paradocs98

Quick background and then I'll get to the point(s). I've been doing DE events for about 5 years now. Around 50 trackdays total--Lime Rock, The Glen, NJMP, VIR (once). Started with a 2011 M3 sedan, then moved to a 991 Carrera S, and now the GT4. I run in high intermediate to advanced depending on the event. White with PCA.

I adore Lime Rock and it has become my personal Everest to break the one minute mark there. Closest I've come is 1:00.4 last fall in the 991. I posted video here and got a ton of great feedback for improvement.

Last Saturday was my first trackday in the GT4. Not sure what I was really expecting of the day, but I came away a bit disappointed. There are obviously so many variables at play to be able to fairly compare two different cars on two different days, but I can't help myself.

I tried to incorporate the good rennlist advice pertaining to my entry into Big Bend, the Lefthander and the Uphill. Overall I felt a bit unsettled in the car. This really surprised me because every word written about the GT4 speaks of how easy it is to drive quickly, how balanced and intuitive it is. And yet I couldn't reach the level of comfort I felt in the M3 (heavy and lots of weight shift, but very balanced and confidence inspiring) or the 991 (over two years I became used to the front-end float and rearward weight bias). I found myself tiptoeing through corners in the GT4 that I attacked much more confidently in the other cars. Just the opposite of what I would expect. And yet the numbers tell the story. Once I shook the cobwebs out of my head, I was doing consistent 1:03s-1:04s, with a best of 1:02.8 for the day. A good two and a half seconds off my normal LRP times in the 991. That's an eternity on a 1.5 mile track. A quick look at my data shows Vmins or apex speeds 3-5 mph slower in the GT4 compared to the 991. West Bend Vmin 76 in the GT4, and 84 in the 991! And yet the GT4 is supposed to be a momentum car, something of a Miata on steroids. I would expect it to corner more quickly and confidently than a 991. My speed at the end of the front straight was 125-127 in the GT4, while it was 135 in the 991. This makes sense given the extra grunt of the 991S and exiting the Downhill at 91 in the 991 vs. 86 in the GT4. But, again, it should be the GT4 that maintains higher cornering speeds...

Details and variables:

• Tires for both cars were new Pilot Sport Cup2s with only a few hundred street miles on them
• 991 had sport PASM and PDCC but no suspension tweaks--factory alignment settings; GT4 has LCA shims, caster pucks and rear toe links to get a proper track alignment
• Both cars had upgraded brake rotors, pads and fluid
• No power upgrades or exhaust changes on either car
• Best time in 991 was in 50°F, dry weather
• Last Saturday in GT4 two of the sessions had solid rain; by the afternoon the track had mostly dried for my 1:02.8
• There were a lot of fast cars running in advanced, particularly track-prepped E36 and E46 M3s
• My neighbor in the paddock was a very nice young guy with a 996 GT3 on old, subpar street tires--nevertheless he ran circles around me, sliding a lot but exhibiting excellent car control

Thoughts:

• The GT4 felt very maneuverable and "pointy," but maybe more than I'm accustomed to
• Perhaps I've grown to like the specific characteristics of the 911 rear weight bias--the planted/solid feel of the rear end under threshold braking and the ability to put down power confidently coming out of corners due to the superior traction
• The GT4 felt a bit unsettled in the rear under heavy braking; this could be due to my alignment (I already have some rear toe-in, but maybe I need more), the LSD (unlikely in a brand new car), or simply the nature of a mid-engine platform; maybe I need to relearn my braking for this car, and allow the car to take an initial set on all four wheels prior to going to threshold braking
• Shifting didn't seem to be the issue--I was in 3rd or 4th the entire course, just reaching redline at the end of the main straight and the end of No-name straight; if I end up faster in time due to higher cornering speeds leading onto the straights, I may need to make that 3-4 shift on No-name and 4-5 shift on the main straight, which further complicates things
• Part of my poor outing may have been due to damp track conditions, but others seemed to be managing just fine; I may simply need more time with the car to feel its limits and capabilities, and work on my own capabilities...

Video clips follow, with representative laps from last year in the 991 and Saturday in the GT4. I apologize for the overall poor quality of the RaceKeeper video, and the tilted camera angle and wind noise in the GT4 clip. I've since adjusted the camera and moved the mic location. Comments and critique welcomed. Thanks for the therapy session...

