ASK THE COACH
10-23-2013, 01:02 PM
#1486
Addict
Lifetime Rennlist
Member
Lifetime Rennlist
Member
Join Date: Oct 2005
Location: On Rennlist, apparently
Posts: 4,447
Likes: 0
Received 37 Likes
on
18 Posts
Well...there is another story from what? 2 years ago? I forget. I was working with a client for 2 days at NJMP, in very cool/cold weather. The 2nd day we were on Lightning. Client runs full slicks on a 911 race car. He asked me to take the car out for a few laps, since we were working on set up & trying to analyze some weird behavior under braking. Maybe it was 45 or 50 degrees ambient. Anyway, pit out at Thunderbolt is just before "the hump" at T5. I was putt-putting out of the pits at maybe 30 or 40 MPH tops, the car was very cold and I knew the tires would be worthless for a couple laps.
As I came out & entered the track, in my mirror I could see another car coming at full warp speed. Being the nice guy that I am, especially at 40 MPH, I hugged the inside (drivers' right) rather than coming "on line" and blocking this other car. He went around me on driver's left, and I went over the hump (which is much sharper & unsettling than it looks) tight on the right...which unfortunately is exactly where the unsettling aspect of the hump & corner is at its worst. Again, this is my out lap on ice-brick Yoko slicks.
The car got light over the severe part of the hump inside, the wheel was turned (much more than normal since I was off line), and of course the car began a nice lurid clockwise spin on the downside of the hump. Awesome. Dave was spinning a client's car for the first time.
I will admit I was surprised this happened at such a low speed. Of course, I couuntersteered to try to correct. But I was hosed, as it was quickly rotating past 90 degrees. And oh my! What is that rapidly approaching in the windshield? Armco! **** !!!!
Not wanting a direct frontal impact in a client's car into the NJMP Armco, I realized the only chance I had now was to steer hard the other way (to the right) to accentuate the spin clockwise and get on the grass immediately preceding the Armco and try to stop parallel to the track, on the grass.
The track & car had surprised me (in part because of my own courtesy to the oncoming car), and I was thinking WTF? in a client's car? Noooooooo!!! But nonetheless, what do we always teach drivers? KEEP DRIVING. Both feet in, staying ahead of the car, putting her into a hard spin, and timing when I straightened the wheel to keep it on the grass & out of harm's way (remember, I am also on the blind side of a blind crest/turn).
And so that is what happened. Got the car hard-spun all the way around, on the grass, parallel to the Armco, and stopped. Whew!
Then came the Drive of Shame back to the pits to check the car & tell the owner. I was MORTIFIED. Spinning a client's car is a cardinal sin (to me), especially on cold tires.
The car was fine. And amazingly, the owner--my client and friend--just laughed. He was not upset or angry. He thought it was hilarious...although he was very happy that I had been able to alter what may have been a metal-bending fvck up into a non-event.
So...as he calls it...I made a spin my "bitch" by staying with the car, continuing to drive, and continuing to work by using a harder spin to get the car where I wanted it in reaction to circumstances.
In part, I was lucky. I screwed up, and had I been at a higher speed, am not sure the ending would have been as benign. But in part, I recognized the problem immediately, despite surprise and embarrassment, and then (more importantly) recognized that my solution was not working, so I had to quickly pivot to Plan B. Staying ahead of the car is key.
As I came out & entered the track, in my mirror I could see another car coming at full warp speed. Being the nice guy that I am, especially at 40 MPH, I hugged the inside (drivers' right) rather than coming "on line" and blocking this other car. He went around me on driver's left, and I went over the hump (which is much sharper & unsettling than it looks) tight on the right...which unfortunately is exactly where the unsettling aspect of the hump & corner is at its worst. Again, this is my out lap on ice-brick Yoko slicks.
The car got light over the severe part of the hump inside, the wheel was turned (much more than normal since I was off line), and of course the car began a nice lurid clockwise spin on the downside of the hump. Awesome. Dave was spinning a client's car for the first time.
