New exhaust for my Jeep - what diameter?
 

Hey guys !

I want to upgrade the stock exhaust on my diesel XJ. It's a 2.5L, 115hp unit and currently running a restrictive exhaust: baffled muffler, crush bends in the tail section, poor downpipe design and 2.25" diameter.

I was thinking to upgrade 2.5" since I don't want to go crazy with upgrades later down the road. Is it worth to consider complete 3" system or is the 2.5" enough for the engine size ? Would it be any louder than a 2.5" ? Yeah, I'm concerned about how loud it is and it will get a straight-through muffler :)

Thanks, Adrian.

Re: New exhaust for my Jeep - what diameter?
 

I believe most on the aftermarket kits are 3".

Luke

The trouble is no aftermarket kits are available for the XJ Diesel. I'll have to build everything.
Only thing I can use from a 4.0 kit is the tail section, 2.5" mandrel bent.

Forgot to mention: XJ diesel...way different animal than the KJ CRD.

Forget about bigger sizes. I would install a complete 2.5" system behind the down pipe. If noise is your major concern- get a cherry bomb muffler first, before you try bigger diameters.
Pro's:
Dirt cheap, easy to get, enough flow, because nearly no restriction.
Con's:
rusts like hell.

PS.: Don't mess with the down pipe, it's a stainless steel unit.
Bolts are no longer available- you need to replace them any time you loosen them.
To replace them with hex heads is not possible due to limited space.(at least the two rear ones.)

After some research I have to agree with the 2.5" exhaust. CRD owners don't see improvements when stepping up to 3" and that engine has to have a higher flow. So 2.5" it is.

Not sure on what I end up doing with the downpipe. Some pics on AJOR showed a horrible design. If I would redo it, it would be also stainless.

Magnaflow or some other straight through muffler will go in for sure.

You need something straight, no chambers and deflectors.
Just enough to make it street legal.

Downpipe:
It must be stainless and it is stainless for a reason.
Space is to tight to develop something different. Been there, asked the pros and got a price quote for something similar not worth the effort. Every bend more than 10° causes turbolences. But there is no space for wide turns...