[TrackClub]

Originally Posted by TheRealJA105

I could clearly use more camber judging by the feathering into the sidewall letters, but then I'd just cord the inside even faster.

Edit: Oh yeah I'm coming for your more even wear with this set I think. Trying to get one more track day out of them if i can ever get on track this year, but I will have a second set of wheels/tires with me in case they cord. Although I've been doing the high pressure thing I mentioned earlier on the street to get this wear.

[TrackClub]

Originally Posted by RUQWIKR

I can dig up past G3 pics like that, too, and some more in the future! My youngest son is still running the car on the G3's while he learns. [-2.76ish front camber]

Ya, your ride is getting one heck of a workout
Hopefully the older kid will be able to get his own ride soon. Seems like he is hooked pretty good, eh? LoL!

[TheRealJA105]

I took a crappy pic in the dark last night of my current front tire situation.

[TrackClub]

Originally Posted by TheRealJA105

I took a crappy pic in the dark last night of my current front tire situation.

Looks good for another day

[GunMetalGrey]

I’m not sure if anyone else put the BMR spherical bushings in the front suspension of their car or not, I did and I guess I’ll soon find out if it’ll make any difference in regards to cording the insides of the tires, hopefully it wasn’t a waste of money. I’ll keep everyone posted after my 2nd track day as I’m sure one day won’t be enough to tell if they make a difference or not.

[TheRealJA105]

Originally Posted by TrackClub

Looks good for another day

That's my thinking and my plan

[glamcem]

some updates:
I had my new rear tires (325/30/19 SC3Rs) mounted and balanced on the new Apex wheels ( 19x12" ARC8) to see if I could benefit from having more grip in the rear.

Poke is not bad at all even less noticeable in person.


I also ordered some 305/30/19 SC3Rs as a spare for the fronts.






I am not sure if I am seeing the benefits of using wider wheels/tires at this track. It was also the case with the previous 1LE, my PBs were on a square setup (305/30/19). Gearing seems better with shorter tires at the ORP. At the Ridge, I think I can see more benefit of using this wider setup. I would like to compare 305/30/19" SQ vs staggered (305/325) at the Ridge so I decided to keep the 19x11" rears and alternate between that and 19x12".

On a faster track with long sweepers added grip in the rear should help keeping the momentum and getting on full throttle quicker at corner exit (at least it was the case with 305/325 NT01s on the previous car).

I have an event scheduled this Tuesday at the Ridge so I will see how it feels there with the same setup.

I also noticed that the front passenger tire wear on the outer edge more noticeable than the other side (since CCW configuration puts more stress on the other/right side) and so I rotated front wheels/tires and it appears to be helping a bit. Hopefully I won't cord another tire after 5 sessions again

The RR tires look normal after about 4 sessions , even though they've been used on the afternoon sessions last time when the track temps were about 20F degrees hotter. A guy at the event who's been using SC3Rs on his Alfa Romeo also mentioned that he starts chunking them much faster than any other tires he used before.

[glamcem]

I was able to improve my PB by about 1.2 seconds at the Ridge yesterday. (1:53.0 with the previous car with 305/325 but in the morning sessions and 1:51.8 with SC3Rs 305/325 afternoon/ewarmer sessions.. track temps are responsible for 1-2 seconds typically)
I was trying the 305/325/30/10 setup (with ZLE fitment wheels yesterday) .. I figured that adding wider/wheels tires would be more beneficial at the Ridge than the ORP. It was in fact the case with the previous car, 305/325 NT01s were faster than SQ 305s at the Ridge ..since rear grip is very useful at many, longer faster sweepers, at the ORP it was the complete opposite and SQ setup was faster ..most likely due to gearing advantage and elevation changes, and more tighter turns.

