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Nice having a "team" that can identify a problem, understand the limitations of off-the-shelf parts, conceptualize a solution, get it drawn up in CAD, and spit it out on a Haas machine all essentially 'in-house'!
Have you had a chance to proof the solution on the track yet?
Hi Paul,
We identified the problem by looking at pictures of the car under hard acceleration on turn exit. This is where a picture is worth a thousand words. The plan was to do the swap this week as Cervelli and I will be running the car this Friday and then I'll run it in the NASA event on Saturday. I did not get a chance to swap it over as I will have to do a fresh alignment to go with it. Most likely won't get to it until the following week after NASA.
I"ve been meaning to do this for a long time but just got around to installing the 997GT3/Cup flat underbody paneling. The panels use the existing attachment points in the center but naturally the attachment points are different around the perimeter since the 996 chassis doesn't have any panels there. You will simply need to install 10 riv-nuts to bolt every thing up at correct locations at the outboard points. I used M5 riv-nuts with M5x16mm flanged bolts. With a lift this is a very easy job for anyone who is moderately handy and knows how to use a rig-nut tool. Sheet metal screws in place of bolts can be used but that's a little more ghetto and not quite as durable long term. This mod can be done to any 996 chassis.
This mod significantly smooths out the airflow under the car. We are in the process of developing strakes for the underside like those used on the later 991 and 992 race cars and also a diffuser which will tie in with the aft-most panel covering the underside of the engine and extending out to the rear bumper.
STOCK 996 PANELS:
997GT3/CUP PANELS:
Last edited by powdrhound; 02-10-2024 at 11:07 PM.
Have you driven it on the track yet with the GT3 underbody panels?
Faster laptimes?
Do you have any plans to take the care to a wind tunnel if you haven't already?
No. Just installed it yesterday. Track season won't start till March. There is some more aero stuff to be done on the underside including strakes and the diffuser. I'll update this when that's done.
I would love to see the car in a wind tunnel but unfortunately there isn’t one around anywhere within a days drive. I would imagine California would be the closest location.
Last edited by powdrhound; 02-08-2024 at 01:06 PM.
That's not suitable for track use. The PDK is more of a street gearbox. Looks like a neat conversion though. Wonder if anyone has done this.
We are actually in the process of going to a Holinger MXT sequential gear box. It's a legit race gearbox with paddle shifting and pneumatic actuation. The programming ties directly in with the M150 ECU. Reliability at 660 ft.lbs is rated at 100% for a 24hr endurance race. It's easily serviceable and made with quick gear swaps in mind if needed for different tracks. All gearing is to specification and the LSD is fully adjustable. Here are the full specs on the MXT.
This is the gearing Chris Cervelli selected of this application. It's similar to the gearing on the RSR except the little taller to account for the extra 300hp. (Thanks to T10Chris for putting it in a nice graph format!)
Last edited by powdrhound; 02-08-2024 at 01:07 PM.
Glad you finally got around to doing the undertrays, now I can't say I'm a step ahead of you in any area of development on the cars, haha I have heard of a wind tunnel in reasonable range, I'll shoot that over to you.
I've had the Manthey intercooler inlet ducts sitting on the shelf for a few years and finally got around to installing them. These are really nice pieces, made from solid carbon fibre and as light as a feather. They follow the contour of the OEM inlet ducts perfectly. I had them painted in matching body color and attached them with silicone adhesive. One can also use window weld. The fit is perfect and they integrate seamlessly for that OEM look. One really can't even notice there is anything aftermarket installed. Manthey had these tested in their wind tunel and claim a 10ºC reduction in intake temperatures by "scooping" more air and forcing it over the intercoolers. This is effectively a very similar design that Porsche employed on the 991GT2RS where the inlets are more pronounced. Cooler charge temps is always a good thing....
Last edited by powdrhound; 04-18-2024 at 12:48 AM.
I always wondered how the Manthey scoops seemed to do anything as they look like small pieces just tacked on. That side/under profile shows how pronounced they are. Maybe I want them now. I never liked my Toth side vents, they seemed too big, even molded to OEM pieces to make them all one-piece.
09-24-2023, 04:34 PM
I have heard of a wind tunnel in reasonable range, I'll shoot that over to you.
