Orthojoe's GT4 track thread and ramblings
03-31-2016, 10:43 AM
#106
Nordschleife Master
Thread Starter
Originally Posted by Leong72
Hi Joe, Thanks for taking the time to post. I'd learnt something from your very first post. Unfortunately I'd ordered the front LCA monoball ends and we couldn’t get more than -2.5 camber. Didn’t realise there were “cup” ones available 
IÂ’ve been getting four trackdays per set of fronts as well, chasing Macca around our local and South Island tracks. Rears had half the tread left but were probably close to heat cycling out. Now on my third set of tyres since getting the car just before Christmas!! Look forward to reading more about your exploits.
IÂ’ve been getting four trackdays per set of fronts as well, chasing Macca around our local and South Island tracks. Rears had half the tread left but were probably close to heat cycling out. Now on my third set of tyres since getting the car just before Christmas!! Look forward to reading more about your exploits.
4 days sounds right, unfortunately. Have you tried keeping the rears and swapping out the fronts only? If so, what did you think? Worthwhile, or better off swapping all 4 once the fronts are done?
03-31-2016, 10:50 AM
#107
But cool, nobody here races but you so thanks for clearing it up for us.
03-31-2016, 10:52 AM
#108
At least one second? No way. I'll prove it on Saturday. It will be 0.1 at the very most. That line doesn't change how early I get on throttle or how much throttle I put down. I'm flat as soon as I hit the apex either way. The only difference is how quickly I can unwind the wheel and how much that extra steering lock slows you down, which is minimal.
You'd be surprised how little certain things affect time. People are always saying that short shifting and lifting at T5 at Laguna Seca loses them several seconds. That's actually not true. I've got data logs that show a 10mph difference entering T6, but that equates to only a loss of 0.5 seconds. Cheating through turn 11-13 at thunderhill will NOT net you more than 10mph down the back straight. Not even close.
You'd be surprised how little certain things affect time. People are always saying that short shifting and lifting at T5 at Laguna Seca loses them several seconds. That's actually not true. I've got data logs that show a 10mph difference entering T6, but that equates to only a loss of 0.5 seconds. Cheating through turn 11-13 at thunderhill will NOT net you more than 10mph down the back straight. Not even close.
03-31-2016, 11:04 AM
#109
Nordschleife Master
Thread Starter
Originally Posted by katmeho
Cool, looking forward to learning and seeing the data. Thanks for being open to sharing about this, it's always been something I have trouble reconciling since the extra pavement went in.
I love this kind of stuff, so I'm looking forward to getting more interesting info. Video and data have helped me learn a lot.
03-31-2016, 02:15 PM
#110
Rennlist Member
I love the data analysis side of this stuff :-)
03-31-2016, 10:57 PM
#111
GT3 player par excellence
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that's work. i do that at work
but i will send u my data and video for your pleasure
right on.
unwind earlier.
i am not sure what i did wrong, but i simply cannot get my car to the left of those white lines.
but i will send u my data and video for your pleasure
At least one second? No way. I'll prove it on Saturday. It will be 0.1 at the very most. That line doesn't change how early I get on throttle or how much throttle I put down. I'm flat as soon as I hit the apex either way. The only difference is how quickly I can unwind the wheel and how much that extra steering lock slows you down, which is minimal.
You'd be surprised how little certain things affect time. People are always saying that short shifting and lifting at T5 at Laguna Seca loses them several seconds. That's actually not true. I've got data logs that show a 10mph difference entering T6, but that equates to only a loss of 0.5 seconds. Cheating through turn 11-13 at thunderhill will NOT net you more than 10mph down the back straight. Not even close.
You'd be surprised how little certain things affect time. People are always saying that short shifting and lifting at T5 at Laguna Seca loses them several seconds. That's actually not true. I've got data logs that show a 10mph difference entering T6, but that equates to only a loss of 0.5 seconds. Cheating through turn 11-13 at thunderhill will NOT net you more than 10mph down the back straight. Not even close.
unwind earlier.
i am not sure what i did wrong, but i simply cannot get my car to the left of those white lines.
