00_WJ_4.0

Hello guys, I'm in hopes someone here knows what I can do to get the most out of my jeeps engine. So...I'll start with what I know of it and we can go from there.
Engine was rebuilt roughly 50 thousand miles ago, and was bored and stroked to a 4.6L. it has icon pistons and crank, stock rods, comp cam, camshaft. Had Ford taurus injectors in it but I've since removed them and went back to stock.
... basically, I'm getting ready to transfer the engine into another jeep and want to get all I can out of it.
Now nothing has been remapped on the computer and I can't seem to find anyone that will do it...or what I'd even gain by doing so.
Basically does anyone know what I can do to get optimal performance out of it?

dave1123

Come on guy! You gained torque with the longer stroke and you can't wind it up higher to gain any more horsepower, so short of nitrous, turbo, or blower, there ain't much more in it! Maybe a bored out throttle body?

00_WJ_4.0

That's a option, I am thinking of going the route of the injectors you mentioned but in having had so many jeeps and alot of them having the 4.0 it just doesn't seem to have the power it in theory should. Maybe it's due to the trans rebuild the guy did not really getting the power to the ground, but I honestly don't know. Then again, it's alot heavier than any of my stock jeeps with the lift and tires and extra weight of the stereo system...maybe weight is a issue. Just trying to figure out of there's maybe something he missed or is that just what it is. The added parts simply increase the HP and torque? Without further modifying the fuel/air ratios and such? Chipping it? Idk. Just want it as beastly as can be lol within reason as far as cost goes anyways.

dave1123

If you're looking for off-the-mark performance, lower gears would help, but that can get expensive, plus you sacrifice top speed. For instance, my Camaro had 4.10 gears and that tached 4000 at 70 mph, however that's in fourth gear 1:1 direct like our 3rd gear. That was also 108 mph at 6000 but got there in 12 seconds. IDK what the car weight was because it was so long ago and it had smaller tires on it than the jeep. 11x15 slicks.

It also had the "truck" 12-bolt rear end in it, much stronger than a D35!

IDK about you, but I got nervous with my WJ at 85 mph. A 4.0 (or 4.6) should run all day at 3000.

00_WJ_4.0

I've cruised at 90 in the first yeti down the highway, shockingly it wasn't bad as far as stability goes. I guess in the end I just have to see if it's any different when it goes into the new yeti.

andrewmp6

Blower and spray and you won't find a lot on ecu flashing,Most use a piggy back system for a supercharger.The 4.0 don't have a huge aftermarket for power and if you want a fast grand i hate to say it but get a v8 zj thats still a old school small block which could be built in to a monster.

dave1123

My point exactly. Don't screw around with a tractor engine! The weakest part of the 4.0 is the pistons. They don't have very much support at the bottom of the stroke.

00_WJ_4.0

I have actually contacted a company that does jeep strokers, said they do about 100 a year and they have their own cam cut at comp cams that's quite a bit more aggressive according to the guy I spoke to at comp. $150 and it's mine. May go that route but at the moment I dropped the old yeti off to get it's heart ripped out, but prior to that they're going to plug her in and figure out how to make her run right first.
And idk if it's gearing or what but it's definitely more sluggish than the 2001 4.0 I gave my buddy. I've been driving his lately and I'm telling you, with almost 200k on the clock it really runs like new. Now if I could just figure out the clunking in the rear end. Thinking shocks because I just did the sway bar links and they're nice and tight now.

extrashaky

You may want to read up some on the Jeep Strokers board:

https://www.jeepstrokers.com/forum/

It's not going to be able to make full power with stock injectors. I'm no expert on strokers, but I have a Golen 4.6L in mine, and they specified 24 lb. Ford injectors. With the stock injectors, you're going to run lean.

The OEM computer should be able to handle the stroker just fine. These things are made to run under a wide range of parameters.

Air in and air out. Install a bored throttle body (NOT a spacer), header, free-flow cats and a decent exhaust. I'm not sure what cold air intake options there are for the WJ, but take a look and see if there's something that gives you REAL cold air from outside the engine bay. Just giving it a chance to breathe will liven it up. I had my header ceramic coated at Swain, but I don't know if it helped any.

Beyond that, you're looking at gearing and possibly building the transmission to shift harder.

00_WJ_4.0

Okay thanks for that and I did actually make a ram style air intake for it. The old one had a k&n "cold air intake that's sucking air from the engine bay.. I cut a jug that fit right around the filter and then ran a tube thru the grille opening to pull fresh air into the filter. I did have a issue with it running lean as hell and like it burnt my eyes on the trip to the shop yesterday...I have the Ford Taurus injectors still, but not sure if they're plugged because it ran like crap with them in it, runs a bit better with the stocks but runs lean.