Anyone with Data Aqu. systems out there? I have a question.
04-18-2009, 12:02 AM
#17
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5G's in turn 10 at Sears Pt................in deceleration on hitting the tire wall. Expensive G's! 
Seriously, 1.2-1.3 lateral and 1.1 decel measured with a traqmate on most flat high speed turns in a spec 911 on RA-1's.
Seriously, 1.2-1.3 lateral and 1.1 decel measured with a traqmate on most flat high speed turns in a spec 911 on RA-1's.
04-18-2009, 12:59 AM
#18
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Id like to know how it works. cliff notes???
mk
mk
Traqmate *should* be able to recognize the track slopes downhill from the change in the Y axis. Whether the software is sophisticated enough to calculate it, or just spitting out raw numbers... is that in the documentation? The numbers I'm getting from my cell phone (Samsung Omnia) are plain old uncorrected raw numbers. But then, this is free software using an accelerometer designed only to know if you're holding the phone up or sideways, so I'm happy with whatever I can glean from it- but if I paid a couple hundred bucks for a professional grade system, I'd want some sophistication in it!
BTW if anyone's interested in how a MEMS accelerometer chip works, I'd be happy to go into details. It's not at all how you might think.
BTW if anyone's interested in how a MEMS accelerometer chip works, I'd be happy to go into details. It's not at all how you might think.
04-18-2009, 01:08 AM
#19
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-brendan
04-18-2009, 01:44 AM
#20
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Ok, so I checked the MoTeC data instead of going from memory.
At Sears Point/Infineon, I get 1.6 - 1.7 max (1.5 without a problem) with up to 1.2 on deceleration. I took this from the 4 hour enduro last October (about 100 laps). Lap times ranged from 1:46 to 1:50's without the caution laps.
At Thunderhill, 1.6 - 1.8 max with 1.2 on deceleration with 1.6ish more typical. Lap times of 1:58 - 2:00 for the event examined.
At Sears Point/Infineon, I get 1.6 - 1.7 max (1.5 without a problem) with up to 1.2 on deceleration. I took this from the 4 hour enduro last October (about 100 laps). Lap times ranged from 1:46 to 1:50's without the caution laps.
At Thunderhill, 1.6 - 1.8 max with 1.2 on deceleration with 1.6ish more typical. Lap times of 1:58 - 2:00 for the event examined.
04-18-2009, 02:39 AM
#21
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According to "Analysis Techniques for Data Acquisition" (published by SAE, author works for/manages FIA GT and LeMan teams), a well driven/well set up car is typically capable of cornering at 103-105% of max braking g.
That's just capability. Actual got to be track dependent also.
That's just capability. Actual got to be track dependent also.
04-18-2009, 08:06 AM
#22
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Following on from what 986 said... if you had a good ABS system tuned for those tires, you could match (or perhaps very near to it) the cornering g's on decel.
Personally, though I can clear 1g decel with my car if needed (manages 1.2-1.3 in the corners, Hoosier R6's), I find it faster to focus on making a good apex and corner exit than fast in.
(seriously, sometimes I'll find myself only pulling 0.8g decel, but still as fast as they come... in ITB.)
Personally, though I can clear 1g decel with my car if needed (manages 1.2-1.3 in the corners, Hoosier R6's), I find it faster to focus on making a good apex and corner exit than fast in.
(seriously, sometimes I'll find myself only pulling 0.8g decel, but still as fast as they come... in ITB.)
04-18-2009, 08:29 AM
#23
Nordschleife Master
Looking at my MoTeC data, I'm showing a 1.6-.17g cornering at WGI and 1.4g braking. However, anytime the ABS is on, the braking g force is reduced to 1.2g. The cornering g is in a corner where the yaw rate is about 30 deg/sec.
04-18-2009, 12:40 PM
#24
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There is some good information. Thanks. So I figure with 1.5 lateral and 1.3braking is probably pretty close to actual values for mine for 1:48ish times
Are you guys at Thunderhill this next weekend?
sorry to hear about turn 10! That is a nasty off there! I guess the good news is that you are lucky you were able to fix it.
