Intake Manifold upgrade?

[Jax MJ Luvr]

I recall reading an article on the web months ago about how you could swap the intake manifold from a 6 cyl grand cherokee in place of the restrictive one normally on the I6 commonly on Cherokees and Comanches, I couldn't find the site that had it, curious if anyone has links or info & details on this. It's been something I've considered doing as I fix up my MJ, or at least have someone help me do it haha :)

[jeepdoggydogB]

There is a really nice write up on gojeeps website documenting a 99+ intake from an XJ, but for us early pre-95 style power steering, a later model power steering reservoir and pulley need to be added. I think I read somewhere that the intakes on the 4.0 grands are the same as the XJ? I did find an engine build write up with a pic of a grand intake here.

 

http://blog.hemmings.com/index.php/cate ... mm/page/2/

 

A RHD centric writeup is here on gojeeps site.

 

http://gojeep.willyshotrod.com/

[feerocknok]

Yeah, the '99 intake manifold is an upgrade. My Cherokee friend has an extra one in case he picks up an older one, because apparently it's quite the upgrade.

[ChiefJosh]

It's not bad- I did it in my 98 XJ. I also bored out the TB myself to match the main body diameter, so it's not like a 62mm or anything, I think I made it a full 60 or so all the way through. I did that stuff about 6 months before I upgraded to 31's. It definately upped the performance, but then when I swapped to 31" tires, my AW4/3.55 combo took the performance back to about normal stock. Hope that helps. It's good, but it's not magic or anything.

[Pete M]

Gear swaps are magical. :D

[rockhardzj]

I know on 93-98 ZJ's, they are good for about a 15-20hp increase on average. Thats upgrading both the intake and exhast, as well as the throttle body. Boring the TB out gives another 1 or two, I beleive, and a nice catback system to help exhale can probably net you a total of 25hp over no mods.

There is a write up over on mallcrawlin.com somewhere. These upgrades are on my list for the MJ, once I get all the 98 XJ engine, and electrical moved over.