With the staggered setup car feels like it has a little bit of understeer but it wasn't as bad as the previous car. I think having stiffer sway bars help getting rid of the body roll and the understeer/push caused by it ..I slightly adjusted my driving style and applied the threshold/trail brake more into the apex to be able to rotate the car easily (especially at the tight turns) and got on the throttle much quicker once I feel the car is rotated ..that felt like helped shaving some tenths here and there. My lap times were pretty consistent throughout the day (low 1:52s) then once I made a slight change at the last couple of sessions I was able to see 1:51s.. I felt very close to take it into the 1:50s at some point but couldn't because of the traffic (or giving a point by to a race car) ..

I am planning to compare the 305 SQ (SC3Rs) and 305/325 SC3Rs at both Ridge and ORP and see if my theory is correct.
Video of a couple hot laps from the event

[GunMetalGrey]

Originally Posted by glamcem

I was able to improve my PB by about 1.2 seconds at the Ridge yesterday. (1:53.0 with the previous car with 305/325 but in the morning sessions and 1:51.8 with SC3Rs 305/325 afternoon/ewarmer sessions.. track temps are responsible for 1-2 seconds typically

Congrats CEM!

What Track PTM mode do you use?
Or do you take all the nannies off completely?

I’m about to use exactly the same tire and wheel set up as you are, however first I have to use the 20 inch SC3R tires I Purchased Due to the delay in receiving my Apex ARC8 wheels.

I just did a day of open lapping with SC3R tires on stock 20” ZL1 wheels for the first time, I am quite impressed with them; so far the tires seem to stay consistent through out the entire 20 minute session . Also my corner speeds are definitely significantly higher than they were with the SC3 tires Every time I glanced at the HUD, so I expect some significantly faster lap times once I start timing myself after I get used to the new tires and reacquainting myself with the track.

I also Spent the whole day in PTM race mode, and was shocked at how much traction control/throttle management still occurs. I was expecting a much different experience and feel compared to being in sport 1 mode, I’m not sure what others have noticed, but for whatever reason I didn’t notice a big difference.
I’m thinking of trying track mode with all nannies off next time.

I’m curious if most drivers on this forum find that they are faster with all nannies completely off in track mode compared to track PTM race mode?

If I recall correctly, I believe that in at least a few magazine articles I read, the drivers said they were fastest with all nannies completely off

[GunMetalGrey]

I almost forgot, every time I accelerated out of the same right hand off camber upward slope corner, my car started doing something its never done before; it was like I was getting some sort of wheel hop, Almost like the rear differential was locked and it was lurching around the corner. I don’t know if it was because I have stickier tires, lowering springs, and was using track PTM race mode, or if something is broken, but I’ve never experienced that before at this track and did it every single time today.

Any ideas what it might be?

[TrackClub]

Hey GMG, glad your first outing on G3Rs went well!
You didnt time the laps....what the heck?!

Not having a vid to see what's going on regarding "lurching" etc obviously makes commenting difficult and largly a shot in a dark.

But, from what you described in both posts, I would hazard a guess that you *lost* traction in the rear even with much stickier tires. Why is the question here. It could be because (purely theoretically speaking):

1. You now run without Stabilitrak and experience greater yaw levels for which you don't compensate as a driver. As in, the car is sliding more including exit phase, in which case TC would interfere as the rears cant hook up (while sliding). If this is the case and you turn TC off be neat and tidy and ready to catch her, lest you will likely spin if you stomp on power while lateral transition is still underway. Watch your steering angle as well!

Note that PTM Race will not manage yaw angles for you. Only tire overslip on exits. That's it. As a result it requires much more attention from a driver to manage proper yaw and balance, something that Stabilitrak would do otherwise on your behalf.

Also note, if you over drive corner entry this will likely carry forward and vastly impact your ability to exit well.
This can happen easily when a driver pushes hard and doesn't achieve proper balance by the time they arrive at the exit phase. This happens frequently to many of us And that's why i prefer lower torque pads that enable me to carry brakes deep, while modulating F end grip and overall attitude of the car for best exit.

