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Had a great day at NCM this weekend to further work on setup. Stiffened rear bar, stiffened all ends by one click, then added an additional round of rear compression. Car was awesome. Much more neutral, and less understeer on throttle now. Alignment stayed exactly the same. Honestly, from a tire wear perspective -3.5 front may be just a tad bit too much for Cup2 grip, and because of highway driving to the track, but on-track handling seems worth it. Also for the Pirelli DH takeoffs and soon-to-be mounted Trofeo-R grip, I know it will continue to be more ideal for, which is why I didn't change anything. Rear at -2.7 ish seems good so far. Wear is nice too.
Also, more seat time def. cures the whole PTV sensation at turn-in. I feel at home in this car now.
Hey Mvez- timely update to this thread. Yesterday was my first experience tracking a GT3 since my 997.2 GT3 that I time trialed. Since then it's been exclusively racing in SRF3, so the 'feeling' I had on the track yesterday was exactly the same as yours! The rear is moving around kind of weirdly as it adjusts to load and turn in which catches you out. My feeling was that something was shifting (low rear tire?), because that is the sensation you get with my race car when a rear tire is low in pressure or a wheel bearing is completely shot. I did about 10 laps and got more used to it, but in fast corners I just didn't trust the sensation- in low speed stuff like the back turn chicane at Leipzig it's different like there is a surface condition issue like oil or water as what I can only assume the rear wheel steering moves opposite to get you more turn in. Like you, maybe my 'racing butt' needs to be recalibrated. After 10 laps I felt like I had better come in! Because either it was me with an early morning hangover or something- but better to stop than to push harder with unknown consequences. Later when the Leipzig instructor took me out on a fast lap, I found the car still moving but at higher speeds where tire slip comes in the rear feels more settle until more directional changes. In a few places my pace was the same, but in the high speed corner with the bus stop chicane he was much faster and the car felt better than my lower pace. T1 I was closer to the limit as I felt safer there with more runoff but still he was faster and of course similarly the car seemed to settle down despite the tire slip starting to come in.
Just thought I would share- I didn't process this feeling until reading your thread this morning (Euro time) and having this "ah ha!" moment.
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Yep, I felt exactly like you did. I'd say another day or two on track and you'll be exponentially more comfortable at all speeds. There is definitely movement going on, between active toe and PTV, but once you butt recalibrates and gets used to it, then you can easily determine the difference between that and actual oversteer. Everybody who told me this was totally right. Couple that with the fact that I've been tracking/racing front and mid-engines for the past 3-4 years, I needed a couple days to fully get back into 911 style-mode.
Yep, I felt exactly like you did. I'd say another day or two on track and you'll be exponentially more comfortable at all speeds. There is definitely movement going on, between active toe and PTV, but once you butt recalibrates and gets used to it, then you can easily determine the difference between that and actual oversteer. Everybody who told me this was totally right. Couple that with the fact that I've been tracking/racing front and mid-engines for the past 3-4 years, I needed a couple days to fully get back into 911 style-mode.
Good to know! Thanks for the posts on your experience so far.
Finally got to drive Grand Full course NCM this weekend, and was able to log a few decent laps on both Cup2 and Pirelli DH takeoffs. Wasn't able to get enough clean laps to set the fastest times possible, but definitely could see where the car stands.
Was able to turn a high 2:11, low 12 on stock Cup2 tires. I think a low 11, or high 10 is possible with more time, chassis tuning, and less traffic. For reference, Andy Pilgrim just recently in very similar conditions on a closed track, turned 2:13's in a stock .2GT3, while also setting the production car track lap record in the GT2RS (2:02.XX) on sticker Cup2R rubber (2:05.XX previously on 8-9 HC tires). The only real difference between my car and stock is Ohlins TTX, alignment, and rear wing wicker. Cars weigh the same, mine has side muffler delete with rollbar, compared to bone stock without rollbar. That is a great illustration of what a good suspension, with proper alignment can do for handling, and why the 2RS and 3RS are so good on track with their monoballs and proper track spring rates.
I also mounted up a set of 8-9 HC'd Pirelli takeoffs, and was able to log two mid 2:07 laps (5 sessions apart), with some high 2:06's indicated each session, but kept hitting traffic. At that pace, you almost need the track to yourself to set clean laps, as you get held up too easily at NCM which ruins a lap. With more seat time, and some fresher rubber, 2:05's might even be possible, but 2:06's will definitely be had. A few other observations.
