Bullet Tooth

The last time out I had a fairly significant oversteer on the last turn in sport 1. That was enough to make me nervous to go to sport 2. Do you typically run in race? I will likely follow the advice above when I am out in a couple of weeks.

sunsalem

Unless I'm mistaken, doesn't Spring Mtn. cover all things PTM?

Bullet Tooth

Yes it does and I understand the settings very well. However I am trying to learn from the guys that are very fast and have much more experience than me. Poor-sha's comment about the PTM being inconsistent is very interesting to me as I believe I experienced that as well. From a practical standpoint I would like to know the difference sport 1 and 2 as they have seen it on track. After all of this I have realized that I am horribly off topic from the OP.

I will take this elsewhere.

Racerdj

Mid Ohio is a fantastic track! Thanks for the great video's! Back in the mid 1990's I ran there for several years in a 77 March Formula Atlantic!

Poor-sha

First session of the day I start in Sport 1, then I switch to race. After that I run in race.

thebishman

I honestly don't believe this to be true. The Z is about 50/50 weight distribution front to rear and has tremendous balance. Frankly an experienced driver can just about place the car anywhere in a corner and get away with it. A novice as long as they didn't constantly floor the throttle in the Z06 coming out of a corner, should be more consistent and 'safe' than in the GT3 IF THEY'VE NEVER DRIVEN A 911 BEFORE and aren't familiar with a car that has 60% of its weight behind the rear axle.

Bish

Bigg Slimm

i would have to agree with you Bish, in regards to non professionals being faster in a gt3 vs a z06, at least from my experience and the video I shared. Neither myself or the gt3 rs driver in the video are professionals and I was able to keep up pretty well with lesser tires and a manual.

Koan

It was a great weekend. I was there too, and did several 1:35 laps in a Grand Sport. Just can't figure out how to post.

FWIW, I prefer "race" mode, but I am still trying to figure out all of the different modes and what effect they have.

rikhek

You will see a certain amount of oversteer using PTM. The amount of oversteer will be dictated by the level of PTM engaged, especially PTM/RACE.

I'm assuming most have seen the excellent, comprehensive, technical PTM discussion provided by Corvette lead development engineer Alex Macdonald in response to an "Ask Tadge" question:

https://www.corvetteforum.com/forums...rack-mode.html

I'm not going to repost the entire, lengthy explanation provided by Alex but his comments on PTM/SPORT 2 and PTM/RACE oversteer is pertinent:

SPORT 2: This mode uses the exact same traction control settings as SPORT 1 but turns off ESC completely. This mode is designed as a way to turn off ESC while maintaining a fairly stable TCS calibration. I use it very often. Basically any time where tenths of a second are not critical to my testing or when the tires are getting too hot or wearing out. After 10 to 15 consecutive laps it is likely that your fastest times will be achieved in SPORT 2 rather than RACE.

Slip targets here are the same as SPORT 1. MR is still in track mode and ESC is turned OFF.

RACE: This one is pretty self-explanatory, it’s as fast as we know how to make the car go. This mode is for a well prepared car on relatively new tires with an advanced driver that is completely familiar with the track. The track should be somewhat warm and the tires should be up to temperature.

Slip targets are 100% optimized for forward acceleration, any small variances in the track or tires can result in momentary overslip that will have to be managed by the driver.

A few notes about RACE mode: I approach this mode as a tool to go faster meaning that I think specifically about it when I go to WOT and I try to change or optimize my throttle application point and steering to help the computer do its job. It can do the job better than me but only if I give it good information. A specific example is how I unwind the steering wheel mid corner and as the corner opens up. When learning to drive on track it is good practice to automatically unwind the steering wheel as you apply throttle regardless of the vehicle response (a string tied from throttle toe to steering wheel is the analogy used by some instructors). The problem in RACE PTM is that by doing that you are telling the car you are ready to go straight. It will add power and drive you to a wider line. The best results are found by holding the wheel as steady as you can and pointing the car to corner exit only when it’s time. Obviously you have to be ready to correct for overslip but as you gain trust you will find this is required less often than it feels at first. It is very useful to practice using PTM in the lower modes where you can focus on letting the car go where you point it and not correcting your steering too early.

We find that the calibration settings that achieve the fastest lap times often result in expert drivers feeling like they are being held back slightly on corner exit. Most of the time that extra little bit of slip that an expert driver wants is over the traction peak of the tire and may feel good but is wasting forward acceleration. The restrictive feeling is not there as a safety net, rather, it’s as close as we can operate to the peak capability of the tire in a robust way.

I wonder if you guys (i.e., Bill and Slimm) need to grow a set and correct the step-out/oversteer with steering input instead of lifting? For the record, a little bit of humor was intended by this remark. As a racer, the last thing I want to do is lift if there is any chance of correcting with other inputs. I experience these step-out/oversteer situations on a regular basis when running in PTM mode but have learned to override my brain and not lift but to correct with steering input. It takes a leap of faith and I still occasionally can't stop my foot from lifting slightly but the more I track the car the less I lift.

