^This. If the Cherokee's OE arrangement doesn't have them, then they can easily be sourced. I would be surprised if they were't there though.

I think intercoolers (not necessarily air-air) are a necessity for FI systems on pump gas. The autoignition temperature of gasoline is around 480*F and surprisingly that can happen fairly easily, internally, in a non intercooled setup. I say this b/c even a slight P/R increase can produce air temperatures well up to 300*F (I spec industrial blower systems ALL the time and have built FI systems). For the XJ I would strongly recommend air-water for simple fact you won't likely ever get much air flow over an air-air in an XJ.

Stock tune... come on... Those days are over. Tuning is what makes or breaks a build. I would absolutely considering monitoring equipment and an ability to adjust both timing and fuel tables. That is if you want to make it reliable. Trust me...

The problem with "cheap" turbos, in my opinion, is that if you ever decide to move away from it, for what ever reason, then your plumbing/piping is set up for THAT turbo. Having to rearrange that b/c the turbo blew seals, and you can't find a way to rebuild it, is going to be an expensive change over to the next one you go with. Not to mention, having a reliable turbo is a nice thing. Imagine how crowded that engine bay gets with ALL of that down there. Don't cheap out on your core component. You can get some really nice turbos in the $1000 range.

 

What about methanol injection instead of an intercooler?

That's kinda what I was thinking with the turbo. I guess I'll have to wait until I'm out of school

 

It has to be refilled. A turbo blows all of the time. I think methanol is great for drag racing and supplementing higher boost settings with a system already containing an air-air intercooled system.

 

I suppose.

For gas, would I have to run premium on 4psi or could I possibly get by with 89oct?

 

Run premium.

 

The more I know, the better I'll be able to handle it

 

^Yup. You'll also have to drop base timing and run cooler plugs

 

And add additional fuel.
You have to be able to add additional fuel and remove timing when under boost, even 4 pounds.

On a stock 4.0, You might be able to get away without removing any timing, but you must add additional fuel even at 4 pounds

 

Yeah, I'd be looking for an adjustable FPR, MAP, and 24lb/hr injectors.

 

As far as timing, on a stock 4.0 you can do a 'crank position mod' and add 6 degrees of timing advance and not detonate, so the base timing table is very 'retarded'. If a good, safe starting point for boost timing is 1 degree retard per pound of boost, it is like the jeep is already retarded 6 degrees and should theoretically be good, timing wise, up to 6 pounds of boost with no additional boost timing retard. I know this as I only am running 0.5 degree retard per pound boost with no detonation, just afraid to take out any more without a knock sensor.

 

Can you Elaborate On this crank position mod Are you meaning Moving the crank position sensor In the bell housing Advancing the cam Cause it says that you Advanced it by six degrees which is throwing me off because I thought we were supposed to be retarding timing?

 

The stock ignition table is very conservative, meaning on an NA application you can advance timing a full 6 base degrees and still run without detonation. I would recommend running whatever premium is for your altitude.

I run a small responsive turbo and had issues with detonation in the transition area below 100kpa and less than 2k rpm.

 

I have A 4.6 Stroker with a GT 3582 Turbo and detonation put a hole through one of my Pistons but they were just hypers so I'm going icon forged and there were multiple other things that attributed to the detonation that I'm working on curing but main thing is is I need to figure out how to pull timing I have made another position for the crank sensor to go in the bell housing but I do believe I need to sync the cam sensor with it at least partially anyway for the timing to move I've seen in some of these forums People have hooked up an MSD BTM but I don't know how that was possible Resistance at least on the jtec I don't think

 

Just hook up an HP Mpvi2 buy the credit and pull timing. You will need a 2 bar map sensor and use the upper half of the load map. With the key on engine off you will see where the ecu thinks 1 atm is.

 

I have an erl mf2 7th injector that is mappable and 36 lb injectors adjustable fuel pressure regulator I'm basically got everything figured out except timing I'd really hate to spend $6 or $700 to do that I realize it's not ideal and that I should go stand alone or at least piggyback but I'm a single dad on disability and I simply don't have the money