Alright so I've got a 1996 XJ with the square intake manifold. I am going to covert it to the horseshoe intake, rotate the throttle body 90°, and modify it in a few other minor ways. Why you might ask? Stay tuned to hear the method to my madness!

 

So first thing, the intake manifold. I know I hear a lot of people say they see some horsepower gain from the newer intake, and some people say none. I don't believe I will gain much apart from quicker throttle response. I do want to upgrade it in hopes of MPG gains through an easier flowing intake. I don't believe it flows more air, just easier flowing air. I'm even going to port the runners to match the gasket. It's kinda tedious but I tend to be a perfectionist!

The second point about this is I'm not going to use a 97+ XJ intake, rather I'll be using a TJ. Not because the intake it's self is different, but because of what the TJ comes with. The TJ intake manifolds has a curved throttle body wire harness cover that goes back behind the manifold. They look similar to the fuel injectors wiring cover and this is why I have chosen to go this route. I find it aestheticly pleasing, also it will pair well with a few other mods I have planned. I want to buy a new valve cover I've been looking at online, not because I need a new one but because I want it.



I've already highlighted a few other parts in my engine bay with silver sharpie and this this would look sharp. I'm also converting my 1996 country into a Briarwood so the chrome seems appropriate.

Anyways, this is part of the reason why I want the TJ harness cover with the new intake. Alongside this, I do not want to cover up the beautiful 4.0L on the valve cover which is why I want to rotate the the throttle body and move the cables!

 

Sorry, I forgot to attach some photos of the plastic cover. It's been impossible to find as a standalone product so I don't have any stock images of it, only screenshots of YouTube.





Anyways, you get the idea.

 

There are two reasons why I turn the throttle body:

1. It will take the cables off the valve cover and place them towards the rear of the manifold. So as explained before, I want to take the cables off the aftermarket valve cover so show off the embossed 4.0L. Rerouting the cables won't be too hard, all I'll have to do is modify the factory or create a new bracket. I'll also have to relocate the vacuum currently located by the PDC. This is already going to get moved because of my dual battery setup so it's not much of a problem.

2. It will align all of the electrical connectors to the drivers side of the vehicle. This is goof for me because I want to utilize the TJ wire cover to keep everything OEM looking, and neat and tidy. I don't plan of having a car show Jeep (yet) but I want it to be as proper as possible.

 

I'm sure I'm going to be asked a lot of questions about why and how, so I'm going to try to predict those questions as I talk. Most of the why's I think I've covered. Now for the hows.

So apart from the cable relocation and rerouting, physically turning the throttle body doesn't seem to be that hard. It may not work. And it may work but not with the larger bore throttle body I plan on getting. Im just trying something new.

First thing's first, remove the current TB.




After 215,xxx miles, she's looking her age. I'll clean it up in the ultrasonic later. Let's get to disassembling.




Most everything looks in good condition, just dirty. Next thing to do is to plan out how we're going to modify to work for our needs.

 

So the sensors are going to be easy. The way these are designed is the soul reason why I think I'm going to be able to pull this off.


MAP sensor can be flipped upside down and put back together with longer screws and spacers.


Top view.


This may be able to be used and it would prevent the use of the spacers.

With the MAP sensor figured out, and the TPS staying the same, the only thing left is the IAC sensor.


Before.

After.
All I did was rotate it in the housing. Good thing it's semantically!

 

So there's a vacuum line that I will have to relocate because it interferes with the IAC.


You can see the fitting installed right next to the TB hole.


And once it's removed...


It's still too high. Ill have to shave it down and plug it. It may be different with the horseshoe intake but this is what I'm working with for now.


Mocked up. You can see how the sensors are all now oriented towards the driver's side of the intake, right where the TJ harness cover will be.

The cable bracket fits right under the fuel rail. I originally though I would have to use a TB spacer to move it above the fuel rail if i wanted to do this but all I will have to is notch the arm just a bit so the butterfly valve can return back to idle.

Ill have to shave down a little bit of the plastic so its not resting on top of the fuel rail at idle.

For the most part, it looks like minimal work is needed to make this work. I don't know, maybe it won't work at all. I'm slightly concerned with the direction of the butterfly valve if it's not at full throttle then the air would be directed more towards the front cylinders and the rear may somewhat be starving. I'm not sure if this would be more of an inconvenience or an actual problem. Anyone got any insight?

 

So alongside the intake manifold swap, the throttle body rotation (and eventually swap) I plan on swapping the air filter. This is partly because of aesthetics but also because of my dual battery setup.

I have a few options. I could route it to the cowl near the cabin air intake or snorkel like a lot of XJ'ers do but I want to go with something more unconventional. I'm thinking about an open V8 carburetor filter style. Let me show you.






After some research, I've found one that I liked:






It measure 13 inches in diameter, which is larger than what I want but I couldn't find the same one but smaller. The lower opening is also too large so I'll have to spot weld an adapter plate to fit the TB. I'll also have to get an adapter to mate a carb air filter with a center screw to a TB. Easier said then done.

 

I already know a lot of people are going to say those are oil baths, but I think it's something I can work with. I am also contemplating on adding a valve cover filter so they are independent from each other.

