2012 BRZ/FR-S Stock Class Autocross Discussion

[des]

Originally Posted by feldy

How low on fuel did you run it? I was having other problems as well today. Going from a FWD car in autocross to this. I spun it drove it slow ect. But my co-driver is a quick driver and he was still 4-5 seconds slower then the 350z today on rcomps. I did take the auto thinking it would be nice not to miss shift in turnarounds ect. It was fighting going back into first when we wanted it to. Couldnt launch the car even with the nannies off. Had torque converter stall at 2k rpms. I spun it in the finish on my 2nd run. I had never spun in the finish before so I got a tad discourged. I was 2 seconds behind my co-driver who has a stx prepped RX8. And he was the one 4 seconds behind the z.

Nearly full tank -- I wasn't competing, just shaking down the car.

We're not even trying to go super fast at this point -- it's more about finding what works and adding speed from there.

No one is fast the first time out in a car. You have to know what you're working with before you make decisions -- if you drive FWD even remotely competitively you've been through this process before.

[jdrxb9]

Well, I ran the BRZ both yesterday and today at two different autocrosses. FYI, my previous autocross experience was fairly extensive, but ~10 years ago in a Neon. I ran fairly competitively locally, but just ok nationally. My only RWD experience is just scattered fun runs, so I've got a lot of learning and re-learning to do with the BRZ.

Sat was a very low key local event and I was really just starting to brush the rust off. Car felt good and I was pretty amazed with the grip from the AD08 'street' tires.

Today was a slightly bigger event at Cumberland MD airport. Again, I'm still just learning the car and my times were pretty far from competitive. My best was 50.7XX vs the top SS cars at 45.XXX. If you pax my time on a CS index and allow an additional .98 factor for the 'street' tires, I was ~3 sec. off.

Some random observations:

VSC off is really all the way off, even with the TPMS light on - witness my spin on the last run.

The car transitions really well, but I need to learn how to rotate it a bit more on entry to the longer turns.

As reported elsewhere, the rev limiter is very 'soft' - just kind of backs you off a bit from redline and then stays there - Subaru guy on site said it was pretty typical behavior for them.

My measured tire temps (cheapo non-contact gage) were pretty reasonable with the alignment above - max difference across any tire was about 10 deg F

The AD08's held up really well and actually took about 3 runs to get to what seemed like a normal operating temperature of ~130F

We started at about 1/4 tank and by the time my better half was done running, the low fuel light was on - no issues with fuel starvation under these conditions.

Owning a RWD car you don't have to worry about putting on 2 wheels is fun

Some clickable thumbnails:
quick snap of the car in paddock


my wheel tire combo - Traklites are functionally better, but I just couldn't put flat black wheels on a black car. These are Velox VX6R cast, ET42, claimed at 14.5 lb but weighed 15.4-15.6 on my scale.


the obligatory tire comparo shot - I went with AD08's thinking their reported driving characteristics would best match my driving style/experience. I went with 225's for just a bit more width and to not loose any max 2nd gear speed vs stock


Two videos:
my best run from Sunday


my last run from Sunday - complete with spin

[EMguy]

Originally Posted by jdrxb9

Some random observations:

VSC off is really all the way off, even with the TPMS light on - witness my spin on the last run.

As reported elsewhere, the rev limiter is very 'soft' - just kind of backs you off a bit from redline and then stays there - Subaru guy on site said it was pretty typical behavior for them.

We started at about 1/4 tank and by the time my better half was done running, the low fuel light was on - no issues with fuel starvation under these conditions.

Thanks for posting! The VSC/TPMS, rev limiter, and fuel level info is all reassuring.

[des]

I'll offer what I can, though what RWD experience I have has been in STR rather than stock, and I'm not exactly a tuning expert.

Only change to my FRS so far is the 235/45/17 Direzzas.

The good: the car was fast right out of the box. C-Stock winner in an RX8 on Hoosiers was at 43.2; my fastest run was 44.2. (I was doing fun runs but that would have paxed 40th or so of 170, better if you adjust for street tires).

The car is much less tail happy on the Dunlops than it was stock -- even on the super-slick lot we use here in the Bay Area. I'm going to slap a rear bar on as soon as possible. And I've never driven a stock car that felt better in slaloms. On Hoosiers it would be a revelation.

I'm not sure I chose the right tire size; it's taller, which may help on faster courses but probably hurt here. There were three places I would have shifted to first in an S2000, and I was surprised at how little grunt there actually was in the FRS. A shorter tire would have made a difference.

I don't think the 235 is too wide -- especially given the car's weight. But I will definitely look at a 40 series next set.

I'm not loving the brake feel: there's no bite at all, and they took a lot of pressure to hook up well.

The car takes a beautiful set into sweepers, but just as the car begins to slide the way you'd like it to, the car abruptly changes position, as if the tires were rolling over (they weren't). A buddy who runs a motorsports shop suggested a bump stop issue ...

Next up, then: camber bolts, alignment, a more aggressive rear pad, a 16mm rear bar and bump stop cups.

[Evil86]

Originally Posted by des

I'll offer what I can, though what RWD experience I have has been in STR rather than stock, and I'm not exactly a tuning expert.

