[BigDan1]

looking for a JK Rubicon for softer suspension then my CJ ....

it has a 3,8L that I had in one of my caravan in 96 , I was satisfied at the time , but I'm a bit aware that a 3,8L in a Jeep might not be the best engine ....

I'm aware that with the 4:10 ratios it might help !

BUt since I have modified about every engine that I had in my hands ( my 4,0L has 235 hp ) and my RV 460 ( 7,5L ) has 420 hp ,,,,
I wonder if I could get some extra juice out of the 3,8L V6

Anyone did or knows ?
Thanks

 

[valiant67]

There's just not much out there for the 3.8. Small things like exhaust and (dubious) cold air intakes as the factory intake is already cold air. Better gearing does help.
Forced induction seems the only way to get much more power. Or an engine swap.

 

[Dave Z]

The main thing you'd want would be low-end torque and I don't know how you'd get it. I'd think gearing would be the best place to look. Manual transmission instead of the automatic.

 

[ka9yhd]

About the only thing I would do is port matching. Send the heads, intake, and exhaust manifolds out and let a machine shop match all of the ports. This will help smooth out the airflow, and eliminate any restrictions in the airflow. Also replace that plastic ribbed hose from the air box to the throttle body, and replace it with a smooth walled tube or hose. This will also smooth out the airflow.

 

[dana44]

Always into head, intake and exhaust work for improvements of power, been porting heads for 40 years now (man, time flies). One other thing you can do, which is a bit of work, is have a cam reground, since there aren't any aftermarket that I know of, to which you want to shorten the duration to improve the bottom end torque. Aftermarket tends to do more lift and duration to increase top end power, so the thing to do is to turn the engine into a low end monster by reducing the duration of the valve opening to close earlier, thus increasing bottom end torque and bottom end power. The computer itself will control the fuel/air ratio so that isn't an issue with this change, and since revving for high rpm horsepower isn't the goal, it's what you have to do. I know Crower can do this, and sure there are many other places out there that can do it, too.

 

[ka9yhd]

Looks like Banks makes a cold air intake and an exhaust system for the Jeep with the 3.8 Liter.
Jeep Performance Parts & Upgrades for Diesel and Gas Utility (at https://www.bankspower.com/c-78-vehicle-specific-performance-parts-for-jeep-vehicles.html )

 

[dana44]

Looks like Banks makes a cold air intake and an exhaust system for the Jeep with the 3.8 Liter.
Jeep Performance Parts & Upgrades for Diesel and Gas Utility (at https://www.bankspower.com/c-78-vehicle-specific-performance-parts-for-jeep-vehicles.html )

Same thing, it does most for mid and top end power to keep the engine from choking so much, really doesn't do much of an improvement for the bottom end, where you need it for rock crawling.

 

[mrkovash]

Swap it for the hemi. I would not be surprised if they have kits for it.

 

[Jack45]

I agree to swapping it to a hemi.

 

[AC TC]

It should be quite right as a jeep engine given its tq curve.
- portmatch, a good valve job.
- mill the head for a slight compression increase.
I suspect that they have a very conservative timing schedule so a good custom tune would be in order.
- if done run it on premium.