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This was my first day at the track with my GTR and a friend’s first day with his brand new GT3.
GTR impressions:
for anybody on this forum who has never tracked their GTR ...big miss ! ....this car shows you how good it is only on the track (same with the Michelin pilot cup 2).
As my first day with the GTR , I kept it on Sport plus automatic. The car simply goes where you pont it ...no matter how hard through the turns, the back end was skidding in such a predictable way that it was almost hard to realize wether I was skidding or not. I pushed the car hard and the steering wheel corrections were so effortless and intuitive...
We decided that I would follow as this was my first time at the Texas Motor Ranch...My friend is a much more experienced track driver and I was easily coming up on him in his new GT3.
The GTR power was always instantly available.....the brakes were awesome and never faded (non ceramic).
I could not believe how flat and balanced the car stayed at all times. You can throw the car left and right in tight S turns and almost any driver can get the most out of it. The traction control is amazing ...made me look like a champ.
GT3 impressions:
i should start by saying that I am actually ordering one as I really want to own on of the last true driver’s 911....the new 992 will have an all digital dashboard...and other stuff that really will mark the end of an era ...
Therefore ...as my first Porsche...I think it is the right one to own.
The two two cars were so different on the track...The GT3 is and feel smaller... but the precision is wonderful....the steering does feel more direct but ...I was really bothered by how thin the steering wheel feels vs. the AMG.
Breaking was also very good. The car was als very predictable. Was able to throw the back end and recoup effortlessly.
Great balance overall. The accelerations feel slower than the GTR ...but the GT3 totally makes up for it in fun with the high reving engine....up to 9000 rpm. The reving sound is truly awesome. GTR has also great sound and popping on down shifts....but the GT3 has that more traditional race sounds...
Verdict :
sorry to disappoint but ....both cars offer such a wonderful display of different DNA that I cannot choose between the two ...both offer a unique experience.
As as this is a AMG forum....PLEASE track your GTR ...you are missing so much if you don’t ....same for the GT3 owners.
I am fortunate that I will probably keep both cars...and therefore can enjoy their delightful differences.
Bravo to Porsche and AMG engineers for offering such a genuine display of the personalities intended in their cars ....wow !!!
I did a similar back to back test here in the UK at Anglesey, its a great little 2 mile circuit with its own (rather smaller) version of Laguna Secas corkscrew. My conclusions were rather different to yours but I suspect you would eventually find the same as you start to push the GTR harder.
Running the car in Sport+ you're actually limiting the torque, you need to be running the car in Race(or turning traction control to sport) to get the full grunt out of the car. The steel brakes are not up to par and neither are the ceramics the key reason is that the GTR (and all other current GT variants) have absolutely no brake cooling, none whatsoever, as soon as you get some proper heat into the system its game over.
Braking in the GT3 is way better than in the GTR. You can hit the brakes in the GT3 as hard as you can, lap after lap and they remain consistent, I also find the GT3 slightly more balanced under braking than the GTR, probably because there is less mass to balance.
In really tight corners the GT3 turns in much better, its a far more nimble car through twisty sections of track. The GTR on the other hand has a high speed stability and power that allows it to gain that time back on the GT3, I was a full 10mph faster in the GTR than GT3 through the 2 fast rights at Anglesey.
I do find the GTR to be a more playful car overall, Anglesey has a corner called Peel which is an early and relatively slow turn in corner which widens nicely on exit, in the GTR I would find myself understeering on entry but then you could simply apply some power early in the corner and turn that understeer into a wonderfully controlled bit of oversteer through the corner, doing that felt comfortable and awesome all at once. Absolutely no chance of me trying it in the GT3 though!
The most obvious difference between the two cars is their stamina on track. The GT3 can go out on track and lap until it runs out of petrol or tyres whereas the GTR generally lasts about 15 minutes before brakes and tyres tell you its time to come in.
Lastly and this only applies for european owners of these cars, the Clubsport pack in the GT3 is perfect, the 6 points fit correctly and hold you in position, the 918 style buckets off tremendous support. In the GTR the trackpack is useless, the harnesses are unsuable (especially for taller drivers) and the recaro pole position seats do not offer enough support for the sort of corner loads the GTR can produce.
