hf1

If you're straddling the grip limit in turns at all times, then any (extra available) HP becomes irrelevant. Adding more power overshoots the grip limit and lowers grip which doesn't help you go forward faster. Plus, down/up shifting doesn't come cost-free in terms of upsetting the car when under load. Your analysis is too simplistic and more reflective of a high HP, point and shoot style of driving, which is never the fastest way around a track.

And in general, I've been driving long enough to know that 'arm-chair driving' a track AND a car I have not driven is a futile exercise.

mark kibort

I think you missed the point here, and missed the analysis.
I was talking about only when the driver and car were at full throttle . no other times. only straight ahead. No turns, no sweepers, ONLY straight WOT.
Ive been doing this a long time as well. what i am advising IS simplistic you're right, because im only speaking to the points on the track where there is no areas where downshifting and going WOT in a lower gear upsets the car. (its that simple)
all you need to do is look at any racer in a high reving car, to see this technique used by all. Ive advised this at tracks more technical and with higher percentage of turns to WOT sections and saved this kind of time in all cases.

all you have to do is try it and see. what can it hurt?
watch the video again. picture downshifts on the entrances of those turns. the LSD willl work better around the turn as well, and on the exits, you are gaining 20% more HP (and rear wheel torque)

again, there is 30seconds of a full lap which is full throttle as it stands now.
23seconds of that is straight ahead no turns or grip to be considered.
23 seconds of the car being at a 50hp deficit. im offering 50 more hp that will not upset the car and increase acceleration in those regions with no downside.

mark kibort

i like the effort, but you got way too caught up in the math with averages. you will need a little more calculus to really get the answer you are looking for.
the bottom line is this. we are not talking about a pro driver in your car, but if you do look at pro drivers in cars with similar redlines, the all do what im talking about. no pro is ever at 4700rpm at lime rock in a car that redlines at 7700 -8000rpm. For get about the name of the gear "2nd" or "3rd" as a boxster would never use 2nd, but the cayman would. (just look at the ratios)
look no farther than Pat Long in his GT3 video.

Now, what I have suggested is that you look at the 23seconds of WOT of the OP, on this track. starting at the 24 second mark on the video. there are 23 seconds of WOT where he is at 4700 to 6000rpm. he could have been at 6000 to 7700rpm. this is the easy math. very simple. a choice to use 50 more hp or not. sure the math will show small changes over small periods of time, (minus the time to shift) but in the end, the gains are quite large given the fact that he wants to gain a second. ive done this test with MANY drivers in cluding myself for many years. it works. trust me. 1 second is an easy gain here for doing nothing more than running the car in the optimum HP range.
Now, let me get into your number and find the info there too.

edit: one glaring error is that your data is for another driver, not the OP.... the OP doesnt get past 90mph on and after," uphill", and after"west bend " into "Downhill". never sees an RPM over 6000rpm. yet the car can run to 7700rpm and have 50more hp doing so. its very simple math

mark kibort

Here is my data: (feel free to check) I went back and was much more conservative in the WOT times in 3rd that could have been in 2nd. ( or 3rd rather than 4th) by the way, in most cases there is no shifting costs because the downshift before would have accomplished that task for no time cost.

After Big bend 2 seconds
after left hander 1 second
aftrer right hander on to no-name straight 2 seconds
after uphill 5 seconds!! (3rd vs 4th)
after west bend and into downhill 3 seconds stay in 3rd
down main straight 3 seconds. stay in 3rd til redline

thats 16 seconds where there could be a max gain of 50hp and min gain of 20hp. this is significant, with no downside effects.

my first swag was a little high, but this is based ONLY on the OP's video and speeds. With a pro driver, i would think that at least two sections noted above would remain in 3rd gear.

the above duration in 2nd gear (or 3rd gear) is ONLY in 2nd/3rd gear and is only a part of the WOT duration on any given straight. (i.e. 6000rpm to approx 7600rpm)
this is where there is a 50hp gain over operating the engine in the 4600rpm to 6000rpm range)

ProCoach

Pat Long's ratios are quite bit different.

