compensation needed for the boost increase....damn turbo

 

hit the nail square in the head... exactly what i gained

 

what? this measurements of gas milage seems to be at cruise and out of the boost. hold on, what?

 

i think he might be saying that percent wise the increase in gas mileage on a turbo car might not be as much since adding a free flowing exhuast increases boost and uses more fuel, and boost should be considered cause most people with a turbo car put it in boost at least a little each time they drive it, i mean how couldn't you?

 

A straight pipe on a turbo also means you'll prob need to put in more fuel to avoid detonation, therefore reducing milage.

 

I get 19mpg city with a straight pipe and mods. Its supposed to help gas milage due to the fact your getting rid of a restriction.

 

Mine stayed about the same when I put on my exhuast.. But only becuase I reved out the car more often.. Revvv Revvv Pow!

 

Yes your getting rid of a restriction which means more boost and more boost equals more fuel and more power. If you just lost the restriction and didn't use more fuel you'd be in trouble running that lean. With that said i'm still think it would offer better fuel economy with unrestriced exhuast that without but just not quite the increase one may see on a non turbo car

 

My mileage has always been between 25-27 mpg with 3 different exhaust setups, the latest being an open system, so I'm in the "not much change" group...

Outside air temps affect my mileage more than anything else, believe it or not...

The car is only driven back & forth to work, 100 miles round trip, so I can get pretty exacting sampling numbers for mileage...Case in point- the last fillup, 11.584 gallons, at 300.8 miles, netted 25.9 mpg...

 

^ thats good mileage i hope to get that much once my safc is tuned and i'm not running so rich

 

i wish i got 20 mpg...or hell...even a steady 16 or 17 would be ok...****** big turbo..

 

you never get good gas milage in boost, you get good gas milage staying out of boost, like during cruising and closed loop.