Alright here's the deal, got a 98 xj, recently motor threw rod #6, haven't torn into it yet to see how bad it hurt the block but that's a different story, long story short through amazing timing I got a free 92 xj off Facebook marketplace, I'm planning on doing a quick rebuild on the motor, (piston rings, bearings timing chain) and have had the idea for a little while now, I've got a holiset turbo laying around, I know I'd need a 2 or 3 bar map sensor, I wanna run around 5psi, just to give it a little more power on the street as it is kinda my daily, but the question is, can I run around 5 psi on stock rods and pistons, I'm in highschool still so I don't really have the pockets for it right now, I just don't wanna go do it just for it to throw another rod in 1000 miles after spending$400 on rebuilding the motor, I'm going to use the head off the 98 on the 92 block, thanks for any advice

 

You will need a tuner box. You can go full standalone with a megasquirt or you can piggyback the ecu like I did. If you go that route let me know I'll help you get the right unit and set it up. When you say you have a Holset what model is it? You wont need a different map sensor as the stock ECU isn't programmed to read the scale correctly. You will need to run 93 octane at sea level.

If the 92 engine is healthy (good compression and leak down) why not run it? Any history on it?

 

the 92 motor has 220000 miles on it and has play in the timing chain, defenently puting a timing chain in the motor and ring, might do bearings depending on how they look, im not sure the model of the turbo, i know its for some form of cummins, if i decide to do it id do a piggy back system, what would happen if i ran just ole 86? would it pre detinate? im about 200 feet above sea level if i would HAVE to run 93 think ill just build a stroker cause i cant afford 93 octane fuel, what tuner system do you got? thanks

 

I'm at 0 to 500 above sea level and I always run 93. It's cheap insurance. The hx35 and bigger is a poor choice for the 4.0L but you can run it, others have. I run my kit with an AEM FIC 1913 with 36lbs injectors.

 

I'd like to know more about the FIC setup. Can you explain how it works?

Edit: Never mind. I just found your thread on the topic.

 

I have a few patch harnesses if you dont want to hack into your factory harness. PM me for detsils.

 

i kinda know what im gonna do for wiring,(my uncles gona help me if i decide to turbo it) can i use stock internals for around 5psi, i dont have money for forged internals, heck dont realy got mon ey to turbo it but ive got a turbo and gotta rebuild the motor anyways, could i get by by just seting the ring gap and using stock internals? and will it last or just be something thatll work good for 3 months and diie?

 

I'm running on stock internals for a few years now. In that time I've managed to break #2 piston skirt. The engine had piston slap when I got it so i cant say that turbocharging didnt do it in but it didn't help it. If you are low on funds and this is a daily driver that you will eventually need to get to work I would discourage modifying it at this time. Service the engine, drive and enjoy.

 

alright thanks for the info cummins, still havent decided if im gonna do it yet, one more question, how much psi where you running when you broke the skirt? really appreciate the info

 

I was actually in vacuum at about 2k rpm when the skirt let go.

 

I’ve also been interested in a turbo xj build. For a 99 HO, how much boost could you run without a piggyback?

 

The best answer is none. Air flow above 1 Bar needs fuel to match it. Your computer is only scaled to read the stock sensor which measures up to 1 Bar. It is also important to retard timing with boost which the ECU will not do.

 

What about using an adjustable MAP sensor? Will that help?

 

No it wont help. Get a piggyback system and dont blow your engine up. Cummins has done this before so you should probably take his advice.

 

Also, HP tuners just released support for the 96 to 01 XJ so that is a huge step forward in boosted Cherokees.