Dented downpipe replacement

I have read all the threads on the mashed downpipe situation and I now know that most XJ's have this dented downpipe and that no one is exactly sure why it is like this. Some say it is to clear the axle, others say it is because the engine needs this crimp in the pipe for backpressure. Anyway, I would like to hear from anyone that has replaced this pipe with either a aftermarket pipe or had a muffler shop make one. Did it help performance? Are there any negative side effects? I am going to replace my cracked exhaust manifold and am trying to decide if it is worth the trouble to replace this pipe. Thanks for any advice.

In the 2000 model they changed the downpipe and manifold and there is no dent in the downpipe. I'd say it's a mute issue.

93XJ2drSport said:

I have read all the threads on the mashed downpipe situation and I now know that most XJ's have this dented downpipe and that no one is exactly sure why it is like this. Some say it is to clear the axle, others say it is because the engine needs this crimp in the pipe for backpressure. Anyway, I would like to hear from anyone that has replaced this pipe with either a aftermarket pipe or had a muffler shop make one. Did it help performance? Are there any negative side effects? I am going to replace my cracked exhaust manifold and am trying to decide if it is worth the trouble to replace this pipe. Thanks for any advice.

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It was done for driveshaft clearance in none lifted HP Dana 30'ed XJ's. If you haven't spent the bucks on a new manifold yet, might I suggest spending a few more bucks and getting a pacesetter header kit, replaces the whole system from engine to cat.

Don't do anything with the downpipe. If you do your wasting your money. Trust me.

I replaced that smashed pipe and about two years later I threw away the entire stock header and un crimped downpipe.

Just save your money until you are ready for a long tube header that comes with a downpipe. You will be much happier.

I replaced my (dimpled) downpipe as part of the header install. I can't say I've noticed any difference due solely to downpipe. But I agree with j99xj, doing both at the same time solves two issues at once

Kent