As you say though, more GTR owners should head out to track. If they did I think we'd see more serious development of this car from MB and we might actually get a properly sorted MB track car.
Last edited by WhiteBlack; 07-05-2018 at 06:02 AM.
I did a similar back to back test here in the UK at Anglesey, its a great little 2 mile circuit with its own (rather smaller) version of Laguna Secas corkscrew. My conclusions were rather different to yours but I suspect you would eventually find the same as you start to push the GTR harder.
Running the car in Sport+ you're actually limiting the torque, you need to be running the car in Race(or turning traction control to sport) to get the full grunt out of the car. The steel brakes are not up to par and neither are the ceramics the key reason is that the GTR (and all other current GT variants) have absolutely no brake cooling, none whatsoever, as soon as you get some proper heat into the system its game over.
Braking in the GT3 is way better than in the GTR. You can hit the brakes in the GT3 as hard as you can, lap after lap and they remain consistent, I also find the GT3 slightly more balanced under braking than the GTR, probably because there is less mass to balance.
In really tight corners the GT3 turns in much better, its a far more nimble car through twisty sections of track. The GTR on the other hand has a high speed stability and power that allows it to gain that time back on the GT3, I was a full 10mph faster in the GTR than GT3 through the 2 fast rights at Anglesey.
I do find the GTR to be a more playful car overall, Anglesey has a corner called Peel which is an early and relatively slow turn in corner which widens nicely on exit, in the GTR I would find myself understeering on entry but then you could simply apply some power early in the corner and turn that understeer into a wonderfully controlled bit of oversteer through the corner, doing that felt comfortable and awesome all at once. Absolutely no chance of me trying it in the GT3 though!
The most obvious difference between the two cars is their stamina on track. The GT3 can go out on track and lap until it runs out of petrol or tyres whereas the GTR generally lasts about 15 minutes before brakes and tyres tell you its time to come in.
Lastly and this only applies for european owners of these cars, the Clubsport pack in the GT3 is perfect, the 6 points fit correctly and hold you in position, the 918 style buckets off tremendous support. In the GTR the trackpack is useless, the harnesses are unsuable (especially for taller drivers) and the recaro pole position seats do not offer enough support for the sort of corner loads the GTR can produce.
As you say though, more GTR owners should head out to track. If they did I think we'd see more serious development of this car from MB and we might actually get a properly sorted MB track car.
Thank you for your great observations. I cannot contest what you are saying ...I have simply not reached this level of track experience to be able to notice what you are noticing.
But it is a great confort to hear about the GT3’s abilities as I am buying one !
I will definitely change the setting on the GTR ...I did notice some lack of torque coming out of a few turns ...I was “waiting “ for the power to come through while my foot completely down.
You do feel more “one” with the car in the GT3 ... but somehow I expected that .... the GTR ...as big as it is ... really does an amazing job helping you control the car...
I guess for now ...my novice status does not allow me to feel the GTR flaws ...no doubt I will get there , especially having the two cars ...
I still think the GT3 needs a thicker steering wheel !! You ?
I have tracked my GT R twice now. Once you gain experience you need to be in Race mode and with ESC in Sport at a minimum. U then need to go to Settings to turn off the Automatic braking.
I though am pretty experienced on track, so I drive the car in Race with ESC Off and TC with two red lights showing. The car is fantastically balanced in this fashion and the Auto Brake feature is disabled. It is wicked fast and handles incredibly well; the fastest car I’ve driven on track and I’ve driven a fair number of decent cars. I have the CCMs and find them to do a great job. Change out the brake fluid to something high performance and brake correctly and you should not experience any fade. I brake hard initially but then trail brake through the initial aspect of most corners. If you brake hard primarily in a straight line to scrub off speed and are applying lots of continuous pressure on the brakes, you may well cause fade even with the CCMs; but I’ve never experienced it. The OEM Sport Cup 2s are only good for a couple of laps and then get greasy as the car is too fast for them. You need to be on the Michelin Sport Cup 2 ZP tyre that is optional in the ROW and is the exact tyre found on the Corvette C7 Z06 with the Z07 option. I had no problems making them last a whole HPDE run session, and they are much faster than the OEM tyres.