Your example of the uphill, off camber corner is also a classic case: most of the weight is on the R, so the car wants to understeer, while off camber robs it of grip even more, while you likely increase the steering lock pointing it towards the apex. The yaw system likely thinks, rear tires are overworked and lack grip, there is a large yaw angle between the car's current direction of travel vs desired steering angle, we will understeer off the track, time to cut power and regain balance so we can turn. At least in theory. Of course the worse outcome would be the rears hooking up and producing snap oversteer, especially if they are initially sliding laterally.

2. Your springs are contributing to loss of traction. Or the pairing of the stiffer and shorter springs vs stock MRC not being able to fully control oscillations and/or transitions. I think you are the first and only track rat ZL1 with those springs, so who knows. (But remember the only bonefide feedback from another track going SS 1LE they made the car slower vs faster.) No first hand experience, so will stop at that, but that's the only major change to your set up as far as i recall, so it should not be discounted as a possible culprit. Just imo.

ELSD does not lock per se, but rather distributes torque to each wheel for best stability and traction, based on a whole bunch of sensors and algos. As do MRC dampers.
Without GM engineering expert jumping in to explain possible inter relationships between highly sophisticated and computerized suspension pieces, the easiest thing would be to try stock springs and see if the balance returns to normal.

If it does, easy peasy, problem solved. If it doesn't, maybe your ELSD is malfunctioning, yet i strongly suspect it would throw a code if that were the case.
Another possibility is over driving of course. If that indeed played a role and you turned everything off, give yourself time to relearn the car on exits. My car feels different with all off, i can only imagine what 650 torque feels like

Hope it helps ya some. Cheers!

[GunMetalGrey]

Originally Posted by TrackClub

Hey GMG, glad your first outing on G3Rs went well!
You didnt time the laps....what the heck?!

Not having a vid to see what's going on regarding "lurching" etc obviously makes commenting difficult and largly a shot in a dark.

But, from what you described in both posts, I would hazard a guess that you *lost* traction in the rear even with much stickier tires. Why is the question here. It could be because (purely theoretically speaking):

1. You now run without Stabilitrak and experience greater yaw levels for which you don't compensate as a driver. As in, the car is sliding more including exit phase, in which case TC would interfere as the rears cant hook up (while sliding). If this is the case and you turn TC off be neat and tidy and ready to catch her, lest you will likely spin if you stomp on power while lateral transition is still underway. Watch your steering angle as well!

Note that PTM Race will not manage yaw angles for you. Only tire overslip on exits. That's it. As a result it requires much more attention from a driver to manage proper yaw and balance, something that Stabilitrak would do otherwise on your behalf.

Also note, if you over drive corner entry this will likely carry forward and vastly impact your ability to exit well.
This can happen easily when a driver pushes hard and doesn't achieve proper balance by the time they arrive at the exit phase. This happens frequently to many of us And that's why i prefer lower torque pads that enable me to carry brakes deep, while modulating F end grip and overall attitude of the car for best exit.



2. Your springs are contributing to loss of traction. Or the pairing of the stiffer and shorter springs vs stock MRC not being able to fully control oscillations and/or transitions. I think you are the first and only track rat ZL1 with those springs, so who knows. (But remember the only bonefide feedback from another track going SS 1LE they made the car slower vs faster.) No first hand experience, so will stop at that, but that's the only major change to your set up as far as i recall, so it should not be discounted as a possible culprit. Just imo.

ELSD does not lock per se, but rather distributes torque to each wheel for best stability and traction, based on a whole bunch of sensors and algos. As do MRC dampers.
Without GM engineering expert jumping in to explain possible inter relationships between highly sophisticated and computerized suspension pieces, the easiest thing would be to try stock springs and see if the balance returns to normal.

If it does, easy peasy, problem solved. If it doesn't, maybe your ELSD is malfunctioning, yet i strongly suspect it would throw a code if that were the case.
Another possibility is over driving of course. If that indeed played a role and you turned everything off, give yourself time to relearn the car on exits. My car feels different with all off, i can only imagine what 650 torque feels like

Hope it helps ya some. Cheers!

