:NERD ALERT: Braking data
Sep 17, 2009, 05:13 PM
#46
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Yeah trail braking makes that nice steady radius from braking to turning on the friction circle, but also can lead to some spinning.
As you can see from my braking I am leaving some on the table at the initial stab, as well as not taking things deep enough. I was really starting to feel comfortable with my car my last time out, as well as understanding the nuances of the track - so next year should be where the real improvement "clicks".
As you can see from my braking I am leaving some on the table at the initial stab, as well as not taking things deep enough. I was really starting to feel comfortable with my car my last time out, as well as understanding the nuances of the track - so next year should be where the real improvement "clicks".
Feb 4, 2010, 01:06 PM
#47
Nerds...enjoy.
Slow week at work, so dove into more analysis.
Here's proof that a good line trumps all. I have 2 back-to-back laps but the first one was 3/4 second faster and I wasn't sure why. Looking at the segmented data, everything changes in 1 particular turn because of the line that I choose. See below.
Short Version:
Look at the red vs black line in the upper right so see the driving 'line' for each lap. Then check out the corresponding Velocity & Time Gap towards the bottom to see how it all added up.
Nerd version:
The red lap is my fastest - and has a good line through the 'S' turn that I highlighted. The black lap is actually about .3 faster up to this point but I loose .7 just in this turn alone and then another .3 on the short straight after because of the slower exit speed.
All the associated data is included. The lateral g's and braking/accel g's are virtually the same showing they were consistent. The velocity (aka speed) shows the real story here and is backed up with the widening Timegap right below. Ugh.
Being out of position on the first corner of this 'S' curve cost me .7 seconds alone just in this corner, and probably a full second when you include the lower exit speed for the next straight where top speed was 89 vs 85mph. If this straightaway was longer; the issue would be even worse!
Here's proof that a good line trumps all. I have 2 back-to-back laps but the first one was 3/4 second faster and I wasn't sure why. Looking at the segmented data, everything changes in 1 particular turn because of the line that I choose. See below.
Short Version:
Look at the red vs black line in the upper right so see the driving 'line' for each lap. Then check out the corresponding Velocity & Time Gap towards the bottom to see how it all added up.
Nerd version:
The red lap is my fastest - and has a good line through the 'S' turn that I highlighted. The black lap is actually about .3 faster up to this point but I loose .7 just in this turn alone and then another .3 on the short straight after because of the slower exit speed.
All the associated data is included. The lateral g's and braking/accel g's are virtually the same showing they were consistent. The velocity (aka speed) shows the real story here and is backed up with the widening Timegap right below. Ugh.
Being out of position on the first corner of this 'S' curve cost me .7 seconds alone just in this corner, and probably a full second when you include the lower exit speed for the next straight where top speed was 89 vs 85mph. If this straightaway was longer; the issue would be even worse!
Last edited by boomn29; Feb 4, 2010 at 01:09 PM.
Feb 4, 2010, 01:26 PM
#48
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I'de say you used much more apex curbing on S11, which is a good corner for that as the curbing is very gentle there. Gains would be even bigger on full course (build speed all the way to N3).
Just don't do the same for S6! (ask me how I know...)
Looks like you made good gains on S13 entry too! Very nice, gypsy.
Just don't do the same for S6! (ask me how I know...)
Looks like you made good gains on S13 entry too! Very nice, gypsy.
Feb 4, 2010, 03:43 PM
#51
I'm suprised your G's in braking are so low. In Portland with a brand new track surface, I'll hit 2G's+ braking quite frequently according to my G-Tech Pro RR. Highest was 2.58G's, where cornering I'm pretty steady around 1.18G. This is using WORKS 2 piece rotors all the way around and Ferodo DS3000's. My temp gun cuts out at 900 degrees, and it's well over pegged after a 15 minute session.
I do threshold and trail brake tho.
This was with Falken RT-615's 255/40/17.
I do threshold and trail brake tho.
This was with Falken RT-615's 255/40/17.
Feb 4, 2010, 04:04 PM
#53
Looking at your overhead of PR, I assume green means WOT, where black is a constant, or slight speed transitions. Between 2 and 3 looks like the only place where you went from throttle to braking immediately. Modulation betwen gas and brake will give you significantly lower intial G readings wouldn't it? I'm not an engineer, so I can't argue physics.
I do know it's the fastest way around the track. When I raced bikes, it was all the same rules, when your not braking your accellerating.
Last edited by GTisRule; Feb 4, 2010 at 04:12 PM.
Feb 4, 2010, 07:07 PM
#54
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The Gtech doesn't have enough filtering and logic. Those aren't real peak loads, they are noise. Traqmate can use the velocity data to calculate acceleration along with the accelerometers, and it uses both to help filter the data.
