Yep. Always compare using distance, because then the events over the lap can be compared, WHERE they occur, not WHEN they occur...

Correct!

Hey, that's why we're here.

 

That's a VERY good point. Off-camber downhill corners for instance

 

OK Coaches, here are 2 runs (fastest laps of the 2 configs last weekend). This is my 2nd time at this track and I'm an intermediate level driver. I took about 6 seconds off my last visit.

Here are my observations:
T1 - Braking too early and getting over late, need to turn in a little later and use the track out to carry more speed
T2 - I can carry more speed here, I picked it up drastically over weekend
T3 - Off camber, not sure I have a whole lot more but I need to get my exit setup better for T4 and stay on the gas around and up the hill
For the bypass, stay on gas, for the over top, quicker movements left-right to get car to land better
T6 - braking and turning in early. can carry a lot more speed here, tracking out at middle of curbing should be at end
T7 - DON'T LIFT! :-)
T8 - Light tap, I'm braking too much, can carry more exit to the curbing
T9 - A bit of over -braking - a little tentative on the downhill, floor it, and shift once settled
T10 - Braking early - this is a blind crest and the run off is a little scary here, its psychological - i can carry a lot more speed through here
T11 - need to brake and turn in a little later
T14-15 - I suck at this corner. :-) Plowed grass 2x here over weekend by early apex. Braking a little early, need to turn in later and ride it out, back on gas sooner out of 15 for the straight.

I feel like I'm getting better at getting on gas to get car settled, but, i'm tentative on track out

Curious your thoughts.

Will be doing another coaching session next month.

Bypass Config:



Over Top Config:

 

Need to see Gsum strip chart...

An awful long time in the corners not doing much change...

Very moderate (slow) throttle progression to WOT. Yes, I know the corners are long.

Brake profile not good. Partial brake pressure, then full brake pressure for a MOMENT, then partial brake pressure. Let's lead with the punch...

Steering shows you adding after initial turn in on T2.

Get it all in, like you do at the 4000 ft mark.

Did not watch the video...

 

Couple things from both videos: if you are going to slow THAt much for T1, go down to 3rd gear. or brake slightly less and carry a bit more speed in 4th.

T2 way too long with no change in throttle IMO. You can add 5%...10%...15%...very smoothly there especially with a rear engine platform once the roear is loaded up.

 

What tire are you running? What car are you in?

The above observations are spot on. I was actually there the same weekend and the data graph on prior page are from same day. Turn 2 is probably one of the safest places ever to learn to throttle steer your car you should for sure get back to gas sooner and feed in until it starts to push then you can lift and feed on and off smoothly to rotate car then feed on all the way about 30' before apex which will Carry the car out to the exit. In general you are over breaking every where that will just take seat time to trust there is more track surface left.

 

I have to move to SoCal, my cars would last a lot longer there..

 

I should clarify brake profile is decel g not a pressure switch. But your point is valid its a tentative application of brake. Needs work. Unsure how accurate the plot is compared to a pressure switch.


Good feedback. This corner is like chuckwalla where I have a lot more seat time and was finally starting to pick it up. I think I'm over thinkng the exit I to 3. And yes way too much slowing for 1

Nt01. They have a lot of room left. Agreed. Corner entry speed and corner speed is what coach will work on next event.

 

I understand the calculated value on your chart and I apologize for not being clear in my measure name.

There IS a correlation that is quite accurate between the value displayed and your actual brake pedal pressure (application of your foot on the pedal, not hydraulic).

You are measuring the end result. The end result shows that you are tentative both on application and stepped in release. It also shows a similar profile each time you apply the brakes in the way that the Long G forces flow and ebb.

That means that IF you can fix this, it will be a global improvement!

Ideally, the decel rate should rise quickly (unless the car is unloaded over a crest) and decay slowly, then completely.

When it decays (better shown with a LongG versus distance graph), there should not be too long a length of time before the LongG goes positive, reflecting at lease some thrust positive acceleration and progressive growth in that acceleration until WOT.

That can take time (especially in longer corners), but it needs to rise and not be in stasis (as it is now, too often). This is also viewable in the speed versus distance graph.

I have lots of knowledge and experience with Chuckwalla, less so here, but the same principals apply.

 

If it helps, here's the brake pressure, long G, and gload graphs from one of my laps at Thunderhill:



-mike

 

Thanks, Mike! THAT is the way the brake pressure/LongG profile should look!

Also, really like that GLoad transition from braking to cornering... Almost can't see it!

This is the reason why I was asking for the GSum from the OP.

The shape the OP should aspire to generate SHOULD look close to this, albeit not quite as high a measured value! Little more capability in this car.

 

is g-load = gsum? i have gsum

This is the 2:08 lap

Appreciate the observations. Getting that braking down is a focus for next coaching session. If i posted the indicated gear you'll see some of (not ALL, but some) of that uneasy braking is coming during downshifts. I'm clearly not a master of heel toe. But, replaying the track day in my head, i can feel my braking, tentative at first, then on it, then sort of casual release. Some of this is coming from braking too early (I think) then "oh, there's track there" and then a lazy transition off brake and into turn and back on gas.

 

Yes, and excellent observation!

It would be helpful to reduce the number of measures viewed at any one time.

Perhaps speed, BrakePressNEG and GSum would be the three I would look at ALL the time to more quickly identify trends.

Not too worried about absolute numbers, just looking at the timing and duration of attack, decay and sustain of all three...

 

I've been working on left foot braking in my auto trans cars as I run around town. I'm no longer imposing whiplash on myself but I'm not nearly as smooth as with my right foot. How close to equal skill with each foot should someone wait before trying it on the track?

 

My view is that you should start trying it now as long as there is no one directly behind you . Heck, I will left foot brake in the paddock and especially as I go down the hot pits towards track out, just to make sure I have brakes. Always helps to avoid an ugly surprise in turn 1 on the first hit lap!