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Yes it will make a big impact on times no matter how good the driver is. At a track like Sebring I have seen 1 to 1.5 seconds gained on upshifts alone comparing manual to sequential/PDK type gearboxes on race cars. To put it into math if you upshift at Sebring 19 times in one lap (counted this off memory of a GT3 Cupe Car and you gain .05 seconds per shift the time gain in shifting alone would be close to 1 second. This doesn't take into consideration the fact you can do no lift upshifts that cannot be done with a production gearbox H-pattern and your acceleration curves on the data stay linear during these no lift upshifts.
Originally Posted by GrantG
This has be debunked repeatedly. The manual loses a Small fraction of a second per 60 seconds of lapping. Nowhere near a car length per shift. And in between shifts, the Manual is faster as it's lighter and has less internal friction.
Only 2 10th's difference on an 84 second lap here (and the PDK has the much more favorable spec - and it seems as though Randy did not use the No-Lift Upshift feature):
We awoke in the morning to find around 2 inches of snow outside our hotel and began wondering whether the track might be closed for the day. We gingerly drove the 6kms to the track on the CUP tires and found the paddock covered in snow. The organizers decided to delay the start for 1.5 hrs hoping the track would clear...which fortunately it did. However, the track remained very wet for the rest of the morning only drying out at around 2pm.
First, the bad news. The GTR is almost undriveable in the wet. The damn thing has so much torque that the back wants to step out ALL the time even under a light throttle. No wonder one of the major magazines recently recorded a time almost 5 seconds slower than a GT3 in damp conditions.
I have never spun a car on any track.......until now that is. I was driving thru a right hand curve under light throttle in 6th...yes 6th...and applied just a bit too much gas and whoops.....it just went. In the very same conditions, my GT3 is much faster. We were even getting passed by BMW M2s and Audi S3s on normal road tyres because we just could not put the power down.
But once the track dried out after lunch, we got to discover its true talents. The Jekel and Hyde character of the car is amazing. Undriveable in the wet but very, very racy in the dry.
It has tremendous grip and it’s very fast. It feels faster in a straight line than my GT3 but I think the GT3 would be faster in the more technical bits. It has very good turn in, indeed it rotates much quicker than a GT3.
It does need better brakes though (mine has the regular iron brakes) because we consistently ran out of brakes after 5-6 hard laps. We had to slow down, let the brakes come back and then do it again. Although its actually more stable under hard braking than a GT3 but you do feel the weight. You can definitely brake a bit later in a GT3.
It rides a lot harder than a GT3 but it still takes the curbs well and doesnt get unbalanced.
The gearbox is not as good as the PDK. It's definitely close, but in some situations the GTR will not change down when you ask it to. Upshifts, no problem. Just the occasional reluctance to downshift when you want it to.
Overall, it’s a great car and very enjoyable, and very fast, on the track. I am looking forward to my next track day at Spa when I will have the GT3 there too for some back to back comparisons.
Attached is a video of 2 laps from the day. Car was in Race mode, traction control 60% off, manual changes.
Nice review. Liking the reference to losing control due to bottom end torque!
the beast from the white Hell...!!!
Good lines and car looks capable .
hoping for a delivery date at some point soon!
any thoughts on on making the brakes work?
i know Renntech has, or is working on a solution.
love the GTR, I can see it being super stiff and so hard to handle in the wet.
It really is a nightmare in the wet compared to a GT3.
For the brakes, I might try a different brake fluid but that’s probably it because it’s not going to be my primary track car. That will be my GT3.2. I will still take the GTR to the track because it’s a lot of fun, but not as frequently as my GT3. And just one small BTW. Hockenheim is 450kms from my home so I cruised down the day before. I must say that I arrived a lot fresher in the GTR than a previous trip i did in the GT3. It’s a consummate GT car...it’s quieter at speed and the fixed buckets are more comfortable than the GT3s too. I must say that MB have done a bang up job. But I still prefer the GT3.
Sums it up nicely, from driving a GTs on track myself and what I’ve seen from friends who have a GTR and what I have read I assumed just about what you actually found out in real life with GT3’s as reference.
As I mentioned on the MBforum, the brakes will probably be much less prone to ‘fade’ with a superior fluid in the car such as Castrol SRF.
Also the SC2s are incredibly temperature dependent and below 40dF resemble ‘hockey pucks’, so it’s not surprising you were having traction issues in the morning.
My good guy dealer/friend called to offer a “Green Hell Green” GTR.
if anyone is interested, please send me a PM, and I will hook you up.
Calling Trakcar...
Damn Phil, just followed one around PBIR and it was faster then the RS!!
I've told Renntech if they fix the brakes and I can empty a tank without problems, I will take it home.
I have two dealers on notice I want the Black Series.
A few laps behind a Ford 350R and AMG GTR with Renntech stuff:
Fun chasing the a 350R and the Green Hell Monster!!
The GTR was pretty well (over) driven, but I did my own overdriving with SC kicking in plenty. I was LMAO, went to talk to the GTR driver and he said the brakes were getting a bit long.
PBIR is a brake killer, even on the RS but with ST rotors it was perfect. Renntech is playing with those rotors as well, add big *** calipers and some proper cooling and the AMG GTR Black series will be a blast.
I had some hopes of running a 1.22 but 1.245 in traffic is all I got. Still, even TBL was 1.23, it was just too hot and greasy. I've gone faster on Michelins ….
The AMG GTR (Black series) with some aftermarket Calipers and ST rotors will be a force to be reckoned with....
Damn Phil, just followed one around PBIR and it was faster then the RS!!
I've told Renntech if they fix the brakes and I can empty a tank without problems, I will take it home.
I have two dealers on notice I want the Black Series.
A few laps behind a Ford 350R and AMG GTR with Renntech stuff:
Fun chasing the a 350R and the Green Hell Monster!!
The GTR was pretty well (over) driven, but I did my own overdriving with SC kicking in plenty. I was LMAO, went to talk to the GTR driver and he said the brakes were getting a bit long.
PBIR is a brake killer, even on the RS but with ST rotors it was perfect. Renntech is playing with those rotors as well, add big *** calipers and some proper cooling and the AMG GTR Black series will be a blast.
I had some hopes of running a 1.22 but 1.245 in traffic is all I got. Still, even TBL was 1.23, it was just too hot and greasy. I've gone faster on Michelins ….
The AMG GTR (Black series) with some aftermarket Calipers and ST rotors will be a force to be reckoned with....
Was that actually a GTR Peter? I could swear from the very brief view I had as you passed it, it looked like a GTC ‘vert! lol
btw: was it running the CCM brakes or the irons? My CCMs, after ‘bedding them in’, or burnishing them during the first session, were excellent without any fade over the next three 25 minute sessions during a recent HPDE in the Advanced group.
03-01-2018, 11:11 PM
