gkmccready

Yesterday I ran Thunderhill in Willows, CA for the first time in over a year. I had just put an MXL Pista dash/data acquisition unit in the '06 C6 and hooked it up to the OBDII/CAN port along with their GPS module.

Loaded up the data, generated a track map, and these are a few of the views I find interesting... I'm still learning what this software can do (read that: I have no idea what I'm actually doing!)...

Minimum and maximum speeds in the various segments:


Lateral acceleration:


Oil pressure: (!!)


This one shows how late I am getting back to the gas sometimes:

[Throttle] Pedal Position:


This is the builtin yaw sensor, but the GPS unit also offers a "gyro" that has the same functionality. If I'm reading it correctly, the blue would be understeer, and the red oversteer.

Yaw sensor:


And, finally, a plot of Pedal Position versus Throttle Position ... throttle-by-wire, remember? This one is kind of neat. When PPS reads 0 the TPS can read between 10-15% but the interesting thing here is actually that the curves *do not* match perfectly. I run with everything off, so this is not AH/TC getting involved...

C5 Hardtop

Thats very cool , thanks for sharing!

What is your ballpark lap time for that track and what tires did you run while logging that data?

gkmccready

That lap was a 2:07, I was on Toyo R888 275/35r18+305/35r18 on CCW C140 18x10+18x11. DRM coilovers, Wilwood SL6R front calipers, Pfadt poly bushings, HardbarUSA harness bar & belt mounts.

It was my first event on the DRM coilovers and I was very very happy with them. I didn't ever feel the need to go looking for an adjuster. I saw trackboss posted a while back about turning a 2:00 lap over the Cyclone -- so my car should be able to come close to that. There was a Turbo NSX with aero and a good driver out there on Hoosier R6s turning 2:03s... he was complaining about lack of grip. It was 100F ambient.

So, yeah, I'm way off what the car can do. But my excuse list is long... :-) It starts with not having been on track since Spring Mountain the spring of '08. :-(

NemesisC5

Quite a lot of data from a single connection point, how much does a unit like this cost?

gkmccready

You really don't want to know. :-)

$1999 AIM MXL Pista Dash with integrated data acquisition
$379 AIM MXL GPS Module



I actually bought it to replace all of the traditional gauges and to add data acquisition to my RX7 racecar that's getting rebuilt right now. It was about 5 hours in labor to get it all mounted and wired. It's built such that I can move it between the C6 and the RX7.

I'm sure there are lower cost options (TraqMate?) that can generate similar data...

C5 Hardtop

Thats moving along pretty good. I wish I had your problems

longdaddy

this is not a Z06 is it? you're moving pretty good!

gkmccready

2006 Z51. No motor, not even an air filter change. I *will* be faster without warped front rotors! :-)

BTW, the speeds on my HUD and on the GMX_SPEED channel are substantially higher than the GPS_SPEED channel. On this lap, the max speed reported by the GPS is 124.7mph and the ECU said 128.1mph, in some segments there's a difference of 5mph or more between the two values. My rear tires are 305/35r18 vs 285/35r19 which is 26.4 vs 26.9 but even then the ECU speed is a bit optimistic when you correct for OD.

0Randy@DRM

Wow, That is a crazy amount of data. Why the over steer on all the left handers? Was that you or the car?

good stuff just don't go looking at all the cool stuff.


Randy

gkmccready

I think the blue on the yaw sensor is understeer, and red is oversteer... why the rights are oversteer and the lefts under is an interesting question. T3 is an off-camber right after braking. T5a is also off-camber and starts downhill after cresting the Cyclone. And T14 is just T14... I tend to trail brake in to it... one day I'll get it right...

BEZ06

WooHoo!!! That really is a great bunch of data to analyze your track sessions!!!

What direction are you running on that track??? It looks like you're running the NASCAR way, i.e. counterclockwise, is that right???

Best I can tell, you're going down that long straight in the center of the track and accelerating from left to right on the track map (about 85 on the left to 124.7 at the point where that arrow points to the right). Is that arrow the start/finish line or something?

I don't think the red/blue is oversteer/understeer at all.

I think all the blue and red is indicating is the yaw rate (the rate of turn). It looks like green is straight ahead, and the blue indicates a turn in one direction and the red a turn in the other direction.

I think the colors just simply show the turn rate. It looks to me like the dark blue and red are the greatest rates of turn in the tightest turns on the track - blue in one direction and red in the other.

Bob

gkmccready

Yup, the arrow is S/F and shows the direction being run.

Ah! That makes sense. Like I said, still trying to figure out the software and what exactly it's got to say. :-)

gkmccready

Just got an email from the AiM guys and they're going to be able to pull oil temperature from the CAN bus, too. Still haven't had to add a single sensor other than the GPS...

ghoffman

Nice! I will see them at PRI next week.

BrianCunningham

MySR71

On my C5Z06, there is a wire leading to dash which has the oil temp. It is in the same bundle that has been discussed before that has RPM (one of 3 or 4 white wires). I tapped into this oil temp wire with my G2X and USM (breakout box). To calibrate the oil temp signal (volts vs. degF), I started the car and wrote down voltage vs. oil temp (as read from the DIC) at a number of different temperatures. I didn't let the oil temp get over 205 or so though so my calibration is a little incomplete.

A downside to doing the above is that based on the way the USM works, the oil temp on the DIC doesn't read correctly if the G2X is turned off. Something about a pullup resistor or something. Anyways, this isn't a big deal to me as I can drive with the G2X on all the time.

Other stock sensors that I have tapped into are:

Throttle pedal position
Steering wheel angle sensor (still working on this one a bit)
Brakes on/off
Brake fluid pressure (taken off the sensor on the ABS controller, no way of calibrating so just read volts)
Tach

I'm hoping to tap into the stock oil pressure sensor too. I'm envious of your guys with C6's that can do all this through the OBDII/CAN bus port.

AtomicZ

I like that you can get oil pressure and oil temp. Can you get tranny temp ?

gkmccready

I can ask them. I was mostly interested in items that I can easily see on the DIC since I assume most of its data is coming across the CAN bus protocols.

AtomicZ

Thanks. I am adding a data aq to the car this winter and the aim is high on the list.

StArrow68

That was fun, wish that was available 7 years ago when I got started.
After 5 years on TH I finally got my C5 coupe on street tires down to
2:09. FWIW you can probably just lift a little going into 8 as I got to
where I could carry just at 100mph through that turn after they
added the extra run off. It took a lot of laps to get there. Also your
estimate of getting close to 2:00 looks good if you enter 15 with just
a bit less throttle and keep from having to lift on the exit of 15. Wow!

Please let us see what you get at LS and Sears Point if you get the
chance.
Randy