I will admit I was surprised this happened at such a low speed. Of course, I couuntersteered to try to correct. But I was hosed, as it was quickly rotating past 90 degrees. And oh my! What is that rapidly approaching in the windshield? Armco! **** !!!!
Not wanting a direct frontal impact in a client's car into the NJMP Armco, I realized the only chance I had now was to steer hard the other way (to the right) to accentuate the spin clockwise and get on the grass immediately preceding the Armco and try to stop parallel to the track, on the grass.
The track & car had surprised me (in part because of my own courtesy to the oncoming car), and I was thinking WTF? in a client's car? Noooooooo!!! But nonetheless, what do we always teach drivers? KEEP DRIVING. Both feet in, staying ahead of the car, putting her into a hard spin, and timing when I straightened the wheel to keep it on the grass & out of harm's way (remember, I am also on the blind side of a blind crest/turn).
And so that is what happened. Got the car hard-spun all the way around, on the grass, parallel to the Armco, and stopped. Whew!
Then came the Drive of Shame back to the pits to check the car & tell the owner. I was MORTIFIED. Spinning a client's car is a cardinal sin (to me), especially on cold tires.
The car was fine. And amazingly, the owner--my client and friend--just laughed. He was not upset or angry. He thought it was hilarious...although he was very happy that I had been able to alter what may have been a metal-bending fvck up into a non-event.
So...as he calls it...I made a spin my "bitch" by staying with the car, continuing to drive, and continuing to work by using a harder spin to get the car where I wanted it in reaction to circumstances.
In part, I was lucky. I screwed up, and had I been at a higher speed, am not sure the ending would have been as benign. But in part, I recognized the problem immediately, despite surprise and embarrassment, and then (more importantly) recognized that my solution was not working, so I had to quickly pivot to Plan B. Staying ahead of the car is key.
10-23-2013, 02:21 PM
#1487
Rennlist Member
Thread Starter
Hahahaha! Nice try 
10-24-2013, 10:10 PM
#1488
If you think about how the ABS works, it primarily senses a very high deceleration of each wheel. If this deceleration is faster than the tire can reasonably sustain the ABS brain will pump the brakes. This is why ABS sometimes chirps the tires - the tires almost stop before the ABS brain reacts and releases the brake pressure.
One more thing is needed however. If the driver mashes on the brake pedal very hard, or conditions are very slick, it is possible to lockup all four wheels at about the same time. Without fine enough deceleration data, or the smarts to realize the car went from 40 to 0 in less than a second, the ABS brain may think the car has stopped. Recall that the ABS will allow a locked wheel with full brake pressure - it occurs when the car is not moving. Also, if this occurs, the ABS brain will sense nothing wrong with the system and you won't get an ABS fail light.
So, the bottom line is if conditions are slick enough, this kind of thing can fool the ABS brain. Another takeaway here is what if one was driving at 10/10s and the ABS happened to fail going into T10? The lesson VR describes here still applies and it is yet another reason not to count on electronic nannies and "be ahead of the car".
I've managed to lock the wheels on my E36 BMW M3 as well, but this didn't happen until well into a spin on a dry track during the "both feet in and sideways phase" and the ABS light came on. The brakes had nothing to do with the spin, the nut behind the wheel lifted in T2 at TWS CCW. In the black flag, shutting down the car and starting it back up cleared the light.
One other odd thing about this story is the single wheel lockup the lap before. I don't have an explanation for that. It's pretty obvious to the ABS brain when three wheel sensors are rotating and one is locked. Perhaps a glitch slightly less serious than the healthcare.gov website.
-Mike
10-30-2013, 02:55 PM
#1489
Race Car
Hey VR et al ... had an interesting second race last week - faced more traffic than ever as I drew back of the grid in class B for heat 2 (don't ask - we use a hat for h2 to keep things interesting).
It's common challenge in DE/Fun racing ie where is the line between aggressive and unsporting/dangerous?
Especially when pros join in - often with alot of rep to protect (see the Nissan 370Z Cup in this vid).
Also had some challenges using the new SQS shifter - simulates sequential ie its just an electronic way of making the H box a seq type movement .... problem is if the downshift clutch and hand movement aren't matched there's no feel to let you know you're not in gear, and car goes to false neutral.
