ITG air filter for 20v ITB

[marvinng]

The installation shown below is my 20v blacktop with ITG air filter and T3 velocity stacks.





To accomplish this setup, the following parts are needed:

ITG Model Megaflow, JC-40/100
9JC40 baseplate
3@ female stud receptacles (BPC)

I purchased the parts from Coast Fabrication. Cost about $150.

The aluminum baseplate is blank, so you’ll need to cut the openings to match the throttle bodies. The female stud receptacles are mounted to the baseplate and they allow the filter frame to be secured to the baseplate. If you have a heater valve, you'll need to install a 3/8" spacer between the baseplate and ITB to clear the heater valve. See picture below:



All machine work on my ITG setup was done by AMT.

Cheers,

Marvin

*****************
(story behind it)

When I decided to upgrade to 20v blacktop, one of my concerns was air filtration for the ITB. Some popular options I have seen are sock-type (Uni-filter, Pipercross) and cone-type (Garage Annex, Jubiride) filters, but neither option looked too promising, from a mechanical engineer’s perspective.

Sock-type filters are directly over the velocity stack inlet, and they tend to get sucked into the throttle bodies. Sock-type filters are also known for robbing horsepower.



Cone-type filters are installed over a short piece of straight pipe. I call it a pipe because it does not have a bellmouth inlet, which is crucial to the design of velocity stacks. I don’t know how good an ITB system is without proper bellmouth inlets.


(Garage Annex kit)

In my search for a “better” air filter, there was only one inspiring setup – in Akira Iida’s famous AE86:


Featured in HyperRev Vol. 48. It says Formula Toyota use air cleaner.

As you can see, the entire filter fits over the velocity stacks (well, actually you can’t see the velocity stacks). The filter is big enough so that the filter element is not in contact with the velocity stacks. This setup is superior to the sock-type and cone-type filters in different ways:

1. You can run proper velocity stacks, and the fluid dynamics of the bellmouth inlet is not compromised. For instance, with JC40-100 and T3 velocity stacks, there is an inch of space in front of the velocity stack inlet.
2. The entire surface area of the filter can be utilized to draw air, thus the air velocity and pressure drop are much lower.
3. Since the entire filter is reinforced, there is no chance of sucking the filter into the ITB.

With the help of a good machinist friend, Adamturbo, and a bit of trial and error, the ITG filter was installed on my 20v blacktop. As far as I know, this was the first ITG filter setup that appeared in AE86 forums.

Concerns:

1. The stock washer bottle doesn’t seem to fit. You can either remove it, or use the one from a SR5.
2. Air filter oil, which is gross and sticky, will unavoidably get on your arms and engine bay while installing the gigantic filter. You can use dish detergent to wash it off.
3. When using it on 16v ITB, will the 3/8" spacer be enough to clear the heater valve? Will it be needed at all? I have no clue ... someone can try it and let us know.