MORE POWER for 4.0

[goodtimes]

the reason i say turbo is because you can keep your i6 gas mileage, ....

I6 gas milage???? who wants that crap! Full size chevy trucks with small blocks are getting better gas milage out of a heavier vehicle than the jeeps. If you wanna go fast, lose the 6.

[Dukes69]

If you wanna go fast, lose the 6.

I've seen some I6's go pretty fast . . .

I've been in one too.

[rick]

What kind of hp and tq gains would there be if i stroked it, cammed it up, port and polished the head, swapped out the crappy manifold for a header, and gave it the full intake-exhaust treatment?

As I said, with a 4.7L stroker (this is a 4.2L crank bored 0.060" over), you can expect 260 hp, around 300 ft-lb torque. All the polishing and loving in the world is not going to change the head design. If you are really going for broke, then bore it to 5.0L (need to UT the cylinder walls to ensure sufficient thickness - potential to scrap a block or two in the process), buy yourself one of these fancy aluminum heads , and then dig really deep for injectors, fuel system, and standalone engine management system to feed and control the beast. I believe this engine would be faster in real world street driving than a turbo'd 4.0L since you introduce zero turbo lag and you will have 320+ hp and upwards of 350 ft-lb of torque. Although in the 1/4 mi a properly designed turbo system might wamp the NA version. You need to carefully consider compression ratio and quench when going to turbo. It's certainly not as simple as slapping a turbo on a stock I6 unless you don't plan on making many dyno pulls as you set out on the many days of tuning it will take to properly set the fuel map with a turbo... This also costs $$$... Don't even think about turbo on a 258 - the head design is a power killer. I would be surprised if you could make more than 250 hp on this head with 10 psi of boost, let alone the modest 5-6 psi you will need to run to make one of these engines last. I am very skeptical that any of the "bolt-on" turbo kits will lead to engines that actually last more than a year or two, especially if you plan on using the turbo because of the above mentioned CR and quench factors on the stock engine...

I think you can build the 5.0L version for about $7-8k...

This Dino guy has a cool site with lots of stoker info and some specs on various forced induction (turbo and supercharger) kits: Dino's 4.0L performance site

[JeepJunkie]

I've seen some I6's go pretty fast . . .

I've been in one too.

yea....dont supras have I6s...?

[assyrianjeep]

yes but those are turbo engines, my friends dads supra runs 645bhp!! thats at the tires LoL so much power