99+intake manifold swap
CF Veteran
Joined: Jan 2009
Posts: 1,964
Likes: 6
From: Baltimore, Maryland
Year: 1994 1993
Model: Cherokee
Engine: 4.0
Seasoned Member
Joined: Sep 2011
Posts: 464
Likes: 0
From: Muncie, Indiana
Year: 1998
Model: Cherokee
Engine: 4.0
I done the intake manifold swap along with speed daddy header, 703s, full 2.5" exhaust, spectre cowl intake, and just installed a bored TB 2 days ago. Mine feels like its got more get up and go. I can really feel it at getting up to speed on highways and passing people. And also just installed the Accel tune up kit today.....she's running better than she ever has
CF Veteran
Joined: Feb 2010
Posts: 12,367
Likes: 23
From: Oroville, CA
Year: 1995
Model: Grand Cherokee
Engine: 4.0 with all of the noise and clatter
The belt from a 96 and newer will work. To do the swap on a 96-98 all you need is the manifold and the gasket for the year of the engine. 1991-95 requires the PS pump and brackets from a 96 and newer and some belt re-routing.
CF Veteran
Joined: Nov 2009
Posts: 8,172
Likes: 17
From: The Republic of TEXAS
Year: 1998
Model: Cherokee
Engine: 4.0L HO
Geeez.....everybody has an opinion, some smell, some don't.......do whatever floats your boat. I can't believe those goobers @ JPMagazine post dyno results instead of another smelly opinion.
CF Veteran
Joined: Nov 2009
Posts: 8,172
Likes: 17
From: The Republic of TEXAS
Year: 1998
Model: Cherokee
Engine: 4.0L HO
Get baseline dyno numbers on a stock XJ. Change nothing more than the intake. Dyno again and post the numbers. Somewhere close to apples to apples would be nice. Chamging a half dozen parts including the intake and then reporting butt dyno results is about as apples to oranges as one can get.
It's going on a 92. I have the manifold, PS pump, and all the brackets that went with it. So, I should just need to get a belt for a 96 and newer? Is it routed the same as the 96 and up?
CF Veteran
Joined: Jan 2009
Posts: 1,964
Likes: 6
From: Baltimore, Maryland
Year: 1994 1993
Model: Cherokee
Engine: 4.0
Beach Bum
Joined: Jul 2011
Posts: 6,123
Likes: 22
From: Cape Hatteras, North Carolina
Year: 2000 WJ
Model: Grand Cherokee
Engine: 4.0
I did the swap and have a left-over bracket for the power steering pump, if anyone needs it. My 1996 did not need it.
Herp Derp Jerp

Joined: Nov 2011
Posts: 18,251
Likes: 17
From: Parham, ON
Year: 1999
Model: Cherokee
Engine: 4.0L OBD-II
Gotta agree about JP Mag... I don't know how everyone can post (albiey mostly anecdotal) positive results yet they're the only entity that managed to observe a decline. Even Mythbusters is more scientific than that and will say "hmm that doesn't seem right, did we do something wrong?"
Last edited by salad; Jun 9, 2014 at 09:08 AM.
Herp Derp Jerp

Joined: Nov 2011
Posts: 18,251
Likes: 17
From: Parham, ON
Year: 1999
Model: Cherokee
Engine: 4.0L OBD-II
I done the intake manifold swap along with speed daddy header, 703s, full 2.5" exhaust, spectre cowl intake, and just installed a bored TB 2 days ago. Mine feels like its got more get up and go. I can really feel it at getting up to speed on highways and passing people. And also just installed the Accel tune up kit today.....she's running better than she ever has
For example:
Ever since I switched from wearing foam flip-flops to steel plate work boots and chainsaw chaps I injure myself less. Therefore I recommend socks to everybody.
CF Veteran
Joined: Nov 2009
Posts: 8,172
Likes: 17
From: The Republic of TEXAS
Year: 1998
Model: Cherokee
Engine: 4.0L HO
The Internet myth is......"on a pre '99 STOCK motor, the '99+ intake, all by it's lonesome, will add 5-30 hp". Again, that's the Internet claim/myth. What JPMagazine did was simply swap the '99+ intake on to a stock '98 motor and post their dyno results.....and their results were a 5 hp loss. They did not start with a motor that had a long list of mods and then the last mod was to swap intakes. Again, what was stock about that motor in that link when the dude changed the intake? Apples and oranges....but hey, at least he post real dyno numbers, not butt dyno numbers. Again, all JPMagazine did was post the results of their apples to apples comparison of a '99+ intake manifold on a stock '98 XJ. What do u want JPM to do?.....dispute their own dyno test results showing a 5 hp loss and say "but that can't be right because we read on the Internet the '99+ intake only swap is good for 5-30 hp and since we read it on the Internet, it's not a myth, it's the gospel".
CF Veteran
Joined: Nov 2009
Posts: 8,172
Likes: 17
From: The Republic of TEXAS
Year: 1998
Model: Cherokee
Engine: 4.0L HO
A direct quote from the apples/oranges intake comparison in the link above:
Head Modifications
As this evaluation of the intake manifold is not being done on exactly a stock engine, due to the oversize valves and ports, I thought I should detail what we did to make sure there is no misunderstanding of the test results. It might be possible that a stock engine might not see quite so much improvement, as my engine has the below modifications to the cylinder head. I have not documented the manifold change on a stock four-liter head engine.
Head Modifications
As this evaluation of the intake manifold is not being done on exactly a stock engine, due to the oversize valves and ports, I thought I should detail what we did to make sure there is no misunderstanding of the test results. It might be possible that a stock engine might not see quite so much improvement, as my engine has the below modifications to the cylinder head. I have not documented the manifold change on a stock four-liter head engine.
CF Veteran
Joined: Jan 2009
Posts: 1,964
Likes: 6
From: Baltimore, Maryland
Year: 1994 1993
Model: Cherokee
Engine: 4.0
How much does a dyno test cost anyway? I have a few '99 intakes and a stock '93 XJ. If we can take up a collection I'll do a before and after test myself.