One of the GT1 guys went off there at the end of last season. there was not much left. One of our ITE mustangs hit it too, and had to replace the entire front clip.
Such a fun turn though!!!
mk
Are you guys at Thunderhill this next weekend?
sorry to hear about turn 10! That is a nasty off there! I guess the good news is that you are lucky you were able to fix it.
One of the GT1 guys went off there at the end of last season. there was not much left. One of our ITE mustangs hit it too, and had to replace the entire front clip.
Such a fun turn though!!!mk
04-18-2009, 12:43 PM
#25
When measuring G-forces, also take note in slopes and banking.
That's a good book to start with and easy to understand. Mainly examples from MoTeC but quite usable for other systems too.
That's a good book to start with and easy to understand. Mainly examples from MoTeC but quite usable for other systems too.
04-18-2009, 12:49 PM
#26
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Thread Starter
Thanks Tom!
I might be in that range now with the bigger tires and bigger (better brakes)
Times now are in the 1:58-9 range at T-hill and 1:47s at Sears. Ill see if the little Ipod can confirm this. Im going to try the other G-TAC program that maps the track too as well as picks up some data points.
Mk
I might be in that range now with the bigger tires and bigger (better brakes)
Times now are in the 1:58-9 range at T-hill and 1:47s at Sears. Ill see if the little Ipod can confirm this. Im going to try the other G-TAC program that maps the track too as well as picks up some data points.
Mk
Ok, so I checked the MoTeC data instead of going from memory.
At Sears Point/Infineon, I get 1.6 - 1.7 max (1.5 without a problem) with up to 1.2 on deceleration. I took this from the 4 hour enduro last October (about 100 laps). Lap times ranged from 1:46 to 1:50's without the caution laps.
At Thunderhill, 1.6 - 1.8 max with 1.2 on deceleration with 1.6ish more typical. Lap times of 1:58 - 2:00 for the event examined.
At Sears Point/Infineon, I get 1.6 - 1.7 max (1.5 without a problem) with up to 1.2 on deceleration. I took this from the 4 hour enduro last October (about 100 laps). Lap times ranged from 1:46 to 1:50's without the caution laps.
At Thunderhill, 1.6 - 1.8 max with 1.2 on deceleration with 1.6ish more typical. Lap times of 1:58 - 2:00 for the event examined.
04-18-2009, 02:28 PM
#28
Here's a graph showing lat Gs vs. accell/decel Gs at Willow Springs.
For those who know Willow, the beginning is the brake point before Turn #1.
The green line is accel/decel.
If you look closely, the green line at the 1st brake point goes down close to 1.5 Gs. That's the max decel Gs.
The red line below "0" is left hand turns; above the line is right-handers.
Turn #1 (left hander) shows a pretty steady 2.0 Gs. In the middle of the graph, the line dips to 2.4 Gs (that's Turn #5 --another left hander). Later in turn #9, a right hander it also goes over 2Gs.
This data comes from a Racepak G2X (we also use an AIM MXL Pista). Not sure how accurate this is. Some of the extremes could be from bumps.
In case this embedded pic doesn't work, here's a link to it.
http://picasaweb.google.com/Johninrs...75067681908066
For those who know Willow, the beginning is the brake point before Turn #1.
The green line is accel/decel.
If you look closely, the green line at the 1st brake point goes down close to 1.5 Gs. That's the max decel Gs.
The red line below "0" is left hand turns; above the line is right-handers.
Turn #1 (left hander) shows a pretty steady 2.0 Gs. In the middle of the graph, the line dips to 2.4 Gs (that's Turn #5 --another left hander). Later in turn #9, a right hander it also goes over 2Gs.
This data comes from a Racepak G2X (we also use an AIM MXL Pista). Not sure how accurate this is. Some of the extremes could be from bumps.
In case this embedded pic doesn't work, here's a link to it.
http://picasaweb.google.com/Johninrs...75067681908066
04-18-2009, 02:30 PM
#29
Probably not a relevant data point for you sedan racers, but in my pro mazda I see higher braking G's than cornering G's. Best I've seen is 2.3 lateral G's in a 100mph turn. Best braking G's 3.5 in a 120 mph threshold brake