Thanks haha, sorry I should have been more clear, I did record my sessions, I just wasn't aiming for fast lap times (it was also my 1st session using left foot braking which I practiced all winter while street driving).

Thanks for the ideas and info TrackClub, much of that is over my head (I don't know what YAW is) but I think you're going to love what I discovered tonight when walking around my car this evening...

I noticed something looked funny about the tires and wheels... it turns out the dealership that put my new 285 and 305 SC3R tires onto my stock 20 ZL1 wheels decided to put one of the front 285's on an 11' rear wheel and one of the rear 305's on a 10" front wheel!

I never checked the side walls before tracking which means I had a 285 front driver side and a 305 front passenger side with a 305 rear driver side and a 285 rear passenger side the entire track day!

I am hoping this is what caused the issue, since I've never felt this ever before in any situation, track or street, and I definitely know what it feels like to be too aggressive with the throttle coming out of a corner on the track even with PTM. Last but not least, also I may have made a mistake, I'm not sure if it's not an off camber corner, but it does have a lot of elevation difference across the width of the track in the corner and that elevation changes rapidly through out the corner. It's corner 14 on the track from my previous videos.



As for having to relearn how to drive the car with all the nannies off, yes I completely agree with you, I think it's going to be a whole new experience and one I'm going to take very seriously and slowly with that much power, yikes!

You'll be happy to hear that during my first session back I quickly realized I was driving too hard and everything was happening too fast and I needed to slow down and start getting more consistent laps before driving faster. That's when all of our "back and forth" about going to stickier tires went through my head again! I even told the track instructors there what you and some others said. While I'm still glad I have these tires, especially since they stay consistent through the whole session, I have realized my effort needs to switch from driving hard, to driving smarter and more consistently with more patience.

When you track do you take all the nannies completely off or use Track PTM Race mode?
And are you faster using one setting over the other?

[TrackClub]

Originally Posted by GunMetalGrey

Thanks haha, sorry I should have been more clear, I did record my sessions, I just wasn't aiming for fast lap times (it was also my 1st session using left foot braking which I practiced all winter while street driving).

Thanks for the ideas and info TrackClub, much of that is over my head (I don't know what YAW is) but I think you're going to love what I discovered tonight when walking around my car this evening...

I noticed something looked funny about the tires and wheels... it turns out the dealership that put my new 285 and 305 SC3R tires onto my stock 20 ZL1 wheels decided to put one of the front 285's on an 11' rear wheel and one of the rear 305's on a 10" front wheel!

I never checked the side walls before tracking which means I had a 285 front driver side and a 305 front passenger side with a 305 rear driver side and a 285 rear passenger side the entire track day!

I am hoping this is what caused the issue, since I've never felt this ever before in any situation, track or street, and I definitely know what it feels like to be too aggressive with the throttle coming out of a corner on the track even with PTM. Last but not least, also I may have made a mistake, I'm not sure if it's not an off camber corner, but it does have a lot of elevation difference across the width of the track in the corner and that elevation changes rapidly through out the corner. It's corner 14 on the track from my previous videos.



As for having to relearn how to drive the car with all the nannies off, yes I completely agree with you, I think it's going to be a whole new experience and one I'm going to take very seriously and slowly with that much power, yikes!

You'll be happy to hear that during my first session back I quickly realized I was driving too hard and everything was happening too fast and I needed to slow down and start getting more consistent laps before driving faster. That's when all of our "back and forth" about going to stickier tires went through my head again! I even told the track instructors there what you and some others said. While I'm still glad I have these tires, especially since they stay consistent through the whole session, I have realized my effort needs to switch from driving hard, to driving smarter and more consistently with more patience.

When you track do you take all the nannies completely off or use Track PTM Race mode?
And are you faster using one setting over the other?

Well, congratulations are in order! Firstly, for using your first day to learn the set up vs going for a PB. Secondly, for discovering the problem!

