I just added a Magnaflow 14377 muffler to my JK and it seems to run worst. It is a 2011 2dr, auto, 3.73 gears, with a dropin KN air filter. Didn't change anything else and now it seems much slower. What happened?

 

how does it sound? Ive been looking.

 

i've had my Flowmaster Superr 44 on for about a week now and love it.....wouldn't necessarily say it feels More powerful but definately not less! sounds cool though

 

You think it is slower because your brain equates a certain level of noise with a given speed. Your brain is programmed with the memories of the vehicle going "so fast". When you install a louder exhaust, your brain thinks that the vehicle should be going faster due to the higher noise level. If the increase is speed is less than the increase in noise, your brain perceives that as the vehicle is slower or not accelerating as quickly as when it was quiet.

Without using a stop watch, there is no way to know whether or not your Jeep is quicker now than before.

 

Give the computer time to "learn" the changes that you made. After a few hundred miles, you will be more satistied.

 

For the Flowmaster Super 44 what model number was that?

 

I've got the Flowmaster Super 40. I put it where the evap can used to be.