I 100% agree that the GT R needs to be let loose on a road course: it is so much fun!!
18'Porsche GT3, 16' Ram 3500 mega diesel,30' Model A Ratrod, 17' E43
Cool write up from OP and commenters, two very capable track cars with two different ways they approach the job. I still have yet to see a GTR on the track (NJMP, Glen, AMP, VIR) but look forward to running with one some day.
For my first track day with the GTR I left it in RACE/sport. The active braking and tightening of the seatbelt was frustrating.
On my second track day I turned ESC off and started on 2 yellow lights. Quickly found that more limiting than sport mode, within 2 laps I had turned TC to 1 red light.
Oh baby, is the GTR beautiful at that setting, I've thought about what you said Bish about running 2 red lights. Honestly I found 1 red light so rewarding I just stayed on that setting for the rest of the day.
I did play with the rear wing a bit. I took a digital torpedo level and set it across the wing. The factory 'neutral' position was actually about 5 degress I increased to 10 degrees total.
Would be nice if Mercedes would release information on different angles of attack.
Bish, I agree with your assessment of the OEM SC2s, mine are trashed after my second day, and last run they were very greasy.
canucklehead: I forgot to mention that my second time at the track I had the wing set at its maximum angle. The rear of the car was just so planted. Now granted I also was running the ZP tyres for the first time, so two variables, but I do think it was providing some noticeable extra downforce;
whiteblack: my first time at the track with the car when I was running the OEM SC2s I started out at around 26 psi F & R. Even though the ambient was only high 70dF’s/low 80dF’s, the tyres, and especially the fronts, were getting far too hot with psi into the high 30’s. On one run my fronts went to 41 psi!. Even dropping the starting psi down to 24 didn’t seem to help much. Wear was consistent across the tyre carcass and they weren’t ‘rolling over’ onto the sidewall; they just lost grip relatively quickly such that I had to back off during the later third of the run session. I have had a dedicated set of track wheels built (Signature SV501s) and will be installing a brand new set of the ZPs at the same time, so am excited to try the new setup. In this way I can just exchange wheels/tyres and drive to the track with the ZPs, then reverse the process during the week.
Those tire PSIs sound really high. Are you running pure Nitrogen?
Well they’re that high simple due to the speeds and stresses placed on the tyres on a road course. I’d never run nitrogen as one, I consider it to be a bit of a gimmic, but two, I tend to vary the psi at the different corners based on which of my local tracks I’m running at, and also based on ambient temps. Since I’m switching pressures so often it doesn’t make any sense for me to use N2.
Now, if I was only using the OEM wheels/tyres for purely street purposes I wouldn’t care if my dealership placed it in my tyres, but I wouldn’t pay for it.
All F1 teams use Nitrogen as the gas in the tire. Not that we are on that level, but the principles are the same. N2 resists water and that’s whats expanding and heating In your tire at high speed.
You just spent $$on the wheel setup, and literally left out a basic element.
Sorry but that makes no sense to a person using the car such as myself. Since I drive the car to the track, then decrease and adjust pressures throughout the day, then increase the psi to drive home, and given I don’t have the resources of an F1 team with access to an N2 source at the track, there is no reason to use anything other than air, which btw is 80% N2!
another thing: the race shop I use that mounts my tyres, etc has a state of the art air compressor system with three levels of air ‘filtration’ in order to remove water vapor. Hence the inside of my tyres is ‘dry’. I carry a pre-filled ‘air tank’ to the track with me that I fill at home to 120 psi, and my compressor is constantly emptied of residual air to avoid contamination from water, etc.
Again, using N2 on the street is fine, but it is useless for a weekend track driver just out having fun like myself. My psi on the OEM SC2s increased due to the speeds and stresses placed on them and they aren’t the optimal tyre on the track for the car. It’s to fast for them.
