Individual Bank Air Filters for MFI?

[bkdamkr]

Where I can I get air cleaners, one for each bank, for my 1973 911S (2.4L, MFI)? Dempsey shows them in a photo on page 96 of "How to Rebuild...", but I can't find them anywhere? I'd prefer chrome-topped ones, but the black rain-protector ones he shows would be OK. I want them for their appearance only - is there any performance drawback associated with them, ie, will they work as well as my stock cleaner with a K&N filter?

Thanks,
Brian

[jpnovak]

You have several choices. THere are the ITG filters which are sock like oiled foam filters. You can also mount K&N watershields with slight modifications. You must trim the base to clear the barometric compensator.

Use the search button in the upper right corner and type in *MFI air filter*" I am sure more choices will come up with better, more detailed descriptions.

[rswannabe]

Here are modified K&N filters on my 2.2S with MFI. Previous owner had the installation done, but it looks like only minor modifications are required to the left filter base to make it fit.



PS. The sound alone makes this modification worth while. Glorious!

[bkdamkr]

Cool - thanks! Do you know what model K&N it is, and/or where I can get a set? I'm not afraid of the sort of mods shown, but I may not even need them, because my MFI pump is located a bit differently. In any case, I'm sure that I can sort it out if I can get the correct ones (ones that fit the base that surrounds the tubes) to start with.

Brian

[jgparker]

These are the Wateshields for Weber IDAs. Available from our host:

http://www.pelicanparts.com/catalog/shopcart/911E/POR_911E_fuelij_pg1.htm#item5

Good luck,

JP

[bkdamkr]

Thanks. The Watershields for the Webers are the starting point for my MFI filters - not some other K&N? Just want to make sure before I order a set and hope for the best.
Brian
'73 911S 2.4 MFI
'73 Ford F-100
Trish's Land Rover
'coupla Ducatis

[rswannabe]

The previous owner did tell me that the water shields were the K&N units for webers, so those should be the ones. They definitley look the same.

[Paul Thomas]

Your set-up is gonna be different than the one pictured. The MFI pictured has magnesium stacks, where your 73 has taller plastic units. The K&N base is made to mount between the carb body/MFI intake and the metal velocity stack. Your motor has the velocity stacks molded into the intake itself, making it about 2 inches taller than its early counterpart.

It can still be done, but you have to have the holes in the bases bored out, drilled a few mounting holes in the stacks, and unless you have a ducktail, the right watershield will bump the decklid grill.

I used to have this set-up, but it is more of a pain than its worth.

Paul

[KALLGREN]

There was an article in the September 2002 issue of 911 and Porsche World detailing the installation of ITG filters to editor Seume's '74 Carrera with MFI.

Thers is a bit of discussion of boring out the base plate which might be of interst. This would be a good source of information on the process involved.

These of course were ITG filters and not the K+N you are considering but still might be worth a look

BK

[KobaltBlau]

Originally posted by Paul Thomas

I used to have this set-up, but it is more of a pain than its worth.

Paul

compared to stock filter set-up?

[slope-nz]

FWIW, I have followed this thread and many like it before now and have come to the conclusion that there isn't any air filters made for Porsche MFI except stock. The watershieds kit looks to be the chose for simple mods to make it work on our MFI unets. I belive the # of cuts nessary relates to how compleat your MFI is. If anyone knows different please tell me about it as I'm soon to buy watershieds . Thanks Randy

[Paul Thomas]

Here is a pic from a few years ago when i had this on my car. Like i said, i bored the holes to the diameter of the velocity stack tops and drilled two mounting holes in each plastic intake. When i hastily shut the decklid, it bent the aluminum fins out slightly in one spot. It works pretty well and makes working in the engine compartment easier. As far as performance goes, who knows.

[Paul Thomas]

Heres a newer pic with shorter mag stacks for reference.

[bkdamkr]

OK, I'll bite. Where can I get a set of the shorter Mg stacks? I'm a metallurgist by training, so I *MUST* replace plastic stacks with the Mgs!
Brian

[Tim Walsh]

Ebay, pelican, I'll bet uncle zak's got a few as well. THey're out there they're from the 69-71 E and S motors.

[Tinker]

Looking at Paul's second photo, it looks like he retained the cold start curcuit which is a smart ideal.

Tinker