Tuesday, June 28, 2011

[6/26/2011] SRTA #2 (DDT)

Event: Sigma Racing Time Attack #2
Track: Mosport DDT (CCW w/ 2 kinks), Bowmanville
Weather Conditions: 21°C, mix of sun and clouds

I can't believe that it's only been 1 month since SRTA #1... it feels like so much longer because of my insanely busy schedule both on and off the track. Two track days at TMP, Cayuga and a week in California with no time to rest! But it's back to business. SRTA is the reason I'm posting so let's get to it :cool:

Test & Tune

The only difference in my setup between SRTA #1 and SRTA #2 was tire size. I went from 235/40/17 RA-1's to 235/45/17 RA-1's because that's the only size I could find (used take-offs). The tires I had this time round also had a bit more tread. Since I didn't know how much the tire size would affect my handling I decided to start off with the same damper settings I had success with at SRTA #1. +20/+20 and tire pressures of 32 psi front, 33 psi rear. This translated to 37-39 hot front and 35-37.5 hot rear after cool-down in the pits.

Balance through corners (no passengers) was perfectly neutral with a bit of trail braking to aid the initial turn-in. If that wasn't enough then I was able to get the car turning with throttle modulation (mainly on the uphill through T7). This is exactly how I wanted it to feel. What I could use more of was higher maximum grip, less compression, and more rebound. Grip could come from newer and/or wider rubber. But with the BC Racing coilovers I can't increase rebound without also increasing compression. Overall I could probably use some more spring rate/wheel rate too as I notice some body roll on transitions. I'm just a bit worried about losing suspension independence (aka tripoding) if I install bigger swaybars, though arguably my coilovers are already bad for that...

Despite these flaws, I managed to set a personal best of the day at 1:11.13 (best T&T time at SRTA #1 was 1:11.37). This run was with a 250 lb passenger on-board and there was a noticeable difference on left turns (understeer) and stopping distance.

I also made some significant changes to my driving:
Taking the kink through T1 and T2 flat out
Braking later for T2
Taking T8 flat out while exiting on the LH curb (thanks PH)
More confidence through T9 and keeping tighter to the RH on exit
Braking earlier for T1, T5 and T10

I didn't play with tire pressure settings as I found the 32/33 psi setting to work well, but I did try different damper settings once. I bumped it to +25/+25 but my best was only 1:11.26 with a lighter passenger. I noticed the car pushed a bit more with this setting, likely because of too much compression. Since I was slower with a lighter passenger, I went back to +20/+20.

Interesting to note is that my Litespeed X-Brace was quite loose on inspection last week. I tightened it significantly the night before SRTA and during my runs I could tell that the brace was doing something in the rear because of the popping sounds the cables made on loading/unloading through hard turns. How much of an effect did this have on my lap times? No idea.

Also, the brake fade issues I've been having were back, although not as pronounced as TMP since DDT is a smaller track. Still, I had to take a cool down lap every 4-5 hot laps to get confidence back into the brakes. I measured surface brake temps out of curiosity in the pits right after a run and the front calipers were 250°C and pads 450°C. Rotors were easily > 450°C (pyrometer couldn't read that high). And this is after cool down ... must be significantly hotter on the track. I have wobbletop's old brake ducts waiting to be installed, and a few more goodies from Chris @ Touge Tuning. I should definitely have those on the car by SRTA #3.

Lastly, I had rubbing issues in the rear due to the 5% sidewall increase. I tore those rubber protection thingies off and that got rid of some of the rubbing, though not all...

Official Time Attack

My goal for OTA was to break into the 1:10's since I had no passenger as ballast. I knew from the last event that I had to make sure the tires were warm for my timed runs. I had a strategy this time. It involved booking it HARD on the warm-up run to get as much heat into the tires as possible, then doing 3 hot laps (flying cooldown) and then cool down outside the DDT park after OTA was over.

My plan nearly backfired through T3 on the warm-up since the tires didn't have full grip yet LOL .. but I willed through the DNF and pushed hard for the rest of the OTA!

For the OTA I was behind Pat B. and I recall a thick cloud of dust at T8 on my first hot lap. I almost expected to see a spun out civic on the other side of it but Pat is too good for that ;) I flew through the dust cloud WRC style and the rest of the OTA was literally just a blur. I actually lost track of how many laps I did and someone told me I exited the track after Lap 3 ... must have been because I was too excited about the 2 laps I had just put down: 1:09.85 and 1:10.38 respectively. I was totally floored by the times and at he same time ridiculously happy about it LOL!! Final standing was 4th place in Group B, 6th place Overall.

I definitely exceeded my goal of breaking into the 1:10's :D The theme of "becoming a better driver" is really starting to take shape...

Other Stuff

danwizzle it was nice to meet you dude. Sorry I didn't see your PM to cruise up but maybe next time since we live pretty close! Hope you had a good time. At least your ball joints didn't explode this time right? :P

Lord_Sid hope your trip from Windsor was worth it! You're welcome to crash at my place for SRTA #3 ;)

MIBAgentQ funny how we never really saw each other during the day despite cruising up together lol. Your "strategy" for the OTA definitely backfired way worse than mine LOL. PS. thanks for remembering the gas!

For Next Time:
Fix the hot brakes, seriously
Roll the rear fenders
Figure out how the hell I pulled those times in OTA and be more consistent with them
Other small improvements to the car as necessary