Mopar Performance 3" Cat-Back Exhaust for ZJ's

By James Hasler

 

I think most people will agree that nothing sounds better than a V-8 engine. So, to gain a little more power and to make my 97 ZJ sound like it should, I got Mopar Performance's 3" diameter, aluminized steel, cat-back system. It came with a 3" mandrel bent pipe and a cylindrical straight-through designed muffler with a 3" input and output. It also came with all the necessary clamps and a pipe to use to go from the catalytic converter's 2.25" output to the muffler's 3" input. (The current version of this system uses a conventional shaped muffler instead of the cylindrical type. This is a very good thing as my cylindrical one hangs quite low.)

The quoted power gain is 13 HP. All I can say is wow! The sound is perfect. Definitely louder and deeper but without any resonance. People WILL hear you coming!!

As for the power gains, they are there too. The way I could really tell is going up steep grades in the mountains where I remembered that I would downshift into third at certain points but I now cruise up in overdrive.

My biggest gripe would probably be around the muffler design, getting the system to fit right and the look of the tailpipe. Since my muffler concern has already been taken care of by going with a conventional style muffler over the cylindrical style, i'll focus this review on the other two issues.

As for fit, it took me many, many tries to get the tailpipe to fit over the axle without banging the gas tank shield or the trackbar. Many muffler shops will tell you it is impossible. It's not impossible, but it is time consuming.

There just isn't much clearance here. My recommendation is to use the clamps provided, fit the exhaust in a way that looks like there is the most clearance and then drive the heck out of it. The pipe really expands quite a bit when hot. Drive it hard and over bumpy roads. If you don't have any rattles, get the entire system welded together otherwise the clamps will let the "over-axle" piece to fall over slighty and start to rattle.

As for the look of the tailpipe:

It's just a big honking tailpipe sticking out. My plan is to cut off part of the end of the tailpipe and get a 3" or 3.5" stainless tip to put on it. That should clean it up without spending too much money.

Overall, I'm very pleased. It is one of two 3" systems around that I know of and is by far the most affordable one. Combine this kit with a 3" in/out catalytic converter and headers and you'd have a very free flowing exhaust and a lot more power as well.