Track report

[Day Laborer]

Originally Posted by FormulaMMM

Another track day, first time out with the AP Racing brakes and seat fully sorted. Quite a machine. Wild, alive, always entertaining. Love it.

Luckily the ZL1 has the performance data recorder :

[FormulaMMM]

Originally Posted by Day Laborer

Luckily the ZL1 has the performance data recorder :

haha awesome! Thanks for tracking down. Waved him by shortly after, I'll see if I can find the chase footage.

[fanatic1]

Originally Posted by Day Laborer

Luckily the ZL1 has the performance data recorder :

Thanks for posting, little loose there at 0:56, haha.

Chase videos are the best.

[FormulaMMM]

Originally Posted by fanatic1

Thanks for posting, little loose there at 0:56, haha.

Chase videos are the best.

Little bit.. Supercar 3R were pretty toasty on both platforms by the time we were through. Great time.

[FormulaMMM]

Few laps chasing the monster. Looked killer in whatever silver/grey color this is

[Gomeler]

That ZL1 has some power, it just walks away on the straight. Looked like the GTS was making you work for those laps.

If you're using a GoPro Hero5-7, this ND filter set was perfect for properly exposing the tarmac -> https://www.amazon.com/gp/product/B074V76DWB. I'm using a ND8 and I can now see the tarmac in my recordings vs it being an overexposed white glare.

[SYT_Shadow]

Originally Posted by Gomeler

That ZL1 has some power, it just walks away on the straight. Looked like the GTS was making you work for those laps.

If you're using a GoPro Hero5-7, this ND filter set was perfect for properly exposing the tarmac -> https://www.amazon.com/gp/product/B074V76DWB. I'm using a ND8 and I can now see the tarmac in my recordings vs it being an overexposed white glare.

I set EV compensation to -1 to achieve this effect. Have you tried this?

[Gomeler]

Originally Posted by SYT_Shadow

I set EV compensation to -1 to achieve this effect. Have you tried this?

Yup, I'm currently set at ISO100 min/max, EV -1.0, shutter speed 1/120. Lowering EV still wasn't helping, but I haven't tried 1/240 shutter speed yet.

Highly recommend messing around with the GoPro Protune settings.

[hC1001]

Originally Posted by Gomeler

Yup, I'm currently set at ISO100 min/max, EV -1.0, shutter speed 1/120. Lowering EV still wasn't helping, but I haven't tried 1/240 shutter speed yet.

Highly recommend messing around with the GoPro Protune settings.

On my GP5, i set auto exposure and target the front windshield where its very bright. After that, the outside is no longer overexposed. I've tried setting a lower EV but wasnt good when weather condition changes from sunny to cloudy...

Just press on the display until auto exposure comes on and then target the front windshield otherwise it adjusts to the interior lighting depending on camera location.

[Gomeler]

Originally Posted by hC1001

On my GP5, i set auto exposure and target the front windshield where its very bright. After that, the outside is no longer overexposed. I've tried setting a lower EV but wasnt good when weather condition changes from sunny to cloudy...

Just press on the display until auto exposure comes on and then target the front windshield otherwise it adjusts to the interior lighting depending on camera location.

Spot meter? That could be an option, I was trying to setup the camera so that I just tell it to record and I don't touch it all day. I wonder if I can enable the spot meter via the app, otherwise I can't really access the touchscreen easily. Would be nice if I could just force the camera to enable spot meter at the center of focus. Will have to experiment with this over the weekend.

[FormulaMMM]

Originally Posted by Gomeler

That ZL1 has some power, it just walks away on the straight. Looked like the GTS was making you work for those laps.

If you're using a GoPro Hero5-7, this ND filter set was perfect for properly exposing the tarmac -> https://www.amazon.com/gp/product/B074V76DWB. I'm using a ND8 and I can now see the tarmac in my recordings vs it being an overexposed white glare.

I was impressed with how well the GTS hung on the straights. If you watch from the ZL1 perspective, there's some gaining, but not a massive difference where both cars get a good corner exit.

yes, GTS is definitely high strung, but always communicative and largely predictable. Unless you really (really...) overcook it into the corner, the front end is going to bite, then it's a balancing act with steering & throttle. Prototypical M handling, except turned up a notch in the GTS because of the power/torque and throttle sensitivity. You have to really be on it, I love that.

