[Osbornsm]

I have an interesting thought regarding lap times vs driver inputs...

Context
I HPDE my SS 1LE in "Track - Sport 1" and my times are mid pack for an SS on OEM tires.

Q: What Track mode do you most commonly use?

I know the car can be faster in more advanced modes, but I tried "Sport 2" for a lap or two... and once active handling is off my talent seems to run out. Counter-steering every other corner.
"Race" is even more slippery than the previous, so no thanks there.

I figure Chevy has tc, so why work without a net? No prizes in HPDE.

[Inthepasture]

Hi Ozzy, Good question. What do you mean by slippery? If you mean the rear end gets slippery (oversteer) through the corner then there are several things to consider. Also when in the turn does the car get slippery? Corner entry, mid or exit?
1. Tire pressure when hot. I like it to be max pressure between 35 and 37 on a hot, dry track, so starting pressure is about 30 cold. Outside air temp about 85. To get more rear grip try 1 pound more air pressure in front and 1 pound less in rear. (2 pound differential; but I don't know your typical pressures)
2. If you have PDR look at when you begin adding throttle in the corner. If it is too early and too much that will cause oversteer.
When I enter a corner (from a straight) I try to balance the car's weight by
1. Let off throttle and weight shifts forward.
2. Brake which shifts more weight forward.
3. Add steering into corner while trail braking. This keeps weight on the front wheels while shifting weight to the outside wheels (front more than back).
4. Continue trail braking while you continue to turn toward the apex.
5. When at the apex begin to add throttle and then lift off brake. This will shift the weight more to the rear (mostly outside)
6. As you continue to add throttle you should be decreasing your steering angle (see PDR)

To answer your question, I drive with car in Track setting and Race in the PTM. I will also use Track and no PTM. Go to track setting and then hold the esc/stabilitrak button down for about 10 seconds until both lights are lit on instrument panel. I find the rear gets light when my right foot is too heavy, too fast.

At an HPDE event, ask a driver coach to ride with you and give some advice. You could also put a PDR video here and the forum can comment.

Best of luck. JJ

[joelster]

Fill the tank. It will help keep the rear planted.

[5.M0NSTER]

Race gives you better turn in, and more rotation. It also allows control with throttle. I personally like the sideslip. PTM Track is definitely more fun. I can see how Sport2 would be quicker at times though.

[khcoaching]

I've run back to back with TC off and then with the PTM in Race mode and went quicker in Race mode. I did the test with the F1 SC3 220tr tires and not an R compound and it will be interesting to see if the R compound with TC off is better. That said, I was impressed with the settings the engineers created and it works....

See post #44

https://www.camaro6.com/forums/showt...=594295&page=4

[Norm Peterson]

Originally Posted by Osbornsm

I have an interesting thought regarding lap times vs driver inputs...

Context
I HPDE my SS 1LE in "Track - Sport 1" and my times are mid pack for an SS on OEM tires.

Q: What Track mode do you most commonly use?

I know the car can be faster in more advanced modes, but I tried "Sport 2" for a lap or two... and once active handling is off my talent seems to run out. Counter-steering every other corner.
"Race" is even more slippery than the previous, so no thanks there.

Learn to add throttle more gently/smoothly. This is more important with either tunes or drive modes that feature aggressive throttle tip-in response.

I figure Chevy has tc, so why work without a net? No prizes in HPDE.

I think this depends on how much you're out there just for the fun of it and how much for advancing your own carbon-based performance driving skill set. Keep in mind that your mix of these two aspects will probably change.


Norm

[Osbornsm]

Originally Posted by Norm Peterson

your own carbon-based performance driving skill set.

Norm

Well phrased sir!

[Norm Peterson]

Originally Posted by weemus

I wonder about the same thing. I run in Track - Race. However there are a few corners where I can feel the car pulling power yet I don't feel like the car's slip angle is excessive (could be saving me or could be hurting me). At some point I will go all off when conditions are ideal and I feel confident to do so.
It appears to me that some of the fastest times posted up seem to be in track mode all off but at that point you need to know the track, the car and your right foot very well. It may just be a correlation as these are the most skilled/confidant drivers...

Even stability control has to leave some margin against the point where they can't do anything to save you either. Your best drivers are most likely capable of operating within that margin on a regular basis.


Norm

[cre8fun]

A GM Camaro engineer told me that they calibrated Track/Race for the Hero lap ( fastest lap with tires NON-overheated tires).

that said, he said once the rear tires get "hot" (as measured by amount of slip and the temp given by the TPMS sensor) he said the car is actually faster with Track/Sport 2 because that is calibrated for ideal slip to produce maximum forward thrust with "hot" tires.

he went on to say that once the tires get hot and start slipping, the slip allowed with Track/Race actually provides less forward force, than the with the slip allowed with Track/Sport 2.

at the tail end of the conversation, he said for this reason it's imperative to use GM TPMS or at least TPMS that will communicate both PSI AND temp, because temp figures into the slip allowed.

crazy the amount of computer control built into the car.

[MakCamaro]

This is a great thread with great info on the different driving/PTM modes:

https://www.camaro6.com/forums/showthread.php?t=496996

[Norm Peterson]

Originally Posted by cre8fun

A GM Camaro engineer told me that they calibrated Track/Race for the Hero lap ( fastest lap with tires NON-overheated tires).

that said, he said once the rear tires get "hot" (as measured by amount of slip and the temp given by the TPMS sensor) he said the car is actually faster with Track/Sport 2 because that is calibrated for ideal slip to produce maximum forward thrust with "hot" tires.

he went on to say that once the tires get hot and start slipping, the slip allowed with Track/Race actually provides less forward force, than the with the slip allowed with Track/Sport 2.

