Scored a large displacement MFI setup

[Flieger]

Thanks for the information. I want to put some nice watershields/aircleaners on my engine, to replace the plastic plenum chamber. I have MFI(an RS pump) but I have 911T plastic velocity stacks. I hear that S stacks are required to fit air cleaners. What modifications to the plastic T stacks would be required or will they work at all?

Thanks!

[Wayne 962]

That equipment looks like stock stuff to me, probably from a 2.7 engine. If the throttle bodies are larger, then they were probably ported out for a larger engine. Good find, but as someone else mentioned, the factory race stuff usually didn't use stock parts like these - they were all custom slide-valve setups and PED (Porsche Engine Development) pumps. The racing pumps are small, and don't really look much like the street pumps. I'll see if I can dig up a photo of my setup from my 3.4 MFI motor...

-Wayne

[Wayne 962]

Originally Posted by Shuie

MFI can be done on 3.2 motors and bigger. People do it all the time. There is nothing complex about it at all. Its just money.

Sorry, I disagree. I've only seen MFI on a handful of motors larger than 3.0. I can think of only two off the top of my head, and I think that Henry at SuperTec did both of them.

-Wayne

[BURN-BROS]

Originally Posted by Flieger

Thanks for the information. I want to put some nice watershields/aircleaners on my engine, to replace the plastic plenum chamber. I have MFI(an RS pump) but I have 911T plastic velocity stacks. I hear that S stacks are required to fit air cleaners. What modifications to the plastic T stacks would be required or will they work at all?

Thanks!

Get 70/71 Magnesium stacks, You can then bolt on K&N stlye air cleaners...With only minor modifications.

[Henry Schmidt]

Originally Posted by Wayne at Pelican Parts

Sorry, I disagree. I've only seen MFI on a handful of motors larger than 3.0. I can think of only two off the top of my head, and I think that Henry at SuperTec did both of them.

-Wayne

Wayne your right, I have built a few large bore MFI engines. These come to mind.







Then I remembered this one. Wayne should recongize this one, it belongs to him. 3.4-3.6 ? MFI built by the factory?

[Bobboloo]

Originally Posted by Flieger

Thanks for the information. I want to put some nice watershields/aircleaners on my engine, to replace the plastic plenum chamber. I have MFI(an RS pump) but I have 911T plastic velocity stacks. I hear that S stacks are required to fit air cleaners. What modifications to the plastic T stacks would be required or will they work at all?

Thanks!

Aarons suggestion is a good one for ease of installing the K&N air cleaners.

Question. Have your T stacks been bored out to S spec? If not then your motor has a lot left on the table for producing HP.

Also, mounting the air cleaners on T,E or S stacks is the same for all plastic stacks. Holes have to be drilled.

If your stacks have not been bored then the 70/71' 2.2 stacks Aaron mentioned would be ideal. They E stacks have plenty of meat in them for boring out. If you find S stacks then, all the better, you don't even need to bore them out.

[Wayne 962]

You're right - I forgot about my Porsche factory experimental 3.6 with MFI built for Vasek...

-Wayne

[Walko]

I had a 3.2 SS built with MFI and had no problem with a 2.7 pump and modified stacks and throttle bodies

Michael

[Henry Schmidt]

Originally Posted by Wayne at Pelican Parts

You're right - I forgot about my Porsche factory experimental 3.6 with MFI built for Vasek...

-Wayne

Wayne, your engine has a 91-92 front crank pulley on it. That pulley would be hard to fit on a 3.6 crank. I wonder if that might be a 3.3 turbo crank stuck in a 3.6 case. That would make it 74.4 mm stroke and 100mm ? bore. 3.5?
The bore is the big question mark. Because of the stud spacing you would expect to find a 100mm cylinder but they could also be 102mm. The funny thing is there were some 95mm high compression pistons and cylinders made for use with the 3.6 case and heads but I never found out what they fit.
74.4 X 95 ? wouldn't that be weird ?

The stacks are a modified version of the Motronic 926 stack/ butterfly housings. They had a 4 bolt flange so my guess is that the stacks were modified (cut and welded) to fit a three bolt intake as found on the 964/993 heads.
Seem right? any feedback would be appreciated.



Here are some pictures of Wayne's engine back in the nest. Check out the company it kept.