Questions on twin charging! Help wanted
A twin charged project is not for the novice. There is much more to the install than just bolting everything together.
I say with nearly 100% confidence that this project will not see the light of day or even work at all.
I say with nearly 100% confidence that this project will not see the light of day or even work at all.
Seasoned Member
Joined: Nov 2012
Posts: 327
Likes: 6
From: Fort Collins, Colorado
Year: 1998 (buggy), 1998 DD
Model: Cherokee
I've been around plenty of hopped up 4.0's, hell, likely one of the first turbo'd XJ's was someone I knew.
I still stand behind it being more work than it's worth.
The owner of Boostwerks is someone I know as well (drive's by my house often). Even he got tired of the turbo setup and how much work/tuning was needed (especially at altitude). He went back to stock.
When done properly, a supercharger can be added to a stock 4.0L and be very reliable and give a great return in power.
At only 5-6 pounds of boost, a supercharger will add +60rwHP and +70rwTQ.
Ask me how I know, there are over 250 supercharger kits out there in the wild and not 1 failure.
At only 5-6 pounds of boost, a supercharger will add +60rwHP and +70rwTQ.
Ask me how I know, there are over 250 supercharger kits out there in the wild and not 1 failure.
I love the 4.0, there's three running at my house. I still run one in my buggy.
However, I'll still stand behind my original statement...stroking, supercharging, or turbo'ing one just isn't worth the effort IMO.
The only time I would say it is, is if you live somewhere like CA where your ***** are in the state's purse, and the likelyhood of getting an engine swap to be "legal", can be more work than it's worth (know several that went through this).
If you have the knowledge, skill, and abilities to do a supercharger, turbo, etc. on your own, swapping in a 5.3 or 6.0 should be a cakewalk.
A cheap stock 5.3L is going to give you ~300HP...and far far more reliable than anything that would be added to a 4.0L.
CF Veteran


Joined: Mar 2015
Posts: 1,203
Likes: 155
From: Northern CT
Year: 1995
Model: Cherokee
Engine: Turbo 4.0
Seasoned Member
Joined: Nov 2012
Posts: 327
Likes: 6
From: Fort Collins, Colorado
Year: 1998 (buggy), 1998 DD
Model: Cherokee
I've been in both turbo'd and stroked XJ's. Sure, there's a significant noticeable different between stock...but still nowhere near even a stock 5.3 or 6.0 XJ.
The one I was first in was a buggified XJ, and it would roast 36's standing still.
To each their own, but 90% of boost/supercharger swaps I've known of were either given up on, on in the end the owner wishes they had gone a different direction with their time/money/effort. I've only known of a few stroker motors (out of dozens) that have survived an extended period of time. That includes full on, built by Golen motors too.
Never heard of someone who swapped in a V8 that wasn't satisfied with the output

Spending a lot of time with other tube-chassis type rigs, getting a much more varied look at engines and such makes you think about it more.
2JZ, 6.0L, 5.3L, 5.0L, etc. Not too many messing with SB350's these days.
It's all relative to what floats your boat. I've thought things like a turbo for the buggy. But I'd rather just swap in an LS, get more HP/TQ, more room, and a lighter, smaller engine.
i was wanting to make the 6 psi boost with the m90 from 1.5/2k up to about 3/3.5k, then the 6psi from the turbo kick in around 3/3.5k and pull to redline. I wanted to try to get the mixture just right so it can have amazing torque low end and amazing hp in the top end with a steady power band
The idea behind compounding is that the atmosphere charger is going to be large in comparison to the pressurized charger. The pressurized charger is commonly sized for drivability at lower RPM if it were run as a single. Similar to what a stock charger would be. The atmosphere charger will mover large volumes of air at a lower pressure to the pressurized charger, where it then increases the pressure into the manifold. Boost will raise exponentially out of the pressurized turbo in this configuration, compared to it being ran as a single, because it is being force fed air instead of drawing from a normal atmosphere.
One isn't for low RPM, and the other for high.
With a turbo over a super charger like you have planned, you would want to under drive the supercharger as not to super heat the air. The pulley ratio might be such that the super charger would only make 2-3 psi on it's own. But, when fed air from the larger turbo, as RPM increases you would see a boost number higher.
CF Veteran


Joined: Mar 2015
Posts: 1,203
Likes: 155
From: Northern CT
Year: 1995
Model: Cherokee
Engine: Turbo 4.0
I'm not sure what an LS swap comes in at but my set up was budget friendly, has good power and runs very reliably. If I want to transfer the set up to a different engine it will swap over in a day. If I need to order a part I order it for a Jeep XJ.
Seasoned Member
Joined: Nov 2012
Posts: 327
Likes: 6
From: Fort Collins, Colorado
Year: 1998 (buggy), 1998 DD
Model: Cherokee
For reference (not for sh*t throwing), a 5.3 swap can be usually done for ~$1500 if you're doing most of the work. This is for full drivetrain (I see 5.3 full drivetrains for about $700), a few hundred $ in gauges, having the new PCM rewired, etc.
That number can easily triple if having someone else doing it.
If you're wanting a 6.0L, you can usually find LQ9 engines for $1500ish. Sometimes more, sometimes a lot less (I know someone that after parting out a vehicle, made money and got the LQ9 for free).
A 5.3 can easily be made to have some more oomph. A 5.3 or 6.0 can easily be modified for a very reliable ~400hp...but with some work and money could be double that

Hence, why with my buggy if I ever decide to really go for something, it'll just be a full swap. The trans might be heavier, but the motor will provide me with more room overall, and lose a few lbs.
Now, I also wouldn't mind a 5.0 Coyote motor either
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