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INteresting that at top of hill / oak tree, there is some pressure maintained thruout that stretch from initial turn in to accel.. DM in his webinars says that whole area is a braking zone..
It is. As long as there is enough energy in the car, it works out exactly that way.
__________________ -Peter Krause www.peterkrause.net www.gofasternow.com
"Combining the Art and Science of Driving Fast!"
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Not sure if it helps much, but here's an overlay of myself and my Pro co-driver at The Glen in T8 the last time I was there in a GT3 car. Personally I don't think it's that great of a turn to look at trail braking just because it's always been the corner for me with the most "coast time" of any at WGI. In my experience that big bump is always where I want to get on the brakes which unsettles the car and the downhill entry always causes entry instability and I always have understeer off apex. lol. The time lost on braking/entry was just under 1 tenth. ((I generally wouldn't post my co-drivers overlay but it's been a few years and the car is mechanically different now so I don't think anyone would care))
Not sure if it helps much, but here's an overlay of myself and my Pro co-driver at The Glen in T8 the last time I was there in a GT3 car. Personally I don't think it's that great of a turn to look at trail braking just because it's always been the corner for me with the most "coast time" of any at WGI. In my experience that big bump is always where I want to get on the brakes which unsettles the car and the downhill entry always causes entry instability and I always have understeer off apex. lol. The time lost on braking/entry was just under 1 tenth. ((I generally wouldn't post my co-drivers overlay but it's been a few years and the car is mechanically different now so I don't think anyone would care))
-mike
Maybe some 8/10 braking would settle the car quicker there, or maybe not even let it get unsettled at all....
This fits into what VR talks about, not "shocking" the car with that FAST hit, but rather building up a TINY bit slower to max pressure. But STILL max pressure, early in the application.
The white lines (corrected speed, from wheelspeed data) shows the instability that coincides with the FAST hit to 2000 psi (136 bar!).
Almost immediately, the pressure goes down at the 3890 meter point into the lap, and as a result, the braking period is not quite as efficient in white as it is in red.
What people who don't do this EVERY DAY need to know is "what good" looks like," so they can emulate that.
Not only does the red brake pressure build SLIGHTLY slower, but it's more evenly distributed over the entire sustained distance, then trails off. So, the decel rate is constant towards the end at entry, making it easier to transition into the corner.
The blue line over the red trace is "what good looks like." The side benefit of this is that the red trace driver is able to brake later, with a more stable platform, and still arrive at the corner entry at the same speed as Mike (the white).
Thanks for the analysis ProCoach! Definitely all makes sense when you say it, but you know what they say: when the helmet goes on, the lights go out! haha!
dgrobs, agreed. But when you're already braking later than you want (to get over the bump) it's hard to go easy on the pedal!
Why is the steering angle input so delayed in relation to the brake input. Is it common to have 1/2 your brake bleed / trail brake done before any steering input? particular to this corner?
Is it common to have 1/2 your brake bleed done before any steering input? particular to this corner?
Shouldn’t you bleed your brakes before you go out on track? I would think it risky to stop at T-8 to bleed your brakes while the track is hot. Maybe pull off line and bleed them
in the run off gravel pit?
Why is the steering angle input so delayed in relation to the brake input. Is it common to have 1/2 your brake bleed / trail brake done before any steering input? particular to this corner?
Have to wait until the speed is off and be disciplined to not "crab in," hence the late, big steering input due to the corner turning back on itself.
Also, this turn is increasing radius due to the increased width at the exit. Hence a gentle build to a peak late in the apex area, then BAM! Open and GO!
Look at the radii in feet on this great chart. T8 is radii 16 and 17.
150' radius is pretty tight. The second part of T8 is ALMOST as open as T10! Look how the Toe opens in the same way.
Also, remember he's got to shed quite a bit of speed for the Toe, Heel and T9. Sixty miles per hour, in this case.
So yes, normal to drag out the release to HELP THE CAR FINISH TURNING. THAT, is trailbraking...
Now, the key would be to add combinedG or GSum and see if it dips anywhere AFTER the bleed-off begins but before MAX steering input...
That tells you how much you're leaving on the table, in terms of total, demonstrated tire grip.
I purchased Ultimate Speed Secrets by Ross because of the trail braking article and this thread. I'm finding it to be a pretty fantastic read so far, especially as I near the end of my first full track season. Highly recommend it.
I'll also be coming back to this thread before heading to The Glen for the first time...
Good! Ross and I talk about about execution, grading each corner and the best integration of trail braking into each corner on our Virtual Track Walks, available at Speed Secrets.com
The Glen was the first track we offered. Right after the repave.
Amazing how much you can drag the brake into T1, T6, especially T7, T8, T9 and T11. Using it to finish turning the car and extending the braking into the corner entry phase is key, for sure.
10-08-2021, 01:11 PM