Sounds exactly like the adjustment a sensitive driver would be making in the absence of drive/PTM modes.

at the tail end of the conversation, he said for this reason it's imperative to use GM TPMS or at least TPMS that will communicate both PSI AND temp, because temp figures into the slip allowed.

Doesn't this also want you to be running on the OEM-supplied tires as well? I mean, wouldn't different tires likely have slightly different slip vs psi and/or slip vs temperature profiles?


Norm

[Alpha1BC]

Originally Posted by cre8fun

A GM Camaro engineer told me that they calibrated Track/Race for the Hero lap ( fastest lap with tires NON-overheated tires).

that said, he said once the rear tires get "hot" (as measured by amount of slip and the temp given by the TPMS sensor) he said the car is actually faster with Track/Sport 2 because that is calibrated for ideal slip to produce maximum forward thrust with "hot" tires.

he went on to say that once the tires get hot and start slipping, the slip allowed with Track/Race actually provides less forward force, than the with the slip allowed with Track/Sport 2.

at the tail end of the conversation, he said for this reason it's imperative to use GM TPMS or at least TPMS that will communicate both PSI AND temp, because temp figures into the slip allowed.

crazy the amount of computer control built into the car.

I think the part in bold could lead to some misinterpretation. Temp plays a part in the sense that once the tires get hot enough they prefer a little less slip so Sport 2 can be a little more ideal then Race if you're relying heavily on traction control, but the actual measured temperature from the tire sensor doesn't have any impact to the slip tuning (for these on-track scenarios at least). On the track the measured tire air temps are only useful as a display for the driver if they're looking at the tire temp screen on the dash. I would imagine the air temps inside the tire change too slowly and unreliably vs. the actual carcass temps to be useful for changing slip tunings.

Originally Posted by Norm Peterson

Doesn't this also want you to be running on the OEM-supplied tires as well? I mean, wouldn't different tires likely have slightly different slip vs psi and/or slip vs temperature profiles

Yes, exactly this. If you want to get the most out of PTM, you need all the stock tires/wheels/brakes/suspension etc. on the car to get the most optimized control. All of the PTM/eLSD/suspension calibrations are built assuming the specific slip characteristics, brake response times, and overall vehicle dynamics of the OE package so any change to that would likely make it less than optimal. Not to say hardware changes would guarantee the car being bad or undriveable or anything like that because it is closed loop control, just the targets that are being controlled to and some of the pre-emptive stuff won't be as optimized anymore.

[VR Baron]

Originally Posted by Alpha1BC

I think the part in bold could lead to some misinterpretation. Temp plays a part in the sense that once the tires get hot enough they prefer a little less slip so Sport 2 can be a little more ideal then Race if you're relying heavily on traction control, but the actual measured temperature from the tire sensor doesn't have any impact to the slip tuning (for these on-track scenarios at least). On the track the measured tire air temps are only useful as a display for the driver if they're looking at the tire temp screen on the dash. I would imagine the air temps inside the tire change too slowly and unreliably vs. the actual carcass temps to be useful for changing slip tunings.



Yes, exactly this. If you want to get the most out of PTM, you need all the stock tires/wheels/brakes/suspension etc. on the car to get the most optimized control. All of the PTM/eLSD/suspension calibrations are built assuming the specific slip characteristics, brake response times, and overall vehicle dynamics of the OE package so any change to that would likely make it less than optimal. Not to say hardware changes would guarantee the car being bad or undriveable or anything like that because it is closed loop control, just the targets that are being controlled to and some of the pre-emptive stuff won't be as optimized anymore.

I have been doing temp/psi checks during this years events. This is autocross mind you and not overly scientific. Just to see how temps per the dic were doing vs tire psi and if I can depend on the car readout. Tire psi from the sensors are to slow in autocross and are always at least 2 psi lower then checking with a accurate tire gauge, and that’s full warm after three laps.Same for street driving, sensors seem to be just slow.As to temps they “appear” to at least coincide to external tire temps by temp gun(I know not the best way to check temps). My dic temp read “normal”(roughly 50-115 degrees range from what I have read )by the end of the third lap temps read warm and tire temps I get 130-140 degree readings with temp gun. So at least temp readout seems to work if it is needed for ptm function. But psi readout sure isn’t keeping up, so hopefully it isn’t a big factor, for autocross anyway. And that’s with stock tires for street, but 19” wheels and 305/30 re71s for track

[Osbornsm]

Originally Posted by cre8fun

A GM Camaro engineer told me that they calibrated Track/Race for the Hero lap ( fastest lap with tires NON-overheated tires).

that said, he said once the rear tires get "hot" (as measured by amount of slip and the temp given by the TPMS sensor) he said the car is actually faster with Track/Sport 2 because that is calibrated for ideal slip to produce maximum forward thrust with "hot" tires.

he went on to say that once the tires get hot and start slipping, the slip allowed with Track/Race actually provides less forward force, than the with the slip allowed with Track/Sport 2.

at the tail end of the conversation, he said for this reason it's imperative to use GM TPMS or at least TPMS that will communicate both PSI AND temp, because temp figures into the slip allowed.

crazy the amount of computer control built into the car.

Interesting read about progressing tire temperatures... cool!
I agree, once the SC3 gets hot, the tail does get "happier".