Hello guys!
The topic of using filters for each cylinder bank on MFI cars has come up a decent number of times. The answers are short, such as: " Yes it can be done, here is a pic.” Well, that gave me enough motivation to go about it myself. I am not reinventing the wheel here, just documenting. However, I came across a couple of hurdles, as well as one compromise. I hope this serves as instruction for anyone wanting to do this for themselves. I do not want this to be an argument against the OEM box setup. I read and saw a couple threads around these filters being not as good and some threads saying they are better once the MFI is tuned proper. For myself, I like the look and sound. I had plenty of years with other platforms looking for just performance only. However, as I age, I am just looking for a good time.
Anyways, this is the PMO kit I bought: https://www.partsklassik.com/p-4533-...rburetors.aspx
It came with water hats, but I will go with the flat tops down the road. The flat tops just look better. Additionally, If you go about putting these filters on a MFI car, doing the flat tops saves a step.
Also, I want to point out that my walk through only relates to MFI cars with mag stacks.
So, the first issue is mounting the filter bases. Each base has four stand offs to bolt on to the filter base. These stands offs are there to be able to mount the rain hats on top of the filter to seal it. The issue relates to the stand offs being mounted with some button head allen bolts. They just plainly get in the way of mounting flush with the surface of the mag stacks.
If you use the filter base gasket as a template it is shown as an issue below:
Now for a picture of the base on the mag stack just to illustrate the issue further:
Now there are two solutions in my opinion. You could opt out of using the stand offs and using springs to seal the filter down. To do so, you will need flat tops versus the rain hats. Then from there you would have drill tiny holes on the edge lips of the bases and flat tops. Those tiny holes you drilled can be used to hold the springs. I did not want to go that route, plus I have the rain hats handy now.
Example of spring method:
So, the other route is to use countersunk bolts and dimple the filter bases to accept a countersunk bolt. There are a number of ways to dimple the filter bases, I chose an economical one. I had my cousin 3d print the female portion of a dimple die. Then from there I could just use the countersunk bolt, washer, and nut to clamp the die into the metal.
See below:
3d printed female die with countersunk bolt
I then greased both sides of the metal, then sandwiched the filter bases between the die and bolt.
From there I tightened the bolt and nut together to dimple the metal. Now if you are unfamiliar with 3d printing, it may be a surprise that the plastic is durable enough for this job. It is strong enough to a point. This dimple die can only be used a couple of times before it starts deforming.
Then I bolted on the stand offs, and I used some red lock tight as well.
The filter bases sit flush now.
The right side bolted on easy, but the left has additional hurdles. I needed to modify the lever arm on the cross bar because as the throttle opens up it will hit the filter base. I deleted the shut solenoid and microswitch, so it wasn't an issue for me to modify. Keep that in mind if you want this setup.
I trimmed the lever arm. I also drilled a hole for an additional spring, as well as put a tiny notch for the oem spring to fit into. Because I removed some material, I wasn’t sure if the oem spring could possibly slip off, which is why I added that notch.
Pictures of the modification of the lever arm below:
Now the compromise in this installation is the left side filter. The filter will hit the baro cell. So you just have to smash the mesh on the filter to have it fit around the baro cell as best you can. I was already aware of this issue. I've seen it on a number of pictures. One solution is to delete the baro cell. I actually bought a delete from Supertec, but I decided to not install. I recently with through the CMA process, and the car is running great. So I rather not mess with it.
Last step is to clearance the rain hat around the baro cell. I still need to remove some more material but the picture below gives you the right idea. I am going to buy flat tops. I figured I would have the prepped rain hats on hand in case it starts raining on a road trip. This process was probably the least smooth. I slipped with the Dremel a couple times and hit surfaces I did not want to. It can be fixed down the road. I am thinking of sending them to powder coat with some other items.
Fully installed:
Thanks for reading.
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