early to late throtle body

i have seen some people recommending to install the 91 to 95 4.0 head and intake to a 87 to 90 renix controlled 4.0. most of that is direct bolt on. has anyone done this. what about the Renix tps wiring. thanks

I haven't done this swap, but I've considered it on my 87. I think you might have to extend the wiring on a few connectors and the TPS you use the newer connector I believe. I was able to Google an install a while back, I want to say a Jeep magazine did the write up. Keep in mind if you live in California like I do you need to keep all the smog stuff on there. Renix Jeeps have EGR and I believe 91 and newer do not.

thats what im worried about good old smog. yep im in C.A. but we only tail pipe here so far

You will need to adapt the Renix TPS to work with the HO throttle body.

Hesco makes an adapter, around $150 if I remember right. Search, there are a number of write ups with photos on DIY adaptations.

I have'nt taken a picture of my set up,but was simple.I used to have the ho tps and the holes were elongated to make it adjustable.I also had to make a MAP adjuster,which is really an adjustable voltage output-from somewhere around 2-7 volts.I found if you made it have 7 volts instead of 5 it would work great.My tps went bad and I had a new Renix tps so what I did was adapt.I made the Renix tps holes larger all the way along the slots-the ho bolt pattern is slightly more towards the inner part,use a dremel there.Next I had a inverted torx socket that slid perfectly over the slotted section of the HO T-body,and cut it down to just where the taper part is.I forgot the size.Make sure that inside the socket there is a lip in the bottom of it,a screw will be used inside of it.You will need to unscrew the arm on the renix one.I believe it is a fine thread metric screw-I looked at H depot and lowes-no size.They have a 4 x .75 threaded screws,but it is 4 x 1.0 thread.What I did was get a 6-32 screws and re-tapped the tps for that.If you go to a hobby store-R/C type place they more than likely would have a 4 x 1.0 allen head screw-which is what i would have used instead iof re-tapping.When you are a lowes or h depot get 2 small spacers i think they were 3/4 " long with an inner size of 1/4? just match it up.5/8 is good.And the screws to thread into the HO T-Body,the length you need.Now here is the trick,leave the arm on the Renix tps and screw the socket onto it using the small screw inside of the socket.You will have to move the socket till you get it rightYou may get lucky if you leave it slightly loose.Use the tps arm to hold it so you do not tigten it up against the tps itself.Now you have 2 adjustments the tps and the socket against it.Once it is where you want it remove the assembly and hold the socket with vise grips and while holding the arm tighten the inner screw,snug but not way too tight
http://www.rockmodified.com/Tech/TB/tb_perf.htm
look at the pics there.I did not use the bushing-but the socket instead.
Get it in 3/8 drive.
http://www.mytoolstore.com/sk/sk03097.html
Lowes may have it or autozone,advanceauto...I had one on hand.Not that size but for refrence.

http://www.hescosc.com/shop.asp?action=details&inventoryID=45563&catId=7902
Somebody is on crack.Look at the pic.......$145 for that? WTF?:nono:

If you swap the intake, you lose EGR, something the smog police are gonna frown upon. For $90 exchange, you can order a 60mm bored out throttle body from www.strokedjeep.com. and retain your stock sensors. Nobody but you will know it's been done.........

i completely forgot about the EGR.oops i should know better.oh well im looking for more performance. im just so used to my 96. its just plain smokes my 87.

Getting rid of the crushed area in your factory downpipe makes a noticeable difference in performance. One of the best bangs for the buck. It's actually cheap.
The bored TB helps, too, along with upgraded injectors.

i just received my injectors.cant wait to install them.the thing i have noticed about my Renix powered 87 is the Doug Thorley header is the only real part so far that has made a power difference.but it so warped that it wont seal any more.so the stock manifold is back on.the Rusty's throttle body spacer made no difference. the flow master made a small amount.ive come to the conclusion the Renix computer doesn't have enough adaptability to compensate for minor changes .

jeeptec said:

i just received my injectors.cant wait to install them.the thing i have noticed about my Renix powered 87 is the Doug Thorley header is the only real part so far that has made a power difference.but it so warped that it wont seal any more.so the stock manifold is back on.the Rusty's throttle body spacer made no difference. the flow master made a small amount.ive come to the conclusion the Renix computer doesn't have enough adaptability to compensate for minor changes .

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the renix ECU is quite adaptable, the bigger problem is that the head sucks. The only difference between renix and HO (and that mysterious 20 HP) is the head design.

A fellow Central Coast person, eh?
Injectors should help ( I have a set of the Ford 19lb orange tops on mine), bored TB will help (60mm strokedjeep.com TB is on my list).. TB spacer is a waste. Flowmasters fail. Better off with a straight thru type muffler.
The Renix ECU has less issues than the later model ECU, only issue is that when power is off it resets itself so you basically relearn everytime you drive it.

87manche said:

the renix ECU is quite adaptable, the bigger problem is that the head sucks. The only difference between renix and HO (and that mysterious 20 HP) is the head design.

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Actually it's 17 HP. The 87s had 173HP and the 88 or 89 went to 177. The last year of the Renix was 177 HP in 1990. So from there, which was enhanced by ECUs each year, is 13HP total.

For what most of us do, the head difference doesn't really matter.

yep central coast person here. i do have a set of injectors to install.im trying to find out if thorley headers is going to repair a header i have. they used my cherokee when i lived in so cal for a moc up vehicle.. i tested it and then they installed the production one. its now warped and leaking.

i believe its the 89 and 90 that got the 5hp increase. there was something in my 89 new model high lights book i have somewhere. also according to the Chrysler parts specifier the 87 computer supersedes to a 90 computer. i do have an 90 computer laying around. hum???

jeeptec said:

i believe its the 89 and 90 that got the 5hp increase. there was something in my 89 new model high lights book i have somewhere. also according to the Chrysler parts specifier the 87 computer supersedes to a 90 computer. i do have an 90 computer laying around. hum???

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If that makes you smile, read this: http://www.naxja.org/forum/showthread.php?t=16630

jeeptec said:

i believe its the 89 and 90 that got the 5hp increase. there was something in my 89 new model high lights book i have somewhere. also according to the Chrysler parts specifier the 87 computer supersedes to a 90 computer. i do have an 90 computer laying around. hum???

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That's where the HP increases in the Renix Jeeps came from, more aggressive timing and fuel curves as the ECUs evolved. I've done this. Try it and post back.

87manche said:

the renix ECU is quite adaptable, the bigger problem is that the head sucks. The only difference between renix and HO (and that mysterious 20 HP) is the head design.

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they had a different cam too....

has anyone use this throttle body from http://www.strokedjeep.com/. the price is decent and easier than doing the early to late throttle body change

jeeptec said:

has anyone use this throttle body from http://www.strokedjeep.com/. the price is decent and easier than doing the early to late throttle body change

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I've done 2, one on my 90 MJ and one on my wife's 88 XJ. You won't be disappointed. Order it and he charges you $140 plus shipping. Return the old one and he refunds you $50. No downtime and he delivers the part quickly and the refund quickly. I'm ordering another for the 87 XJ I'm building up for my son-in-law soon.