1. I'm now certain I don't like Ferodo DS1.11. They get into ABS too easily, because their torque curve is so flat, with no real friction rise with heat. Very grabby initial bite. This makes it hard to modulate and tricky on initial application. A lot of people like these because they do stop the car like hell and last long, but in terms of feel and initial bite, they just don't work with the 911 chassis as well as perhaps with a mid-engine or front engine, IMO. I have them on my M3, and they are easier to use on that chassis, as it doesn't require nearly as much trailbraking or finesse. I think the car would benefit from a pad more like the PFC08, with a rise in friction with heat. The DSUno offers that, but the friction level of that pad is so high, it too would easily overwhelm stock Cup2 rubber and get into ABS or ice mode. Even with Pirelli rubber, the DS1.11 grab ABS too easily. I wonder if re-programming the car for PCCB brakes ABS would help, as that's what 987.1 race cars do to increase the ABS threshold. Typically PCCB ABS programming is less intrusive due to the typical higher bite of that stock brake setup. Sadly, not much of a wide pad offering for the GT3. Wish PFC would offer their 12 compound for stock calipers, or if Friction One would offer their RS1 for front and rear. Pagid is great, but pads still seem to wear insanely fast and fall off once you get to 40-50% of pad thickness, and very fickle bedding process.
2. Tire wear on both types of tires continue to look good. Cup2 fronts at -3.5 have a little bit more of inside edge wear at 3300 total miles (mostly from 100 mile highway driving back and forth to track, and a little from long duration right hand corners), but rears are perfect at -2.8. Pirellis look good too, but rears seem like they want more. I think ideally the Pirelli takeoffs would like -3.7 and -3.2 ish, or something in that neighborhood.
3. Stiffer bar and shock settings definitely put to good use by the Pirellis, or by any other sticky tire like Hoosier, Trofeo-R, etc. Much less understeer and more balance, as previously noted while on Cup2.
4. Rear mechanical diff/LSD seems to be working pretty good. Car feels pretty stable under heavy braking, and locks nicely under hard 2nd gear acceleration off corners. Might play with gear oil to see if I can get more lock out of it. I drive with all nannies off, but on one session, I did forget to turn them off, and wow, what a crazy difference in handling and speed that made. I much prefer them both off, because it is SO easy to feel the electronic wizardry tugging and pulling at the throttle and brakes, which is very bad for confidence. It literally tugs the car in different directions, and makes for unpredictable handling, and sensations. I literally thought something was wrong with my car or the tires before I realized I forgot to turn it off, lol. Plus, skids are fun!
5. I no longer even notice any RWS or torque vectoring while driving with all nannies off. Car is brilliant.
Finally got to drive Full course NCM this weekend, and was able to log a few decent laps on both Cup2 and Pirelli DH takeoffs. Wasn't able to get enough clean laps to set the fastest times possible, but definitely could see where the car stands.
Was able to turn a high 2:11, low 12 on stock Cup2 tires. I think a low 11, or high 10 is possible with more time, chassis tuning, and less traffic. For reference, Andy Pilgrim just recently in very similar conditions on a closed track, turned 2:13's in a stock .2GT3, while also setting the production car track lap record in the GT2RS (2:02.XX) on sticker Cup2R rubber (2:05.XX previously on 8-9 HC tires). The only real difference between my car and stock is Ohlins TTX, alignment, and rear wing wicker. Cars weigh the same, mine has side muffler delete with rollbar, compared to bone stock without rollbar. That is a great illustration of what a good suspension, with proper alignment can do for handling, and why the 2RS and 3RS are so good on track with their monoballs and proper track spring rates.
I also mounted up a set of 8-9 HC'd Pirelli takeoffs, and was able to log two mid 2:07 laps (5 sessions apart), with some high 2:06's indicated each session, but kept hitting traffic. At that pace, you almost need the track to yourself to set clean laps, as you get held up too easily at NCM which ruins a lap. With more seat time, and some fresher rubber, 2:05's might even be possible, but 2:06's will definitely be had. A few other observations.
1. I'm now certain I don't like Ferodo DS1.11. They get into ABS too easily, because their torque curve is so flat, with no real friction rise with heat. Very grabby initial bite. This makes it hard to modulate and tricky on initial application. A lot of people like these because they do stop the car like hell and last long, but in terms of feel and initial bite, they just don't work with the 911 chassis as well as perhaps with a mid-engine or front engine, IMO. I have them on my M3, and they are easier to use on that chassis, as it doesn't require nearly as much trailbraking or finesse. I think the car would benefit from a pad more like the PFC08, with a rise in friction with heat. The DSUno offers that, but the friction level of that pad is so high, it too would easily overwhelm stock Cup2 rubber and get into ABS or ice mode. Even with Pirelli rubber, the DS1.11 grab ABS too easily. I wonder if re-programming the car for PCCB brakes ABS would help, as that's what 987.1 race cars do to increase the ABS threshold. Typically PCCB ABS programming is less intrusive due to the typical higher bite of that stock brake setup. Sadly, not much of a wide pad offering for the GT3. Wish PFC would offer their 12 compound for stock calipers, or if Friction One would offer their RS1 for front and rear. Pagid is great, but pads still seem to wear insanely fast and fall off once you get to 40-50% of pad thickness, and very fickle bedding process.
Thanks for the feedback on the DS1.11's MVez. Would you be interested in being a guinea pig for the Ferodo DS2500 compound on a GT3? We typically suggest the DS2500 for 'sport' or autoX use on most platforms here in the USA, but it is more broadly viewed as a 'track day' compound elsewhere in the world. We've had several Corvette customers run the DS2500 on different tracks both accidentally and intentionally. The pads have held up incredibly well, in two cases on roughly 700HP C7 Z06's at VIR. The overall mu level is considerably lower on the DS2500, and may be just what the doctor ordered for you. Please shoot me a PM and we can get them going for you asap. Thanks!
