hal93

ok guys forgive me but i have not been on here in a long *** time. so i have some questions regarding turbocharging my XJ. i want to do a turbo setup on my stock internals XJ 4.0 HO. i wanted to know what the limitations of the Stock Internals were before i do anything so i have an idea of how to run it.

Atmos

RubberSideUp

Most reports I've seen say that, properly tuned, they are experiencing 12-12.5psi is the limit for boost on a stock 4.0L head gasket, especially mileages over 100K (i.e. no ported head, bone stock 4.0L etc). It's a good idea to at least install a cometic / MLS head gasket and ARP head studs.

Boostwerks.com

First of all, there is a lot of "blah blah" opinions around the interweb from those who have never even touched a turbo, so be careful of what you hear. Having said that, we are one of the few to actually turbocharge the 4.0.

I daily drove my rig for 4 years and have no complaints. Only reason I stopped is that we bought another vehicle for my wife, and started commuting with her old car (much better on gas).

Proper tuning is by far the most important part. Boost pressure is only one of the variables in the mix, so to say that it will hold XX psi or HP is pointless. Point being, you can blow up an engine very easily on just a couple PSI if not managed properly. I run 10psi from a large T3/T4 and it does just fine. I have 40lb injectors managed with the AEM FIC piggy back controller, and roughly 1deg of timing retard per lb of boost.

Here's some pics of our rig...






Here's a dyno plot of one of our customers BTW (stock 4.2 block)...
Specs: Boostwerks manifold, Garrett 57 trim T3/T4, 6PSI of boost, 92 octane pump-gas, 4.2 bottom end, '92 4.0 head, stock 4.2 cam, 2000 intake, Megasquirt MS3Pro w/ distributorless coil



Compare it to some of the stroker plots out there and you might be surprised how the torque curve compares.

Feel free to PM me any specific questions you might have!

hal93

Boostwerks. i like that curve. i would have some better internals for the heads maybe since the 4.0 heads sometimes have issues....at least with the gaskets. I would like to know what the setup you have on that XJ costs or if i can inquire about getting the parts for it.

RubberSideUp

It depends on what you want. If you just want 5-6psi (211rwhp on a bone stock 4.0L), get BBuchta's M62 Supercharger kit. It can go higher (some have run it to 10+). But it's less efficient (IATs rise dramatically) when you get above 8psi. It's a chemically intercooled kit (using 7th injector). Check it out. Perfect for rocks and mud. Less heat under the hood to deal with too. Sub 4 hour install time and can be removed easily and resold for it's original value should you dislike it (yeah, right! who dislikes 211rwhp?).

http://www.jeepsuperchargers.com

More info here: http://jeepm62superchargerkit.blogspot.com/

hal93

I see. word. i thought of doing a super charger system but found it to be more expensive when i priced them last. maybe it would be cheaper now. my xj is currently 2wd and i use it on the street alot.

RubberSideUp

The JeepSuperchargers.com kits are bolt on. No welding or fab skills required. It'll take half the time or less to do the install vs turbo. I'm a fan of turbos too, but in terms of cost effectiveness and simplicity, the supercharger kit from BBuchta is hard to beat.

PseudoSport

Our turbo Cherokee is making 274hp/322tq from a stock 240k mile 4.0L Like boostwerks said tuning is key.

hal93

now thats what i like to hear. i am shooting for 300hp but i will take what i can get. since i have a 5 speed i want to have a bit of fun. i may put a locker or an lsd in the rear as well.