04-01-2016, 12:30 AM
#112
Drifting
I know I asked this differently already, but what is the likelihood that these early tire lifespan impressions are down to quirks of the sample we're dealing with? There aren't a ton of people reporting in yet, and I'm also wondering if driving styles based on the cars people have previous experience with is contributing to this. I found the post from the GT3 forum I mentioned earlier and quoted it below. It paints a completely different tire picture about a faster car, so once the necessary steps have been taken to get a proper alignment out of a GT4, I'm having trouble fathoming how it could still somehow be inherently prone to consuming tires more quickly. And yes of course not all tracks or drivers are equal, but elsewhere in the thread the quote below came from, Macca mentions that his data is based on input from lots of drivers from all over the world at a variety of skill levels, which makes me wonder further whether GT4 tire impressions might improve once we get more people reporting in. And yes of course there's some self-interest on my part in hoping that's the case since I was expecting 6-8 track days with some road mileage out of a set, and even though it's not as if the costs of a 4-day lifecycle would send me to the poor house, it would still rankle for the reality to be that far off what a fair amount of research had led me to expect.
Manifold. In the early days Max or Sam thought the tires would only last maybe 3 sessions. However it turned out they lasted much longer than they anticipated. I Europe Philgv who is giving the car a very hard work out on track at Spa, Monza, Imola etc has been getting 6-8 days out of the MPSC2. In NZ Ive seen 3 track days and 6000 road KMs including so fast road and autobahn work. A NZ friend is on 4 track days and 3000km and reckons 2-3 more track days and 2-3000km more touring. Seems the general consensus amongst all is 6-8 track days + 3000 miles touring average. Thats pretty impressive I think. Lane above has done better than most but the tracks are faster (not as tight) and he is a very experienced driver so probably less duress on pads, discs and tires.
In terms of factory pads and fluid none of us have had any issues with the factory set up. Phil changed top SFR which I think a few others have done also as a precaution. For pads Philgv changed to Pagid 29 and I think a few US guys have too. I think this is more for longevity and pedal feel. Front pads are wearing faster than rears (same as discs) and if pushed really hard are lasting as few as 6 full days but most I think have seen 8 plus touring. Mine are looking like they will be 6 + 8000km touring/road. Philgv has been eating discs at 4-6 sessions for a set of fronts but he is putting in near 7.1 GT3 cup times at most of those European circuits - and they are very tight after long straights - so that's likely why. From talking to the wider group both on here and by PM I should say front discs on average will be good for 8-12 track days, rears for 10-14. Front pads probably 6-10 track days and rears likely 8-12.
Overall running costs of 991 Gt3 look reasonable. The tyres are a big surprise. The fact the fronts wear out faster is a surprise too. Also many thought rear pads and discs before fronts due to PTV and ESC but neither seem to be active or have an effect so more like traditional F to R wear...
In terms of factory pads and fluid none of us have had any issues with the factory set up. Phil changed top SFR which I think a few others have done also as a precaution. For pads Philgv changed to Pagid 29 and I think a few US guys have too. I think this is more for longevity and pedal feel. Front pads are wearing faster than rears (same as discs) and if pushed really hard are lasting as few as 6 full days but most I think have seen 8 plus touring. Mine are looking like they will be 6 + 8000km touring/road. Philgv has been eating discs at 4-6 sessions for a set of fronts but he is putting in near 7.1 GT3 cup times at most of those European circuits - and they are very tight after long straights - so that's likely why. From talking to the wider group both on here and by PM I should say front discs on average will be good for 8-12 track days, rears for 10-14. Front pads probably 6-10 track days and rears likely 8-12.
Overall running costs of 991 Gt3 look reasonable. The tyres are a big surprise. The fact the fronts wear out faster is a surprise too. Also many thought rear pads and discs before fronts due to PTV and ESC but neither seem to be active or have an effect so more like traditional F to R wear...