991 Carrera S:

GT4:

Veloce Raptor

Well, for one thing, you take an entirely different entry into 1 in the GT4 than you did in the 991, and it forces you to wait...wait...wait before you apply any throttle whatsoever, whereas in the 991 you are able to use some throttle for parts of the curve. You are losing tons of time right there...

chrisc

Was the 991.1 a manual?

NYC993

You are not the first to share these observations. Perhaps it's matter of adjusting to a different platform. I drive older 911 (no stability controls there) and the weight in the rear helps to rotate the car but in controlled manner. It did take me a while to get used to higher speeds and to learn what rear does in various scenarios. Then the weight plants rear down.

I havent driven Cayman at the same level as my 911, but my understanding is platform rotates much better, which makes it hard to control in amature hands. Most of people I've talked to (similar intermediate level), spin out as soon as they try to go out without psm on not knowing what just happened. At last DE, GT4 span out 4 times.

paradocs98

That's a very good point, and ironically, was one of the "improvements" I had been working on. A BMW club racer taught me that first approach to T1 a couple of years ago--crab over tight on the approach to T1, nip the curbing, throw the car into Big Bend and then sort it out for the second part of the complex. Probably makes sense for a racing line where you want to defend the inside. But most people here corrected me on that, telling me to stay to driver's left all the way to the 2 marker, carrying speed deeeep into the corner before initiating the turn. That's what I was trying to do on Saturday in the GT4. Later turn-in. But maybe I'm faster the first way. And maybe on Saturday I was doing a weird hybrid of the two approaches, making it as slow as possible. Something to work on with the AiM Solo next time...

Aspen Autosports

Sounds as if you may not have had enough confidence in the GT4 and therefore are not driving it to its full potential. I bet seat time in the car would make a huge difference.

I don't know many people that are 100% comfortable jumping from car to car and being able to lay down a fast time. Don't get discouraged, take the car back to the track, and keep plugging away.

Veloce Raptor

I don't know (and yes, data will help, as would putting someone much faster in the driver's seat). But remember, the GT4 may work very well with the previous line (or both), and definitely can take some throttle in Big Bend like the 991, likely more
One of the beautiful things about the GT4 with a proper alignment is the ability to place it pretty much anywhere and have it work great...

User 52121

Likely not all that helpful but I'd also echo part of what NYC993 stated.

It's a new platform to you that handles completely differently. Sure it's very capable, but coming off of a 911, I'd expect it to feel a little different. Especially when you're coming from, what was essentially a STREET 911, and into a GT4 (which, even when stock, is pretty aggressive and "track" focused).

I've done LOTS of track events, mainly (over the last 9 years) in a 944 Turbo. Coilovers, big sway bars, aggressive alignment, etc. but still a streetable car. I jumped into a friend's stock Cayman at one and instantly took to it.... went over a second faster on a ~1:20 laptime course.

Bought a Cayman for myself and instantly had it gone through by a local race shop... GT3 control arms, no rubber anywhere, etc. etc. etc. and it took me the better part of 3 days at a track event over Memorial Day at Road America before I finally started to feel comfortable, and better my times that I'd previously set in my 944.

The first day, I was *really* disappointed - I too expected to hit the track FLYING, and instead was down 2s+ over my 944. By the end of the 2nd day, I was starting to "get it", and by lunch on the 3rd day, things were making sense and I was starting to get the hang of the new car. I eventually beat my previous best by almost 2s.

So... IMO? Give it time to get used to it.

multi21

Guaranteed it's seat time in a different car like others have said. New car too, you probably don't want to screw it up but I'd be surprised if after 10 track days you're not throwing that thing around and shaving significant time.

Frank 993 C4S

Sheesh - You should not be beating yourself up over taking a new to you car to the track for the first time and then running slower than the car you were familiar with. Get some seat time and get used to it!

I know these GT4s are great, but Lime Rock is not a track where a fast car ends up automatically with a faster lap time. Most people don't brake far and soft enough into Big Bend and over brake for all the other corners. Low mid corner speeds can mean that you simply don't have your eyes up and are not looking far enough ahead. ... or maybe you were simply over braking.

