TJ 4.0 exhaust manifold on yj

john327

Well-Known Member
Joined
Oct 15, 2009
Location
marion,sc
Has anyone put a newer style TJ header on a yj? I've got a 95 yj I was thinking about putting one on since mines cracked. Is there any benefits other than the exhaust running under the oil pan for higher clearance?
 
4.0 YJ and early TJ (97-99) headers are the same. Only the downpipe is different. So if you are looking to run the exhaust around the pan, you'll either need a TJ downpipe or a trip to the exhaust shop.
 
The TJ versions have two seperate outlets on them. Wasn't sure if there would be any power gains by switching over. And my down pipe is about flat where it crosses under trans anyway.
 
john327 said:
The TJ versions have two seperate outlets on them. Wasn't sure if there would be any power gains by switching over. And my down pipe is about flat where it crosses under trans anyway.
Click to expand...
Only the 2000-2006 versions do. The early TJs used a single outlet manifold.
 
Ok. That was the ones I was looking at. I like the way the exhaust runs under the motor, and tucks up higher. Was wondering if bolted the same to the motor, and if it would help with power. Got to order one soon
 
those "double manifolds" are only good for better sound in the exhaust. i've experimented with lots of them on older xjs and they help with improved sound when running performance mufflers otherwise didn't notice any other gains. biggest benefit too is they won't crack as much like the one piece design. now i will tell you this, the early RENIX header is the best flowing manifold in my long time with the 4.0 if you look at the design itself you can tell it flows better and a friend in Raleigh had even confirmed with Dyno tunes that it flowed better than 91+. Every 87-90 XJ i've built motor/power speaking has always been way stronger than the 91up and even the 99-05 (which suck horribly internally speaking)
 
Tell me how you installed the later "double manifolds" on Renix heads. Specifically while using Renix intake manifolds?
It's not a bolt and go swap.

The two piece obviously flow better, that's simple physics. Their shorty design aids in building better low end torque and promotes better balanced cylinder scavenging.
 
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Jody Treadway said:
Tell me how you installed the later "double manifolds" on Remix heads. Specifically while using Remix intake manifolds?
It's not a bolt and go swap.

The two piece obviously flow better, that's simple physics. Their shorty design aids in building better low end torque and promotes better balanced cylinder scavenging.
Click to expand...
i've put them on older meaning xjs without them. u have to make the gasket work though which is a pain to get not to leak but it's doable. never tried it on Renix being that old, plus the renix is (for me anyways) twice as strong as the newer 4.0s
 
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