To shift or not to shift....

[R13]

I did a little experimenting at Talladega GP this past weekend amidst my other issues. Normally I'd been down-shifting twice during a lap, once going into 2, once going into 6. So 4 shifts total. This kept the car well into the power band, but also put me at the limiter in the short chute between 2 and 3, so I ended up going to neutral throttle to keep it off the limiter (not a race, had to drive it home, etc.).

After a few sessions I decided I'd try running the entire thing in 3rd gear to see if I could keep the car a little cooler since it'd been overheating towards the end of sessions. To my surprise it didn't feel slower and I observed a higher v-max at the end of at least one of the straights. My average lap time was approximately the same (mid 1:10.xx range) between the sessions. Grant it, the 3rd-gear-only session was later in the day so the track was warmer, I was warmer, and had probably 3 gallons less gas on board, so everything with a grain of salt. Still, I was pleasantly surprised.

There is probably a happy medium in there somewhere, but I'll have to play with that another day.

Video:

Using 2nd & 3rd:
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Using 3rd only:
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[W]

Nice videos.

It looks like heel-toe messes up your braking sometimes and you end up going slower through the turns, especially at the second left hander after the front straight (turn 3?).

It also doesn't look like you're full throttle in second gear for very much which would help explain why the laptimes are close. I'm not saying that there is something more that you can do and 3rd might be a better gear in certain areas for consistency sake.

That part throttle thing in 2nd in a straight line isn't helping. Why not upshift to 3rd? I know, you'd have to heel-toe back into 2nd.

It does look like the gear changing laps are faster but not by much. A datalogger could help determine where you're gaining and losing time and where you're more (and less) consistent.

 

[CL65 Captain]

I have a datalogger and there is a turn (7) at Putnam Park where I can go down to 2nd, otherwise it's a 3rd and 4th gear track. My datalogger shows that I gain 2/10th of a sec going into 2nd. However, it is rougher on the car and on me having to brake hard, downshift, make the turn in and then shifting back up. Since it's a HPDE I decided it wasn't worth it and instead decided to see if I could leave it in 3rd and work on trail braking and going in hot, sliding the back and keeping the momentum up. After 10+ weekends on this track this year, I'm now faster through that turn leaving it in 3rd.

Something else to think about, there are times when you are over slowing the car to get it into a lower gear. The data logger at turn 1 at Putnam looks like a V if I go from 4th to 3rd. If I leave it 4th and then downshit to 3rd before turn 2 instead it looks like a U. In other words, I am over slowing the car to get it into 3rd and then accelerating through the turn. Leaving it in 4th I am maintaing a higher speed through the turn but not accelerating out of it. Turn 1 is followed by a very short straight before braking for turn 2. After studying the data logger it is obvious that the U is faster than the V. :tongue:

So, my point of the story is sometimes (usually) you are faster keeping it in the higher gear and working on things to go faster through the turn.

 

[R13]

Turn 2 is a little deceptive in that it's banked on camber when you turn in, but it transitions to flat at the apex or slightly off camber if you run wide on the exit. Watching the playback I agree that I was overslowing to get it in 2nd there. I think that was a hold-over from the last time I ran there with stock-sizes sumitomos. More grip means I can carry more speed through the turn making the down-shift unecessary or at least, as Captain points out, trickier and harder on the car.

The part-throttle in 2nd between 2 and 3 (3 is the slowest corner) is to keep it off the limiter. It sucks because it's basically coasting, and coasting, I know from autocross, is the devil. That said, I'm sure I could have nearly matted it in 2nd coming out of 2 and just dealt with a little wiggle...but as you say I'd just get to the limiter quicker or have to upshift (and then down-shift again)

Captain, I totally agree about the "harder on me" part. I felt much more relaxed and able to focus on the line when I wasn't fooling with shifting. It was much easier to look ahead vs. getting tunneled-in on a braking zone thinking about 3 different things.

I think what I may try next time is keeping it in 3rd through 2, down shifting for 3 since there's just no way to carry speed through it, then short-shifting to 3rd before slowing for 5.

I've got a GTech Pro RR that I've just been too lazy to plug in. It's no traqmate, but it's probably better than nothing.

 

[docjohn]

see what kind a fun we low torque track guys go through vs the lazy no shifty Zo6 and viper guys:wink: