Filters / screening for the 72-73 MFI Plastic Stacks

[bavaria911]

Please post a photo of your modified air filter or screening for the tops of the 1972-73 MFI plastic stacks. I want to try something real radical. I can always use the stock air box for rain and bad weather days.
Post even a concept drawing.



Thanks,

[Danny_Ocean]

I was thinking about running velocity stack screens on my 914-6, but not sure if the screens provide enough filtering for occasional street driving...

[bavaria911]

Thanks -- I was hoping that someone modified the actual plastic stacks to look like RSR (the individual red ones) but leave the center support between the stacks to provide support for the linkage (grind away some of the black plastic).

Anyone thinking that way or is that just way too much "out of the box"!
You could attached the filters posted above to the tops to keep objects from being sucked into the internals.
Your Thoughts,
Bavaria

[Steve@Rennsport]

You mean something like this:

[bavaria911]

Steve,
Nice!
Can you show more pis of the filters off the stacks, how do they look on the mounting side?

I was also looking for a more radical concept with someone actually cutting away plastic support that is aroud the top section of each 3-section stack to fourm a more individual stack that allows for the three piece filter element.

I may need to buy a spare set of plastic stacks and experiment on a concept that is in my head - those like the RSR red version...knowing there is a requirement to support the indivdual stacks to support the cross bar and linkage. I poor mans RSR look.

Scott

[Steve@Rennsport]

Originally Posted by bavaria911

Steve,
Nice!
Can you show more pis of the filters off the stacks, how do they look on the mounting side?

I was also looking for a more radical concept with someone actually cutting away plastic support that is aroud the top section of each 3-section stack to fourm a more individual stack that allows for the three piece filter element.

I may need to buy a spare set of plastic stacks and experiment on a concept that is in my head - those like the RSR red version...knowing there is a requirement to support the indivdual stacks to support the cross bar and linkage. I poor mans RSR look.

Scott

Scott,

The ITG's mount to an aluminum plate thats been bolted down to the tops of the plastic stacks.

You really do not want to cut away the OEM stacks as there is already precious little to support everything. The RSR used mag throttle assemblies with only the intake bells being plastic so they were pretty rigid. Same for the slide-valve cars (I owned both).

I would also recommend staying away from the individual bells as pictured above since they are all genuine "flow killers" as tested on our flow bench.

[tobluforu]

This is the only car that I have seen these itg filters on, did he have to modify the plates that are attached to the stacks? I almost bought some but was worried that my skills could not make them work.

[356RS]

Scott, I would have to agree with Steve on the screen covered stack horns as a air flow killer. I wanted them on one of my MFI engines, and after some discussion with people that have had dyno runs with and without the screens proved the screen will alter the flows at mid to high rpm's. As for the red RSR high butterfly or slide-valve look the safest TB's to modify would be the mag TB's. I think I have a photo of a set with the top flat area cut down a bit to resemble an individual stack look. IMHO your engine looks great as is. Nice job.

[Henry Schmidt]

Here are a few conversion we have done for MFI.






We are working on a filtered version of the slide valve stack the use on modified production throttle bodies.

[911pcars]

Various ITG images:








Sherwood

[RSTarga]

As expensive as these engines are, I would never run one without some air filtration. Those ITG filters look nice, do they have good flow? How is the foam supported? I've seen some of these foam filters get sucked into the engine.

[Danny_Ocean]

Wow! You are truly the Leonardo DaVinci of MFI...

Originally Posted by Henry Schmidt

Here are a few conversion we have done for MFI.






We are working on a filtered version of the slide valve stack the use on modified production throttle bodies.

[911pcars]

Originally Posted by RSTarga

As expensive as these engines are, I would never run one without some air filtration. Those ITG filters look nice, do they have good flow? How is the foam supported? I've seen some of these foam filters get sucked into the engine.

Agree. Screens are good for twigs, leaves and large bugs.

Good flow? Hmm. I've never seen a comparison test. Might be comparable to other reticulated foam filters (Amsoil, etc.).

Foam is supported by plastic structure.

Not sure about foam replacement cost.

Sherwood

[bavaria911]

Steve and Mark - Thanks for the feedback, I'll research the ITGs.

Henry - that is pure eye candy and what I say is thinking out of the box.

How are those ITG brackets bolted to the tops. Anyone have better photos that show the drill markings ?
TIA,

[tobluforu]

Originally Posted by 911pcars

Various ITG images:








Sherwood

The top image on this post shows that the car is using SS braided hose for the pre-heater hose, has anyone else used this with out issues?

[JohnJL]

Originally Posted by Steve@Rennsport

I would also recommend staying away from the individual bells as pictured above since they are all genuine "flow killers" as tested on our flow bench.

Steve,

I'm surprised, but clearly you have all the tools and experience here! So do I understand correctly, ITBs with long horns flow worse than shorter ITB-filtered ones?

I was under the impression, I dont recall when or why, that long horns such as with the high-butterfly MFI injectors gave better torque and response than other arrangements?

I love the look of the long trumpets with screens and was planning on that but certainly dont want to lose any performance.

John