4.0 HO Intake Manifold?

[Legacy]

Does any on make a proformance Intake Manifold for the 4.0 HO?
Thanks for any input, Legacy.

 

[5-90]

Nope - not just yet...

One option is to get a newer "generation" intake manifold - if you have an HO. It is possible to adapt an HO manifold to a "RENIX" engine (1987-1990,) but it does take some work.

The "generations" for intake manifolds are:
1987-1990 - RENIX
1991-1995 - HO/OBD-I
1996-1998 - HO/OBD-II
1999-2004 - HO/OBD-II (Mk. II)

By all reports, the 1999-2001XJ and 1999-2004 WJ manifolds offer the best improvement due to runner design, but I've not done the maths myself and I've not been able to compare them yet, so I'm not sure. One of my "blue-sky" projects is to work out a manifold design that can be "home-fabbed" from plenum to mounting flange, and is tuned to either peak torque or peak horsepower (I'll have to come up with a few versions...) No estimated date for this idea - I've still got to get some information...

I plan on something similar for exhaust as well, so we'll see how that works out...

5-90

 

[MN-Cherokee]

I have heard that the 1999+ manifolds will bolt up to the head, but is there any other modifications??

It would be for a '97 XJ.


Brian

 

[pec50]

This might provide you with useful info:

http://go.jeep-xj.info/HowtoIntakeManifold1.htm

 

[MN-Cherokee]

Ok, I read through Go-Jeep's article. It seems pretty straight forward. However, I noticed he had to customize a few things.

Is the PCV valve he refers to as the "later model" the one my '97 already has???

What about the vacuum lines??

Also, will my stock fuel rail and injectors fit the new manifold??

Although his is a '95. Does that make any difference??

Will I have to do these things to my '97??

Brian

 

[rsalemi]

A 97 should be a straght swap with the 99+ manifold. I have sold several for $149 to Jeepers doing this swap. The fuel rail is a bolt on, as is the PS pump.
[email protected] if you want one.

 

[jpdriver1]

will these maifolds fit with the renix system? trying to figure out what series of engine to put in my 90 mj
thanks

 

[Mike@Accurate]

I posted this 2 days ago in the HO TB on a RENIX thread:
>Although an HO manifold can bolt-up to a RENIX head, the ports won't line up. If you mod the dowels to line-up the ports, the injectors will fire into the manifold face of the head. (injectors are in the same location on both, RENIX have a longer "slot") Furthermore, RENIX and early HO's have adjustable PS pumps to achieve belt tension. Late HO's (including the '99-on) have rigidly mounted pumps and a sliding belt tensioner. You would have to swap the whole package. It would pay-off to swap to HO if you did a head swap at the same time. Better (cheaper/easier) to just use an HO TB on the RENIX manifold. I haven't made the TPS adapter before, but someone has, I'm sure it is on the web somewhere. I have adapted RENIX intakes to work on HO heads, takes welding & grinding ($300) to raise the ports. It would be a similar process to lower the ports in an HO manifold to match a RENIX head. Good luck, MIKE<
Good ?
MIKE

 

[MN-Cherokee]

Would the late High Outputs include the '97 year??


Brian

 

[Mike@Accurate]

I think that the pumps became fixed late in '95 or with OBDII in '96. Adjustable pump manifolds will have 2 bosses for the pump brackets and fixed will have 3 bosses that the pump mounts directly to. The sliding belt tensioner also has 3 holes for the pump in it. The bolts go through the steel adjuster bracket, then through the pump body and thread into the manifold. Wranglers have a fan mounted to the water pump and XJ's ZJ's etc have the idler mounted fan. Belt routing and associated brackets are changed a few times depending on model & year.
Your '97 (and the late(st) manifold) are fixed pump. Hoses are all there, but in different places due to the different layouts of the plenums. You may have to lengthen/shorten the IAT wires, late (pencil) injectors won't plug into your harness, but fuel rails are the same. You (and the late(st) manifold don't have a PCV valve, the tube from the rear of the valve cover is an "orifice tube" and it's flow is calculated in the idle air circuit. Get one from the donor, or don't shorten yours from the VC end.
My '00 XJ got recalled to put a shield between the intake & exhaust, seems leaves could get in there and set the fuel rail on fire, you might want one.

 

[MN-Cherokee]

You (and the late(st) manifold don't have a PCV valve, the tube from the rear of the valve cover is an "orifice tube" and it's flow is calculated in the idle air circuit. Get one from the donor, or don't shorten yours from the VC end.

So I need a new "Orifice Tube", or does mine just need to be shortened?

BTW, thanks for the time in explaining this to me.


Brian

 

[Mike@Accurate]

I really don't know if changing the "orifice" tube a little in length will effect things much. It is roughly 1/4" id plastic and the plastic tube goes into the valve cover a little bit. I wouldn't be tempted to put 1/2" hose on there, because too much air will get in. The tube will be a different length/shape on the donor and your truck, but either will probably be adaptable. Just don't make a drastic change in the air-flow capacity of whatever you use. MIKE

 

[MN-Cherokee]

Ok, I already know that the fuel rail fits. Do the stock '97 injectors fit the manifold??

Brian

 

[Mike@Accurate]

Yes. MIKE

Ok, I already know that the fuel rail fits. Do the stock '97 injectors fit the manifold??

Brian