• NAXJA is having its 18th annual March Membership Drive!!!
    Everyone who joins or renews during March will be entered into a drawing!
    More Information - Join/Renew
  • Welcome to the new NAXJA Forum! If your password does not work, please use "Forgot your password?" link on the log-in page. Please feel free to reach out to [email protected] if we can provide any assistance.

Xj downpipe questions

traitor5150

NAXJA Forum User
Location
Dartmouth MA
OK I just orderd an APN header for my 4.6 stroker build. I was running a pacesetter before :laugh2: Junk... Now I have no downpipe I trashed the stock one a long time ago and I dont want to go with a facory crushed stocker. Who sells a downpipe for an XJ/MJ I see a Banks for a yj but the yj goes under the oil pan not behind it like the xj. Looking at a yj pipe it looks like it is possible to adapt but does anyone know as I would rather buy a xj pipe then buy a yj one and cut it up. Thanks
 
I bent my own for about $20, but I have access to a mandrel bender.

Any exhaust shop that's half-way decent should be able to make one for you.
 
I am needing to get a header as my stock one is cracked, and I want a better one. If I get a new one should I replace the downpipe? Also, what size pipe do I need. I put a new high flow cat and the Dynomax Super Turbo system in. Basically, everything in front of the cat is stock (down pipe and header). Do I need to do anything as far as changing size when I get new header? I am not sure what size the collector goes to, and downpipe to the cat.

Thanks,
Silent
 
the apn header looks very similar to my banks... and costs about 2/3 less... i got a downpipe, 2.5 bent for 45 bucks + 15 welded in at my local exhaust place = 60 dollars
 
Because its the same Borla one over and over again just in a combo kit or for a different year, then one pacesetter which Ive heard to stay away from due to paint chipping (not sure if it goes for Jeep exhaust manifolds too).
 
Ok, So I called Clifford Performance today to ask some questions about their exhaust headers. I asked the guy on the phone, what is the difference between your headers that have 2 pipes for the collector, and others that have 1 collector. He told me that it helps with mid range power, and that if I ran 2 pipes, 2 mufflers (basically a semi-dual exhaust). I proceded to tell him that I just replaced the cat, and muffler, and exhaust pipe. And I did not want to replace the current set-up with another 2 exhaust mufflers and so on. I asked him if there was a way that I could replace my headers and downpipe without going 2 setups. He said I could but I would only get about a 10% gain in power. He said with the dual setup I would get about a 30% gain in power. He also said the exhaust would heatup the muffler to something like 1300 deg. I was like whoa. HE said it should get to about 425 or something like deg. He also told me that the XJ's fuel injection was not good, and that it inherently had a condition that always runs rich. I said I am getting ready to replace the injectors. He told me that it would not correct the problem. He then told me that I should get this redline system that I could program it with a laptop. I am thinking I am not going to spend all this money for all that. Anyhow, what are you thoughts on what I was told? Lets hear it. :explosion

Thanks,
Silent
 
polar_jeep_04 said:
4.0 run rich is this guy on crack? i always hear thay run lean! does banks make a down pipe for a XJ? borla is sweet if you have the money
My 95 ran way rich with stock injectors. I've heard that the renix motors run lean, but for the most part I think the HOs run really rich.

Kyung
 
Hiyah Kyung! Ok, back to the headers...the dude from Clifford is smokin' his breakfast.....there is NO WAY HEADERS ALONE will net 30% power increase.

If that was true, nobody would need to build a stroker....Hmmmm...take a stock 180hp engine, add a header.....gain 30%...have 234 HP.....

A header as PART of a well thought out PACKAGE will CONTRIBUTE to large HP gains...I'm throwing a confident :nono:
 
Headers really don't add much top end horsepower for racing etc. (at least with the jeep 4.0)

But they do add more beef to the low end and mid range.

A 30% gain from a header is bunch of crap, even if the engine in question was a full blown drag racing engine.
 
Yeah, the downpipe in my 93' was 2", and with the kink in it, i knew it wasn't good for performance. I had a 2.25" pipe fabricated, cost me like $50. I believe the header collector is 2.25", so I don't know if going to 2.5" will do much.
 
Back
Top