Hey Eric, remember just after the corkscrew at Seca...

[sperry]

...how the brakes would feel mushy braking for T9, and I mentioned "pad knock back"? Well, here's the whitepaper from StopTech that describes it.

http://www.stoptech.com/tech_info/wp_knockback.shtml

(I just happened to be browsing StopTech's tech page and remembered that I meant to post this right after the track day, and hadn't.)

[AtomicLabMonkey]

That's when it's time for the lovely left-foot-brake-tap every lap...

[Dean]

Originally Posted by sperry

...how the brakes would feel mushy braking for T9, and I mentioned "pad knock back"? Well, here's the whitepaper from StopTech that describes it.

http://www.stoptech.com/tech_info/wp_knockback.shtml

(I just happened to be browsing StopTech's tech page and remembered that I meant to post this right after the track day, and hadn't.)

That is actually a very good article, but there isn't much if any braking for turn 9 at LS... T10 is where I have noticed it most as 8, and 9 shove them back quite a bit.

The funny thing is that good old stocker 1-2 pot single sided floating calipers are much less suceptible to it as they can move as things deflect.

[sperry]

In Eric's car, I was using just a touch of brake into 9 to help the car turn in. It's a pretty quick corner, and you're not going all that fast coming off of 8/8a, but it's also downhill and off-camber, so the car doesn't exactly want to dart to the apex.

Speaking of 9... I had a very hard time getting that corner "right". In the simulators/games, I could get the car all the way left to the curb, and have enough speed to let it wash all the way out to the exit curbing. But in reality, if I got it all the way into the apex, I scrubbed off so much speed, that there was no reason to track all the way out. Or, if I kept the car about 1/2 a car width off the apex, I'd carry more speed throught the corner, and need to track out more. Something tells me I'm not getting into the corner correctly... I'm probably just apexing too early, and not waiting long enough to turn in.

[Dean]

Originally Posted by sperry

Speaking of 9... I had a very hard time getting that corner "right". In the simulators/games, I could get the car all the way left to the curb, and have enough speed to let it wash all the way out to the exit curbing. But in reality, if I got it all the way into the apex, I scrubbed off so much speed, that there was no reason to track all the way out. Or, if I kept the car about 1/2 a car width off the apex, I'd carry more speed throught the corner, and need to track out more. Something tells me I'm not getting into the corner correctly... I'm probably just apexing too early, and not waiting long enough to turn in.

Turn 9 is quite a check clencher of a turn, but it definitely is not off-camber! Downhill, yes, but not off camber, especially if done correctly.

There is a valley that runs through the corner from about where the geometric start of the corner is straight to the apex. the trick is to be turning the most as you compress hitting the far side of the valley and be unwinding as it tails off at the apex. I seldom go more than 2/3rds out at entry. any more, and you miss the valley, and/or have to turn to much. a touch of brake or lift helps set the car at turn in, but is often unnecessary if you are on line.

This valley is full of water in the wet, so in that situation, you cross the valley straight, brake, and ride the right side of the valley and miss the apex very late and track out much less.

[sperry]

Thanks for the description Dean. I realize there is banking to the turn, but at the turn in point, everything feel like it's sloping away and to the right, which makes the transistion from the straight off of 8a to turning in on 9 feel very harry.

[Dean]

Originally Posted by sperry

Thanks for the description Dean. I realize there is banking to the turn, but at the turn in point, everything feel like it's sloping away and to the right, which makes the transistion from the straight off of 8a to turning in on 9 feel very harry.

I think the key is to not go all the way out, and make the turn in very slow hitting the maximum lock required at the maximum traction point as you hit the banking.

I've probably been through that corner over 400 times now, and it still bothers me sometimes even though I know the car will stick. It is probably the most disturbing corner I've been through at any of the tracks I've been to.

I hate to sound like a broken record, but the key to it is getting your eyes down the straight towards turn 10 as early as possible. Only then does your brain accept the actual geometry of the corner. Whenever I find myself uncomfortable in that corner, I know it is because I'm not looking through it enough.

That whole sequence, 7-11 has a tendency to suck your eyes down. When working with students, I tell them to start looking for things well before they can see them. The 8A oak tree while still in 7, and The outside turn 9 worker station and Apex of 9 while still in 8 & 8A.

The sequnce goes something like: Parentesis means the car is at the entry of that turn) "(7)braking zone, don't cheat the turn in, oak tree ( turn 9, (8A)worker, Apex, through the corner, (9), down the straight, remember to unwind/track out, braking zone, garages, (10), braking zone, bleachers, (11) remember to track out, Mazda bridge...

I can't wait to get back there in February...

[sperry]

BTW Dean... they moved that bridge up the hill towards the corkscrew.

http://www.laguna-seca.com/PressRele...dex.cfm?ID=122

[Dean]

I bet that improved visability greatly as well through 9. I try and not use landmarks as much as possible presonally, just keep my eyes scanning forward, but find them incrediably valuable for instructing and for getting my head back in the game when it isn't.

[qksubi]

Originally Posted by sperry

...how the brakes would feel mushy braking for T9, and I mentioned "pad knock back"? Well, here's the whitepaper from StopTech that describes it.

http://www.stoptech.com/tech_info/wp_knockback.shtml

(I just happened to be browsing StopTech's tech page and remembered that I meant to post this right after the track day, and hadn't.)

Yeah Thanks man that explains it a lot better not that I did understand what you where saying but it much clearer!