Air Cooled Porsche Heads?

[Powerman]

I working on some VW/Porsche Type 4 heads for FP SCCA racing. 42mm intakes and 34mm exhaust. I paid $$$ for a ported head, and built a flowbench with the idea of copying the ports. Every porter's heads has ports that looks slightly different? I guess I need an engine dyno next, the neighbors already think I'm kind of wild. Any thoughts or experiences?

[larrycavan]

Powerman

I have no experience with those heads. The only thing that jumps out at me is the size of the exhaust valve looks like it might be a tad small. That's purely unscientific speculation though..The heads may well flow the proper E-I ratio.

Have you run them yet...did they make a difference.?

There's a lot of information here for building a bench. Pitot or Orifice...you'll find the help you need here.

Larry C

[Tony]

[Powerman]

I have already built a pitot flow bench.

The valves are spec size.

I was asking about porting ideas! I already know how to act wild enough. You ought to see the busybody ladies from the neighborhood gathering at my driveway when I had my race car hanging from the rafters welding on the bottom of it. #### commuter residential developement. The guy with all the loud Harley buddies moved, they made me look calm.

[Unkl Ian]

The stock exhaust ports look pretty restrictive,depending
on how much air your trying to move.

And there isn't much extra material in the castings to remove.

[larrycavan]

[PFM]

Powerman,

I have a bit of input on this head / motor. First you give the valve size but no other info. Are the base heads from a two liter or a 1.7 / 1.8? The better two liter heads have three studs to hold the intake manifold in place. What is the engine size? Bore and stroke? Compression? Are cams free or limited in some way? What RPM is the engine to make HP at? What is the cross section of the intake port? What kind of TQ / HP do you think the engine should produce? Were the heads welded before porting? Was the combustion chamber ported? All these need to be looked at to determine if the porting job already done will do what you need. If you have a flow bench what are the flow numbers you see with these heads.

If this is too much info to share with the board drop me a note off line.

Regards,

PFM