Turbo Jeep Cherokee XJ-R Build

[PseudoSport]

Thanks! I actually saw your for sale add and checked it out but currently we have too many other projects going on right now.

 

[DAINGEROUS]

Hi I'm new to this site and I have read your whole build, I was wondering how much boost, if any, I could run on a stock computer in my 99 cherokee. Maybe just changing injectors and like 5psi? I don't want to spend money/ deal with wiring stuff. I'm just looking for a little boost to play with and sound good! Gotta love that spool!!!

 

[PseudoSport]

Personally I wouldn’t run the stock computer boost. Even with larger injectors the stock computer is not going to pull timing. Guess you could install a rising rate fuel pressure regulator and a MDS ignition box that would pull timing. Best option is to have a tuner reflash the 97+ computer to work with a different map senor to handle boost.

Proper engine management is critical and one of the first things we sorted out before installing the turbo. We got the Jeep up and running on MegaSquirt and raced it N/A to work out the bugs then boosted it.

 

[Talyn]

Hi I'm new to this site and I have read your whole build, I was wondering how much boost, if any, I could run on a stock computer in my 99 cherokee.

0 psi is how much you can run on the PCM in stock form. You have options though. A piggy back to control larger injectors injectors that works in conjunction with your PCM. A PCM tune + 2 bar MAP sensor + larger injectors ([email protected]).

Someone tried to put a turbo on an 4.0L engine once with 0 fuel system modifications. I don't think he even changed the injectors. That engine had a very short life and he didn't understand why.

 

[DAINGEROUS]

Ok thank you guys I'll start looking into it, I'm just terrible with wiring and dealing with stuff I cant see or hear that's broken lol if I knew exactly what to do step for step with the right parts I could figure it out. Hahaha I did install a vortec v2sq on a 94 mustang but it was a complete kit with instructions.

 

[DAINGEROUS]

It would be really easy if someone could actually send me the exact mega squirt kit link and injectors I should get. Haha I'm not good with this stuff ��

 

[PseudoSport]

We’ve been distracted with our projects but finally had time to pull the Turbo 4.0L. Jeep has been sitting since July because at the last autocross the wastegate never opened so we ran way more boost then we wanted to. Dave was driving and said it felt stupid fast right until it blew a cloud of white smoke out the exhaust and engine bay.

Engine is now on a stand till we decide what to do with it. We did remove the head and confirm that we blew a head gasket on #5 Cylinder. Fire ring was pushed about a ¼” into 2 coolant passages. It also looks like coolant pushed out the side which would have sprayed on the exhaust explaining the steam from the engine bay.

Head gasket was a Felpro HD we installed a few years ago.

So far everything else looks ok but we are going to tear down the block and make sure.

 

[sidewaysstarion]

I've done that with a copper gasket, lots of boost + lots of nitrous can do fun things with head gaskets.

 

[embs2001]

Do you know what psi it hit when it blew the gasket?
you dynoed 270rwhp right? was that at 12psi?

 

[PseudoSport]

Not really sure what it spiked to. We’ve been running around 10 psi but the wastegate never opened since we messed up the hose going to it and we were not data logging at the time. No signs of detonation and it should have pulled timing down to 10 degrees when it overboosted. Any specs you see in the picture are paper towel fuzz. We dynoed 274whp/322wtq at 12 psi but there is a lot of room for improvement. We were running out of fuel above 4300. New fuel pump and different injectors are on our list of things to improve.

Our team’s other turbo 4.0L in the Spirit is running 16 psi from a 60 trim T3/T4 turbo with a MLS head gasket and fresh head bolts. So far its holding up. Just wish the trans didn’t slip under boost.

 

[embs2001]

I can't wait to see what it does when its back together with more fuel.
This thread is my favorite to follow!

What was 16 psi good for on the 4.0? Stock longblock other than gasket and bolts?

 

[PseudoSport]

All I can say is a stock 1997 4.0L with fresh gaskets, rings, bearings, and non-ARP head bolts, has survived 20-30 drag passes, 5 autocross runs and a few street miles at 16 psi. How long is it going to last? No idea. Is this a good idea? Probably not, lol.


Below are some pictures of the turbo 4.0L in the Spirit.

So far we have about $1600 into the whole project. If anyone is interested click here for the build thread:

http://grassrootsmotorsports.com/forum/build-projects-and-project-cars/1982-amc-sprit-challenge-build/78512/page1/

 

[embs2001]

You are using injectors out of gm 3800 correct? Do they have a part number on them? It would help me in my hunt for injectors.

 

[PseudoSport]

Injector part # is Bosch 0280155868. BOSCH 0280155811 should also work.

 

[Goose_XJ88]

I love this jeep and almost picked up a Comanche Eliminator 2wd for a dd because of this build. Quick question tho, How has or did the polyurethane
injected stock trans mount hold up? My new grocery getter (FWD car) probably has some worn motor mounts and I was contemplating doing this
polyurethane injection on a mount to see if it would increasing longevity.

The stupid car has 4 motor/trans mounts that total $360!! I don't feel like putting that amount of money into the car considering I bought the car
for $400. I figured this might be an acceptable solution for something that doesn't get driven very hard; depending if your mount held up of course.

 

[88JeepXJ]

I love this jeep and almost picked up a Comanche Eliminator 2wd for a dd because of this build. Quick question tho, How has or did the polyurethane
injected stock trans mount hold up? My new grocery getter (FWD car) probably has some worn motor mounts and I was contemplating doing this
polyurethane injection on a mount to see if it would increasing longevity.

The stupid car has 4 motor/trans mounts that total $360!! I don't feel like putting that amount of money into the car considering I bought the car
for $400. I figured this might be an acceptable solution for something that doesn't get driven very hard; depending if your mount held up of course.

It's a vehicle that doesn't get driven very often and it held up fine. There is a large void space un the mount where this method works perfect, but not sure I've seen a motor mount this would work for. Picture?

For a DD I'm not sure how well it would hold up but worth the effort if you can save $360.

 

[Goose_XJ88]

Here is a crappy pic of all 4 mounts. There doesnt seem to be a void all the way through but figured filling any type of recess might help longevity.

This seems to be the mount that fails on my car. You can see what looks like thinner webbing in the middle of the mount. All 4 seem to have this issue/recessing.

And a used one

 

[88JeepXJ]

Yeah looks like those could be filled. Go for it.

 

[Goose_XJ88]

Where do i find the stuff you used and what is it called?

 

[88JeepXJ]

A local speed shop called Home Depot

It's polyurethane in a caulk tube. Make sure it's the Z-rated speed poly though. Haha