RENIX REPLACEMENT QUESTION

I have a 96 block with the head from an 1988 with all the renix crap installed. Can someone tell me all of the stuff I would have to replace to switch over to the OBD2 system of the most recent XJ's. Would it be easier or more beneficial to go to the OBD1 system? Which swap would require the least amount of parts for the most gain? And which ever swap would be best what all parts will I need? I can do it myself, I just want to know what all I need to do it and what the best option is.

Ok, what BODY do you have--the year?

Renix to OBD-II: You have to replace ALL the renix sensors, TB, add a after-cat O-2 sensor, the wiring harness, (inside and out) computer, gas tank and pump, TCU, evap system, and I've probably left out a few things. Really not worth it.

The renix system isn't "bad". The difference between 1st year renix and last year OD-II "HO" is 19hp: 177 to 196. Most of the HP improvement was due to mechanical improvements, not electronics. The electronic upgrades were due to govt mandates and/or emissions.
If you're already running a late model cam('96 was an HO, right?)and you have the '98 head, you already have most of the mechanical improvements. Try getting a late model(HO) intake, or the '99-up intake, a good header, late model TB converted for the renix sensors, modern multi-port injectors, and if you want to get really crazy, a aftermarket "RV grind" cam. That'll bump you a little over 200hp, and be a LOT easier then converting to either OBD system.

Edit: Oops! read that wrong: 'thought you said "98 head" not "88 head". Add a late model head to the list: up to '99, don NOT get a '00-01 head, especially out of a junk yard or "re-manufactured". Still easier then the electronic conversion.

Hey Joe, it's a really long story. i have an 86' xj wagoneer body that I took the entire drivetrain out of my 88' xj including 4.0L with renix system AW4 NP231 Rear 29spline Chrysler 8.25 with disc brakes, 7" lift front and rear aussie lockers and all the other goodies and transplanted into the wagoneer. the only things remaining from the waggy are the interior wiring and the solid dana 30 front axle. The waggy had the 2.8L carb V6All of the exterior wiring is from the 88' and the block has been replaced by a 96' block. Thats the short version! Hope that helps.

If you're looking for power, there are cheaper and easier ways to get it without switching to any type of OBD system. The HOs biggest gains in horsepower came from an increased size of the throttle body and an improved header design. Possibly a little better high RPM breathing wiht the newer port design. As tbburg mentioned, OBD was to satisfy government mandates, not increase power.

I've considered the same thing in my Renix rock buggy, but it's really not worth all the trouble. Not much, or not any, improvement.

Are you going to run into problems dropping the 4.0 in the 2.8L rig.

Well, yes and no, actually the bulkhead hooked right up and all the instrumentation works and all of the interior stuff works. The whole entire wiring harness was transplanted with the drivetrain, and the engine mounts were different but located in the same place so I just switched them out as they had the same mounting holes. It took a long time to do because I did it myself but it was a great swap... I did not encounter a whole lot of problems. I had to make a few holes in the firewall and switch out the heaters. I wish I had an ac delete bracket but most of the stuff is minor that I have encountered, maybe one I should write it all up but as far as I know only one other person has done the swap and their XJ was a 93 and they had a lot more problems because none of the interior wiring really matched up.

go1lum said:

Are you going to run into problems dropping the 4.0 in the 2.8L rig.

Click to expand...

I got the impression it is all in and running Renix and he is thinking of changing the engine management.

As Cruiser54 posted, you have the HO block and cam, you could adapt over a later intake and bored throttle body and adapt it to work the Renix TPS (Hesco makes an adapter--little spendy--and there are threads on DIY), free-flowing CAT back system.

If you are after more torque, gearing is where it is at.

I am running 32" KM2's now but I am going up to 35"s so I just regeared to 4:56's, I am really just tired of all the vaccum issues with the renix system and all the pipework.

Some replace all the hard vacuum lines with regular rubber vacuum lines for a cleaner appearance.

Renix and HO share much of the same vacuum stuff through the years.

joe_peters said:

Some replace all the hard vacuum lines with regular rubber vacuum lines for a cleaner appearance.

Renix and HO share much of the same vacuum stuff through the years.

Click to expand...

Not that big of a difference in vac lines as Joe stated. .

How do you get the rubber lines to stick into the manifolds? Or do you just eliminate the manifolds?

truck7575 said:

How do you get the rubber lines to stick into the manifolds? Or do you just eliminate the manifolds?

Click to expand...

Are you talking about the squarish thing where all the lines congregate by the front of the engine? That is eliminated as it is the junction of the front and rear vacuum harness sections.

Otherwise, I'm not getting your question.

Yes it is kinda square it has the vaccum tubes running through it. So ill just get some vaacum lines and one by one run new lines until I get them all done then I will just remove the hard tubing system.