On the front end -- in the chase video from my perspective really chucked it into turn 1 2:46 - 2:54. Probably shouldn't have been able to hit apex there. But front end still dove in, back came around. The front axle in the F8X gen has always been immense and GTS maximizes it. I haven't maxed out camber yet either.

But if I can get the rear axle to calm a little bit with damper and psi adjustments, that would be ok...

Thanks all for the video tips. I'll try to adjust next time around.

[hC1001]

Originally Posted by Gomeler

Spot meter? That could be an option, I was trying to setup the camera so that I just tell it to record and I don't touch it all day. I wonder if I can enable the spot meter via the app, otherwise I can't really access the touchscreen easily. Would be nice if I could just force the camera to enable spot meter at the center of focus. Will have to experiment with this over the weekend.

Never tried to see if the app has the option. Yea, i wish it had some type of spot meter memory. I forget to set it one time before a cloudy session and footage wasnt so great.

[fanatic1]

As previously mentioned, lower operating temperatures with BBK. Additional benefit, you can remove studs without breaking them - broke 3 on the rear axle and of course, 0 on the front axle. Guess how much fun removing 3 broken studs is......if I keep this car, BBK on rear!

2nd image of rotor wear, this time w/o cracking to perimeter

[FormulaMMM]

Originally Posted by fanatic1

As previously mentioned, lower operating temperatures with BBK. Additional benefit, you can remove studs without breaking them - broke 3 on the rear axle and of course, 0 on the front axle. Guess how much fun removing 3 broken studs is......if I keep this car, BBK on rear!

2nd image of rotor wear, this time w/o cracking to perimeter

That sucks! Thanks for the update and additional disc photo. How did you remove the broken?? With a lot of swearing and persistence?

[fanatic1]

Originally Posted by FormulaMMM

That sucks! Thanks for the update and additional disc photo. How did you remove the broken?? With a lot of swearing and persistence?

There was a fair amount of swearing, but in the end, it wasn’t that bad once armed with the proper drill bits

[fanatic1]

Originally Posted by FormulaMMM

That sucks! Thanks for the update and additional disc photo. How did you remove the broken?? With a lot of swearing and persistence?

One additional thing I have noticed, rotating the 25mm pads across the axle and inside to outside dramatically improves pad life

[FormulaMMM]

Originally Posted by fanatic1

One additional thing I have noticed, rotating the 25mm pads across the axle and inside to outside dramatically improves pad life

I have maybe another 1/2 season with current studs. Ran them initially with ccb, so might have to get some more info on those bits...

Nice insight on the pads. Was recently schooled on pad taper and extending life with intermittent rotation/flips by an indy P shop. Believe tech said sometimes as much as 50% more life if you're consistent with it. I do see developing after a couple of events on RSL1 and stock calipers. The longer the pads, the more taper.

AP Racing system and calipers are designed to counteract, pretty cool:

The pistons in our AP Racing calipers have differential bores (pistons are different sizes) designed to combat this issue. The piston on the leading edge is smaller to apply less pressure, while the trailing piston is larger to apply more pressure, which helps even out the wear.

https://www.essexparts.com/news-blog...d-owners-guide

[Gomeler]

I flipped my pads once with my AP setup in 2020. I only ran ~5 days with them, but I noticed some serious taper in.. the rear. I wasn't expecting that. The fronts were okay, the rears would have been comically lopsided if I hadn't flipped them.

[4play]

What pressures / camber settings are you guys running on the rear?

I was having a lot of trouble with entry/mid-corner oversteer. Front axle grip is excellent but the rears just cannot keep up, and this is off-throttle or maintenance throttle. Part of the issue I'm sure is that I was running street height and damper settings.

Difficult to really maximize entry speed when you are worried about the back coming around the entire time. On the exit I'm fine with managing oversteer, but would much rather have a neutral/understeering car at entry.

Fronts are 275/35/19 AMG GT R Sport Cup 2s, was running ~35 psi hot.

Rears are 305/30/20 458 Speciale Sport Cup 2s, was running ~32 psi hot.

The front grip was pretty solid, especially once I got the tire up around 170F. But I was getting entry/midcorner oversteer at only 0.9G, which is terrifying in the faster stuff.

