DarinB

I'm just curious if anyone out there has a plastic 964 intake plenum lying around that they wouldn't mind selling. I am in need of one for a street car of mine.
Thanks,
Darin

chancecasey

Generally they're about $300 at places like Parts Heaven.

DarinB

Thank you. I'll check it out.
Darin

chancecasey

of course, you aren't *replacing* an existing aluminum one are you? IHMO that would be a mistake cost vs. benefit-wise.

DarinB

No. Just have a project i'm working on.
Darin

1990-964

Chance,

Can you elaborate more on the benefits or not of the plastic manifolds. Do they help or is it P-car urban legend?

Thanks,

Darren

joey bagadonuts

Not entirely urban legend. It's mentioned, almost in passing, in the Bruce Anderson book ... improved flow, lighter weight, used in Cup cars. However, there are no accompanying dyno plots nor changes to Factory hp/torque specs.

Okay, so maybe it is urban legend.

1990-964

Hey Joey B.,

So the points you make sound good. Have you changed to them on your '90?

ilko

My feeling is that plastic is cheaper than aluminum, so maybe that may have had something to do with it. IIRC, Porsche switched back to aluminum intakes in the 993 series.

joey bagadonuts

No, I still have the originals. I had a 91, before, with plastic intakes and, really, there's no noticeable difference.

chancecasey

It's been covered many times - but - the plastic saves about 2.7 pounds, is not as much of a heat soak so in theory the intake charge is a "little cooler", and has smoother inner walls so in theory it breathes a "little better". I haven't seen dyno plots but my guess is the difference would be too small to measure. $300 / 2.7 pounds is extremely expensive weight loss, so this is just one of those areas that if you already have the aluminum, keep it until you've done "a lot of other things" first.

DarinB

I'm not changing to a plastic one. I just have a motor that needs one to get back to stock.
Thanks,
Darin