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That's some beautiful head work - quite the contrast to the OEM ones.
Have they been on a flow bench yet? Curious what they flow at 9k rpm...
Todd actually did not do any porting on these. What you see is 100% stock. He said there is simply no area of improvement to be had over what Porsche already did on these. I did not have him flow these although it would have been nice to have a comparison to the 996 heads he ported for me that are on my car currently.
To answer you previous question, the heads are available from Porsche but you need the cam housings and all the other matching supporting parts. Both intake and exhaust cams along with cam housings are from a 997.1GT3 which has fully variable variocam on the intake side with 52º or swing vs. the 30º on the 996 variocam we are using now. I don't anticipate us swapping this over until the next time the engine comes out and we have some downtime as there is going to be a decent amount of ECU mapping involved.
Last edited by powdrhound; 02-21-2023 at 04:19 PM.
Looking good dude! It'll be fun comparing the difference in those heads/cams/variocam relative to the setup in my engine. We should've both had Todd flow the heads while he had them, I didn't even think of asking about it though.
Looking good dude! It'll be fun comparing the difference in those heads/cams/variocam relative to the setup in my engine. We should've both had Todd flow the heads while he had them, I didn't even think of asking about it though.
Yeah, I totally agree. Too late now. lol. It's gonna be very interesting to compare data since we are going to be on essentially identical tunes.
Last edited by powdrhound; 02-21-2023 at 08:32 PM.
Todd at Protomotive used the gt3 intake manifold and it brings in huge result difference.
Protomotive uses the earlier gen 996GT3 manifold but without the resonance chamber as they don’t have a way to control the flapper valve. Even in its dumbed down version the gains are apparently notable. The key to unlocking substantial gains will be via the resonance chambers which is the idea behind those manifolds. The 996GT3 has a single variable resonance chamber, the 997GT3 has dual variable chambers..
Last edited by powdrhound; 02-22-2023 at 06:12 AM.
Protomotive uses the earlier gen 996GT3 manifold but without the resonance chamber as they don’t have a way to control the flapper valve. Even in its dumbed down version the gains are apparently notable. The key to unlocking substantial gains will be via the resonance chambers which is the idea behind those manifolds. The 996GT3 has a single variable resonance chamber, the 997GT3 has dual variable chambers..
So that means the dual version is controlled by the ECU, but then does that mean it's 'throttled' through the RPM range to optimize the amount of air exchanged, or simple I/O?
Also, at the switching point (from small to large) are they individually controlled or singularly controlled by a dual action (to prevent both of them being closed)?
Interesting idea, but must be a proven technology, even though it appears a bit clunky... I would have expected something like an Iris / radial valve that could eliminate the use of 2 ..
02-21-2023, 03:52 PM
