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I do think though, that a manifold like this would be super cool if they can get it to run right - top end should be ferocious.
On top end, the flaps are open so it'd effectively be like running with no flaps. It'll be fun to play with and see what happens. Calibrating it and seeing where it likes to be compared to the OEM GT3 application is going to be interesting on a turbo application, since resonant frequencies change with both temperature and pressure and neither of those are as constant when air is being forced through a manifold (turbo) compared to being drawn through in a naturally aspirated application.
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 ..
T10 touched on this above. The valves are vacuum controlled and are either open or closed, they are not variable. Each valve has its own dedicated actuator so they can function independently. They essentially optimize the back and forth resonance caused by the opening and closing of the intake valves thought out the RPM range. A stock ECU is not set up to operate this but a standalone ECU can naturally do this. We have the wiring already in place to operate both flapper valves at our choosing. By controlling (optimizing) the resonance within the intake manifold, you can optimize the power band throughout. By optimizing the power band via the valves, you can reach your target power / torque at a lower boost level. Lower boost = less heat = less stress = win/win.
Dialing this is will be similar to dialing in the variocam. While we had the variocam profile used on the GT3 as a staring point, Cervelli ended up optimizing that on the dyno for our particular turbocharged application. The process of fine tuning the intake for our turbocharged application will be similar using the 997GT3 flapper valve sequence as a starting point. The resonance in the manifold is there in both N/A and boosted applications but may be slightly different due to the pressure and temperature of the air. Porsche, for example, uses the same 997GT3 dual resonance intake manifold on the 997Cup/R/RSR but likely with slightly different valve actuation sequences on each application. Yes, as you state, the system does seem a bit "clunky" on paper but it certainly works as Porsche uses this on all their 997GT cars and all 997/991 Mezger powered race cars.
Last edited by powdrhound; 02-22-2023 at 04:29 PM.
Yes, as you state, the system does seem a bit "clunky" on paper but it certainly works as Porsche uses this on all their 997GT cars and all 997/991 Mezger powered race cars.
Not entirely true. RSR engines -both 996 and 997- with ITBs have just a CF airbox with restrictors on the inlet side.
I did the alignment and CB today. Same basic specs I used last time, -4.2 degrees camber front and -3.6 rear. Car came in pretty much as anticipated, 2845 lbs ready to run with 3/4 tank of fuel.
Last edited by powdrhound; 02-28-2023 at 04:10 AM.
We are in the process of finishing up the last few pieces to the project, the aero. The guys at the shop drew up the wing uprights in CAD and have already fitted the prototype mounts. A few changes have been made and a second tweaked version is now being machined for installation. The wing uprights are bolted directly to the chassis of the car instead of the rear decklid as that would not have sufficient strength. Bolting the wing mount directly to the chassis will give it the most rigidity and ability to cope with the loads.
We are in the process of finishing up the last few pieces to the project, the aero. The guys at the shop drew up the wing uprights in CAD and have already fitted the prototype mounts. A few changes have been made and a second tweaked version is now being machined for installation. The wing uprights are bolted directly to the chassis of the car instead of the rear decklid as that would not have sufficient strength. Bolting the wing mount directly to the chassis will give it the most rigidity and ability to cope with the loads.
That's cool Paul. I've never seen the close up on the 3RS actuator. We are using a bi-plane set up also (not depicted in the CAD drawing) but it will be fixed with the ability to change the angle of attack on that also same as on the main wing, minus the ability for active aero. I suppose the OEM system could be purchased and implemented if one really wanted to but I would imagine that system is $$$. With Motec, actuating would be easy. I wonder if that''s a hydraulic actuator or electric?
That's cool Paul. I've never seen the close up on the 3RS actuator. We are using a bi-plane set up also (not depicted in the CAD drawing) but it will be fixed with the ability to change the angle of attack on that also same as on the main wing, minus the ability for active aero. I suppose the OEM system could be purchased and implemented if one really wanted to but I would imagine that system is $$$. With Motec, actuating would be easy. I wonder if that''s a hydraulic actuator or electric?
That's cool Paul. I've never seen the close up on the 3RS actuator. We are using a bi-plane set up also (not depicted in the CAD drawing) but it will be fixed with the ability to change the angle of attack on that also same as on the main wing, minus the ability for active aero. I suppose the OEM system could be purchased and implemented if one really wanted to but I would imagine that system is $$$. With Motec, actuating would be easy. I wonder if that''s a hydraulic actuator or electric?
And this article talks about the wing actuation being hydraulic, though I would have guessed electric. I suppose it could be like the 996 rear wing, a single electrically driven hydraulic pump and two hydraulic slave cylinders.
02-22-2023 | 02:52 PM
