TXE36

Skiing down the side of the plateau is a lot more fun than staying on top of it. Back in September I had a spin in T20 at CoTA that revealed the next missing link to lowering my laptimes. I was getting on the throttle a bit too early. By backing this up just a bit, my laptimes have been falling ever since.

Yesterday, at Chin I had a great Saturday with three back to back PB sessions. I had been stuck at 2:02.3 on Nitto NT-01s forever. At that time a 2:03.3 was a ***** out lap, now 2:03s are much more typical and "***** out" is now a 2:00.45


Decently tight grouping:
Lap:Time
Lap1: 2:02.90
Lap2: 2:02.30
Lap3: 2:01.90
Lap4: 2:01.35
Lap5: 2:00.45 <--- PB!
Lap6: 2:02.00
Lap7: 2:01.65
Lap8: 2:01.55
Lap9: 2:03.00

I've done a 2:00.7 on Z214s. They good for about 1.5 seconds, so on those I'd be doing about 1:59 flat.

My chickenlift habit in T1 is back and I'd like to be better about holding the throttle down in T15. Honestly, I think my T1-T2 is pretty good, as even after the PB the predictive timer was saying I was 0.3 seconds ahead at the entry of T3, only to lose it as I went around the track.

I would appreciate advice on what to work on next.

-Mike

ETA: The only bummer of the weekend is I thought I had run a 2:00.3, only to find out afterward it was a 2:00.45. I could swear that TM display said 2:00.3, oh well.

Veloce Raptor

MUCH BETTER!!!!!

BobKid

Cute socks!

Thundermoose

Mike - good job. 2 seconds is huge.

I'd offer up two things:
- gotta stay flatfooted through transition but you know that.
- hold a 1/2 beat longer before turning into 14 so that you can roll into and stay on full throttle at 15 and into the straight. I see that you give and take throttle at 15. You may need to play with line a bit but 1-2 miles faster out of 15 will be 5-7 mph faster at end of straight. Look through your data and try to find your fastest exit speed out 15 and see how fast you were at end of straight.

AGO

Here is a lap at COTA during Edge Addicts last Sunday, lots of traffic most of the times but this is one of the cleanest until I hit traffic after T15 (then an overtake using the Alonso exit line on T19).


I can see a few things to work on but would like your views just from watching the video.

For your reference, I'm driving a 2010 GT3 no mods other than Brembos on the front, track alignment (~2.5 neg. camber) and MPSC2.

Also, I had a "chase cam" in the below linked video (from 3:58 on), chase car is a GTR (which is about 10-12 MPH faster at braking point on T12). Great to be able to access to this one, so if you have a little time please have a look.


Thanks for you help!

Veloce Raptor

JC, I just had a chance to finally watch your COTA video. Nice driving! A few observations that pop to mind!

Upshift to 4th at the apex of T2 and carry that into the esses rather than upshifting just before the bridge

Turn in sooner for T7 and use all the apex curbiing

Hold that tight line on the curbing of T8 a bit longer and then transition into T9 a bit sooner, in order to use less track out curbing from T9

Use a lot of curbing in T10 if your car can take it, so as to stay off the track out curbing and get a faster exit

Use all the apex curbing in T11 and T12

Upshift to 3rd gear either just before or just after T13...it'll allow more throttle for longer through that section

Upshift to 4th gear in the carousel

You are way way early apexing T20, which a lot of folks do. it's killing you

-Dave

Veloce Raptor

As an aside, JC, it looks like I am hired for the first day of the 3 day MVP event at COTA in February. If you'd like to work together on either the Saturday or Sunday, it would be my pleasure!

AGO

Thanks Dave, good observations and yes after being so much on the outside of 19-20 I lost a bit my reference points. T7 is a good place to improve, need to get more consistency going faster (i.e. use more curb on 10, 11 and 12)
I'm working my schedule to see if I can make it to MVP, hopefully it'll work out. I'll let you know as soon as I know.

Dr911

Short shifting question:

There is a current thread w a lively discussion around shifting in a 997.1 is on the main forum.
This led me to wonder as to the value of short shifting in general.

The specific locations I wondered about was just after three (before the esses) at Rd Atlanta, and also right after turn 11 (going under the bridge) at the same track.
Another such example might be just entering Thunder Valley at MidOhio (I think but can't remember for sure, it was a while ago).

I thought it was to avoid breaking the momentum when you redline at a later/inopportune time, but now I'm wondering how much of the value is car-dependent re gearing ratios etc.

Any insights?

ProCoach

Sweet! That's video from the new Waylens camera. The software combines the data with the video post recording, and the quality is outstanding for less than $500!

ProCoach

This is correct. Going downhill, especially with a direction change during or immediately after, you WANT to DO this... No matter what the curve/gearing/etc.

Veloce Raptor

Yes it can be useful at key locations on many tracks in most cars...also to help stabilize the chassis when it is loaded, versus the instability at redline, to allow more throttle position for more real estate.

bldn10

I short shift in those very places. Otherwise I'd be shifting in 4 and at the turn in at the bottom of the hill. My first time in my Cayman S 3.8 (after an AWD Audi) at Road Atlanta I blasted down the hill in 3rd and when I put in the clutch to shift, the back end snapped around and I backed into the tire wall. Even short shifting to 4th I'm still over 100 at the bottom of the esses and start/finish.

sbelles

Is there a reference out there somewhere that gives the radius, or even better, the effective radius (including camber) of corners on US racetracks? Secondly, are there corners that you believe serve as a good baseline (corner is flat with average grip) to use in determining max G for a car? I'd like to take some time over the winter to look at my theoretical Vmax for various corners. I have a lot of data and I could calculate the values based on that but it wouldn't be very helpful. Knowing the radii and having some corners as good baselines would help a lot.

MarcD147

unlikely...

its a combination of elevation changes, camber, track surface, tires and track conditions and that is assuming car, weight, setup are all constant.....

in my GT4 on RE71R I never see more than 1.3x G sustained on flat corners;
some days I can t get to those numbers (cold, wet)
some corners I cant get to those numbers; especially higher speed corners I tend to see lower numbers (maybe I should look for a set of bigger *****)
some times my tires are head cycled out and I cant get to these numbers
etc

btw did you mean you wanted to look for highest vMin in corners instead of vMax?