Cracquisition

[Steve Ekstrand]

Spent lunch with Will Kalman today reviewing our DL1 laps in fun runs in the SameSexMarriageBleuCivie.

I'm fully a Data Cracquisition addict now.

[Marshall Grice]

welcome to the club

[Jason Flores]

lets see some screen shots of the data output....ive never seen the data from a DL1 is it anything like the MAXQ?

[Aaron Goldsmith]

lets see some screen shots of the data output....ive never seen the data from a DL1 is it anything like the MAXQ?

Look in the Casoc Event thread, marshall has a touch of thier data. DL1 data is MaxQ data on steroids, you get hotness like, individual wheelspeeds, throttle and steering possition, etc.

[Steve Ekstrand]

Some of the modern cars like the Evo have a lot of factory sensors you can monitor.

But even on the old cars, aftermarket wheel sensors and such are pretty cheap.

I'd like to figure out my brake applications. I know you can monitor the brake lights like Stephen and Jason do, but since I rest on the brake pedal, I often trigger the light without really applying any brake pressure. On the drag cars we have actually logged brake pressures for our start procedures. If pressure is too difficult, I might just work on a switch just like a brake light trigger, but mounted so the pedal has to be depressed more to reach it. And steering input might be interesting. Again I think the aftermarket sensor is pretty straight forward. And of course throttle position.

Then I wonder if I can also record engine functions like a wideband monitor probably as a custom defined variable. Then I wouldn't need the Auxbox. I know it can do RPM.

How about heartrate displayed on the virtual dashboard?

[Jason Flores]

I'm actually working on a light that works on a pressure system that will get brighter as u apply more pressure...but it is going to have to be specifically built for our pedal system since the current sensor is on/off the new sensor would have to be stepped so that maybe you could measure 4 levels of braking...I have some for RPM now so the lights get brighter and brighter till its time to shift but that just for fun...

Sad thing is data no fun unless you have someone to compare to...i.e when i go to SD i have no one else driving the civic so data analysis is hum drum but with both of us in the car we can find places that there are difference so that we can go faster just like you did in X runs...

Now if we could only make sure we all got out 5 minutes between runs so we can go over data it could actually help in between runs....

[Aaron Goldsmith]

I'm actually working on a light that works on a pressure system that will get brighter as u apply more pressure...but it is going to have to be specifically built for our pedal system since the current sensor is on/off the new sensor would have to be stepped so that maybe you could measure 4 levels of braking...I have some for RPM now so the lights get brighter and brighter till its time to shift but that just for fun...

You might want to talk to marshall about brake pressure sensors before you spend a lot of time working on one...

end result, turns out.. not worth the time

[Marshall Grice]

I'm actually working on a light that works on a pressure system that will get brighter as u apply more pressure...but it is going to have to be specifically built for our pedal system since the current sensor is on/off the new sensor would have to be stepped so that maybe you could measure 4 levels of braking...I have some for RPM now so the lights get brighter and brighter till its time to shift but that just for fun...

You might want to talk to marshall about brake pressure sensors before you spend a lot of time working on one...

end result, turns out.. not worth the time

yeah we had brake pressure sensors on the formula car. by and by it was pretty boring data. you could write a math function to calculate brake pressure based on longitudinal accel. in general you don't really care about how much psi you're generating so much as how fast you're slowing down. infact a speed plot is much more valuable for analysing braking performance.

now if you had front and rear brake pressure sensors and you were adjusting brake bias and comparing to wheelspeed data on a non abs car...that's a different story.

[Will Kalman]

yeah we had brake pressure sensors on the formula car. by and by it was pretty boring data. you could write a math function to calculate brake pressure based on longitudinal accel. in general you don't really care about how much psi you're generating so much as how fast you're slowing down. infact a speed plot is much more valuable for analysing braking performance.

Steve's looking to see if he's inadvertantly left-foot braking. Maybe he could determine it if he had TPS wired in and looked at the long accel data but it will be difficult to determine if he's taking 5 or 10 hp out by dragging the brakes. If not brake pressure, a brake flag that tripped further down the pedal stroke would be helpful, as he stated.

Or a strain gauge on the pedal stalk ;)

[Steve Ekstrand]

The reason for brake pressure on me is mainly because of me....
The brake goes on a lot when I'm driving. Often with the throttle position is 100%.

I've always done it. You do it in drag racing, you do it in stunt driving. You do it when you're scaring yourself on an autocross course. So, people chicken lift. I ride the brake.

If you drove properly I don't think it would matter much. But I'm addicted to the brake pedal. So, I'm wondering if watching a few laps of data acq with the brake on all the time will shame my subconscious enough to help break me of this bad habit.

[Steve Ekstrand]

Or like Will said.... ;)

[Marshall Grice]

The reason for brake pressure on me is mainly because of me....
The brake goes on a lot when I'm driving. Often with the throttle position is 100%.

I've always done it. You do it in drag racing, you do it in stunt driving. You do it when you're scaring yourself on an autocross course. So, people chicken lift. I ride the brake.

