Engine management

[Pharaoh XJ]

I m getting involved in the rally scene here in Egypt, since XJ s are assembled here its easy to start with an XJ.

A freind of mine has bee racing this same XJ for 13 years :banghead:
http://i191.photobucket.com/albums/z308/gabroxy/EL_PyrV_97.jpg
http://i191.photobucket.com/albums/z308/gabroxy/EL_PyrV_154.jpg
http://i191.photobucket.com/albums/z308/gabroxy/El-Faruqi.jpg

it has a stroker, but with added weight and the load caused by the sand, its needs more power and he is sure he is not going to get any furthur in terms of engine performance without a good engine management.

What are is options ? who sells engine electronics for jeep ?

[j99xj]

For driving in deep sand at high speeds with that much weight, the best engine management is a big V8...somthing along the lines of a 454 Chevy.

When I went to Walden, Colorado and drove on the sand hills there, I quickly leaned that driving through sand effectively with the 4.0 requires keeping the rpms relatively high. Thus I was in low range the whole time. High range simply doesn't allow the engine to rev high enough to attain any decent speed.

A large displacement V8 will have enough power at all rpms to move much better in high range. So it would be a much better race engine because the vehicle's speed would be higher.

Low end torque is of no worth when trying to race in sand, it just doesn't work. You have to be able to rev and have tons of high rev power.

[BBeach]

It looks to be a race only kinda thing, maybe he should consider regearing to something more aggressive. What does he have for current gears? Transmission? I couldnt see why 4.56's or deeper arent used unless he's got them.

[Pharaoh XJ]

I m not sure about the ratios but i know that it has a rear currie 9 inch & front D30
& here we race 80 % of time in 2WD the D30 wont take any beating.

A V8 is a lot of work & tech/parts not available here so the 242 makes more sense because easy to find.

Anybody has any input on painless wiring ?

[87manche]

painless has always made good stuff.

what year is the XJ?
might want to look into DIY with a megasquirt setup. Completely tuneable and pretty cheap if you have any electronics skills.
jhere's a fellow with an AMC spirit that he's transplanted a 4.0 into.
http://amccars.net/cgi/yabb2/YaBB.pl?num=1180803230/30
megasquirted and turbo'd apparently.

[Pharaoh XJ]

Got this reply from painless tech support:

Hello; I don’t think our harness will help you it is not designed for the 4.7L stroker, it is designed for the 91-97 4.0L stock motor.

its a 93 HO & we lack electronics skills & a dyno

[wolfpackjeeper]

look into mega squirt, It is what I am planning on my 4.7 stroker. I am also working on a turbo setup for the motor which may help you out some in the sand. Squirt will let you control fuel, air, spark, timing, and boost.

[Pharaoh XJ]

I ve looked at megasquit its even quite cheap 500 comparing to a motec. How difficult is it to program using nothing but a BUTT dyno ?

[wolfpackjeeper]

you will need to have a computer or palm PDA to tune it, unless you buy one of the input/output screen. The tuning software is free. You can tune it while driving, you just need to have a laptop to do it

[Pharaoh XJ]

Thats great. Is it a stand alone ( need to map everything from scratch) or does it override the stock ECU ( just need to fine tune the curves) cause as I said we dont have a dyno

[wolfpackjeeper]

it is stand alone. however there is a guy on here currently farther along than I am. U can fake some tuning values to get it running, then drive it and fine tune on the road. A dyno would be better but having someone else drive on the highway wile you tune the computer would work.

[JJacobs]

Actually driving on the road always trumps the dyno for tuning. The dyno will give you a good tune for max power only and the rest will be nearly useless. Even load cell dyno's while an improvement over an inertia dyno will still not quite simulate the road perfectly. This is of course assuming the vehicle has a wide band 02 monitoring system onboard- trying any sort of tuning without one is a waste of time.