I must admit, as much as i trust my mechanic completely, i always double check when new tires are mounted. Shit happens to the best of us

Anyhow, very glad they you have spotted it! Indeed such issue would cause major handling problems (obviously).

As to T14 i think you are right in the fact it is a bit off camber. If anything, it doesn't have much positive camber. In any case, while off camber would make things worse, even with positive camber my comments as far as up hill corners still stand. Fyi.

Going fast is "all" about effective weight transfer management. The more stable the platform using the most of all 4 contact patches, the faster it will be capable of going.
That's why what the driver FEELS grip wise and how they influence weight transfer by applying controls re: F vs R balance specifically is king.

L foot braking can help those very weight transitions become smoother, by overlapping throttle and braking in a proper fashion and hence achieving more grip. Usually, it takes years of a pre teens time spent in karts to achieve proper L foot sensitivity to do it effectively. But, it is worth trying. You'll know sooner vs later if it works better, or not. Dont feel bad if results are not there, as even some pros were never successful in transitioning to L foot braking. Just an fyi.

Yep, your last paragraph made me very happy indeed and I thank you for including this feedback: that's very gracious of you! I also need to congratulate you on your approach, as it is absolutely correct. When things happen faster than we can process them, we need to slow down. And then we drive our fastest laps, yet we dont feel rushed. Meaning we feel, anticipate and correct the balance almost ahead of the car's feedback. Proper vision has much to do with it btw. Also mental focus plays a role here obviously. And sometimes, when i cant dial it in, i either stop pushing or just go back to the paddock, visualize a perfect lap in my head and go out again.

You remind me of myself when i first started tracking in a highly modded and supercharged Mustang. I had visions of dominating until a 70+ yr old gent in a stock Stang absolutely spanked me. And then to add insult to injury, he came over and blasted me for not pointing him by faster. It was a lesson i never forgot. And we become good friends after that. I remembered this story well, when i passed a McLaren 600LT at Mt Tremblant in a top group last year. I have a feeling that with your renewed focus youll have your own stories like this

I run my car in PTM Race. I've tried all off and i am not faster. Having said that, i absolutely do not find PTM Race to be intrusive. Only a couple of times early on did i feel power pulling back, but that was due to me testing the limits and without PTM Race I would have had to correct for excessive oversteer in those moments. Meaning the rears were still loaded cornering while i also asked them to accelerate. So driver's issue not the car's (take note here). I think TC in Race is very effective if used properly. Of course some prefer to have all off and manage overslip manually. But the moment you get overslip you are affecting forward movement one way or another. PTM Race is designed to avoid it.

Lastly:

Yaw is an angle between actual direction a car is heading and the intended direction based on steering input by a driver. If you are driving straight the yaw is zero. If you turn the steering sharply, the car's momentum will still have it going straight, while the F tires are already turned. The difference between these two directions is a yaw. The more yaw (or difference between the car's direction and what the steering demands) the more risk of a spin due to weight transfer which might be too much for tires to hold. That's what Stabilitrak controls, by applying brakes to a specific wheel to reduce the yaw and hence possibility of a spin. Without it, the driver has to manage any excessive yaw usually by applying steering corrections, to momentarily reduce the yaw and keep from spinning. That's why you see pros "sawing" the steering wheel back and forth sometimes (see my notes on this for more info and PM me if needed). Some wait for when it is absolutely necessary, while some do it proactively to test the limit. Both are valid and depend on individual driving style.

Needless to say, if you see somebody not needing to do any corrections at all, it means they are never over the limit, meaning they might never be close to the limit to start with...

Anyhow, very glad you found the issue and renewed focus! That's fantastic x2! Onwards and upwards

Cheers!

[TheRealJA105]

GMG glad you caught the tire shop's screw up. Hopefully it didn't permanently screw up your diff running the different diameter tires hard on the track. There was probably alot going on inside the diff even driving straight with the computer trying to figure out what was going on and when to slip/engage clutches.