If you drove properly I don't think it would matter much. But I'm addicted to the brake pedal. So, I'm wondering if watching a few laps of data acq with the brake on all the time will shame my subconscious enough to help break me of this bad habit.

well take your foot off the brake

but seriously that exact sort of analysis is very easy to see in a speed plot...if you have someone to compare to. my personal biggest problem currently is chicken braking. turns out that instinct is damn near impossible to overcome. I used to think i was ballzy...turns out i was just hanging out with the wrong people.

[Marshall Grice]

btw, I still have the brake pressure sensor. it reads up to like 100bar or something stupid like that. i might be interested in selling it.

[Max Hayter]

I find Data Acq. to be much more useful now that I have Aaron to interpret the data!

One of the main things we use it for during an event is to determine whether to use 3rd gear. For instance, on my first run on Sunday, I went to 3rd twice and we then looked at the data to see the terminal speed I reached when i did that. It showed that by the time I shifted, I got no faster than just banging away on the limiter in 2nd!

Conversely, at the San Fran Divisional, it shows that going to 3rd was totally worth it.

[Marshall Grice]

I find Data Acq. to be much more useful now that I have Aaron to interpret the data!

One of the main things we use it for during an event is to determine whether to use 3rd gear. For instance, on my first run on Sunday, I went to 3rd twice and we then looked at the data to see the terminal speed I reached when i did that. It showed that by the time I shifted, I got no faster than just banging away on the limiter in 2nd!

Conversely, at the San Fran Divisional, it shows that going to 3rd was totally worth it.

yeah but you also need to figure out where to shift. i find it hard to believe that 2nd gear was faster for you guys on this last course.

i'd guess that going up hill, rev limiter in 2nd is faster but doing down hill 3rd would be faster then 2nd. what's your topspeed in 3rd?

[Jason Flores]

what was everyones top speed on the downhills and the uphills on sunday....ill post mine in a few hours when i get home...but it would be interesting to know

[Sebastian Rios]

I find Data Acq. to be much more useful now that I have Aaron to interpret the data!

That's what is really holding me back, I've used the max Q software before, but I couldn't really figure it out. So I just ended up watching the lines chase each other around the course.

[Aaron Goldsmith]

i'd guess that going up hill, rev limiter in 2nd is faster but doing down hill 3rd would be faster then 2nd. what's your topspeed in 3rd?

The 2 downhill sections were the parts where he shifted to 3rd.. first downhill was boarderline worth it.. second one he went 2 miles per hour slower.

[Greg Peng]

Does your data show how long it took him to shift? Is he a granny shifter?

[Marshall Grice]

i'd guess that going up hill, rev limiter in 2nd is faster but doing down hill 3rd would be faster then 2nd. what's your topspeed in 3rd?

The 2 downhill sections were the parts where he shifted to 3rd.. first downhill was boarderline worth it.. second one he went 2 miles per hour slower.

2mph slower where? the video show him on the revlimiter for like 30seconds of a 60sec course. i gotta imagine 3rd is faster somewhere. what's the topspeed of 3rd?

[Jason Uyeda]

btw, I still have the brake pressure sensor. it reads up to like 100bar or something stupid like that. i might be interested in selling it.

Is 100bar enough? I'd think you'd want closer to 250 (depending on where you mount the sensors).

Marshall, you have something like this:
http://cgi.ebay.co.uk/Pressure-Transduc ... m153.l1262

Or something nicer?

[Will Kalman]

what was everyones top speed on the downhills and the uphills on sunday....ill post mine in a few hours when i get home...but it would be interesting to know

55.07mph top speed coming downhill toward the finish in the SK2/HS Civic. The chart shows the rest...

[Marshall Grice]

btw, I still have the brake pressure sensor. it reads up to like 100bar or something stupid like that. i might be interested in selling it.

Is 100bar enough? I'd think you'd want closer to 250 (depending on where you mount the sensors).

Marshall, you have something like this:
http://cgi.ebay.co.uk/Pressure-Transduc ... m153.l1262

Or something nicer?

exactly like this http://www.aim-sportline.com./download/ ... 00_eng.pdf

the 2000psi version.

[Jason Uyeda]

i'd guess that going up hill, rev limiter in 2nd is faster but doing down hill 3rd would be faster then 2nd. what's your topspeed in 3rd?

The 2 downhill sections were the parts where he shifted to 3rd.. first downhill was boarderline worth it.. second one he went 2 miles per hour slower.

2mph slower where? the video show him on the revlimiter for like 30seconds of a 60sec course. i gotta imagine 3rd is faster somewhere. what's the topspeed of 3rd?

2 second rule - If you're on the limiter for 2 seconds, and can go to third and straight back to WOT (and maintain WOT for the rest of the 2 sec sector), 3rd will be faster by at least a tenth if not a couple tenths (for a reasonably powerful car like an STU STi). Assuming you can shift reasonably well.

If you're on the limiter, you're not accelerating (unless maybe, you're going downhill ). Obviously there are some exceptions, like transitional elements where peak is only a few MPH over the limiter and you're better off with the extra engine braking in 2nd.

[Max Hayter]

Top in 3rd is 72mph.

The trouble with that course was that we were shifting just entering a slalom. That threw the car offline. Both sections were followed by very tricky corners which would only be further complicated by shifting back to 2nd. If done right, I'm sure it might have been quicker, but it didn't work very well when I tried it!