Gibson exhaust with K&N CAI = loss in power and drop in gas mileage
03-12-2012, 03:04 PM
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JK Newbie
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Gibson exhaust with K&N CAI = loss in power and drop in gas mileage
Hello all, I just recently bought an '09 Jeep Wrangler Unlimited X all stock (wife wanted it, which I was like, HELL YA!! 
). So anyways I have been reading up on this forum quit a bit and there is a ton of good information on here. This is my first post and I want to know what you guys think of my situation.
The first mod I did to the Jeep was add a K&N CAI, took it for a test drive and noticed nice gains in power off the line and through out the RPM range. I also noticed an increase in my gas mile. Next I added a Gibson signal exhaust and the result was unexpected. Infact, I got worse gas mileage than stock exhaust and the HP dropped considerably in all RPM range. I called Gibson and they told me to buy a programer to reprogram the computer so it can compensate for the improved airflow and that they would not take it back on return. They also said when they dyno'd the exhaust, it was on an all stock Jeep and they did notice Hp gains. Do you think I should buy the programmer and take a chance to see if it works? Has anyone else done this? Thanks for your help!
). So anyways I have been reading up on this forum quit a bit and there is a ton of good information on here. This is my first post and I want to know what you guys think of my situation.The first mod I did to the Jeep was add a K&N CAI, took it for a test drive and noticed nice gains in power off the line and through out the RPM range. I also noticed an increase in my gas mile. Next I added a Gibson signal exhaust and the result was unexpected. Infact, I got worse gas mileage than stock exhaust and the HP dropped considerably in all RPM range. I called Gibson and they told me to buy a programer to reprogram the computer so it can compensate for the improved airflow and that they would not take it back on return. They also said when they dyno'd the exhaust, it was on an all stock Jeep and they did notice Hp gains. Do you think I should buy the programmer and take a chance to see if it works? Has anyone else done this? Thanks for your help!
03-12-2012, 03:08 PM
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JK Enthusiast
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I ran the Gibson split rear for a year and sold it, much happier with the stock muffler.
At idle the Gibson sounds pretty bitchin', but it's way to loud in general. I also noticed a loss in low end power.
At idle the Gibson sounds pretty bitchin', but it's way to loud in general. I also noticed a loss in low end power.
03-12-2012, 03:33 PM
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JK Junkie
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Shouldn't be more than a nominal change one way or the other. Chambered mufflers are made more for sound than performance, but again I don't believe it should make much of a difference.
