Track Rat

Yep the wing is at max angle of attack. Maybe a Gurney flap and dive planes will do the trick. I’m thinking I’ll try that next. It just needs a little more aero for turn 1.

Oh cool that you’ve seen my videos, I’ll get the camera installed next event, which will be early next year.

cheers

Todd

Track Rat

No kidding? Very cool, congrats 🍻
have you had a chance to track it yet?

Yes it is adjusted for full aero- wing at max downforce, front screens removed, lower deflectors gone as well.

CRex

Great post and glad to read everything about your positive experience with the car. Confirms our collective belief that these things are proper weapons in the right hands.

You're obviously at a point where setup measurably influences your experience. The "Cup2R falling off cliff" comment has me wondering if you have the right tire temps and pressure when this happened?

I'd be apprehensive of anyone saying "X bars and Y Fahrenheits are optimal" for you. But if I were in your shoes I'd really take note of what the temps and pressures were when you ended your :34 session, and compare that with what they were when the tires start to fall away from you.

ipse dixit

Great write up.

Are you running stock alignment?

Track Rat

Thanks, it is a beast without a doubt.

Air pressure was 33-34 psi hot front and rear, same as my fastest lap. Front tire temp on the inside was about 180 F, 160 F on the outside (they had cooled a bit when I was able to measure temps). Rear tire temps were more even across the tread, around the same temps. I think this is about the same as my best lap, if I recall. I should have written that down to be sure, I will next time. Thoughts are welcome on what I should aim for.

Track Rat

Appreciate it.

No, I went with an aggressive track alignment with a lot of camber.

Yargk

Cool. Gurney flaps are pretty amazing btw. Their benefit seems to depend on the shape of the wing. If the wing is flatter, I've seen some data showing a greater than 40% increase in downforce with minimal reduction in the lift/drag ratio. If the wing already has a very curved shape, the benefit is smaller, but should still be there. The GT2 RS wing doesn't look hugely aggressive in shape, so I bet the effect would be noticeable behind the wheel and against the stopwatch. Paired with dual element canards would be even better.


(Jain et al. Computational Investigations on the Effects of
Gurney Flap on Airfoil Aerodynamics 2015)
See also (Suresh and Sitaram GURNEY FLAP APPLICATIONS FOR AERODYNAMIC FLOW CONTROL 2011)

dewilmoth

Doesn't that beg the question why Porsche doesn't capture that efficiency and effectiveness in stock form?

M3the01

I hear u but Manthey does, they use the gurney flap on the lower spoiler... that said, why it is not used on the upper spoiler, beyond me.

My plan of attack on the gt2rs, upper and lower gurney flaps, canards and lower front strakes like on the gt2rs CS. Im also looking at the rear diffuser strakes and a slight lowering, only 1/4" is supposed to be a large increase in DF on the gt2rs, especially on the front.

The setup from Dundon is pretty amazing but remember you obviously need to do the suspension, that much DF the suspension cant handle it as you need stiffer springs. Also i cant live with the looks of the swan spoiler, very functional but not for me.

Track Rat

Dundon Verus V1X wing also uses a Gurney flap.

I think I’m going to start with a similar set-up as you. I’m not yet convinced that we would need to do suspension upgrades if we ran a Verus wing. Because our GT2RS’s come with a factory splitter that likely has less downforce than an aftermarket splitter, we would run the wing at a lower angle of attack to keep the aero balanced. The stock springs may be stiff enough. I am tempted to do the Verus wing instead of the Gurney flaps. Undecided at this point. Plus I think it looks sexy on Apex Ace’s machine.

Yargk

Good question with a simple answer. Gurney flaps do hurt the lift to drag ratio, just not that much. Porsche is interested in absolutely maximizing that ratio, that is, having the least possible drag for a given downforce. This helps crazy things like 100-180 mph autobahn runs. However, more drag is faster on track if it means more downforce.

M3the01

Isnt it still 200-300lbs of additional rear end downforce at 0 degrees? Im excited to follow along in this adventure but im really thinking to get the most out of it ur going to need stiffer springs. Another issue with lowering, additional DF, is risk of body damage or the terrible / disastrous shock tower blowout when it bottoms out.

RaceMattC

Todd,
Since you go to the track plenty, I might recommend getting a second set of wheels and throwing Hoosier R7's on it. We did that with the GT3RS and it is honestly the best. They are at least 1.5 seconds per lap faster than the Cup 2 R's and their performance is much more consistent. I found with the Cup 2R, I better have my best lap on lap 2 or 3 of the session. Everything after that was just downhill. The R7's are much more consistent over a session and can withstand hotter days at Thunderhill.

Here is the best part. A set of Cup 2R's would be worn in a single day. The Hoosiers last me a solid 2 days. The cost of the R7 is ~1/2 the Cup 2R. So the stickier, more consistent rubber is 1/4 the cost to run. Win all around.

Here is the worst part. You have to switch wheels to convert back and forth. Plan on a solid hour for the job with a second person. I just did a day at Thunderhill where I got there at 7 AM with a friend carrying the track tires. I just barely made the first session by the time everything was swapped and ready to go.

Track Rat

Hi M3, good talking with you today as always. I talked with Dundon about this and then you and I discussed, but for the benefit of the others... Good news is that their wing is about the same downforce as the stock wing at 2 degrees, and double the downforce at 4 degrees. Adjustable all the way to 14 degrees. So I could dial in perhaps 3 or 4 degrees, adjusting to balance the car. My goal is to avoid a suspension upgrade, hopefully I can achieve that with a small wing angle. Sticky Hoosiers and a bit more aero will go a long way, looking forward to the journey.

Track Rat

Awesome, that's my plan too, and great to get confirmation that it works well. I am working on figuring out the final tire and wheel package now. You mind sharing what you're running? Sizes and offsets of wheels and Hoosiers.

I'm already getting used to wheel swaps, using the Renntorq torque multiplier. Still takes a lot of time, as you said!

Maybe we can connect for a track event soon, I live fifteen minutes from Willow Glen.

Todd