XR4 Cold Air Intake

[Luke Plaizier]

I've been ruminating and disliking the Mountune 'Hot Box', or those that put pods on their Fiesta intakes just to suck in all that hot engine bay air.

The Mountune solution looks professional but has holes everywhere, and will suck in just as much hot air as without the box, but the box is needed to pass Australian compliance.

So I'm doing some researching on my own to see if I can come up with a 3D printed solution for a revised intake system that is sealed and can draw air in from over the radiator or through the lower grill. This is road-car focussed so I'd not be keen on the lower fog replacement options I've seen.

The first thing I looked at was the factory solution - for both the 1.6 and XR4 over-the-radiator intake plastics. And interestingly there is already a difference. The 1.6 draws air just through the hole in the top cross member, by the XR4 draws are through that AND through a gap over the cross member itself.

Of note, the profile of the top cross member on the XR4 and 1.6 is different, so the XR4 intake will not fit on the 1.6 or vice versa.

Cross Member intake 'hole' - this image from a roadgoing XR4.



The 1.6 Intake shroud:



This is the XR4 shroud just loosely sitting in place:



Comparisons of the 1.6 and XR4 shrouds - the XR4 is noticeably higher due to the space above the cross-beam that allows it to draw more air, and the tube is offset to clear the XR4 send-throttle body vs the 1.6 'within the intake manifold' throttle body:





Lukeyson

[Luke Plaizier]

So, the Mountune Kit. It consists of some silicon piping to connect a K&N RC-5134 70mm offset pod filter and fit it inside a plastic 'box' with upper and lower half clamshells. You can see from this image that the upper clamsell uses the same mount holes as the factory plastics, but it does not provide any 'over the cross beam' additional air flow.



You might think that cold air would get sucked through that port, but you'd be wrong. The upper and the lower box are significantly different shapes, they don't seal together, and there are holes all over the place.

On the back:


On the side facing the engine:


It's just not conducive to Cold Air at all. It does have a lower hose connecting down to the lower front grill for cold air, but that's a bit of a waste of time when hot air can be so much more readily drawn into it.

There's not much room in there when you see the top off - it's all a bit of a squeeze - so you can't really be too critical for them making the best of a difficult situation. The location of air pod is somewhat limited by the use of a 45 degree silicon tube with the head breather offshoot.



So that's the constraints of what we're working with.

Is there a better way? I'm hoping to give it a try.


Lukeyson

[Luke Plaizier]

Firstly, I think there's good room in gap between the hood and over the cross-beam to make for a wider 'ram' style Cold Air Intake as used quite often on CAI kits for Holdens and Falcons.



One of my efforts therefore may be to draw up an over-the-cross-beam CAI ram-intake that feeds to the standard XR4 intake piping. I might need one version with the standard diameter tube or might also do one with a large diameter tube. Along the lings of this BF Falcon 'big mouth' cold air induction kit:





Lukeyson

[Luke Plaizier]

If I want to enclose the box, it will need to be in a fixed location, which means I'm going to need an induction tube solution that can accomodate a lot of movement. I spent a bit of time trawling some websites to see what options I had. The two that look like they might be useful are the 80mm long 70mm to 70mm hose hose from a lexus ES300, or the 100mm long 80mm to 700mm hose from a Nissan Maxima.

Lexus ES300 Intake Hose (Image shows a DAYCO part number)



Nissan Maxima Intake Hose (Also a DAYCO part number)



Both of those parts appear to have $8 options on Aliexpress, so for the purpose of testing and sizing, I bought both from there.

I was also after a 70mm pod filter, and while I can continue to work with the offset K&N filter we have, I had a look also at Aliexpress, and found a 70mm pod airfilter non-offset for small dollars as well, so have ordered that.

https://www.aliexpress.com/af/70mm-R...20210701013506

So other than the 'wide mouth' intake, the intention is to:

(1) Create a lower box with sealed edge and clip faces.

(2) Create an upper box that does the following:
(a) Adapts to the over-the-cross-beam intake.
(b) Mounts the Pod Filter
(c) Adapts to one of the selected Intake Tubes
(d) Has a rear outlet for the Head breather line
(e) Has clip faces and a sealed surface to seal to the lower half of the box.

We could optionally have a lower tube for routing to the lower grille, and I could make a proper 3d print contoured adapter for that. We'll see.

When parts start to arrive, we'll see how much progress I could make on such a system.

In the meantime, back to making progress on the climate control and MTX75 mounts.....


Lukeyson

[LeighMJ]

There's also this - https://www.knfilters.com/69-4002tb-...-intake-system

[Crazy Dazz]

Originally Posted by LeighMJ

There's also this - https://www.knfilters.com/69-4002tb-...-intake-system

Wrong model.
We have the WQ, and one of the reasons for fitting a 3rd-party intake, is that it can be done with a very short run.

[LeighMJ]

Originally Posted by Crazy Dazz

Wrong model.
We have the WQ, and one of the reasons for fitting a 3rd-party intake, is that it can be done with a very short run.

