99+ Intake onto a Renix head with Renix exhaust

One of my buddies has a 1990 XJ 4.0/AX-15. We want to swap a 99+ intake onto his existing Renix engine. Now, I have done this swap before so I know about complications with the TPS, etc., but since his is a manual we shouldn't run into that, the HO one should just plug in. When I did the swap before though, I used an HO exhaust manifold, but on his, we would rather not have to swap exhaust manifolds if it's not absolutely necessary. The Renix exhaust manifold is fairly tight and low-profile to the engine especially compared to the HO headers so I don't see why it wouldn't work. The one thing I noticed is, when I tried to put a Renix intake with an HO exhaust manifold, it didn't work, so I'm hoping the reverse isn't true. So my question...has anyone actually retained the Renix exhaust manifold with the 99+ intake? Any help would be greatly appreciated!
Thanks,
Collin

90PioSport99 said:

One of my buddies has a 1990 XJ 4.0/AX-15. We want to swap a 99+ intake onto his existing Renix engine. Now, I have done this swap before so I know about complications with the TPS, etc., but since his is a manual we shouldn't run into that, the HO one should just plug in.

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It probably won't. renix tps are diff voltages than later ones.

but the real question is "what are you going to gain by putting a new intake on the renix head?" the head is the restriction on your breathing now. i would suggest swapping the head at the same time as intake. then you only have to swap the tps and you might see an actual increase in power.

cumorglas said:

It probably won't. renix tps are diff voltages than later ones.

but the real question is "what are you going to gain by putting a new intake on the renix head?" the head is the restriction on your breathing now. i would suggest swapping the head at the same time as intake. then you only have to swap the tps and you might see an actual increase in power.

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Thanks for the response. I want to say either the voltages are the same or you can use the Renix manual transmission TPS on the HO throttle body...one or the other. I know about the head restriction and port misalignment, but I put one on my 90 about a year ago and I still noticed a huge difference in power. The other reason is that he needs a new power steering pump anyway, so we figured why not get one from a 96+ which all use the different mounting system. I still want to know if the 99+ intake will fit with a Renix exhaust though.

90PioSport99 said:

or you can use the Renix manual transmission TPS on the HO throttle body...

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yes. this works


i don't know about the exhaust. the renix head and exh i have laying around don't appear that they would work with newer style intake, but i don't have an intake to check for certain.

The exhaust is ported slightly differently, use the manifold that comes with the head. Also the exhaust flanges are different thickneses we had to use shims to complete one install we did a few years ago. We were using the newer manifold with the renix intake.

The intake ports are different shapped between Renix and the HO motors. I don't think he will gain a thing by bolting this on his Jeep. On the renix head the ports are short and on the HO head the ports are taller. You also will need to adapt the TPS to the new throttle body. Voltage is different and they bolt on different.

rockhounds4x4 said:

The exhaust is ported slightly differently, use the manifold that comes with the head. Also the exhaust flanges are different thickneses we had to use shims to complete one install we did a few years ago. We were using the newer manifold with the renix intake.

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Well the thing is we're not getting the whole head. I have bolted a 99+ intake onto a Renix head and have gained power with the ports mismatched. But you're saying that the Renix intake won't clear the HO exhaust, I knew that, I'm wondering the reverse though.

jeepboy381 said:

The intake ports are different shapped between Renix and the HO motors. I don't think he will gain a thing by bolting this on his Jeep. On the renix head the ports are short and on the HO head the ports are taller. You also will need to adapt the TPS to the new throttle body. Voltage is different and they bolt on different.

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I know it doesn't theoretically make sense but I have felt the difference even with mismatched ports, it is noticeable. I don't think with a manual transmission TPS adaptation is necessary. I believe the Renix manual transmission TPS will bolt on to the HO throttle body; but you may be right.

Listen guys, I know it may sound like I'm being difficult or not wanting to take advice, it's just that I've done this before and I already had a different set of people tell me the things like "the ports won't line up", "no power will be gained", etc. I ran this setup for a long time in my 1990 with Hesco's TPS adapter (since mine was an auto) and I did feel an increase.