Get an AIM Solo and a Pro back to back in the car and you'll see where your biggest areas for improvement are. Look at getting to your 1:00 Minute Lap time goal as a journey.

paradocs98

No, PDK. I always drove it in manual mode. Most of the time it was great on track, but occasionally it would do an automatic kick down during acceleration, even when in full manual mode, and it would startle and annoy me. Apparently the PDK-S in the GT3 does not do this on its own--sounds like a better transmission than the standard PDK. Someone on the GT4 subforum recently commented on how the 3.8 liter 9A1 as implemented in the GT4 (smaller throttle body and intake plenum compared to the standard 3.8 991 Carrera S engine, and therefore less high-rpm breathing potential) seems to have a limited power sweet spot of 5K-7K rpm. I've also noticed this, and PDK would be more ideal to exploit this relatively narrow power band to always keep the engine "on boil." The other solution, though, is to just substitute in some of the Carrera S intake parts and/or X51 heads and tuning for a broader, more robust power band.

Good to know. It almost sounds like the idea behind an aerobatic or fighter plane, where the platform is made to be hyper maneuverable to the point of being twitchy or unsteady. Becomes tremendously capable in experienced hands, but a real handful for those less experienced. I will leave stability control on for some time, especially given the limited run-off room of our east coast tracks. NJMP at least has some space for runoff.

That is TREMENDOUSLY helpful and makes me feel much better--thanks for the good words.

Yes, probably just need to keep at it.

Great attitude. Thanks. I have a Solo in the car and it should prove very helpful. I'd also like to enlist the help of Elivan Goulart or Simon Kirkby or someone with similar talents and knowledge. A day with one of them would be much better than any other "upgrade."

NYC993

Btw, 991.1 S did better time (7:37) than GT4 (7:40) on the ring.

Just because "motorsports" put some gt3 pieces and then dropped a detuned 911 engine and slapped a big wing doesn't make it a race car. Others have been doing this long before Porsche.

Olemiss540

But on a tight short track, the GT4 "should" have a pretty good advantage compared to the Nring.

OP, the PDK accounted for the time differential. PERIOD. You are talking about a very capable car in the 991S vs an extremely capable car in the GT4. Not like you went from a miata. If buying lap times is your poragative, perhaps a Viper ACR would have been a better choice. A GT4 is a SUPERB track vehicle, only partially due to its lap time abilities.

Also, the extra power in the 991 has probably lent to covering a few extra "mistakes", the GT4 is the opposite, and is praised in that it will only do what the DRIVER asks of it with as little interference as possible.

I am of the opinion that even if your lap times were 5seconds slower, you have a FAR superior track car vs the 991.....

scorcherjf

Honestly at LRP I wouldn't expect the 981 platform to be faster than the 991 if you equalized weight and power. The 991 has more mechanical grip in sweepers and especially when getting on the power with a multi-link rear suspension. Struts in the rear of the 981 don't do it any favors with regards to maintaining camber and also kinematic toe. The 981's major advantage is quicker transitions, something that you don't really see at a track like LRP. If you look at the Sport-Auto supertests (the guys who do those huge Nurburgring tests), the lateral grip of the 991 Carrera S (even on PZero's) is similar to the lateral grip of the GT4 (on Cup 2's) yet the max slalom speed is much higher with the GT4 as expected. You're losing time on the 991 on the long straight, so you're already starting with a losing battle where you have to claw back time through faster cornering.

That's my take on the chassis differences. As for the driver - perhaps PDK vs. manual plays a role? Since this is your first time there with the GT4, maybe not being completely used to having to heel-toe downshift caused you to over-brake for some corners? (I'm quite guilty of doing this myself and it's something I'm constantly working on). Perhaps, as others have said, with more seat time you'll get those 2 seconds back once you get used to the different platform. Also, since it's mid-engined, the polar moment being lower means you'll have to be that much quicker to countersteer and catch any oversteer. It also makes for a less confidence-inspiring experience knowing that you have less time to react to the tail stepping out compared to the 991. In the end, I think you might be able to match your times in the 991, but I don't think you'll end up being much faster in the GT4 unless it's through improvement via driving.

TL;DR version - Lime Rock is a power track with no quick transitions which favors the 911 over the Cayman imo.

wanna911

PDK is not worth 2.5 seconds on a 1 minute lap. Maybe try less trail braking and softer inputs. The driving style of the 911 is intricately different to other platforms. Not to mention a more track oriented car is made to respond quicker. So the same inputs will feel scarier when you are using the same grip level (as far as tires).