04-01-2016, 01:59 AM
#113
Nordschleife Master
Thread Starter
I know I asked this differently already, but what is the likelihood that these early tire lifespan impressions are down to quirks of the sample we're dealing with? There aren't a ton of people reporting in yet, and I'm also wondering if driving styles based on the cars people have previous experience with is contributing to this. I found the post from the GT3 forum I mentioned earlier and quoted it below. It paints a completely different tire picture about a faster car, so once the necessary steps have been taken to get a proper alignment out of a GT4, I'm having trouble fathoming how it could still somehow be inherently prone to consuming tires more quickly. And yes of course not all tracks or drivers are equal, but elsewhere in the thread the quote below came from, Macca mentions that his data is based on input from lots of drivers from all over the world at a variety of skill levels, which makes me wonder further whether GT4 tire impressions might improve once we get more people reporting in. And yes of course there's some self-interest on my part in hoping that's the case since I was expecting 6-8 track days with some road mileage out of a set, and even though it's not as if the costs of a 4-day lifecycle would send me to the poor house, it would still rankle for the reality to be that far off what a fair amount of research had led me to expect.
1) These aren't quirks. I think you're not appreciating the large variation in the drivers and the tracks. At least where I'm from, someone driving in the 'advance' group and being an 'instructor' is not enough information for me to figure anything out. I need lap times, track, and setup
2) I own a 991 GT3 and the cup2s on that car only last 3-5 days (depending on the track), which is the same I am predicting with the GT4. The GT3 is worse in the fact that the rear outer edge of the tires get really chewed up and are done about the same time as the fronts are totally worn down even though the rest of the rear tire is ok. It looks like with the GT4 at least you have a chance to run the rears longer
3) I recently corresponded with Macca and he is only getting 5 days max out of cup2 tires on the GT3 himself, so I think you are getting info from an old post.
4) To squeeze out an extra second tears away at tires exponentially more. If you're trying to gauge how long the tires will last for you, the better question is to ask what lap times the person is running and how that compares to your lap times at the same track. If it is faster, you will get more than the posted tire life. If it is slower than you, you will get less.
5) In reality, the only way you're going to find out how long these tires will last for you is for you to go out there and do it yourself. It doesn't matter what others are getting, it only matter what you are getting, right?
04-01-2016, 02:03 AM
#115
Nordschleife Master
Thread Starter
04-01-2016, 02:22 AM
#116
Did you try the new firmware yet and confirm it's correctly switching to quiet mode on the GT4?
I'm going to swap my GT3 to the 4-wite install soon...
04-01-2016, 02:58 AM
#117
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Originally Posted by Mech33
Not going to wait for the 4-wire version?
Did you try the new firmware yet and confirm it's correctly switching to quiet mode on the GT4?
I'm going to swap my GT3 to the 4-wite install soon...
Did you try the new firmware yet and confirm it's correctly switching to quiet mode on the GT4?
I'm going to swap my GT3 to the 4-wite install soon...
Maybe I will wait until the 4 wire install for full write up
Got to put up some teasers lol!
04-01-2016, 03:00 AM
#118
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Originally Posted by orthojoe
Dude you gotta tell me how to put this box enclosure together. The instructions don't have any pictures! LOL!
04-01-2016, 03:34 AM
#119
Instructor
Yes, I wasn't aware of the cup monoballs either until they showed up. Mooty ordered them for me. My shop initially thought they would give you too much camber for street tires like the cup2, but they turned out to be perfect for any type of track alignment. I'm using the standard monoball on my gt3 and maxxed out at -2.7.
4 days sounds right, unfortunately. Have you tried keeping the rears and swapping out the fronts only? If so, what did you think? Worthwhile, or better off swapping all 4 once the fronts are done?
4 days sounds right, unfortunately. Have you tried keeping the rears and swapping out the fronts only? If so, what did you think? Worthwhile, or better off swapping all 4 once the fronts are done?
04-01-2016, 06:46 AM
#120
Ooh, great question. Joe, what hot pressure were you using? I found pressure of 34-35 measured with a gauge after cooldown produced some very enjoyable handling on track. TPMS showed 35-36 on track, but I don't trust it too much because it seems that it will skip certain numbers. I've never seen it display 31 or (I think) 34, for example, but I've seen it bounce between 29 and 31 a couple of times in the course of a few minutes, and one tire that's 29.1 on my gauge will read as 29 on TPMS whereas another tire that's 29.6 on the gauge might read as 31 on TPMS. Strange....
2.1 bar = 30.45 psi = 30 psi
2.2 bar = 31.90 psi = 32 psi
2.3 bar = 33.35 psi = 33 psi
2.4 bar = 34.80 psi = 35 psi
That is the reason for not seeing 31 or 34.