XJ vs TJ Exhaust manifold?

How much loss (horsepower and/or torque) can be attributed to the TJ manifold? I picked one up free the other day in prep to swap out my cracked one and add a '99 intake, but realized there are major design differences:

98 TJ:


Don't recall the year, possibly '99 XJ:


The TJ manifold is uncracked, but the XJ has the usual cracking around the collector. I can get it welded, but know that it's not a permanent solution. I'm also going to be adding a flex section in the exhaust this time around, but wanted to know if the HP and torque gains of the '99 intake are going to be cancelled out by the '98 TJ exhaust.

This is on my '96 XJ 4.0L http://www.yuccaman.com/jeep/myjeep.html

Jim www.yuccaman.com

The upper picture is a stock manifold, the lower picture is of an after market manifold. The lower picture looks just like the APN header that is on my new engine.

Jes said:

T The lower picture looks just like the APN header that is on my new engine.

Click to expand...

or the banks torque tube it was copied from.

Is that even a stock TJ manifold? The stock mani off my 97 doesn't have the bellows- I've only seen that on replacements. Anyone else?

The top one is an aftermarket manifold that was sometimes used by Mopar IIRC. The bottom is definitely an aftermarket of either APN or Banks variety. You are going to notice very little HP change either way.

On the newer TJ's the exhaust goes around the front of the motor crossing under the harmonic balancer.

On the newer TJ's the exhaust goes around the front of the motor crossing under the harmonic balancer(just like the early FSJ's).

hubs97xj said:

Is that even a stock TJ manifold? The stock mani off my 97 doesn't have the bellows- I've only seen that on replacements. Anyone else?

Click to expand...

Oh...sunnuva... :doh:

I just realized I assumed a wee bit much.. The top picture is a stock (replacement) '98 TJ manifold. The initial '97 and '98 TJ manifolds had (gasp) the same cracking problems as ours. Daimler-Chrysler never acknowledged that there was a design problem, but quietly started replacing cracked manifolds with the one shown in my first pic. The bellows conveniently helped stock some of the cracking.

The pic below is a stock '99 XJ 4.0L exhaust, with ceramic coating:


I know it is, because that's what is currently cracked. I thought it was more like the design of the second manifold above, but realized I had a good photo to compare it to...and that's it. Apparently the second photo really is an aftermarket piece. No biggie.

Sooo....without further ado, it's time to really start preparing to swap in yet another exhaust manifold and the '99 intake. arty:

Jim www.yuccaman.com