Yes red is braking, green accelerating and black is coasting. What my PR data shows is that I am a huge wuss-pants and my car scares me. I coast on the front straight because my car could do 150 through turn 1 and I wasn't ready for that yet. Between 3 and 5 I hit the top of 4th coming up the hill and so I just coast instead of banging the rev limiter for a long time or short shifting into 5th and coming into turn 5 so fast that the corner workers would crap themselves. I also cost over the hill top coming into 8 because I don't want to go off and put my car in the cyclone fence.
All gas to all brakes is fastest fo sho.
Yes red is braking, green accelerating and black is coasting. What my PR data shows is that I am a huge wuss-pants and my car scares me. I coast on the front straight because my car could do 150 through turn 1 and I wasn't ready for that yet. Between 3 and 5 I hit the top of 4th coming up the hill and so I just coast instead of banging the rev limiter for a long time or short shifting into 5th and coming into turn 5 so fast that the corner workers would crap themselves. I also cost over the hill top coming into 8 because I don't want to go off and put my car in the cyclone fence.
All gas to all brakes is fastest fo sho.
Mar 23, 2011, 12:08 PM
#55
13 month resurrection!
Wanted to illustrate how easy it is to spin on track. So learn from me!
I had an easy spin late last year. Below is data from that session including my fastest lap and the lap with the spin (in red obviously). I took a slightly sharper and more aggressive line into a right-hander as I was nearly glued to the car in front of me. I came out a little wider (and we're talking probably 1 foot). You can see from the data that I went to the gas harder and a bit sooner as well. This is all a bad combination!
I pride myself on using the entire track - all of it. If I miss a few inches I'll go in harder next time. So when I went a bit wider with the red lap, I was well onto the gaters on the outside of the turn - which provide little/no traction. So the car started to spin and it was already too late. I slid across track and off the opposite side and ended up backwards.
Note this was the slowest turn on the track and all happened around 40-60mph and there was no danger off-track (wide-open grass) so you can try to be aggressive in these spots.
If you check out the track map to the right you can see where I ended up!
Wanted to illustrate how easy it is to spin on track. So learn from me!
I had an easy spin late last year. Below is data from that session including my fastest lap and the lap with the spin (in red obviously). I took a slightly sharper and more aggressive line into a right-hander as I was nearly glued to the car in front of me. I came out a little wider (and we're talking probably 1 foot). You can see from the data that I went to the gas harder and a bit sooner as well. This is all a bad combination!
I pride myself on using the entire track - all of it. If I miss a few inches I'll go in harder next time. So when I went a bit wider with the red lap, I was well onto the gaters on the outside of the turn - which provide little/no traction. So the car started to spin and it was already too late. I slid across track and off the opposite side and ended up backwards.
Note this was the slowest turn on the track and all happened around 40-60mph and there was no danger off-track (wide-open grass) so you can try to be aggressive in these spots.
If you check out the track map to the right you can see where I ended up!
Mar 23, 2011, 01:32 PM
#57
Nothing special.
As I recall I actually had the car into a slight skid prior to hitting the gators and I just left my foot buried in it.
It was Sunday S1 and I was playing with the rear diff trying to force corner exit oversteer - or in this case mid-corner oversteer!
lol. In my head - clearly I caused it.
As I recall I actually had the car into a slight skid prior to hitting the gators and I just left my foot buried in it.
It was Sunday S1 and I was playing with the rear diff trying to force corner exit oversteer - or in this case mid-corner oversteer!
lol. In my head - clearly I caused it.
Mar 24, 2011, 05:36 AM
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Ok, now it's kinda fun! Here's a different track that I'm more comfortable with. You can see the lateral curves are more rounded - ie steady.
Here's a comparison of 2 different weekends. Drastically different temps and tires; I'm also running different tunes hp wise. One is with 245 Dunlop's and the other with 245 Hoosier R6's. Bet you can tell which is which just by looking at the friction circle! You can look at the track map and see that I'm gassing and braking nearly the same. But with just extra sustained corner speed I end up nearly 5 seconds faster with the better tires. Which is why I say build the car around the tires in a limited budget or pts (aka NASA TT) type event.
Here's a comparison of 2 different weekends. Drastically different temps and tires; I'm also running different tunes hp wise. One is with 245 Dunlop's and the other with 245 Hoosier R6's. Bet you can tell which is which just by looking at the friction circle! You can look at the track map and see that I'm gassing and braking nearly the same. But with just extra sustained corner speed I end up nearly 5 seconds faster with the better tires. Which is why I say build the car around the tires in a limited budget or pts (aka NASA TT) type event.
someday when i get the money i'll get some data goods.
anywho, i have always had confidence issues on turn 4 with that damn bump before turn in. how do you navigate through that?
Last edited by heel_touge; Mar 24, 2011 at 05:41 AM.