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'09 Carrera 2S, '08 Boxster LE (orange), '91 Acura NSX, Tesla Model 3 Performance, Fiesta ST
Jeff Ritter
Mgr. High Performance Division, Essex Parts Services Essex Designed AP Racing Radi-CAL Competition Brake Kits & 2-piece J Hook Discs Ferodo Racing Brake Pads Spiegler Stainless Steel Brake Lines
704-824-6030 jeff.ritter@essexparts.com
Thanks for the feedback on the DS1.11's MVez. Would you be interested in being a guinea pig for the Ferodo DS2500 compound on a GT3? We typically suggest the DS2500 for 'sport' or autoX use on most platforms here in the USA, but it is more broadly viewed as a 'track day' compound elsewhere in the world. We've had several Corvette customers run the DS2500 on different tracks both accidentally and intentionally. The pads have held up incredibly well, in two cases on roughly 700HP C7 Z06's at VIR. The overall mu level is considerably lower on the DS2500, and may be just what the doctor ordered for you. Please shoot me a PM and we can get them going for you asap. Thanks!
Hi Jeff, thanks for the suggestion, and yes, I would. I was actually looking at those as a potential candidate for testing, because I feel like the GT3 venting and your J-hook rotors already provide substantial cooling, and might/should keep them in their operating temp range. The tradeoff would be pad-life, but it might be what I have to give up to the get the brake pedal I want. Either that or simply try the Dsuno, I'm just worried they will be too aggressive for Cup2/Trofeo-R type tires. I'm also looking the potential to switch my Steel ABS to PCCB ABS in PIWIS, similar to how it's done for Spec 987 race cars, to help improve on track race performance. I own a 987.1 track car, and can certainly appreciate even the slight improvement that provides. Perhaps just the ABS mode switch alone would be enough.
Regardless, by no means do I have a problem with the pads, it's just their particular characteristics don't fit with my wants for this chassis. You know I love all your stuff!!
Those are some amazing times, thanks great feedback.
I see a 2.5-3.0 second difference vs. Trofeo R on a 3.3 mile track with new DH in time attack mode.
I run F -4.0 and Rr -3.7 and front and rear slight toe in.. tire useage is perfect.. KW MR competition on 991 Turbo with 275/675 and 315/705
Full race alignment. I like your style! That sounds about right. I expect Trofeo-R to be about 2 seconds quicker than Cup2 around my 3.15 mile track, and then Pirelli DH another ~3 seconds from there. Thanks for the confirmation. I have to say though, the Pirelli DH's are still great after 14+ heat cycles, they just take time to get up to temp, and slide very predictably. I have a feeling I'm going to need a little more rear camber once I install Trofeo-R's, which the DH's will also appreciate.
Actually, Phase II of this build is now underway. Just ordered the full monoball package from Joey at E-motion. I like the design of his parts better than anybody else's. Decided to go all-in after seeing how the new RS benefits from full monoballs, especially the rear with it's ability to handle crazy-glue CUP2-R tires. Those are basically slicks, so Porsche clearly designed this car to handle that. I think the sphericals in the toe links is key, and will be worth the effort IMO. The car was already phenomenal on just TTX, can't wait to enjoy the additional precision and feel from the full moonball setup. Once that's done, if I'm still not fully satisfied, I'll pull the RWS and install some standard adjustable toe links. Next round of modifications are:
Front spring increase to 120 N/mm (~700#)
Front and Rear inner control arm monoballs - E-motion
Are the front strut tower support brackets being done out of an abundance of caution? Have we seen failures on a .1 or .2 GT3 car?
No, just doing them because they are available. Support for suspension mounting locations never hurts, even if this bracket is very minimal. They have them on cup cars, so figure it can't hurt. I'm sure it offers some additional, albeit minimal, reinforcement for on-track curb use.
Countless 991 GT3's out there with countless track days with no issues. All this really helps protect is if you have soft stock spring rates, and absolutely hammer a huge pothole bottoming out the shock. If something was to break, it helps prevent the shock tower from damaging anything else or hitting the hood. Chances of this happening are almost nil.......
I've got a fair amount of track miles on my E46 M3 with MCS two-way non remotes, and they allow the car to absorb the track-out curbing like it's nothing. In my first outing with the GT3 10 days ago my initial thought was that the dampers aren't nearly as good in this regard. Getting back on full throttle at track out isn't possible because the curbing upsets the car and the nannies turn on. I don't recall that being a problem on the M3 but then again you can mash the pedal in that car in third or fourth gear and because of the power deficit compared to the GT3, it just kinda goes about it's business.
So tracking out is a necessity and the additional reinforcement, even if it is minimal, is something I'll consider. And at some point I need to post a thread with my impressions of the GT3 at Road America.
09-19-2018, 05:45 AM
