I'm looking at upgrading the intake manifold on my 92 Jeep Cherokee 4.0. I picked up a 99 intake manifold. What parts do I need to make this happen? Do I need to do anything with the power steering set up?
Any help is appreciated!!

ghawkes  

It should just bolt right up. Since you have the manifold on hand, just check the bolt pattern on your existing PS pump to see if it fits: if it doesn't, then, yes, you will need the '99 pump.  

Why are you replacing the intake manifold? Is the original broken?  

ftgiles:
Why are you replacing the intake manifold? Is the original broken?

The '99 intake manifold has more volume, and smoother runners, so it provides a mild low-end boost.

Basically, a standard motorhead thing to do with any engine is to  yank out the stock intake and exhaust parts and replace them with  higher-flow, aftermarket parts.

With the 4.0, (unlike, say, the venerable 350 or 5.7) there's no aftermarket IM that I'm aware of, so the '99 IM is an option, I guess...  

Intake manifolds, heads, cams, and exhaust manifold/headers are all tuned to work together. Changing one piece without regard to the others, and expecting an improvement in performance is silly. There is even a chance that it will have a negative effect, as headers often do in the low-end range.

Is there some test data that shows this low-end boost? Higher air flow builds hp in the higher rpm ranges at the expense of low-end torque.

Just because it has a bigger volume does not mean it will perform better. None of the changes that Chrysler has made to the 4.0L in the last 10 years had to do with increasing hp and torque output. They have all been done in order to be emission compliant.

The only reason you don't see the 4.0L in the new JK is because of emission concernes.

The head, cam profile, ignition system and PCM have all changed numerous times in the last 10 years, and the performance has stayed the same.  

Intake manifolds, heads, cams, and exhaust manifold/headers are all tuned to work together. Changing one piece without regard to the others, and expecting an improvement in performance is silly. There is even a chance that it will have a negative affect, as headers often do in the low-end range

Agreed


Just because it has a bigger volume does not mean it will perform better. None of the changes that Chrysler has made to the 4.0L in the last 10 years had to do with increasing hp and torque output. They have all been done in order to be emission compliant.

Indeed. Rumor has it that changes to the catalytic converter on the 4.0 made it lose HP, and that the intake manifold was changed to offset the loss in HP caused by the exhaust modifications.


The head, cam profile, ignition system and PCM have all changed numerous times in the last 10 years, and the performance has stayed the same.  

I think that this statement might just prove both our points...    

AAmmmmmm NO, no and NO. enough of you two blowing smoke, everybody's an expert huh, well the real expert says that the real reason they made a new intake manifold was to cope with the smaller exhaust PORTS on the motor. And the reality is that this intake manifold is actually genuinely a highperformance manifold and is excellently fitted to this motor,like it always should have been. Furthermore, when delaing with the 4.0 which is s tourque motor,any real jeeper knows that something that tourqy get's great gains off of small mods, and bolting on that manifold does alot for peoples hp and mileage, and noones gonna not notice it. And all that garbage about cam profiles changing, it's BS, every change made yielded power weather in tourue or hp weather down low or up high.Fact. If you get the real statisitics on the hps of the years, you'd know. the 4.0 didin't need 4 valves a cylinder becasue it had a cast iron head and could run hot and lean and mean with quality valves stock. running lean means High oxides of nitrogen which is emissions problems, but emissions wasn't the only reason they dropped it, it's becasue a straight six with that much tourue idles like a friggin caterpillar after 140k and has a noisy top end, the losers at mercedes wanted to have a  smooth runnin v- block,alumnum head party,which ultimately lead to so much public outcry that you  will soon be able to purchase the 4.O again,yes it's true crate for your own use,the real deal, oh and by the way 97 and 98 have exhasut ports bigger than anyother years and can make some real ponies,I really wish everyone could do what I didi,make small block v8 power with better low end and steal 520 miles to a tank, and be able to growl down the highway at 2150rpm at 77 mph  

hahah the REAL expert says =) this is gonna be good.  

The only point that I got from your post is that everyone is an idiot. Except you.

Calm down and try to state what it is that you disagree with. Maybe we could have some civil discord.  

lol, he's gonna get whipped by a bone stock 4.0 thats properly geared anyhow runnin 77 @2150 rpm.

sounds like he may be talking about all these upper rpm, unusable power gains for a 4.0 and has a diesel..

520 miles on a tank from a 4.0/stroker? ... LMAO how many gas tanks do ya have?  

^^ well on his behalf i have seen kits for a bolt in 28 gal gas tanks.... maybe he has one of those lol  

I don't know if anyone is still interested but here is a link to a very good article on this very subject.
http://www.mallcrawlin.com/forum/showthread.php?t=6355
http://www.mallcrawlin.com/forum/showthread.php?t=6355  

Yes. I have read this. This backs up some of the remarks that I have stated in this thread.

Making changes to the intake manifold without regard to the other intake parts of the engine is silly.

In the Mallcrawlin forum there are dyno results to show masive head work alone provided litlle to no power increases. But coupled with a '99+ intake did make some nice improvements.

Also stated in the Mallcrawlin thread is a swap of just the same intake, again with little to no power gains.  

I actually performed this swap last year. The cost does not justify the slight gain in torque, even with a Hesco aluminum head and cam.  

I have a 98 4-cyl Wrangler and was considering an intake manifold swap as well. I already have a full Borla exhaust w/ Random Tech cat, an AEM brute force intake and stage 2 Jet chip (uninstalled). Does anyone know if the 62mm Hesco throttle body will be negated by a bottleneck in the manifold (if the manifold opening is < 62mm), to determine necessity. (I'm on tour in Korea and can't exactly look for myself at the moment.)

Edit** Obviously I'm not referring to the '99 4.0L when mentioning a swap, I mean in general. Just wanted to put that out before anyone thinks "This guy's an idiot."