zeep99xj

I know sorry for another exhaust thread, but i need a little help.

So i want to replace the exhaust on my 99. Im talking the whole thing from headers back (ill replace the headers later when i get more money). First i have a few questions. Is the double walled part of the exhaust before the cat 2.5"? That is what the guy at a muffler shop told me. And is $320 a good price for getting it all welded up? I of course want to replace the kinked part of the head pipe but if i want to run a 2.5" system all the way through do i need to replace the double walled section? The guy at the muffler shop builds his own hi flow cats so im going to get one of those and im thinking of running the flowmaster original 40 series or super 40. The big thing i cant decide on is the tail pipe. I am thinking of running a 2.25" tail pipe to keep back pressure at a good level and not lose any torque. Or is this a bad idea that will defeat the purpose of opening up the exhaust? Also how would that affect the sound? I have heard that bigger pipes will lower torque and sense i only drive in the city and offroad i need that low end power. What do you guys think? Whats the best setup i should run?

Sorry for all the questions but i really appreciate any help.
Thanks,
Zeep

EMAXX620

before the cat was 2.5" on mine. then after the car it was 2.25. not to sure on the backpressure question but id like to know also.

zeep99xj

Thanks! That definitely helps!

95Cherokee

Yea that kinked part of the pipe has got to be restrictive.

djb383

Lots of BS out there in what you hear/read on the Internet. Going from 2" to 3" pipe may be overkill but going to 2.5" pipe/muff all the way back isn't going to hurt low end performance, rather improve it slightly. You have a good start 'cause the exhaust is 2.5" from the motor to the cat. Wonder how a guy at a muffler shop "builds his own hi flow cats"????? Hummm. $320 for a cat, muff and some pipe seems pricey to me. I think u can buy a decent header for +/-$140, a hi flow cat for +/-$90 and a 2.5" center in/offset out stainless steel performance muff for +/-$80. A few hours, a few beers, a few muff/pipe clamps later and that smile will be on your face, rather than on the face of the dude at the muffler shop.

THENNING

yea $320 seems a bit steep...im runnin a 2.50 mandrel bent tailpipe and it hasent seemed to effect my torque....it actually improved my throttle response

RENIXBEAST

Mines 2.5" mandrel bent tailpipe with flowmaster original 40 knock-off. Sounds great and it could just be me but I like to think it made more power.

zeep99xj

I want to get everything welded and i have never even touched a torch lol so im willing to spend what i need to to get it done right. So from what im understanding running 2.5" all the way is the way to go?

IWannaGoFishin

I think you've got the right idea. Sounds a little pricey for me. But some people say I'm cheap.

FWIW. I recently replaced my CAT and muffler. Kept 2.25 pipe from the CAT back. Used a Magnaflow Universal CAT ($75 at O'Reillys) and a Thrush Welded muffler. ($30 from Jegs) Local shop welded it all in for $60. Sounds a lot better and got a little better throttle repsonse. Several days later, I added a CAI. Definitely noticed an improvement in throttle response from a dead stop.

I love the sound with the Thrush Welded (nice low RPM rumble), but I would not recommend the Thursh Turbo muffler. The Turbo muffler sounds like a bee hive.

djb383

What's so great about welding the exhaust? The factory system uses clamps ahead of and after the cat. Only place it's welded is the tailpipe to muff. Rust starts instantly at the welds. Just noticed u r @ Galveston, the new exhaust u put on tomorrow will start rusting yesterday. LOL

EMAXX620

dont forget about the vender here who sells high flow cats!
https://www.cherokeeforum.com/f10/ou...nverter-45340/

zeep99xj

haha yeah rust is a big issue down here. I had a tail pipe rust clean off the muffler on my chevy. But the xj is more important and stays in the garage

Diesel

Super 40 will sound too raspy with your engine, 50 would give it a crisp clear low tone without that skipping sound.

zeep99xj

Thanks for the heads up! I might order the cat and muffler from here. Is it a trustworthy site? Wouldnt i need like a center in offset out muffler or something like that?

95Cherokee

This article says there is no such thing as high flow cats, just marketing hype to get you to spend money.

http://www.discountconverter.com/cat...erter-&News=89

Has any of you dyno'd your Jeep before and after installing a high flow cat and seen a HP increase?