Anyways, with me not adding a TB spacer, I think I'll have enough room under the hood the open air filter. If not, I can get a lower profile filter. Also for anyone wondering, this is how much room you have under your hood:



Additional information:


This is the style adapter I was talking about, otherwise ill have to use silicone tubing and clamps to put it together (which I don't want to do)



And if there are clearance problems, i could look into getting an aftermarket fuel rail with hopes it would be enough to solve them.

 

So everyone who has an XJ know of the infamous overheating problems such as heat soak. Fortunately for me, my 96 doesn't have that yet. In mdifying my Jeep, it is my concern that I'll change the geometry in air flow and make it hotter to the point where I'll be forced to join the club. So I'm going to do what I can to prevent that. Now I do understand that engine temperature is different than engine bay temperature. In the 4.0 community where the intake and exhaust is on the same side of the engine, this can sometimes be confusing as they play roles into each other's problems. With a new manifold, TB, filter, and probably the fuel,, 'm sure I'll need to update the exhaust to compliment it. I've already added heat wrap to the exhaust manifold when I repaired my head gasket, but there's more I can do. I would like to swap an aftermarket header that is slightly larger and easier flowing. With all of this I plan on adding a heatshield to the underside of the intake to keep that cool. Because of the temperature change based of the parts swapped, I need to plan on improving the quality of air going into and out of the engine, and the engine bay.

 

Now I'm sure it's not a shock that I'm waiting to add a hood scoop or hood vent onto an XJ. The long time problem that I've had is I require a good balance of form and function. To me, if it doesn't look good, then is it even worth it? In a daily driver I think it's more important that its reliable regardless of how it looks but for my Jeep, that's not the case.

Now, where to begin? I have four problems to solve. I need to make sure that air taken into the engine is cool, enough air can come into the engine bay, air exiting the engine doesn't soak into the engine bay, and the air in the engine bay can be exhausted. Pretty simple when you break it down.

To solve both intake problems I believe I have an answer with a hood scoop. To regulate engine bay temperatures I need to not crowd the engine bay too much an control the heat from the exhaust, and make sure I have enough ventilation to get rid of the excess hot air from the bay.

So first, the hood scoop. with an open air filter, I can tailor a hood scoop to work for it, no problem. Like everything else, I NEED that balance between form and function. With the hood scoop I believe I can get cooler air to come into the engine bay also. Now with an open filter I know that my intake is only as cold as my engine bay temperature which is what most people don't understand about short ram intake mistake them for cold air intake that draw air directly from outside, which is exactly what I would want to do, and I think I have a solution, hear me out.

 

So I have a problem in finding that good balance. Since my build is to heavily modify my jeep and also retain the OEM look, and since XJ's and MJ's never came from the factory with scoops, it's hard to predict what OEM would look like. My taste in scoops is subtle and low profile so I've got to find a mix of what meets my taste and what the needs of the Jeep. Most people have installed Grand Cherokee and LeBaron vents and I don't rhino they look that bad. I think the GC ones look better on the 97+ and the LeBaron ones fit the squarebody -96. But most people cut the holes and lay them ontop where I would want to countersink them in (have I mentioned I'm a perfectionist?) I am at a disadvantage that the intake is off center and the hood has deep body lines in the center anyways so to me,, that's shot. The solution that I've came up with is a roadrunner air grabber!

There are two basic styles. The first is a pop up hatch that is operated off the vacuum system and the other is vent system that channels the air to the open air filter. If I'm able to, I'd like to incorporate both styles.

 

So air grabber parts are EXPENSIVE even used on eBay, so I will have to fashion my own. I plan on using an electric actuator instead of pneumatic and run it off of my second PDC. No biggie.

I plan on mounting the air grabber hatch right above and slightly in front of the filter. I am hoping that the engine bay temperature will be fine to intake but if not then the air grabber will supplement. It will also take cool air into the engine bay to prevent heat soak. The retractable hatch is also a benifit that I would have to worry about trays to direct water.

I also want to have exposed hood vents that exhaust hot air out. Because if my tastes, this was tricky to decide upon. I've came up with firebird transam vents. They are low profile, subtle, and will do nothing but aid with heat soak from engine bay temperatures. I plan on mounting them in the same location. I'll have to cut through the hood's underside skeleton but that's fine with me, I'll supplement with reinforcement somehow. These are them:





With the air grabber intake straight to the filter and the fire bird exhausts, I think it will be a good clean look and have good funtion and the engine bay air is pushed to the back to exhaust out while driving. I do take my jeep offroad so I'm not too worried about near-idle temperatures, just red light temperatures. If temperature becomes a real problem, then that sounds like a problem for my future self. 🤣

 

You're in deep !! When you said air grabber I thought you might have had one to use.. Yep, the sticker shock is there for those parts.. There's a few companies that make reproduction parts for them as well but even those aren't cheap..As you've already stated you'll need to direct rain water away from the scoop's air charge no matter what you use..Heck even the factory air grabbers weren't completely dry in a rain storm regardless of the factory routing.. I remember soaking the air cleaner more than once.. You may need to modify the TA rear air vents I don't remember mine being open to the elements..Keep the thought processes flowing you're doing great..

 

Thank you for the detailed thread. Very clean amazing work.