omnious

looking to fond some info on 4.0 turbo builds. I am a horse power junkie and would like to give the xj some spunk.. I did a search, but not finding much after 10 mins of flipping through threads.

if anyone wants to see my last build, here it is. I made a facebook page for sponsor but no one ever bit

https://www.facebook.com/HannibalSRT8


time for something that I can treat like a bastard ginger, and plus the xj off roading is more fun to me..

andrewmp6

Most of us run a stroker or do a v8 swap for power.

mschi772

"Some spunk?" The XJ has a rather respectable power:weight ratio, nice torque peak down low where it is good and useful, and a truly respectable 0-60 of roughly 8-10 sec. Frankly, the 4.0 already has all the power the XJ needs--and if you get too much power, and you really have to start concerning yourself with unibody reinforcement--which is why efficiency is more appealing to me personally. I could see guys who have XJ's loaded with tons of armor, cages, beefy axles and big tires wanting some more power to move all that extra heft, but proper gearing can account for most of that.

Stroking is very popular and versatile. I know most people who go for boost do superchargers because that's a bit easier, cheaper, and mainstream for the 4.0. I will at admit that from my perspective, the efficiency of a good, mild turbo is VERY appealing. The incredible cost of a turbo setup, unfortunately, is intensely unappealing.

heavy2500

Well for a xj that will go off road a super charger makes more sense. A super charger starts making boost right off idle where a 4.0 spends most of its time when off road. A turbo requires some rpm to make boost, if your building a mudder or DD/race jeep sure a turbo will do wonders over a super charger. That's why you don't find to much on turbos.

mschi772

Turbos are more versatile that you're giving them credit for. There is no reason that a turbo setup couldn't provide boost at low RPM. You just don't see that as often because most turbos implemented by the factory and by street enthusiasts are more interested in higher RPM boosts.

heavy2500

Yes they are versatile an I didn't say they weren't. You can get a turbo to start spooling not far off from idle but it will run out of air in the upper rpms an get really warm on egts. Or you can get a slightly bigger turbo an pick up the air in the upper rpm, but loose out on that low rpm spool up. Don't get me wrong I love turbos, so much so that I built compounds for my truck. But in a 75-80% of xj off road will be better suited with a super charger for there off idle boost.

omnious

yeah I want a small turbo that will spool very quick and not much power past 5k rpm. I am searching for info, so if anyone has a build please let me know would love to read about it and how it was done.

heavy2500

Not sure on the numbers or name of the turbo, but something out of an EVO or a Subaru might be a good choice small enough to spool quick, not so heavy that you could fab up a support bracket to mount on the passenger side an run a down pipe right back to the cat.

mschi772

I know Banks sells kits for the TJ... just in case you weren't aware of that. Not sure what it might take to get something like that to work for the XJ; I can't imagine it would take a whole lot.

andrewmp6

Honestly off road you don't want a blower or turbo you want everything as simple as you can.Trail fixes you want fast so you can keep on playing or it can kill your weekend if you break something big.For the price of a blower or a turbo kit i can swap in a ls1 if i find one cheap enough.Or even the truck 6.0 will do in a pinch.A ls1 is lighter then the 4.0 and a lot more power and easier and cheaper to build up for more power if you want it.

mschi772

(Points at self as example) Not everyone is into offroading with their XJ.

CobraMarty

Some problems with turbos on the XJ-
-XJ always run hot
-non cross flow head and limited space on that one side.
-no ready made exhause manifolds and down pipes, all custom (boostwerk exception but no downpipe)
-plumbing and piping difficult
-tight confines for an intercooler
-tuning
-get expensive fast, look at a Banks kit with intercooler

Now with a stand alone, like megasquirt, or blow thru carb, some sand/mud drag guys are making 400 HP.