Multiple sites list that it fits the 2.0L ST150/XR4

https://www.focusrsparts.co.uk/ford/.../cat_2164.html

Install instructions - https://static.speedwaymotors.com/pdf/465694002TB.pdf

Or there's this one which looks to sit just behind/under the passenger side light - https://motorcade.co.za/product/ford...ld-air-intake/

Cheaper option than the 69-4002TB - https://www.focusrsparts.co.uk/ford-...prod_4695.html

[Crazy Dazz]

Originally Posted by LeighMJ

Install instructions - https://static.speedwaymotors.com/pdf/465694002TB.pdf

Looks like the design was a collaboration between a German, an Irishman, and a Mexican..
Apart from the expense, and the absurdly complicated install, I can't even tell where the filter ended up?
Obviously it's hard to find a spot that's big enough for the K&N filter and gets cold air, but I'm not convinced hanging them down so low is the right solution.

[Crazy Dazz]

• I'd be interested to know what if any gains were achieved with these mods? When these cars were new, and we had our own enthusiastic forums, they were all the rage, but the best ever claimed was that they sounded better.
• Yes, never understood the point of claiming "cold air intake" then positioning it to suck in hot air from the engine bay.
• Never fully agreed with the point of the factory shroud. I gather it's meant to protect the intake form water and debris, but it also interrupts the flow of air from the front, especially when not moving
• One option is to relocate the battery, but that's a lot of work
• Another option is to put the filter in a shroud (or use a SAAS setup) and try to source the air from behind the headlight, as there are some large gaps there

[Crazy Dazz]

The GGR system is another interpretation. It's basically a dome-shaped housing with a duct to draw the air through the cross-member:

No idea how hard that might be to replicate.
Given how small that slot is, I was thinking maybe something that also left the end of the dome open to pull some air from that gap behind the headlight

[Luke Plaizier]

Bits arriving. That cheap pod filter is all plastic and does not fill me with confidence. I thought it would be a bit bigger going by the dimensions. Notably it is a 76mm inlet diameter pod with a 76mm to 70mm rubber 'shim'. It's main purpose will be to serve as a sizing and fitment dummy anyway, and the equivalent K&N can be sourced later, so it still fit for purpose. The Maxima 70mm to 80mm intake tube is also here...



Lukeyson

[Crazy Dazz]

Just a thought, if going down this route, do you think it's worthwhile upgrading to a 60mm throttle body?

[Luke Plaizier]

I understood that the 60mm throttle body still had an O/D of 70mm, and was essentially the same throttle body physically bar the internal throat diameter. So any plumbing factory or otherwise should still work.

I've not had experience with the larger throttle body myself. Does it make much difference?

Lukeyson

[Crazy Dazz]

nfi
Seems to have been a popular mod

[LeighMJ]

Originally Posted by Crazy Dazz

nfi
Seems to have been a popular mod

Yes, a popular mod. I have one but haven't fitted it yet. Some people say it helps, others say it's no use unless you're doing other mods to go with it like an inlet manifold - https://www.sico-developments.co.uk/...inlet-manifold

[Aaron]

I have a 60mm on my car. I run it with a tune and have been able to shift fueling to compensate for it and the other bolt-ons I have.

Effectively it’s no different to adding a throttle controller that opens the throttle earlier than the foot says, on a stock tune it means lots of lean outs as the ECU gets more air per the tile position (remember drive by wire still has a relationship of pedal movement to throttle body movement) and then has to adjust the trims to suit. My car was showing consistently positive Fuel Trim values and also would lean out when looking at logged data.

I’ve shifted to running about 8% more fuel across the board and it’s better to drive.

Anyway I wouldn’t bother with it, mine was cheap and new and as such doesn’t have some roughness of motion that my stock one had.

[Aaron]

On the airbox front I made a shroud to keep more incoming cool air around the TB while moving. It helped a bit, it sealed the upper area from cross member intake over the filter up to the washer filler and walled in the back and side of the filter. Like the mountune, warm air was always coming in, but by making the air from the vehicle movement move in a more set path I did see drops in intake air temp “sooner”. But not significant enough.

No perceived power change.

I’m of half a mind to blow mould some spray foam in a bag with some basic walls to get a volumetric representation of the space then shave that buck down 10mm and vacuum form around it.

[Luke Plaizier]

Or cut up a block of light foam from Clarke Rubber...


Lukeyson

[Aaron]

I mentioned this elsewhere but after an especially depressing long drive on a very hot day where intake temps were heading toward 60 degrees Celsius I decided to experiment more.

I had removed the shroud from around the pod a while back, so obviously the high ambient temperature, massive radiant temperatures off the road surface and engine temperatures were all working against having lower engine intake temps.

The biggest flaw with the shroud Is made was that it lacked a floor - the filter was directly above the upper rad hose and every bit of heat in the engine bay was available to be drawn into the filter.

So I made a floor, lined the outside of it with some foil/butyl deadener then wrapped it in 5mm closed cell foam. I also wrapped the inside of the shroud in the foam. Managed to wrangle it all into the engine bay and sealed it somewhat together.

I now have consistently much lower intake temperatures, and can push very close to ambient temps very quickly when driving (in Summer). Otherwise the intake temps take a little longer to rise in traffic.

My setup is ghetto - but I think taking the Mountune and applying some heat reflective materials to the underside and insulating on the inside as well as making sure the lower intake gets good cool air from the grille will work better again.

One other thing is that by shrouding and then insulating the shrouds the intake noise is reduced a lot. Both inside and outside of the car which is actually a good thing.