Almost like going up the esses at the Glen in a race car. My mind is screaming lift/feather a bit but I know the aero down force, tires, suspension, etc. will allow me to keep it to the floor all the way to the bus stop. I've learned to clench my *** and keep it pegged...

I stress it's taken me time to learn to trust PTM and even now when I go watch my PDR video I catch myself not committing to full throttle application at the apex and/or lifting due to a bit of oversteer tracking out. I see this even though I swear to all my friends I go to the floor and don't lift, however, the curse of video/data is that it doesn't lie.

On a side note I've been chastised at races where Mike Levitas or Randy Pobst are helping me with coaching and data analysis. They'll come over and tell me I'm braking too early for a corner or lifting/feathering through a section and I tell them they're full of ****, they're wrong and I'm all in. They then say, "OK, pull up your video/data and let's have a look".

They've shown me to be a liar and lacking ***** more times than I care to admit. Damn video/data sucks as it doesn't lie like I do ...

Rick

Bigg Slimm

I have video trying to keep up with you also on Saturday and Sunday.

I posted the videos in my original post on YouTube and linked them here. You could try doing that.

I will see you again this weekend but I don't plan to put the cup2 tires on until Sunday. Hopefully this weekend will be just as fun.

rikhek

I run in Sport 1 or Sport 2. More often Sport 2 as the car responds and reacts better for me and my driving style than Sport 1 and it's quicker for me. I've found my lap times to generally be slower in PTM/RACE as I'm getting tire slippage tracking out of corners that feels faster but in fact is slower. Same as described in the PTM Ask Tadge discussion posted in my above post.

Sport 2 with PTM provides a safety factor even though TC and Active Handling are disabled as is also discussed above. When I do run Sport 1 I don't find the AH hurting my times or intervening to an extent that's annoying. It's not a bad mode to run, however, I guarantee it's not too difficult to spin in Sport 1. I speak from experience...

Rick

rikhek

Good read for you:

https://www.corvetteforum.com/forums...rack-mode.html

rikhek

Agree with the comments offered. As stated above and also provided in the Ask Tadge response, you'll get occasionally get throttle induced oversteer in the advanced PTM modes and have to be ready to correct with steering input. Also, as you stated it's not always consistent even on subsequent laps through the same corner. As tires go away and track temp changes the car's reaction sometime changes through the same corner(s). However, I've learned the PTM system well enough to not have to lift to correct MOST of the time.

FYI, Mike does not track his car in SPORT with everything turned off. That's how he runs his car on the street as he loves sliding it around. On track he "always" runs in a PTM mode. He's using PTM/RACE nearly all the time.

AVETTE

I have a Z07 with the MSRC, when I set the track mode in the sub menu to 'race" does PTM still operate? Would hate to drop the throttle to the floor at apex if it wasn't going to kick in.... thanks

rikhek

Yes. However, to get comfortable with something so completely foreign to what our brain tells us I'd suggest starting in Sport 1, then Sport 2 and then going to race. As mentioned above, some oversteer "might" occur in RACE to which you need to provide a bit of steering input to correct. If it occurs, don't lift, just steer.

Mad Dog 24

Great thread! My experience has been there are specific tracks for specific settings based on driver experience. For instance I ran a shorter technical track this summer in Sport 1 most of the day and switched to sprt 2. Yes the car had better lap times but it was some work and hardly worth it! Now Watkins Glen and the infamous Esses I will not switch to 2. Climbing the hill even in Spt 1 the back gets loose with a steel wall only 100 feet away! Pucker factor and my brain have a fight and its a toss up who wins per lap. My suggestion to many at the track is keep it safe first speed comes with seat time.

Hey Rick I turned a couple 2.03 lap times this summer at WG on worn out cups, very happy and surprised as I had a rider! I like to send you my videos to critique if you have time. PM me your email. Looking for 2.0 or sub on slicks next summer.

Koan

Bigg Slimm,

I'll look for you. It looks like we'll have great weather again. I have an Admiral Blue GS #219

CORVETTEZL1001

The GT3RS is an Awesome track car.

PRE-Z06

Enjoyed the videos OP.

Correct me if I'm wrong, but the rear brakes will wear faster with PTM intervention (less in sport 2 than 1 depending on drivers input of course) and extra torque is managed by throttle blade, fuel and timing only in race? At some point all the electronics will take the challenge out of it and it'll literally just be a roller coaster ride it seems.

Bigg Slimm

Pre z06, racerdj and anyone I may have missed thanks for the comments on the video.

Koan, we've met several times. I have the black c7 z06 and my brother has the white c6 z06. I previously had the orange (dsom) c7 z51.