DTMiller

Rennlist, where you can use your ignore list and still completely follow the conversation.

Beantown Kman

Precisely! At this year's Thanksgiving I will be thankful for three things: my great family, good health, and the ignore option on RL. Not necessarily in that order.

mark kibort

I'm not reallly concerned with what numerical gear he is in, just where he is in the HP curve. as i mentioned.... im only suggesting that more of the higher HP range is used.. thats it. As the car goes faster, you naturaly get higher up in that region. (i.e. a pro driver in this car) But for the OP, he wants a second, mathematically it is possible to pick up some significant time just using more HP for the 16 seconds I reference.

For reference though, the 2008 GT3 RS has pretty close gear ratios.. i would think that the RSR might be pretty close as well.
GT4 gear ratios vs GT3RS 1st through 6th
12.8 vs 13.1
7.6 vs 7.7
5.5 vs 5.6
4.3 vs 4.4
3.7 vs 3.6
3.15 vs 3.16
the big difference is the RPM ranges of the engines 7700rpm vs 9000

mark kibort

Using your data.... using 2nd where you can in place of 3rd, or (3rd in place of 4th) gives an advantage of near 80 feet...(23.8 meters) (just using the above acceleration rate differentials for the 16 seconds the OP could be in 2nd gear)

edit addition: now if you look at the data, you can clearly see near 3500ft of full throttle operation. 2nd gear /3rd gear, could effect 1/2 of that WOT with the different in acceleration rates you note above. i roughly estimate a .5 to 1 second gain with doing nothing more than downshifting into big bend into 2nd and using it until the shift at No-name, and down shift again before Uphill.
You cherry pick a reference "no-name " throtttle time and distance, but that's not the straight where you get the most benefit. (only 2seconds there of 2nd gear WOT possible)
it's really the next straight after UpHill to westbend ghat gives about 5 seconds of WOT in (CORRECTION) 3rd gear

mlct

Interesting idea about trying 2nd in spots. Have not tried it nor have any of my coaches but I will try it next time out. I do have some old data from a friend running a 2011 or 12 Cayman R on pure street tires with PDK which does not go down to 2nd. It would be interesting to know what a newer PDK street car does. This was a 1:03.77 lap from three years ago before he switched to a 944 race car.

mark kibort

Based on the speed data in those sections, it certainly should be worth a try.
I did this with a few students as well as myself when i got a much higher torque engine, with slightly higher HP. thought i could short shift a little ..... ended up being a second slower. drove the car like normal and picked up the second i was looking for at a very technical track.

ProCoach

^^THIS^^

Mark, I'll try one more time.

Lime Rock is about slowing less, not accelerating more. It's a VERY fast track...

THAT is how you get time at Lime Rock...

mark kibort

Peter, I more than get your point. we have a track called Infinion, with the same gains for the same things. you can find all sorts of time at lime rock as you have coached.... im pointing out one thing that was missed. you still accelerate, and it still puts you ahead of someone or shortens the time.
its no faster than tracks out here.
My advice is to modify only a small section of performance on the track.
just those 15 seconds of when he is straight and NOT turning or pulling a wheelie. an extra 50hp can pay big dividendfs in free time, with no other changes. Ive coached this idea sucessfully many times with great success.
again.. one more time..... im not talking about anything other than changing points where he is WOT and going straight.

winders

I still don't see the sense of the two still photos showing cars at 66 MPH and 4782 RPM exiting The Right Hander on to the The No Name Straight. Is that the slowest point in the turn?

mark kibort

I think it was showing that with Peter's help, he was able to get to that same spot on the track in 23.4 seconds vs the other video at the same spot at 25 seconds. (saving the mentioned 1.5 seconds by line alone). I would think that there are other factors to be considered to account for the differences.
anyway, I was curious about that too.