yea i just got my new exhaust today, from the cat back. the pipe goes straight through the back to the bumper. im not sure but i thought it was better for gas millage, but it seems its eating gas?
i dont know....what do i do?

 

get smaller tubing and increase backpressure???? shouldnt be that different.

 

Usually the stock exhaust is pretty much tuned optimally for Hp, Tq, and MPG, but not for sound, so that's about the only thing that will change for the better. Try adding a muffler, it may help some.

 

wait, i dont understand, i got a new muffler and 2 1/2" pipes, it has a alot deeper noise....

 

2.5 might be to big but if you can deal with the mileage it will work.

 

dang. is there anything i could do?
whats increaseing back pressure?

 

The first thing you can do is tell us what your set up is! What kind of muffler? Single out or dual? How big is the pipe from the cat to the muffler? This is what we need to know....

 

okay its a single, 2 1/2 cat to the muffler, and its a cherry bomb

 

I picked up mileage with my JBA, t's a 2.5 with a magnaflow muffler. The cherry bomb may not be creating enough back pressure. Back reassure helps to give you low end torque, not enough back pressure and the torque suffers, too much and the torque suffers and peak horsepower suffers. Backpressure is how restricted the exhaust is.

 

how do you get more back pressure? bend the pipes?
what if i put the stock pipe from the cat to exhaust back on?

 

You don't need more back pressure. Your cats give you plenty. By the way, too much back pressure is BAD, excessive scavenging is bad.

Back pressure is just a measurement. Means nothing. Measure it a few inches away from another measurement and it's different. It varies over time. Everybody talks about it, but nobody really understands it, and they have no measurements or numbers to tell you. Ignore it, lol.

But there is an optimum "pull" on the exhaust gases and that depends on the vehicle and configuration. The back pressure will to some degree reflect this pull and movement. But, since you have 12 billion cat's ahead of your muffler, I wouldn't worry about back pressure.

The most likely problem is happy feet. Since you got the exhaust you're mashing the gas to hear it and driving your mileage down. Try driving like you used to.

A dramatic decrease in mileage from just a cat-back on a 3.0 is extremely unlikely.

 

my gas milage went down bc i liked the sound as my right foot pressed harder

 

^^ the first week or two wasnt my best ever recorded gas mileage because i to liked the sound that was made when my right foot pushed harder

 

Once I got over mashing the pedal all the time my mileage went up.

 

Ha ha! We have a consensus here, lol...happy feet...

 

its only a 4.0, but they sound nice, not too loud like dodges

 

When i had my dual exhaust, i got awful gas millage, when i cut the pipes off so its just a muffler dump, millage improved greatly.