4.0 performance

adam greene

adam greene

Well-Known Member
Joined
Sep 9, 2008
Location
morganton
ive got a 97 jeep wrangler 4.0 how do i get some power out of it i thought bout puttin a v8 or stroker but it cost so much so whats some other things i can do to get power out of it i already have a cold air intake, jet chip .
 
not much.

different exhaust
throttle body spacer and overbored tb

ive heard of some power being gained from these but i dont know any numbers. you really arent going to pull a whole lot more hp out of a 4.0 w/o strokin it.
 
You can put together your own stroker kit for a pretty decent price, 4.2 crank and rods with 4.0 pistons and you would definitely be happy. Short of that or forced induction, you're not going to buy any bolt on crap that is worth the install time or money.
 
did you regear after you put those big tires on? Little bolt-ons such as tb spacer and whatnot will not make too much of a difference. You could supercharge it but thats gonna cost ya too
 
yea i regeared to 410 wish i would have went 456, its not that bad but it could be better i can tell a big difference with the chip
 
From what I have been told, stroke it. A crank new isn't that bad, not sure about the rods. But you can find a 258 pretty cheap. Have crank turned, have rods resized, and put it together. Of course while it's down you would want to check cylinder bore and at the very least, if it checks out OK go with new rings. While it's down you may want to slap in a little torquer cam. When it's all back together you will think you not only have a new engine, but a healthy small block under your pedal.
 
If your TJ is a 97, get an intake mani from a 2000+ model. It should net you ~20hp and bolts on.
 
NCbluetj said:
If your TJ is a 97, get an intake mani from a 2000+ model. It should net you ~20hp and bolts on.
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It kinda bolts on. You'll need the powersteering bracket that goes with it. I have a manifold that I'll sell if you want it, but no power steering bracket.
 
Yes, it will bolt right up to your head. Your powersteering bracket will not bolt up to the later intake though. If you buy a power steering bracket from a later model, you'll be good to go. And yes, I've heard 15-20 hp.
 
NCbluetj said:
If your TJ is a 97, get an intake mani from a 2000+ model. It should net you ~20hp and bolts on.
Click to expand...
Do you have proof of this? Most of the dyno sheets on the web have had other mods performed at the same time as the intake swap. It is really more like 3-5hp and a 5-10ft/lbs of torque gain on the intake only swap. The dyno post on mallcrawlin.com got the results from the new unclogged injectors and mildly ported intake.
MichaelT said:
will that work on a '99?
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It is already installed
matt97sport said:
has anyone had problems with the 2000 manifold with aftermarket headers ? i've been looking for one and was wondering
Click to expand...
It will bolt on with no problems.

When I install my stroker I'm toying with the idea of installing a ported stock intake and having it dyno'd then swapping in the late model intake which I'm porting this week so it is done when my stuff is finished at the machine shop. It will be a 4.7L when done 258 crank and rods(I wanted to keep the 4.0 rods but had to change plans) .060 over 4.0L pistons ported and polished head, 3 angle valve job, Mopar Performance stage 1 Purple Shaft cam and lifters.
 
Rob92xj, I have no proof of this and have not done it myself (planning on it though). The increase may not be a full 20hp, but just looking at the two manifolds, I'd be willing to wager it is more than just 3-5hp. The old-style mani is basically square tubing. It appears to be both low in volume and poor flowing. The new one is much larger and has smooth, large radius bends that taper as they approach the ports. It resembles a BMW straight six manifold in many ways. I'll be sure to get before and after dyno runs when I do the swap this spring.
 
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