Bish
Last edited by thebishman; 07-07-2018 at 02:42 PM.
Insightful commentary and experiences from those who track the GTR and GT3. Dailying the GTS and GT3, my experience is far more limited. It's fascinating to see what these machines are truly capable of on the track.
i really wonder the difference of feeling plus handling on the GT R with the Carbon cernanics ?? Considering the big save up on weights on roatating mass i am sure it can really help around the corners and the precision of the steering just to mention 2 aspects.
whiteblack: my first time at the track with the car when I was running the OEM SC2s I started out at around 26 psi F & R. Even though the ambient was only high 70dF’s/low 80dF’s, the tyres, and especially the fronts, were getting far too hot with psi into the high 30’s. On one run my fronts went to 41 psi!. Even dropping the starting psi down to 24 didn’t seem to help much. Wear was consistent across the tyre carcass and they weren’t ‘rolling over’ onto the sidewall; they just lost grip relatively quickly such that I had to back off during the later third of the run session. I have had a dedicated set of track wheels built (Signature SV501s) and will be installing a brand new set of the ZPs at the same time, so am excited to try the new setup. In this way I can just exchange wheels/tyres and drive to the track with the ZPs, then reverse the process during the week.
Sounds like your tyres are just getting far too hot, the GTR puts loads of heat into the tyres! I never measure tyre pressures at the start of the day/session, I only measure hot pressures and aim for about 32psi hot. Running like that I've had no issues with tyres at all especially since I have to come in early for the sake of the brakes!
Sounds like your tyres are just getting far too hot, the GTR puts loads of heat into the tyres! I never measure tyre pressures at the start of the day/session, I only measure hot pressures and aim for about 32psi hot. Running like that I've had no issues with tyres at all especially since I have to come in early for the sake of the brakes!
My OEM tyres will be at 32 psi in just two to three laps even when starting them at 26 psi ‘cold’. I really do not want to start them at <24 psi just so that they remain mid-30’s at the end of a session; especially when the ZP tyres are so much faster and consistent. I have easily made it to the end of every session without any brake issues; I’m sorry you’re having trouble.
I am am getting my track wheels this Friday, and I’ll have everything mounted ready to go sometime next week. Having a dedicated set of track wheels/tyres has always worked out best on multiple levels for me.
My OEM tyres will be at 32 psi in just two to three laps even when starting them at 26 psi ‘cold’. I really do not want to start them at <24 psi just so that they remain mid-30’s at the end of a session; especially when the ZP tyres are so much faster and consistent. I have easily made it to the end of every session without any brake issues; I’m sorry you’re having trouble.
I am am getting my track wheels this Friday, and I’ll have everything mounted ready to go sometime next week. Having a dedicated set of track wheels/tyres has always worked out best on multiple levels for me.
Bish
The tyres take so long to return to cold that I can’t see that ever being an issue? After lunch having sat for an hour they’ll be mid twenties but nothing a gentle warmup lap won’t take care of.
I’ve given up on the brakes entirely, they need to be extensively “managed” just to keep them working. No magic brake fluid or pads is going to fix the fact that there is no brake cooling.
Renntech quoted e800 for their cooling upgrade which is fine but they will only fit in Germany and I don’t have them time to take the car there at the moment. At the moment I’ve decide to wait for the Clubsport which I’ve been told will have a cooling upgrade and just live with brakes as they are.
The tyres take so long to return to cold that I can’t see that ever being an issue? After lunch having sat for an hour they’ll be mid twenties but nothing a gentle warmup lap won’t take care of.
I’ve given up on the brakes entirely, they need to be extensively “managed” just to keep them working. No magic brake fluid or pads is going to fix the fact that there is no brake cooling.
Renntech quoted e800 for their cooling upgrade which is fine but they will only fit in Germany and I don’t have them time to take the car there at the moment. At the moment I’ve decide to wait for the Clubsport which I’ve been told will have a cooling upgrade and just live with brakes as they are.
