Looking at more gear changes at Summit Point Main course - help?
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From: NY Tri-State
Originally Posted by steveP911
As to the basic downshifting question, it appears as though Frank does utilize lower gearing in pretty much exactly the way I wrote it above for my “plan”, except he shifts a little earlier than I wrote in the area of T7. I don’t see or hear anything that the car doesn’t seem to like but much of that may be due to Frank’s ability to manage the car far better than I ever could.
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From: NJ
T1 is a no brainer 2nd gear for you. In your fast lap from the spreadsheet your vmin is 41 mph. Reference video is 45mph. If your redline in 2nd is 68mph that means you have plenty of RPM and acceleration left to go down to second and accelerate hard in 2nd out of that turn. Reference video that Frank posted shows exactly that. You'd pick up 3rd at exit of the turn. Downshift should be done towards the end of the breaking zone. You should be going down the gears as you're braking. Should be done with the downshifts by the point you're off the brakes.
saying the obvious here but T1 is a very slow turn, one spends a lot of time in it, it's even more important that you'd want to reduce the time spent in that turn as much as possible
T5 will be very similar story.
saying the obvious here but T1 is a very slow turn, one spends a lot of time in it, it's even more important that you'd want to reduce the time spent in that turn as much as possible
T5 will be very similar story.
Given the weather and location of my car (in the shop for normal winter track update/upgrade stuff), I am looking through my past videos and data in preparation for the start of the DEs season with PCA Potomac at Summit Point (main) WV, on March 20-22. One area I would like to get advice on is gear choices throughout the track. I have tended to shift less in order to keep the car a bit more settled and reduce my efforts. But as I review things, it seems like there are some opportunities if I explore more downshifting. If you have any thoughts, I'd love to hear them. I'm kinda bored and there's not much thread traffic on this forum for me to peruse.
My car is a 2005 997/1 C2S with a Slakker 4.1L engine rebuild. I am in PCA White (still
). The car is pretty well track oriented and I run 200tw tires typically. Seats, roll bar, harnesses. I have a Garmin Catalyst and AiM MXM data logger.
Here is the car speed info for each gear. My ideal shift point is based on 6700 rpm, my best guess for optimizing power and reducing chances of bouncing off the redline (7200 rpm).
Max in 2nd gear = 64 (ideal)/68(redline) mph
Max in 3rd gear = 92/99mph
Max in 4th gear = 115/124mph
Max in 5th gear = 137/147mph
Here's my thoughts on each turn and possible shift changes:
T1: I normally stay in 3rd gear] Is another downshift to 2nd worth it to gain better exit acceleration? Have to find out where this downshift can be done effectively (somewhere in the apex area?). Will the 3rd gear upshift also be problematic with steering angle (and lateral g’s) in effect on outside of turn exit? Two shifts while turning – make it worth it or don’t do.
T3: I normally stay in 4th gear] Is downshift into 3rd helpful or will it unsettle the car? Should be plenty of time to utilize 3rd gear before upshifting to 4th as the car straightens out, so exit acceleration could be improved.
T4: Stay in 4th gear.
T5: I normally stay in 3rd gear] Downshift into 2nd gear at opportune time (around apex?) to provide better exit acceleration towards T6. Should increase pace through this short straight and force higher entry speed into T6.
T6-T7: I normally stay in 3rd gear] Stay in 2nd gear to improve torque and throttle steering. Upshift to 3rd around T7 apex when the car straightens out (briefly).
T8-T9: I normally upshift to 4th prior to T9] Stay in 3rd gear until car straightens out along outside curbing (before it ends, to stay under redline). This should improve exit speed towards T10. Max speed of 99 mph.
T10: I normally stay in 4th gear] Is downshift to 3rd helpful or will it unsettle car? Downshift has to occur smoothly as part of primary braking while car is still straight, prior to turn-in. Will help with exit acceleration. Still enough time to upshift into 4th as car straightens out along outer curbing (on the rumbles?).
Main straight: Try to stay in 4th gear (without redlining) through start/finish line. Max speed of 124 mph.
Here is the link to my five best laps at SPM. They are not my latest laps as I seem to be slowing down, which I would like to address and fix.
https://youtu.be/wGIPzzU-TAw?si=JAGyORudq65KL-_a
Thanks! Hope it gives you something to noodle over.
My car is a 2005 997/1 C2S with a Slakker 4.1L engine rebuild. I am in PCA White (still
). The car is pretty well track oriented and I run 200tw tires typically. Seats, roll bar, harnesses. I have a Garmin Catalyst and AiM MXM data logger.Here is the car speed info for each gear. My ideal shift point is based on 6700 rpm, my best guess for optimizing power and reducing chances of bouncing off the redline (7200 rpm).
Max in 2nd gear = 64 (ideal)/68(redline) mph
Max in 3rd gear = 92/99mph
Max in 4th gear = 115/124mph
Max in 5th gear = 137/147mph
Here's my thoughts on each turn and possible shift changes:
T1: I normally stay in 3rd gear] Is another downshift to 2nd worth it to gain better exit acceleration? Have to find out where this downshift can be done effectively (somewhere in the apex area?). Will the 3rd gear upshift also be problematic with steering angle (and lateral g’s) in effect on outside of turn exit? Two shifts while turning – make it worth it or don’t do.
T3: I normally stay in 4th gear] Is downshift into 3rd helpful or will it unsettle the car? Should be plenty of time to utilize 3rd gear before upshifting to 4th as the car straightens out, so exit acceleration could be improved.
T4: Stay in 4th gear.
T5: I normally stay in 3rd gear] Downshift into 2nd gear at opportune time (around apex?) to provide better exit acceleration towards T6. Should increase pace through this short straight and force higher entry speed into T6.
T6-T7: I normally stay in 3rd gear] Stay in 2nd gear to improve torque and throttle steering. Upshift to 3rd around T7 apex when the car straightens out (briefly).
T8-T9: I normally upshift to 4th prior to T9] Stay in 3rd gear until car straightens out along outside curbing (before it ends, to stay under redline). This should improve exit speed towards T10. Max speed of 99 mph.
T10: I normally stay in 4th gear] Is downshift to 3rd helpful or will it unsettle car? Downshift has to occur smoothly as part of primary braking while car is still straight, prior to turn-in. Will help with exit acceleration. Still enough time to upshift into 4th as car straightens out along outer curbing (on the rumbles?).
Main straight: Try to stay in 4th gear (without redlining) through start/finish line. Max speed of 124 mph.
Here is the link to my five best laps at SPM. They are not my latest laps as I seem to be slowing down, which I would like to address and fix.
https://youtu.be/wGIPzzU-TAw?si=JAGyORudq65KL-_a
Thanks! Hope it gives you something to noodle over.