***2012 Autocross at Barber Motosports Park**

[Interjon]

What time do things get started tomorrow?

[Jedi1]

930-10ish should be good.

[engled]

Glad you had fun Darryl. The car looked dialed!

The car felt great on the RS-3s, a little pushy but not bad. On the A6s (with 75+ runs and 7-8 heat cycles) it was still a bit pushy and not much (if any) faster. I managed a 28.2 on my last run. There was a high 27 in the car but not with me behind the wheel. Sparky said the car needed less front bar but overall liked it. With fresh A6s on it the push will go away, it always does...

"Tune for wore out tires because that's what we always run on." -- John W8

[Sparky]

The car felt great on the RS-3s, a little pushy but not bad. On the A6s (with 75+ runs and 7-8 heat cycles) it was still a bit pushy and not much (if any) faster. I managed a 28.2 on my last run. There was a high 27 in the car but not with me behind the wheel. Sparky said the car needed less front bar but overall liked it. With fresh A6s on it the push will go away, it always does...

"Tune for wore out tires because that's what we always run on." -- John W8

We talked about the front bar but I actually think you could benefit from a little less rear camber and more front shock to compensate. Yesterday it was a little pushy steady state and loose in transcients. You want the opposite. Thanks for letting me drive it! Had a blast!

[Cholewa]

Just curious, what's the weight of those monster wheels/tires you had on there yesterday?

[engled]

If you were asking me the wheels are pretty heavy, 15 pounds or so. The 275 A6s are listed as 20 pounds.

[Jedi1]

So much fun was had this weekend! Learned so much about the new car. I'm feeling confident enough with the transimission choice to go ahead and commit to the rest of the RTR build with an eye on possibly pushing past that into STX.

HUGE thanks to everyone that ran the event! I know I had a blast and I'm pretty sure everyone else did as well. Sorry to run away when everyone started cleaning up, but I picked up a slot in the last run group and threw the FRS onto the big track for the first time. That had to be done! I did stick around with a few other folks and reset the Porsche School layout, so I didn't completely duck out.

[Cholewa]

If you were asking me the wheels are pretty heavy, 15 pounds or so. The 275 A6s are listed as 20 pounds.

Is the additional grip worth the additional rotating mass? We've been having a heavy discussion on TB about the merits of running smaller tires and weight savings seems like a big part of it, as well as sidewall deflection under load causing a much higher rolling resistance, and the ways to avoid all that junk.

I'd be interested to see a scientific approach to testing where the width of tire difference starts to inhibit performance due to weight. I know there's plenty of tests on wheel size and performance, but I can't recall ever seeing one for tire size.

[CPMaverick]

Had a great time. Thanks to all of you that contributed and/or volunteered for the event.

The little car ran remarkably well and after the tires got clean we were able to tweak the setup a bit. It sure felt good.

[ZX3Focus]

Thanks, workers! This was a blast!

[TouringBubble]

Is the additional grip worth the additional rotating mass? We've been having a heavy discussion on TB about the merits of running smaller tires and weight savings seems like a big part of it, as well as sidewall deflection under load causing a much higher rolling resistance, and the ways to avoid all that junk.

I'd be interested to see a scientific approach to testing where the width of tire difference starts to inhibit performance due to weight. I know there's plenty of tests on wheel size and performance, but I can't recall ever seeing one for tire size.

Tire performance will always be relative to power and weight. With a light car with little power, larger, heavier tires will negate gains much sooner than a 500 hp behemoth.

Basically, the gains on a 2100 lb Miata won't be the same for a turbo Volvo.

[Cholewa]

I understand that, I just wish there was more information on the subject available like how basic tire performance is available. Tire rack could easily do the same tests they do to rate tire performance and instead of changing tire brand, change size.

That would be cool.

[ZX3Focus]

I'd like to see that test, too. If they keep the wheel constant, it could also lay the pinch vs. square vs. stretch argument to rest.

Beware a wider tire that's wider and taller (RX-8 wheels on our 3 for instance). In addition to adding mass, you make your effective gearing several percent taller.

[Sparky]

Grassroots has done some testing:

http://grassrootsmotorsports.com/articles/speed-holes/

[HPEVOX]

Thanks for the ride at the end Dennis! Gotta get me some better braking like that rx-8 lol fun ride. Hopefully i can upgrade my brakes before next year along with the A6's and maybe try improving the driver even... may shoot for some of those FTDs i hear you guys talk about!