Please remind me again, do you have the CCMs or the iron brakes?
CCM. Renntech Europe sent me some horrendous pictures of failed GTR CCMs but they are in the business of selling brake upgrades so
I would be very interested to see said pictures since I’m not too sure lots of people have been tracking the car extensively thus far. But as you say, Renntech are a business trying to develop and sell a product.
Your tracks must must be much harder on brakes than my local track as I’ve had zero issues with my brakes. I’ve got Castro’s SRF I stalled and the brakes just stop lap after lap. I can highly recommend it, or Endless 650. One thing: it can be a ***** to get all of the bubbles out of the brake system and your local race shop needs to take the time to do so. I had to have the system bleed twice after the initial flush due to retained bubbles, especially in the rear brakes.
If you have a decently firm pedal but are experiencing lack of braking, it’s your pads overheating. I would recommend that you’ve done a thorough burnishing procedure, or switch to the Pagid RSC1s which are available for our car. If the pedal feels ‘soft’ but you do eventually slow down OK, you’re ‘boiling’ the fluid in the calipers or you have air in the lines. In which case get the system bleed ASAP.
I do agree that extra cooling would be a plus and I’d purchase aftermarket cooling scents for sure.
I would be very interested to see said pictures since I’m not too sure lots of people have been tracking the car extensively thus far. But as you say, Renntech are a business trying to develop and sell a product.
Your tracks must must be much harder on brakes than my local track as I’ve had zero issues with my brakes. I’ve got Castro’s SRF I stalled and the brakes just stop lap after lap. I can highly recommend it, or Endless 650. One thing: it can be a ***** to get all of the bubbles out of the brake system and your local race shop needs to take the time to do so. I had to have the system bleed twice after the initial flush due to retained bubbles, especially in the rear brakes.
If you have a decently firm pedal but are experiencing lack of braking, it’s your pads overheating. I would recommend that you’ve done a thorough burnishing procedure, or switch to the Pagid RSC1s which are available for our car. If the pedal feels ‘soft’ but you do eventually slow down OK, you’re ‘boiling’ the fluid in the calipers or you have air in the lines. In which case get the system bleed ASAP.
I do agree that extra cooling would be a plus and I’d purchase aftermarket cooling scents for sure.
Godd luck getting this sorted!!
Bish
Pics are on my mobile, now I'm back from FOS I'll PM you them. Certain tracks here are very hard on brakes as they're based on old airfields which tends to mean some high speed straights into tight corners. I think the lack of brake cooling means that the GTR brakes don't recover on the straights like they should. I'm boiling fluid (regardless of manufacturer) and cooking pads.
Interestingly I spoke to a few MB guys who were willing to discuss the clubsport at FOS and was told that it definitely will have cooling ducts and some project one style wheels that will aid brake cooling as well.
TBH I’ve been tracking for many, many years and know a lot of others who’ve done the same. I don’t know of anyone who truly has ‘boiled’ SRF at the track, regardless of configuration. Many reasons for a soft pedal and ‘mushy’ brakes, but normally a really top of the line brake fluid such as Castrol SRF, or Endless 650, as long as the flush has been done correctly; (critical that), won’t be the reason a person is losing their brakes.
AMG GTR (sadly now sold)+991.2 GT3 RS+GT3 Touring+991 GTS+997 GT3 RS+996 GT3 RS+964 RS+Mini Cooper S
Just chipping into this conversation.
I have now tracked my car at Hockenheim and at Spa and while the brakes drastically faded at Hockenheim after only 5-6 laps, they lasted a lot longer at Spa largely because Hockenheim is actually harder on brakes. You also have 3-4 big braking points at Spa but the lap is so long that the brakes get a bit of a chance to cool down between the "big" application points. In fact, it runs out of tires before it runs out of brakes. Whereas Hockenheim, which also has 3-4 big braking points, is a much shorter lap so the brakes get no rest at all and quickly over heat. At the same tracks, my GT3 runs all day.
07-05-2018, 12:34 AM
but they are in the business of selling brake upgrades so
