I know that there is already a billion threads on gas milage, but being that Ive had a few people ask me personally about milage after exhuast install, and that Ive seen it asked on here a few times with no real definitive answer, I thought some may be interested in knowing. Anyway, I calculate my MPG at each fill-up, no real reason just something Ive always done. When stock I was consistantly seeing about a 28MPG average. Ive now ran 4 tanks through since installing a Berk testpipe and HKS cat-back, and Im now seeing about 31.5MPG average. Pretty soon the mods will pay for themselves Just for some additional info this is mostly highway driving with cruise set at 70MPH, but I dont baby it. I redline 1-2-3 gears at least once a day coming off an on-ramp, and do the occasional 120MPH sprint on my way home from work just to relax. I really dont understand how some people can be averaging so low MPG with these cars, unless mine is some sort of freak

 

I just did a testpipe and catback 2. I havnt calculated the mileage yet but Im sure its gone up somewhat. Also I seem to have more usuable power down low and rev up quicker(with less effort) then before. Exhaust was a great first mod

 

you're getting some really good mileage...i do the exact same thing that you do during fill up (calculate mpg, no real reason either, just curious). and i average about 24mpg...
i, too, have a tp and catback

 

WOW great news I just ordered a berk test pipe for my car for sound. Thats just icing on the cake that it gives me better mpgs, and maybe it might have a slight performance on sound.

 

Some type of controlled testing would probably be needed to verify the gas mileage increase. Some times wishful thinking and behavioral changes influences what is being done and what is being perceived. There are people that swear that after purchasing "moleculear alignment" magnets for $9.95 to $129.95 and placing them on their gas lines, they see big increases in gas mileage. People generally want to see some positive improvement for all the work, $$$ spent, and increased noise level.

 

Do you guys thing the exhaust or the TP is causing the biggest change in gas mileage?

 

There's no reason to believe reducing restrictions wouldn't increase efficiency. I've seen it in other cars I've owned, I'm glad to see it confirmed on the S

 

Haha....pulling cats for more fuel economy in a high price of gas market caused by environmental whackos (i.e cannot drill our oil). The irony is absolutely delicious.

 

I LOST MPG's when I had my berk test pipe and Megan single. I think it was just me being Rev happy though.

 

The magnets don't work, I've tried them and mythbusters tried them and showed no gains in mpg.