Only change to my FRS so far is the 235/45/17 Direzzas.

The good: the car was fast right out of the box. C-Stock winner in an RX8 on Hoosiers was at 43.2; my fastest run was 44.2. (I was doing fun runs but that would have paxed 40th or so of 170, better if you adjust for street tires).

The car is much less tail happy on the Dunlops than it was stock -- even on the super-slick lot we use here in the Bay Area. I'm going to slap a rear bar on as soon as possible. And I've never driven a stock car that felt better in slaloms. On Hoosiers it would be a revelation.

I'm not sure I chose the right tire size; it's taller, which may help on faster courses but probably hurt here. There were three places I would have shifted to first in an S2000, and I was surprised at how little grunt there actually was in the FRS. A shorter tire would have made a difference.

I don't think the 235 is too wide -- especially given the car's weight. But I will definitely look at a 40 series next set.

I'm not loving the brake feel: there's no bite at all, and they took a lot of pressure to hook up well.

The car takes a beautiful set into sweepers, but just as the car begins to slide the way you'd like it to, the car abruptly changes position, as if the tires were rolling over (they weren't). A buddy who runs a motorsports shop suggested a bump stop issue ...

Next up, then: camber bolts, alignment, a more aggressive rear pad, a 16mm rear bar and bump stop cups.

Hey, that looks like my car.

[uspspro]

Oakland...
I almost went last weekend too. were there any other FRS/BRZ there?

[Evil86]

First autox will be this coming weekend at El Toro. I am running RTR, there are 18 entries, and three are FR-S drivers (two cars). I stayed with the stock size tires but went with Hankook RS3s on Kosei rims. I want to try out the production stock size (if I remember the pre-prodction size was 205) to see how the car felt. If I need to go wider, I will.

I installed the camber bolts Saturday, and took it out for a test drive on a twisty mountain road. It was plain fun. I never threw the ass out because on the road I was on, the consequences in most sections are dire if not fatal.

Today PPE Engineering yanked my muffler and fabricated a turn down that is really an exit out. They made a stainless turndown that exits out of the left hole. We all thought the car sounded great sans muffler. It had a deeper throat with a little rasp. They did the turn down for a trade. Next month they want to hoist my car up and explore my exhaust ala Perrin and see what the can develop. How can I say no?

I bought the lightest trim, dropped 27 lbs. of exhaust weight, at least twenty pound in over all rotating weight. By the time El Toro arrives, break-in will be over. Friday is test and tune so a crap load of runs on a 40 sec practice course, and Sat and Sun will be on an out freakin standing course. Hell yeah, I think this is going to be fun.

[Vanguard]

Originally Posted by Evil86

First autox will be this coming weekend at El Toro. I am running RTR, there are 18 entries, and three are FR-S drivers (two cars). I stayed with the stock size tires but went with Hankook RS3s on Kosei rims. I want to try out the production stock size (if I remember the pre-prodction size was 205) to see how the car felt. If I need to go wider, I will.

I installed the camber bolts Saturday, and took it out for a test drive on a twisty mountain road. It was plain fun. I never threw the ass out because on the road I was on, the consequences in most sections are dire if not fatal.

Today PPE Engineering yanked my muffler and fabricated a turn down that is really an exit out. They made a stainless turndown that exits out of the left hole. We all thought the car sounded great sans muffler. It had a deeper throat with a little rasp. They did the turn down for a trade. Next month they want to hoist my car up and explore my exhaust ala Perrin and see what the can develop. How can I say no?

I bought the lightest trim, dropped 27 lbs. of exhaust weight, at least twenty pound in over all rotating weight. By the time El Toro arrives, break-in will be over. Friday is test and tune so a crap load of runs on a 40 sec practice course, and Sat and Sun will be on an out freakin standing course. Hell yeah, I think this is going to be fun.

Go get it, Kev (and Matt)! Any idea who that other FR-S driver may be?

[des]

Originally Posted by Vanguard

Go get it, Kev (and Matt)! Any idea who that other FR-S driver may be?

Me! WIll see you guys this weekend. Looking forward to comparing notes.

[des]

Originally Posted by uspspro

Oakland...
I almost went last weekend too. were there any other FRS/BRZ there?

Nope. Three or four people drove my car, though ...

[Evil86]

Originally Posted by des

Me! WIll see you guys this weekend. Looking forward to comparing notes.

Are you going to there for the Test and
Tune?

[Scooby South]

those wanting to run Stock and want a decent but pricey package...
Subaru Option BBS 17x7 53...mine are running 235/40/17 RE-01r's...

Cstock Tire class

[xwd]

Wish there were a few more wheel options available in 17x7. Right now I'm looking at the Kosei K1-TS, they are <$800 17x7 +50. Don't think the Traklites are available much of anywhere right now.

[Kido1986]

Originally Posted by dwx

Wish there were a few more wheel options available in 17x7. Right now I'm looking at the Kosei K1-TS, they are <$800 17x7 +50. Don't think the Traklites are available much of anywhere right now.

Where have you found them? I can't seem to find those koseis in stock size