[FormulaMMM]

Originally Posted by 4play

What pressures / camber settings are you guys running on the rear?

I was having a lot of trouble with entry/mid-corner oversteer. Front axle grip is excellent but the rears just cannot keep up, and this is off-throttle or maintenance throttle. Part of the issue I'm sure is that I was running street height and damper settings.

Difficult to really maximize entry speed when you are worried about the back coming around the entire time. On the exit I'm fine with managing oversteer, but would much rather have a neutral/understeering car at entry.

Fronts are 275/35/19 AMG GT R Sport Cup 2s, was running ~35 psi hot.

Rears are 305/30/20 458 Speciale Sport Cup 2s, was running ~32 psi hot.

The front grip was pretty solid, especially once I got the tire up around 170F. But I was getting entry/midcorner oversteer at only 0.9G, which is terrifying in the faster stuff.

Pressures look fine.

For sure street ride height isn't helping your cause. The most settled I've had an M car was on Clubsports and the rear slammed. Fall Line E9X alignment spec back in the day.

Another member has reported rear traction gains below the blocking ring. I may be headed that direction next season.

Slackening rear dampers might also help. Intend to try -2 -3 clicks rebound than recommended track spec next time out.

I don't know if neutral/understeering on entry and midcorner is in the cards for the GTS. Front axle is absolutely pinned. But there are major lap time gains to be achieved by getting the rear under control.

It's an uphill battle, always going to be moving around on you. Reportedly also a weakness of the M4 GT4.

You have aero at maximum attack?

[4play]

Originally Posted by FormulaMMM

Pressures look fine.

For sure street ride height isn't helping your cause. The most settled I've had an M car was on Clubsports and the rear slammed. Fall Line E9X alignment spec back in the day.

Another member has reported rear traction gains below the blocking ring. I may be headed that direction next season.

Slackening rear dampers might also help. Intend to try -2 -3 clicks rebound than recommended track spec next time out.

I don't know if neutral/understeering on entry and midcorner is in the cards for the GTS. Front axle is absolutely pinned. But there are major lap time gains to be achieved by getting the rear under control.

It's an uphill battle, always going to be moving around on you. Reportedly also a weakness of the M4 GT4.

You have aero at maximum attack?

Yeah, had my sacrificial replacement splitter all the way out and wing at max. But most of the corners are 70-85mph, so probably only 15-20 pounds of downforce at those speeds.

Lowering to track height would definitely give more rear camber, which can't hurt. It was just frustrating to look at the telemetry and see that I was well below 1.0G in almost every corner and the back end was stepping out or wanted to step out every single time.

Tried everything I could think of too - less/no trail braking, little bit of maintenance throttle, no maintenance throttle, different lines, etc. Even the corner workers were commenting that it looked like I was on roller skates, particularly in off camber sections. Just frustrating to be running 305 section Sport Cup 2s and have absolutely no grip or confidence whatsoever. Maybe they weren't getting fully up to temp?

Part of the issue likely stems from the fact that my previous track car (CTR) was ridiculously chuckable and planted at the rear. Also the track I was on does not have any functional runoff (little bit of grass and then either a berm or woods), so it is a bit sketchy to get entry oversteer at 85+ mph.

[Lienrocs]

Originally Posted by 4play

What pressures / camber settings are you guys running on the rear?

I was having a lot of trouble with entry/mid-corner oversteer. Front axle grip is excellent but the rears just cannot keep up, and this is off-throttle or maintenance throttle. Part of the issue I'm sure is that I was running street height and damper settings.

Difficult to really maximize entry speed when you are worried about the back coming around the entire time. On the exit I'm fine with managing oversteer, but would much rather have a neutral/understeering car at entry.

Fronts are 275/35/19 AMG GT R Sport Cup 2s, was running ~35 psi hot.

Rears are 305/30/20 458 Speciale Sport Cup 2s, was running ~32 psi hot.

The front grip was pretty solid, especially once I got the tire up around 170F. But I was getting entry/midcorner oversteer at only 0.9G, which is terrifying in the faster stuff.

You could try running a little more pressure in the rear as well. They're big and heavy cars.

Completely different tire/suspension so I'm not sure how relevant it is but I was running around 32 pounds on A052's and the car didn't have the grip that it did with 38 pounds at all four corners.