Then you have to reverse into the gear you were in and try again ... need some practice (apologies - frustrating to watch!)
But seen it done better so not really concerned.
Anyways .. fun vid .. would enjoy hearing your opinion on some of the 'blocking'
It's common challenge in DE/Fun racing ie where is the line between aggressive and unsporting/dangerous?
Especially when pros join in - often with alot of rep to protect (see the Nissan 370Z Cup in this vid).
Also had some challenges using the new SQS shifter - simulates sequential ie its just an electronic way of making the H box a seq type movement .... problem is if the downshift clutch and hand movement aren't matched there's no feel to let you know you're not in gear, and car goes to false neutral.
Then you have to reverse into the gear you were in and try again ... need some practice (apologies - frustrating to watch!)
But seen it done better so not really concerned.
Anyways .. fun vid .. would enjoy hearing your opinion on some of the 'blocking'
10-30-2013, 03:12 PM
#1490
Rennlist Member
Thread Starter
Good patience, waiting for your opportunity rather than forcing it & making a big mistake...or having them make a mistake at your expense. Yellow car & white car were VERY slow in that first left hander...wow.
SQS is crap, IMO. I have experienced this exact same behavior in 3 different client cars equipped with it.
SQS is crap, IMO. I have experienced this exact same behavior in 3 different client cars equipped with it.
10-30-2013, 03:27 PM
#1491
Race Car
Yes I got lucky there ... While I was royally screwing up that downshift! they got into a three way 'who's going where' with the 5.7L panoz ... Hope I find the way of the SQS soon tho - Chose it as a safety mechanism re money shift .. 4 other cars running it well enough.
Here's one of them sowing how its done ...
Here's one of them sowing how its done ...
Last edited by HiWind; 10-30-2013 at 04:27 PM.
10-31-2013, 03:47 PM
#1492
Nordschleife Master
Nice driving Matt. You should try the CAE shifter if you ever get a chance; still a "H", but has some real feel to it, while shortening the travel and adding some springs in the shifter itself.
10-31-2013, 06:16 PM
#1494
Nordschleife Master
11-01-2013, 06:21 PM
#1495
Rennlist Member
Sebring lap comparison
Absolutely! Please post it here! Or, if you prefer, feel free to email it to me for a private evaluation: dave@racecoach.net
A few weeks have passed and I haven't had (or just taken) the time to understand RS2. I was able to zip all of the files for the 3 lap session the experienced driver did in my car. It includes an out lap, a 2:33.xx lap and an in lap. I haven't been able to attach the 2nd zip file that has my lap files in it. Maybe RL doesn't let you attach multiple files or the two together are too large to send. I'll try again in a separate post.
I'm headed back to Sebring this weekend and, thanks to reading many posts on this forum and to the great folks at Apex Performance, will be equipped with a new helmet / HANS combo. It will be my first experience with a HANS - here's hoping it never comes into play!
Thank you.
11-01-2013, 06:34 PM
#1496
Rennlist Member
^^
I was including too many files it turns out. Here is the file with my laps to compare with the experienced driver's lap sent previously. Thanks in advance for your help on this and to everyone for sharing their knowledge and experience on so many topics.
I was including too many files it turns out. Here is the file with my laps to compare with the experienced driver's lap sent previously. Thanks in advance for your help on this and to everyone for sharing their knowledge and experience on so many topics.
11-07-2013, 11:04 AM
#1498
Rennlist Member
Thread Starter
Sorry, I missed this. Will look today!
11-11-2013, 01:37 AM
#1499
Just discoverd this thread last week and spent some time reading though it. This is the best driving information I've seen anywhere on the net. Appreciate everyone's posts. As a newly promoted intermediate level driver I know my next skillsets to master will be exploiting the car at the limit and mastering braking. Especially agree with the opinions about having instructors spending time with intermediate and advanced level drivers. My focus is still DEs but it sounds like there's more to learn at this level from "race" instructors. This thread has also convinced me of the value of data logging and coaching.
Thanks.
Thanks.
