John's CS BRZ progression

[AustinTX]

This is not a test of ultimate track time - that would be best done with all 4 tires swapped and take several runs back to back. I'm just looking to see how the balance is affected. If the car gets more pushy with 225's out back, they win. If the car gets loose, they lose. Hopefully this works out. I don't expect any revelations.

[bimmer635csi]

Originally Posted by AustinTX

If the car gets loose, they lose. Hopefully this works out. I don't expect any revelations.

Tire pressures will be critical here then. I've seen cars go from loose to tight with less than 4 psi change in tire pressure. It is your test, but it seems like it could be misleading performing it this way.

Originally Posted by chkltcow

Run the 245s first to get rid of the "confirmation bias" of going faster as you learn the course. And run data so you can actually see the lateral Gs and compare segments between 225 and 245 runs.

I agree with that thought process. But because this is an unscientific test, it is would have been easier to have run the 225s first, then swap to the 245s and finish out the remaining runs. To do it your way would require 2 tire changes in limited time, which often leads to errors.

[AustinTX]

Serious people are serious

To quote Kimi, Iknowwhatiamdoing

[Kido1986]

Everyone here's a crew chief :P

[AustinTX]

We ran at Circuit of the Americas yesterday. Beautiful site, nice smooth asphalt, a bit small, but we'll take it. The course was good, but had a drag start and a tight sweeper with an uphill exit right at the beginning. Overall, pretty low average speed and long, slow sweepers. Yesterday's event confirms that my car still understeers on low speed sweepers. Perhaps the FR-S spring rate balance has some advantages in conditions such as these. Poor little car had a hard time climbing/pushing through this course. I ended up 12th in X class and 15th in PAX out of 158, 1.1 PAX seconds off. Not a great day, but I understand the reasons. I tried lowering the front pressure from 38 to 35 to 32 to combat the understeer, but it did not help. I probably should have tried upping the rear pressure. It stayed at 32 all day. It's good to see that the car generating a balanced 1.2G in both directions, though. It was in the 1 to 1.1 range for the Z2's with the Strano bar.

I did not try the tire change, as we just didn't have the time or energy to deal with it in the 105 degree heat index and sub 5 minute turnarounds in grid.

PAX results:
https://axwaresystems.com/axorm/file...event7_pax.htm

Video of one of my runs, not by best. I definitely overcooked the entry to the first slalom on the downhill run:
[ame="https://www.youtube.com/watch?v=ocyXx1MzdVA&list=UUDpcx_HInFvumt9VwUW59ig"]CS BRZ at Spokes 07/20/14 - YouTube[/ame]

[7thgear]

so this FRS also had the strano?


seems like it might just a tad too stiff for the otherwise OEM setup

[AustinTX]

Just stating that the FR-S may have a better static balance for sweeper elements. I was still the fastest twin at our event, but not by much. Eric Jones was within .3 seconds in his FR-S with new MCS shocks.

I do still have the 25% setting to try on the Perrin bar. I just worry that it will cause too much shoulder wear. I may give it a try at a practice event this weekend.

[SubiePig]

Originally Posted by AustinTX

Just stating that the FR-S may have a better static balance for sweeper elements. I was still the fastest twin at our event, but not by much. Eric Jones was within .3 seconds in his FR-S with new MCS shocks.

I do still have the 25% setting to try on the Perrin bar. I just worry that it will cause too much shoulder wear. I may give it a try at a practice event this weekend.

Going to College Station this weekend too?

[AustinTX]

Considering it. Still plenty of time til nats, so maybe not.

[edj]

Originally Posted by AustinTX

edj was within .3 seconds in his FR-S with new MCS shocks.

I may give it a try at a practice event this weekend.

please, those are "Monro-Matic Car Shocks".
and if you don't count those pesky cones i was only 0.01 behind you.

so, Sat or Sun for A&M practice this weekend?

[AustinTX]

Originally Posted by edj

please, those are "Monro-Matic Car Shocks".
and if you don't count those pesky cones i was only 0.01 behind you.

so, Sat or Sun for A&M practice this weekend?

I dunno. Possibly Saturday. Most likely won't go, though. There's one more practice before nats, and I'll definitely make that one.

[SubiePig]

Originally Posted by edj

so, Sat or Sun for A&M practice this weekend?

Its a two day event.
https://www.facebook.com/events/795767797123270/?ref=4

I am going if the weather is looking good, scrub in tires for Nationals and play with a few things since we don't have a good concrete lot here to run on. 2 days of running there will be a big help for me.

[AustinTX]

Busy pre-nationals weekend for me. I ran a practice at the famed A&M site on Saturday to test air pressures and tire heat behavior. I also ran a shootout between my car and the 370Z on fresh RS3V2's.
Pressure: 38F/36-38R pressures were working the best. Considerably higher in the rear than most have been running, but it gave the car the best balance to me.
Tire heat behavior: I ran 4 runs back to back to back to test heat dependency, and the tires really didn't fall off much to me. Maybe a bit greasy by the end, but within a tenth from first run to last.
370Z vs. BRZ: Another surprising result - I'm taking the BRZ to nationals. I ran 12 runs in my car, 3 runs in the 370, and I just couldn't match my BRZ times. The 370's ABS was freaking out, the car was overloading the front tires too easily and going into massive understeer, and it didn't feel as sure-footed as the BRZ on high speed sections.

On Sunday, I ran with the local club. I had a consistent understeer at the practice, so I decided to try setting some rear toe out Saturday night. I changed it from 1/8" in per side to 1/8" out per side. The car still drove straight and had no odd behavior in a test drive, so I drove it to the event and ran it that way. Result: pretty dang good. The car had just a bit of extra turn in before stabilizing into normal understeer. The car was fast all day, and I ended up 2nd in X class, 3rd in PAX. Looks like I've found my setup for nationals, and just in time

Results: (Pinto's run is a timing error, and Jerry was running double entry)
https://axwaresystems.com/axorm/file...ug2014_pax.htm

Video:
[ame="https://www.youtube.com/watch?v=f3V6EWWfPnA&list=UUDpcx_HInFvumt9VwUW59ig"]CS BRZ at SASCA 08/10/14 - YouTube[/ame]

[bimmer635csi]

Originally Posted by AustinTX

Pressure: 38F/36-38R pressures were working the best. Considerably higher in the rear than most have been running, but it gave the car the best balance to me.

I had a similar experience on Sunday. Ran almost 5 psi higher than at CotA and the car felt way better.