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intake swap Questions

truck7575

truck7575

NAXJA Forum User
Location
georgetown
I have an 88 xj and with the older intake and throttle body style. I would like to go to a junkyard and get the parts to upgrade it to the newer system. What all parts do I have to pull from the junker to make the swap and what all gets tossed from my current system. Any recommendations would be great! Also links to any writeups on this subject would also be much appreciated.
 
you can't just swap out the intakes. Renix and HO heads have different port locations. If you want the HO intake you'll need a HO head, and exhaust mani. Hesco makes a kit to adapt the HO throttle body to the Renix TPS, you'll have to hack up yout TPS with a dremel or buy the kit.
 
There is a lot of wild info on the newer 99+ intake. If that is what you are refering to. I think it would have to be port matched and probably welded up, then port matched. From some of the sources with a dyno run, maybe 5 hp gain.
I'd probably lean to the larger bored TB, first. Also, for more power, you will need to do some exhaust mods: header, down pipe (cross over section), btter flow cat and muffler (cat-back). On either you will probably see some gain in power and MPG. If you do both and match them, then you will notice better gains.
Tom
 
75SV1 said:
There is a lot of wild info on the newer 99+ intake. If that is what you are refering to. I think it would have to be port matched and probably welded up, then port matched. From some of the sources with a dyno run, maybe 5 hp gain.
I'd probably lean to the larger bored TB, first. Also, for more power, you will need to do some exhaust mods: header, down pipe (cross over section), btter flow cat and muffler (cat-back). On either you will probably see some gain in power and MPG. If you do both and match them, then you will notice better gains.
Tom
Click to expand...

It's not even going to fit, the Ho intake and the renix head are radically different in the intake side. I don't think you could get the HO intake to clear the exhaust manifold on a renix head, no matter how much shaving and welding you do. Besides, the head on the Renix is the limiting factor, that's why Chryco redid it and named it the HO. They raised the intake porting for a better flow into the cylinder and got an extra 20 HP out of it.

If you want the performance the best bet is to just swap an HO head complete with intake and exhaust manifolds, then adapt the Renix TPS to the HO throtle body. Easiest way to get from here to there, and if you use the HO exhaust manifold then you don't have to make an EGR block off plate, and you can easily delete the EGR system. You can use the HO fuel rail and stuff too, which is a better (sturdier) design than the Renix era part.
 
87manche said:
It's not even going to fit, the Ho intake and the renix head are radically different in the intake side. I don't think you could get the HO intake to clear the exhaust manifold on a renix head, no matter how much shaving and welding you do. Besides, the head on the Renix is the limiting factor, that's why Chryco redid it and named it the HO. They raised the intake porting for a better flow into the cylinder and got an extra 20 HP out of it.

If you want the performance the best bet is to just swap an HO head complete with intake and exhaust manifolds, then adapt the Renix TPS to the HO throtle body. Easiest way to get from here to there, and if you use the HO exhaust manifold then you don't have to make an EGR block off plate, and you can easily delete the EGR system. You can use the HO fuel rail and stuff too, which is a better (sturdier) design than the Renix era part.
Click to expand...

Now I will agree that the HO is the better head. I don't know where you are getting your info on HP numbers. All I've read is 178 HP for the Renix and 190 HP for the HO. So, that 12 HP gain. The torque difference is like 2 ft-lbs.
The next problem he might face is emmisions. From his signiture, I don't know what state he is in. If emmisions checks are done, then it depends on tailpipe, like some counties in OH or components check like other places. So, swapping on a '95 head nad intake deletes the EGR valve. Then your back to adapting the Renix manifold to the HO head, or the EGR boss to the HO intake. Then agian he might not have emmisions checks at all.
Tom
 
75SV1 said:
Now I will agree that the HO is the better head. I don't know where you are getting your info on HP numbers. All I've read is 178 HP for the Renix and 190 HP for the HO. So, that 12 HP gain. The torque difference is like 2 ft-lbs.

Tom
Click to expand...

first year 4.0's were 173 HP, I've got two of them.
not that it matters. point is, you can't just stick an HO manifold on a renix head, it won't fit.
 
87manche said:
first year 4.0's were 173 HP, I've got two of them.
not that it matters. point is, you can't just stick an HO manifold on a renix head, it won't fit.
Click to expand...

I agree you can't just stick on an HO intake and go. I did write that a port match and possible/probably some welding and a port match would be needed. The OP only stated newer manifold. That is open to interpretation to an extent from HO to the 99+ manifold. I think some have adapted the 99+ to a Renix head. I might be wrong on that though.
Tom
 
joe_peters said:
4.0 head differences with pictures: http://www.enginebuildermag.com/Art...again_the_facts_about_40l_cylinder_heads.aspx

You can make a spacer plate to put the HO throttle body on the Renix intake: http://www.rockmodified.com/Tech/TB/tb_perf.htm
Click to expand...

