salad

Trufax

ARB Safari snorkle goes down to like a 2.5" diameter. To remain free-flowing, especially at such length, 4" or more is appropriate.

Gary Briggs

At hwy speeds wouldn't there be a forced air induction effect? Might neutralize those choking elbows a some degree. Either way the ARB snorkel is hideous.

XJlimitedx99

I've always been more of a fan of the cowl intakes because they appear to flow better than a conventional snorkel.

You won't get big numbers out of this engine, BUT you can smooth it out a bit and maybe squeeze a couple mpg out of it.

This is what I would do if I were gunna spend the money:

-spectre cowl intake
-62mm butterfly valve
-injectors
-headers and a 2.25" high flow exhaust

I'm not sure about the intake. I've never researched it cause I have a 99.

Personally, I would stick with 2.25" exhaust because IMO I think it's better to keep the exhaust velocity up. The 2.5" will sound mean though. Some people will bash on headers because they're so expensive for little gain. I think it's worth it just to say you have headers

As far as computers or ignition goes, it all seems to be a gimmick with these motors. It would be nice to have an aftermarket ignition so you could gap your plugs bigger, but I don't know of any.

Short of building a stroker motor, there isn't much meat left on the bone for our 4.0s. This setup could easily run you upwards of $1,000 for maybe 20hp.

denverd1

One word: regear.

I realize you've already done 3.07 to 3.55, but money would be better spent IMO on putting more torque to the ground through deeper gearing.

XJlimitedx99

I disagree with this for only 31s. If he was going 33s or 35s I would agree all day but I think it would be too much gearing to go any deeper on 31s

denverd1

If we could cam, intake and flow these engines there would be no question. you could make significantly more ponies with a few mods and stay under a $1k. deeper gears would let PO move to bigger tires at some point and still create "more power" with 31's.

Gary Briggs

$1000 for a few ponies seems really silly to me.

XJlimitedx99

I could agree with this. Regearing also isn't cheap either, but I could see it being a more worthy investment down the road.

salad

Sure, at highway speeds. While you do get the cooler air it's still a lot more restrictive than a stock intake - so not that great at low speeds unless the air under the hood is REALLY hot. A cowl intake has the same induction effect without the restriction.

To what end? Any gears worth spending money on (as in, 4.56:1 or deeper) are going to be way too deep to use with 31" tires in any daily driver situation. Yes you get "MOAR POWAR" - however you've decided to quantify that - but 3000 RPM on the highway is not fun.

Turbo X_J

"Didn't", "did", "only" 140,000 miles = sorry, it's too circular for me, I'm un-subbed...

Metmknice

Maybe MLS head gasket, head work, port match 99+ intake, aftermarket header. etc.

Hexaphobia

I think I will just stick with injector swap and headers. Everything ells sounds like alot of work and $ for almost no return, I have other places I can spend that money. Thank you all for your input.

md21722

I believe cold air intake and free flowing muffler are the two most cost effective ways to get another few HP out of the 4.0L. If that's not good enough, build a stroker.