alwan16

Me driving Reza's Car



Reza Driving my car




Me and Reza decided to do some technical analysis at the Sacramento Autocross practice in his car this weekend. We logged all the parameters possible on the default PowerFC and then overlayed the results to see how our driving differed. The results are pretty much as we expected but helps put the driving characteristics into visual technical terms.

The course was a short ~35s that was tight and a small loop at the beginning. The first spike in speed was accelerating toward the little loop and braking hard. Coming out of the loop we went into a 3 or 4 cone slalom with slow speed 90 degree turn at the end. The rest of the course was a whole bunch of slow and medium speed turns.

All in all the PowerFC + datalogit is a neat little toy. Now we just need to tune it


Somebody need to brake harder and stop enjoying those high slip angle through the curves




feathering the throttle through much of the curves can help build boost for later [boost and vaccum were normalized!]


not sure why my line goes so much farther up so disregard data past 2.5V

reza

Don't disregard the data past 2.5V, that is correct. You are feathering the throtle fully!!! on/off quickly, that is why the graph shows that.
I did not go full throtle for most part.
My graph from Sunday would be different though

DamonB

I'm assuming reza was the slower of the two? reza's throttle inputs closely match alwan16's with the exception that they are later and not as aggressive. Common mistakes that can be cured with some practice once you know you're making them.

My gf has the same problem. She drives the car through the course very well IMO but is not agressive enough with the throttle or the brake. She's trying to be smooth but when you begin to see daylight get the throttle to the floor right away! I've just been drilling her to "Punch it! Punch it! Punch It!" as I honestly feel she's pretty good everywhere else. She's improved a lot over the last few weeks.

Here's some of our Geez! data from the same day. I have the maps drawn on a usage scale. Anything light blue is 90% or better usage of the tire, dark blue 80%-89%, pink 70%-79% and anything under 70% is red. All the spots that are not light blue are spots where the car is being driven too slowly. Keep in mind the colors have nothing to do with speed, they are showing how much of the available grip was being used at every given time. Sample rate was 10hz.

Here's one of my runs:


You can see that by far my worst part is after the first big left (start is lower right corner). This area is downhill out of the left, through a valley, and then uphill while turning the car hard into a fast slalom. I wasn't turning the car in hard enough and therefore was slow all the way through.

DamonB

One of my gf's runs from the same course:


She lost the most time on the final turn heading to the finish, after that is was the 3 real fast transition areas. She's still learning how hard you can yank the car through there (these sections were my worst as well). The big sweeper was uphill and then crested right at the tightest portion. You had to accelerate hard until braking hard just before the top and then turning and accelerating through the finish; fun turn.

Comparing our data overall she is not that far off, but becaause she is not as aggressive with the throttle I leave her a little behind everytime I hit the gas and through all long corners; all those add up as my time that day was over 3 seconds faster on roughly a 55 second course.

DamonB

Can the datalogit chart every parameter the PFC measures, or only some of them? If only some, which?

Wargasm

The Datalogit will store delimited text files of tons of parameters and then you pull them into Excel and graph away...

A few things I can remember:

time
rpm
speed
throttle position (via the TPS)
boost
air temp
water temp
leading and trailing ignition timing
primary and secondary fuel injector on-time
duty % on injectors
condition of numerous switches like clutch, a/c, p/s, etc
fuel temp
what "P" and "N" rows the map is using right now
o2 sensor voltage
stuff related to twin turbo operations like wastegate vent% and precontrol vent %

it's ridiculous....

DamonB

That sounds like about all of them

reza

Yeap...I am the slower one. about 2 second on a minute course, or 1 sec on a 30 sec course.
What bothers me is that I am about 4-6 sec + cones behind Gary Thomason at the San Diego National.
How to beat that guy with over 20 years experiece/seat time, and daily job of working for Kumho and Road and Track?

alwan16

if you read the latest issue of grassroots motorsports about how to go fast in solo 2 he is quoted as being one of the experts. he says "go out and drive like crazy"...so basically seat time, seat time, seat time....and ask the fast people how they go faster...pick their brains about it. it's all about experience. your 2 years of experience is nothing compared to his 20+ or whatever. 10x more than you!

DamonB

I like to think I am capable of learning new skills but some people will always be more talented than I am. I absolutely love to see really gifted drivers and that's why I go to the large events when I can.

I'm lucky that even locally I run with lots of national champs and trophy winners every other weekend; Texas Region is a very competitive one.

You don't realize how far you can go until you see it done. Brian Matteucci was incredible in Houston. His DSP 325is ran times that would have placed him fourth in SS, and SS was already thick with 3 SS trophy winners from last year's nationals! His raw times beat every stock or street prepared class except SS and ESP!