I wouldn't take the first article as gosple:
'From 1996-1999, the Jeep 4.0L used head casting 0630. This cylinder head has two receiver holes for two dowel pins that were added to the block for cylinder head alignment (see Photo 3). The intake ports were changed once again, and there was a newly designed rocker cover and gasket on the scene, that will not retro back. Also, the move was made to lighter pressure beehive-shaped valve springs and a different profile cam. '
I think there are more than a few who have the latter style valve cover on older engines. Also, I do have a '95 cylinder head on an '03 block. Others have done the same thing.
Tom
 
87manche said:
first year 4.0's were 173 HP, I've got two of them.
not that it matters. point is, you can't just stick an HO manifold on a renix head, it won't fit.
Click to expand...
It will fit fine, the bottom of the ports will be off a little less than 1/4". Always use the gasket for the intake manifold, not the head if swapping. Sometimes you need to file a little bit off the lower outside edges of the intake manifold to clear the exhaust manifold, a 10 minute job. I have successfully match-ported a Renix to HO with great results. Personally, I feel the power increase on the HO wasn't so much due to the head change as it was the increase in throttle body size to 58mm from 52mm and of course a more finely tuned injection system. Hence, my suggestion to get a 60mm throttle body which bolts right on from www.strokedjeep.com. The intake manifold is already 60mm so there's no mods needed. Done this to 2 of my Renix Jeeps with great results. One has a stock Renix and the other an HO with Renix injection.
 
An afterthought, since it's before 6 am, the exhaust manifold was improved considerably with the introduction of the HO, which also eliminated the "crush spot" that the Renix exhaust downpipes had in order to clear the front driveline. Having a muffler shop make you a sweeping downpipe to clear the front driveline, eliminating the "crush spot" will add a seat of the pants performance increase. Add those things up, along with those mentioned above, and you've got your HP increase. I really don't feel the head port design was the bulk of it at all. Also, as introduced in 1987, we had 173 HP, then an increase to 177 Hp and on up incrementally through the Renix years. This was done with ECU changes. We would take a 1989 or 1990 ECU and put it in an 87 or 88 and improve throttle response and performance. In other words, the HO is a fine motor, but it ain't magic by any means. Chryco's use of the term "HO" has served them well.
 
good info there Cruiser. Did you really think that the manifold upgrade was worth it without the upgraded head?

I think it would be much more beneficial to just swap an HO head and the HO manifolds, you would pick up that extra flow and the better manifolds. Personally, if I was going to be swapping manifolds I'd take the head off anyway and go do it on my workbench. I've not had to deal with mine yet, but it looks like it would be a PITA to do all of that in the engine bay.
 
It's not too bad if you yank the air filter housing. Some aftermarket exhaust headers are just plain nightmares to get bolted up, but OEM ones are not bad at all.

I would much rather do manifolds in an engine bay than do a valve cover, head gasket, etc in an engine bay.
 
kastein said:
It's not too bad if you yank the air filter housing. Some aftermarket exhaust headers are just plain nightmares to get bolted up, but OEM ones are not bad at all.

I would much rather do manifolds in an engine bay than do a valve cover, head gasket, etc in an engine bay.
Click to expand...


So you feel like flying to IN when my header cracks? :D
 
No. Go get a 9/16" socket, some extensions and u-joints, and a ratchet, and do it yourself :moon:

Unless you're buying the ticket, then sure, long as you have a couch I can crash on and a beer fridge I can raid.
 
cruiser54 said:
An afterthought, since it's before 6 am, the exhaust manifold was improved considerably with the introduction of the HO, which also eliminated the "crush spot" that the Renix exhaust downpipes had in order to clear the front driveline. Having a muffler shop make you a sweeping downpipe to clear the front driveline, eliminating the "crush spot" will add a seat of the pants performance increase.
Click to expand...

At least on the 95, 96, and 97 I've checked out, that crush was still there and at stock height, the front driveshaft will still "self-clearance" a pipe without it. Tested this personally... Not really relevant to the Renix-HO head discussion, but I wanted to point that out. Lifted and bump-stopped, it might not be an issue.
 
X2, I've seen it also on a '99.
 
kastein said:
It's not too bad if you yank the air filter housing. Some aftermarket exhaust headers are just plain nightmares to get bolted up, but OEM ones are not bad at all.

I would much rather do manifolds in an engine bay than do a valve cover, head gasket, etc in an engine bay.
Click to expand...

meh, I'd rather pull the head. It's not that difficult ya sissy!

I only say that because I've got an unknown age renix motor, I know that the studs/bolts are seized up, and I'd rather do it on the workbench, because once I shear one off the head's coming off anyway.
 
joe_peters said:
4.0 head differences with pictures: http://www.enginebuildermag.com/Art...again_the_facts_about_40l_cylinder_heads.aspx

You can make a spacer plate to put the HO throttle body on the Renix intake: http://www.rockmodified.com/Tech/TB/tb_perf.htm
Click to expand...

After doing the HO Tb modification, would I be able to use a newer air intake kit say from K&N? Doing a custom snorkel so not too relevant for me, but would be nice to know if I ever need to remove the snorkel or do another Jeep... Thanks,

Paint
 
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