Just spitballin' - 3.6 plenum fit to 3.2/3.3 heads?
 

Hey,

Just wondering; does a 964/993 plenum line up with the ports on a 3.3 motor, or is there a difference in port-to-port spacing between 1-2-3 on the same bank?

Looks to be pretty trivial to deal with bank-to-bank spacing, if that's different...

Thanks in advance!

They’re the same

I think you just need adapters for the studs. I think rothsport makes them

Clewett makes some or TurboKraft can make them from their 930 aluminum EFI injector blocks. That's the route I went to get a proper taper from the ~42mm VRam intake runner ID down to the 39MM big port SC head size.

PM me.

Cool, thanks guys!

Had hoped it'd be that simple, but wasn't that hopeful...

Was looking at some of these (well, actually, a GT3 RS intake plenum caught my eye first), noticed ends obviously intended to fit straight onto ITBs and thought "hmmmm",

Then, not actually having $4K lying around for a rare carbon fibre motorsport part, I looked at some 964 manifolds and thought "gee, these look functionally identical - but much cheaper...", and "be pretty easy to connect the intercooler outlet to where the throttle body used to bolt on"... :)

I'm leaning towards alloy over plastic - other than weight, any reason to prefer the plastic ones?

The GT3 plenum is too big for a 3.0-3.3 and N/A engines will lose a lot of low & mid-range power unless ITB's are installed under the plenum. This one is best suited for 3.5 & larger.

The late 964/early 993 plastic ones can be made to work, however you will lose some low end power (unless ITB's are used under the plenum for N/A applications).

For turbo motors, its a nice upgrade when bigger cams are used. :)

Apparently, the plastic ones flow more evenly from runner to runner.

I have an aluminum set if that is not a super concern for sale. It does not have a center section or any other supporting parts. It's just the manifold halves.

True, but aluminum ones may be Extrude-Honed for effect.

OK, I probably shouldn't be too coy about why I'm asking, 'coz guys are guessing :D

Car's a Motec 3.4 930, 8:1, heads ported to match 3.2 manifold(s) and SC cams. Runs great. Throttle response totally unlike CIS...

However, distance from the throttle butterfly to the valves is still ~2 feet; ITBs would seem ideal to further improve throttle response low speed/off-boost.

964 manifolds look like a laughably easy route; drop them on top of ITBs, the intercooler outlet->plenum joint is one fitting, one bend and a straight shot to the manifold throttle body flange...

Or am I missing something obvious?

Exactly what I am going to do. Read my sig.

The 964 intake couples to ITB's with a simple silicone coupler and hose clamp.

I’ve have done similar recently using 993 intake and ATPower ITBs - more work still needed due to failed valve stem seals, but runs pretty well. Looking to use the opportunity to increase the CR with new JEs:

http://forums.pelicanparts.com/uploa...1535576555.jpg

I don’t see a distributor. What sort of EFI setup are you running? (If it’s not a secret I mean.)

Motec m84, Audi COP

what's the advantage of running a system like this instead of trumpets?

Torque is meant to be the primary benefit - i’ve read that the plenum provides a ready (pre-collected) dollop of air to expedite/improve combustion and sharpen throttle response.

William Knight mentioned to me that a common plenum will always provide more area under the torque curve than straight stacks.

interesting. i have CNC'd mounts for the plenum but my tuner prefers the trumpets (perhaps for setup). i may look at doing back to back dyno tests down the line.

The atPowers leave you with stubs so relatively easy to mount the plenum with use of silicone connectors.

http://forums.pelicanparts.com/uploa...1537861049.jpg