After having added a 3.5" intake it was time to create and install a divider to keep cold air separate from hot engine air as much as possible. (The R loves colder, denser air!)

I bought galvanized flashing, pipe insulation, and flower bed metal edging trim at the hardware store. I got together some cardboard, a marker, straight edge, and scissors for cutting metal/cardboard.

Using the scissors and marker I created a mock up of the divider. I then transferred the cardboard mock up to the galvanized flashing and cut it out. I trimmed pieces of metal edging trim for the edges that were not along the top. I then cut pieces of pipe insulation and fitted them along the top edges as a seal against the hood. Over time I will determine if the seal is good enough; if not, I will replace the current insulation with thicker insulation until I can get a good seal.

A nice plastic molded one that fit perfectly would be great, but I am hopeful my home-brewed creation will get the job done for very little money

I hope this is helpful to others.

 

Let's hope it works...... I must admit I am not a fan of having the filter in the engine bay but looking at the XJ you really are restricted, I've even thought about relocating the washer tank and piping it down there, I may even go the CDA route...... I am unsure yet, my new bumper design does give me more room but we shall see

Well done

 

I will use my OBD2 reader to test intake air temps (IAT) to determine if it is doing its job. I have seen the filter placed in the cavity just in front of the passenger (USA) wheel well. Unfortunately, the XJ's don't have the room to do so.

 

This is what I did on my XK but I no longer feed the breather into the intake, so this particular tube will be sold and I will make another, I have done it now on quite a few XKs with 4.0s, not so much on 4.2s as the breather is a different setup and goes into the tube by the TB



I still like to use an enclosed air box and I am using a Green Cotton twister aluminum case with a large cone filter rated to over 700bhp, the point is I would like do something similar on the XJ

 

Wow, that looks great!

Question: I see a brace attached to the strut mount. Is that stock or did you add those? Could they be applicable to the XJ? If so, that could be a simple way to tighten up the front end.

 

I added the strut brace, my XKR is a coupe, I got the idea from the convertibles, when I took a look at the bulk head on my coupe I discovered the same fixings were also present as on the vert so I made them up out of solid aluminum with a stainless ball joint attaching it to the strut tower which also has one of my strut caps on it......

I have noticed the strut top on the XJ is a bolt on steel item, I might remove these and get them chrome plated, I have not thought about attaching a brace but I will take a look.....

 

Now THAT is the way to do it!

 

Prior to installing the cold air divider my intake air temperature (IAT) was running 10-15 degrees warmer than the outside air. Today, I hooked up my OBD2 and watched the IAT. When at a stand still the IAT warmed to about 15 degrees higher than the outside air. However, when moving the IAT dropped to the same temperature as the outside air - a good sign! I will continue to monitor how well it can keep the warm/hot engine separate from the cooler outside air.

 

Nice one Dan...... All you got yo do now is bring it down below ambient

 

Okay, XK, you got me: how do you bring IAT below ambient air temperature? Are you referring to products such as Killer Chiller or water/meth? If so... in due time

 

Easiest way is water/meth, I did find a website that shows you how to make a setup for $240, CLICK HERE, lots of good info......

 

This is what I am using Snow Performance Boost Juice Water Methanol Mix 1 Gallon Set of 4 | eBay

Your IAT#1 was showing 10-15 degrees above ambient, but that is BEFORE adding 14 psi of boost. It is the after boosting temp that matters.

 

Agreed, WD.

All I am saying is that the cold air divider appears to be doing what I was "designing" it for. Namely, to minimize hot engine air from the intake.

Once I have verified it is doing it's job I can move on to lowering the air temp as you and XKRacer have said. Or, to put it another way, I can then move on to the fun stuff!

 

Mine reads approx +2-5 degrees over outside air. There might be some air coming in from over the top of where the tube is going through. You could try sealing that area off too. I also used tape to seal off as much as possible.

And I also cut a larger hole behind the headlights on that side, and I'm running a 3" hose from the fog light hole to this area as well.

 

I just did another intake today, this is a 4.2 (05MY) XKR, did the tubing trick behind the headlamp too, in the last pic you can see the pipe under the headlamp, bumper will go back on tomorrow, making a special grille for this one to...... I might take some IATs out of curiosity..

 

Gotta get rid of that cobra head or what is the point?

 

The effectiveness of the full intake can be measured by reading the vacuum at full throttle. You want close to 0 mbar, and I think a stock car (so also stock setup), would be somewhere arround 130 mbar or so.

Increasing for instance the supercharger speed, would also increase here the vacuum if you leave the intake stock.

Less vacuum = more power

As long as one doesn't post the vacuum readings with their intake setup you have no idea about its effectiveness at wot.

 

The elbow into the TB is different to your stock 4.0, I would not necessarily say it would make that much difference, if anything losing the breather going into it would be more beneficial, having smooth air flow and not having all the baffles help, damn thing looked like an octopus!

 

An octopus that got run over by a lawn mower!

 

Has anyone thought of running a velocity stack with the filter over it? I think that would be nice having smoother air drawn in.