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in prepation for my new car I have been starting to learn H/T over the last two track weekends.
below are some data traces of shifts in my GT4 (sport button off)at the PCA DE at NJMP Thunderbolt that I would like feedback on:
Can you switch it from distance to time, for THIS specific analysis, please? Plus, we need throttle position...
__________________ -Peter Krause www.peterkrause.net www.gofasternow.com
"Combining the Art and Science of Driving Fast!"
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in PTPA I cant change the x-axis to time and I can only select 3 y axis components. which ones besides throttle do you want?
brake pressure and rpm?
in case it helps or is more convenient I have done a vbo export of the whole session in case that helps. just change the file extension of the attachment back to vbo.
Agreed it looks pretty good. If you can calculate gear through a math channel, look at for non smooth gear changes. Those are an easy way to see poor heal/toe.
This is a good spot to look. It's one of the areas that ends up very important for transmission longevity. I've worked with a few people on the same in prep for the 24 Hr races.
what about the G-force dips (bumps in the chart) at the end of my shifts.
is that a sign of too much blip?
Marc, I'm in the middle of a small thrash, and I will respond in more detail (looking at your three examples, plus my example, shown above) later, but to start...
The g-force anomalies are not present every downshift. As a matter of fact, they shouldn't be present at all.
In order to gauge effectiveness of heel and toe (throttle blips to match revs and proper timing of clutch release vis-a-vis engine RPM, you MUST look at the LongG braking FIRST, to make sure that you are constant in your rate of deceleration.
The reason why there would be anomalies (and it's generally at the end of the brake zone, when you're trying to juxtapose many different commands to the car while selecting an entry speed and effecting the change in direction) are twofold.
Either the LongG is good initially, then there are momentary losses of Long G values (doesn't have to go away, just a deficit occurs somewhere over the length of the slowing period, usually MORE than once but coinciding with the number of downshifts) when the "blip" distracts the right foot from steady pressure on the brake pedal OR,
The LongG is deficient (gentle braking, well under other sampled LongG values while slowing in a straight line) and while "blipping," the stab of the throttle also causes a stab of the brake pressure UP, causing the car to spike in LongG when the car is blipped.
The former is MUCH more common than the latter, but the thing to remember is that braking is the priority, and drivers can afford some sloppiness in the blip as long as the LongG reading shows the proper profile for most effective braking.
The most important thing to remember is that these are all braking zones and you should primarily focus on your brake pressure traces. It is very easy to release brake pressure momentarily when you are heel toeing at the same time which can significantly compromise braking performance.
It is very easy to release brake pressure momentarily when you are heel toeing at the same time which can significantly compromise braking performance.
Exactly, and I think the spike of longG at the end coincides with a REAPPLICATION of brake after an inadvertent release, resulting in a concomitant spike in the brake pressure...
It is going to be little different for Marc in the cup car...with the low mass fly wheel and race clutch: revs drop very fast when off throttle. Timing of the shift is the main thing...and you only need a small blip.
My advice is to practice 5-4-3 sequence and shift through every gear at the start to get a feel for the timing required: It is best to avoid downshifts to 2nd as much as possible early. 2nd is short and it often a very late shift on most tracks..sometimes mid corner.
When you get timing right, you can skip gears and shift directly to the gear needed..saves the box a bit and allows you to focus on smoother braking.
10-02-2017, 10:44 AM
feedback on heel/toe data trace
