Will anything off a 99+ WJ 4.0 fit my 87 Renix?

There is a burnt WJ in a local junkyard and it has a 4.0 that isn't burnt too bad. Most of, if not all the electronics and wires are burnt off, but the fire in the engine compartment wasn't too bad, so I was wondering if anything like the Throttle Body could be used on my 87 Renix to boost its out put. I could probably get the parts off the WJ for cheaper than it would for me to get high performance parts for my 4.0

In a word, NO. The throttle bodies are not inter changeable between a Renix and an HO (’91 and up), they have different bolt patterns and the TPS isn’t the same. The head will work, but you would have to use the WJ intake manifold. You would have to build an adapter plate to use your throttle body on the WJ intake or figure out how to adapt the WJ throttle body. The camshaft would work and also be an upgrade, but you would be better off just getting a new Crain or Comp Cam camshaft. If you are looking for some more power Dr Dyno has a pretty good site and most of it can be applied to the Renix system

http://www.jeep4.0performance.4mg.com/

The head, intake manifold, and throttle body would be a very nice upgrade. (you'd basically have an HO) The only problem would be adapting your old TPS to the new TB. (and it's been done) I don't know if your stock exhaust manifold would bolt up to the newer head, but it might. If not, you could use the WJ exhaust manifold, but you'd probably have to modify it slightly to hook up to the rest of your exhaust.

I would disagree on the head. The exhaust port is a lot smaller on the 99+ heads, than earlier heads. The intake manifold may fit with a port match. There is an article to adapt the TB to an earlier motor.http://www.rockmodified.com/2003/april/TB/tb_perf.htm
Tom

75SV1 said:

I would disagree on the head. The exhaust port is a lot smaller on the 99+ heads, than earlier heads. The intake manifold may fit with a port match. There is an article to adapt the TB to an earlier motor.http://www.rockmodified.com/2003/april/TB/tb_perf.htm
Tom

Click to expand...

The exhaust ports are smaller, but it's still a hell of alot better than the Renix head. The intake ports are much bigger.

So, which would be easier, adapting the Renix TPS to work with the WJ system or get the WJ TB to bolt onto my Renix manifold. I saw a page about how to convert a H.O TB over to Renix, but is the system the WJ uses the same as the 91 and up H.O. 4.0, I haven't really seen the intak on H.Os too much, but the WJ one says 4.0 Powertech and looks a bit different from mine.

You really want the intake manifold and TB. The intake manifold will bolt to the Renix head, the ports won't match but it doesn't matter, it'll work. Supposedly the larger volume of the intake manifold gives quite a boost in performance. You'll have to adapt the Renix TPS to the TB, probably not a trivial exercise.

My wife's 99 WJ 4.0 runs better than any 4.0 we test drove in XJ's, part of the reason we got it instead of a late model XJ.

Fred

I heard that the early 4.0 heads don't flow as good as the ones on the H.O, will porting and polishing give me just about the same flow rate as a H.O. head, or are the Renix heads just too inefficient to match the H.O (they can't be ported enough) I'm on a pretty tight budget so I think I'll only get the intake manifold, and I'll use my own fuel injectors, which should cut down on the price. does any one know what a fair price for one would be in canadain dollars, just so I know where I stand. One more question, would the WJ valve cover fit my head. I have the horrible PCV system in mine and I've seen people switch over to newer 93+ valve covers and PCV systems to stop blowby. Would it be possible to get the valve cover and switchover my PCV so that I don't have any more blow by?

Oh and by the way, will I need the fuel rails off the WJ or will mine work. I'm pretty sure my Injectors will work.

I remember that when the WJ came out they emphasized that there were only like 8 pieces of hardware that were common between the ZJ and WJ and all of those were bolts... Can stuff be made to fit, sure, I'm quite confident that there is more assembled talent on this site alone than are being paid by DC/Jeep..
Just thought I'd throw that in....