i am having problems with my Gibson dual exhaust muffler -



had it for 5 days and MPG dropped from an average of 16mpg to 13 mpg-

also low end torque has much less power -

anything under 2000 rpm's it almost bogs down -

there is no exhaust leak - connection was welded, not just clamped -

strange thing is that the right exhaust pipe extracts about 85% of the exhaust and the left pipe 15% -

i think the torque and mpg problem is due to the engine NEEDS backpressure -

i will call Gibson on tuesday to see what they say -

i will either take it off - and put on the factory -

or

put a resonator or small muffler in the line to add in backpressure -

problem is how do i judge how much backpressure to add?

any help?

thanks

 

Probably needs a Air Raid or AEM CAI to balance it out. I'd try that first. I would imagine the computer needs to adapt to it as well.

 

Iv seen exhaust kits lower power and mpg a few times. Its wierd but iv also seen identical vehicles respond to exhaust mods very differently. More flow is not always better. I really doubt a CAI would change anything. Not sure what advice I can give you besides putting the stock back on. Anyways good luck.

 

i have the AIRAID - been in jeep for 2 months - it helped with the power and mpg's -

just bummed out about the gibson - gonna be out $400.00

 

Stick a bannana up one of the tailpipes & see if the restriction helps. ..probably the one with less output I would try first.

Just kidding about the bannana part, but you get the picture...

Dual 2 1/2" exhaust on this size of a V6 might be too much....as someone else said, engines need backpressure & what each engine needs is different for each motor....

Anyway, just a suggestion...

 

I installed the same duel gibson exhaust system and experienced the same drop in mileage (from 16 to 13.5) and drop in low end torque. I also have an Air raid intake. I'm currently in a research mode to replace it with a single outlet as I believe the duel system is too free flowing.
BTW, my exhaust outlets appear to be flowing equally.

 

This Is probabbly extra flow to account for future trail damage. Take it rock crawling this weekend and see if you have better performance after a few rock mdifications.
They forgot to put this step in the directions.

 

I spoke with Gibson, today and they seem interested in helping figure out the problem -

I will let you guys know how it works out -

 

I spoke with the guys at Gibson, a while back. They had called me to do a free muffler on my JK, but I didn't have my JK yet... They made it sound like they definitely design with power as their first priority. I think they even have a dyno on site, in Corona. DirectedBy, you could probably run your JK out their and have them test it. I'm sure you already know that they are in Corona.

 

Idk what the problem is with your jeep, not to be smart but to be frank. I took my intermediate pipe and muffler off mine today just to test the low backpressure theory and I only felt an increase in hp and torque all around. I'm going to be putting in a very low backpressure system in and I can't see that the Gibson system decreases backpressure all that much. The gibson system is pretty much stock besides the muffler in the rear that splits into two exits. I see a very little change in backpressure between the stock and gibson exhaust systems; and furthermore see that, with the test on my jeep that this engine can significantly have reduced backpressure and gain hp and torque. Maybe it's isolated either with your jeep or mine.