Ive recently had a flowmaster axleback exhaust put on my car. Dont make fun of me I like the sound its not too ricey and not too mellow just right. But my gas mileage has decreased by about 40-50 miles to a full tank of gas. Anyone know what the problem could be. I dont drive any different then I did when I had the stock muffler.

Thanks for your time.

 

Have that been the only mod? It shouldn't have that adverse affect. If anything...it should minimally increase gas mileage. Larger piping, wider flow-through design ='s a more efficient exhaust system. If nothing else...it is only an anxle-back. Put the OEM back on. Good luck though.

 

maybe you have a leak or something...

 

i tossed my headers in about 2 weeks ago and i lost about the same amount on a tank of gas...two different mods but i understand where you are coming from with that new found hole in your pocket...but try switching back to OEM and see if anything changes...like SLVROZ said, "it's only an axle back"

 

Like SLVROZ_03 said I would you have a small exhaust leak. Did you replace your gasket when you put it on? Did you remember a gasket? Is their a joint in your piping where your leaking exhaust gasses? Look around your exhaust system for carbon build up around all the joints and fittings.

 

this happened to me before. after having my hks exhaust installed for a week, i noticed my gas mileace decrease. we took the car to a mechanic and apparently, some punk kid had stuffed a 5 bananas in my exhaust.

 

I don't blame him. You are a jackass.

 

Bananas in the exhaust...that's the oldest trick in the book!!!

 

Well they installed it by cuttin off the old muffler and welding up the new muffler. They didnt unscrew it but just cut and welded up the new one.

 

Perhaps your giving it a bit more throttle so you can hear your exhaust? I did this when I had a new exhaust installed. Hell, I did it when I got the intake as well. Once I got over how "cool" I sounded, I eased up on the throttle and found my gas mileage went back to normal.

 

Im passed that. I may take it back and let them look at it.

 

I also have remote start installed on my car and use it alot. So sometimes it may idle for like 5 minutes. Dont know if this would have an effect or not.

 

idling the car wouldn't suck down that much fuel....i used to let my car idle for 15 minutes 5 days a week before school so it would warm up and that wasn't even all to noticable.

 

Hall OF Fame reply if i ever heard one

hahahahahah wikked

 

this is a non turbo lancer right?? if so it's more than likely that your exhaust removed the back-pressure your enginge needed for low end torque. you now have to apply more throttle to get the same acceleration feel. your top end will more than likely be better though. you just moved your powerband up.