Bigeasyvette

I agree with you, my bad...…...I should not have posted that question out on the open forum. I was not trying to be rude at all, and not trying to put Sean on the spot, just curious on that subject since I always buy a track policy for my track events...…..

No offense intended...…….

Racingswh

Coming from someone who has an ACR-E and also had the GS the differences are pace and the fact that the ACR-E is dirt cheap in comparison.

The GS was nowhere even close to as fast as my ACR-E is. The ACR-E has appreciated in value, needed nothing to run consistent sub 2 minute laps at Watkins Glen with me driving and every single thing that's ever broken on the car, the differential and the right rear shock specifically totaling over $12,000, has been covered under warranty.

I do however understand completely why you would choose a Corvette. To me they are the most fun to drive. I personally have settled on our C6Z to be my serious track weapon which now will smash my ACR-E. When Sean is done with his GS my ACR-E won't have anything for that car either.

Mikec7z

agreed, acr is a faster track car for sure over a grand sport. But, maybe once porsche sheds all the weight and adds some wings, it will be more of an even fight.

Racerdj

Very painful but informative to watch! I'm glad you walked away. Good luck with the new build!

TopQuark

I was on Shenandoah with my C6 ZR1 on Nov 17 ... I know this accident didn't happen that day, but it looks like it was probably the same weekend? There was snow on the track on the morning of the 17th, but the snow melted off the track by the afternoon, and the snow piles by the side of the track in the video look very similar to the ones that remained in the afternoon on the 17th.

It was terrifying for me to watch this video, as this could have been me, and I am a far less experienced driver and probably wouldn't have handled it as well. After the track dried off in the afternoon on the 17th, I remember my back end kicking to the left each time I accelerated under the bridge (due to the wet pavement under the bridge), but luckily I never lost traction at the crest of the hill.

A few things I noticed while obsessively over-analyzing this video (in the hopes of learning how to avoid making the same mistake):

• Under the bridge there was a slight steering input to the right, and the pitch graph shows the car pitched slightly to the right when the tires broke loose (which would correspond with the back end kicking left, as I also experienced under the bridge).
• At the crest of the hill, there was a slight steering input to the left (about the same amount of steering input as there was under the bridge, but in the opposite direction). Shortly after the rear tires broke loose, the pitch graph shows the car pitched slightly to the left, and watching the video it appears that the front of the car continued tracking straight but the back end kicked out to the right. So it appears to my naive eyes that this was the same kind of kick that was experienced under the bridge - it was simply the combination of slight steering input while still on the throttle with loose rear tires.
• In response to this pitch left, the steering input was adjusted to the right. At the far edge of the bypass road there is a slight bump, and according to the graphs there was a moderate steering input to the right at the instant the front tires crossed that bump. I assume this input was slightly too large due to the fact that there was little or no feedback until the bump was hit, although I suppose it might also be partially attributable to a change in steering geometry when crossing the bump? Either way, this moderate steering input at the instant the front tires briefly regained traction appears to be what pitched the car hard to the right.
• Immediately after that bump, the suspension unloaded again (you can see from the video that the hill drops off rapidly after that bump). The steering wheel was then turned significantly to the left in response to the hard pitch to the right, but as mentioned in the video, there wasn't any weight/traction on the front wheels until the car was almost into the grass, and at that point it was too late to recover.

So, in addition to lifting before cresting the hill, my takeaway is that I should also carefully avoid any steering angle when approaching the crest of that hill (or any other hill with a similarly rapid change in grade - to ensure that the car stays straight even if I don't lift quite early enough). I might also want to try to suppress the urge to over-adjust the steering if the car pitches while there is no traction on the front wheels, although I suppose under-adjusting the steering in that case might be just as perilous in some cases, so that part is a tough call ... I guess that after the point where the car started pitching to the left while the suspension was unloaded, it would probably be a coin toss whether any particular reaction would have improved or impaired the chances of recovering, so the key is to simply avoid ending up in a situation where the car is pitching while the suspension is unloaded.

Thanks for posting the video and your analysis! I've learned a lot from it.

Mikec7z

without a long analysis, when i have the back end of the car kick out at high speed, i just firm up if you will and let off the throttle enough to let the back end snap back, and when i steer back into it, its a small quick blip, and then back to straight, and wait to see if i need to do another small quick blip or if the car is going to come back on its own. I learned long ago that the last thing i should do is try to steer too much back into it.

The momentum of the car will 9 times out of 10, force it to take the straight path is is already on and straighten out.

The biggest key is cutting the throttle 30% asap, and letting the car straighten itself.... but not completely letting off the throttle.

If i do correct in steering, it is only for half as long as I think i need... just quick small blips and back to straight. A little goes a long way. As soon as i feel the car is on it way back the correct direction, im steering straight again because i know its going to snap back the other way twice as hard if i keep steering into it.

if i go messing with trying to steer back into the problem to solve it instead of have faith that the car will come back to straight on its own, then the result is what happened here, ill go off the road in that direction i steered when the back end comes snapping back.

Easier said than done, and it takes a lot of guts and patience to hold the wheel as firm as possible and not over-react. The throttle is the key tho... and not over-correcting and just having faith in the car and the laws of physics that you'll keep going in the direction you are going in due time.

It looks like that hill top is a bit of a square to it, and that makes things much worse if it is, a double bump..

That double bump is why i say it is probably almost impossible to recover... if you go sideways after the first bump, the car is going to compress and have massive grip at that second bump, that second bump threw your back end to the left hard, and off the road you go in whatever direction the car was pointed after it hits that second bump, as the road then goes back out from under you again after that second bump which threw your rear end left hard

There was probably nothing you could have done Sean... you would have to have steered left after you felt that rear end get batted left by that second bump... and things probably would have still ended badly.

Palantirion

Thank you for posting the video and your analysis. Took courage to post the actual incident, and we will all learn from the vid. Very glad you are ok, scary crash!

TopQuark

Yeah, the top is definitely squared off, due to the bypass road that exits to the left at the crest of the hill, so there is definitely a double bump.

Thanks, this is helpful! I will definitely work on this.

fatsport

A question about the super sports: why are they always recommended for new track guys(like me) if they’re notoriously cold blooded? I know the standard reason is they break away less suddenly, foreshadowing the loss of grip. They sure didn’t predict anything here.

truth.b

I think a fairly reasonable assumption is that if the event took place in the middle of the summer the incident would not have happened. At cold outdoor/ground temps super sports take a while to warm up and provide limited grip. Hence with more mechanical grip (i.e. warm tires) the car has a smaller chance of stepping out.