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      05-03-2009, 12:34 PM   #1
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Power isn't everything....

So, yesterday I went to an AX practice at Cal Speedway and was putting in some decent times for SST on my worn out PS2's. It was pretty slippery, but I was doing great compared to some other cars similarly modded to mine... THEN IT HAPPENED.

One of the instructors that's cool has a Miata that he runs in a stock class. He has some Dunlop Star Specs and everything else is stock. He asked to drive my car, so I said I wanted to give his a spin for fun as well.

He jumps in my car, spins out twice, and was really all over the place... hahaha He couldn't believe the power. So, I jumped in his car, never have driven it before, and put in a 2 second slower lap than my best lap in my M.

That said, to drive an Z4 M I gotta say, is ALOT tougher to drive than a Miata. I could put the Miata on the exact line I wanted, and rail a lot quicker through the turns because of it's light weight. I'm sure the tires helped as well, but still.

Anyway, now I need to do some more suspension stuff to my car if I'm gonna have a realistic chance at competing against these things in SST. It was a real eye opener for sure... So if any of you are really thinking about doing the track / AX thing, I suggest you forget about all the motor mods, and really invest in making it handle. All the power in the world means nothing if you can't control it....

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      05-04-2009, 01:37 PM   #2
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I'm not sure the suspension is the issue, but that's just my 2 cents. Worn out rubber vs. fresh rubber is probably the biggest equalizer.
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      05-04-2009, 02:14 PM   #3
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Quote:
Originally Posted by Dammmittt View Post
Worn out rubber vs. fresh rubber is probably the biggest equalizer.
Typical street tires, worn out rubber has a lot more grip than fresh rubber. GRM (grassroot motorsport) did an article trying to get to the magical 1G barrier on street tires (on a Subaru Impreza WRX), and they've found that a nearly worn out OEM Bridgestone had more grip (and significantly more grip) than a set of fresh (and wider) Nitto NT05s.

As street tire wear closer and closer to the wear bar, the tread block becomes shorter and wider, therefore providing more grip and consistent traction. Just right before it cords is when a set of street tires are at its best grip. That's why you'll see racers where lap time matters actually SHAVE off most of the treads before they use their tires.
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      05-04-2009, 02:50 PM   #4
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I don't know what Miata he's running or if it's spec'd out, but those things are insanely light. Depending on the year, a stock Miata weighs between 2,100lbs and 2,400lbs. If its been modified then expect it to be even lighter! I'd put money on that being the primary reason why the driving experience was so different between the two. I don't know the AutoX layout but I'm guessing there aren't very many places to really use all of the S54's power to its advantage.

I'm not surprised that the Miata driver was all over the place in your car and that you were quicker in his car.

Miata's are an exercise in momentum and are AMAZING (and common) track cars. If I had expendable cash, I'd totally put together a Spec Miata.
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      05-04-2009, 04:00 PM   #5
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His miata was bone stock except for the Dunlops ( Direnzza Star Specs )... it looked like an '01 or so, no idea if it was a 1.6 or 1.8...

Yeah, I think the weight was really the key factor because I was definitely going faster around the sweepers in his car, but it was SLOOOOW on the straights... hahahaha We were laughing cuz out of the corners I kept going, COME ON .. COME ON !!! Go go go !!! hahahahaha

The course was actually pretty wide open for an AX, but the pavement there is asphalt so it's pretty slick compared to concrete like at El Toro. I was having a hard time not breaking loose accelerating, even being super smooth with the throttle.

I think my 2 main upgrades asap are gonna be Vorshlag Camber / Caster plates and some new Re11's or Advans. I only have about a degree 1 1/2 of neg camber up front and I bet with the plates and another -1 degree ( so 2 1/2 total ) or so it'll really help up the cornering speed and give me more tire on the ground.

Oh and trust me, I spent all morning looking at how much miata's cost... hahahahha A dedicated ax / track spec miata would be a blast. They're really cheap ! You'd never catch me driving it on the street tho...
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      05-04-2009, 07:55 PM   #6
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Miata's are great handling light cars. As an SCCA autox yesterday I was 3 seconds slower than one (half stripped out on street tires-driven by a very good driver). I was one of the fastest street tired BMW's at the event.

I have Star Specs, and when I switched over to them from the stock Conti's last year I dropped 1.2 sec against my class competitors. PS2's aren't good autox tires for sure. Unless you're really itching for camber plates, I think you should put a little more time in with the stock suspension, but I def. think new tires are in your future.
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      05-05-2009, 06:04 AM   #7
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Quote:
Originally Posted by The HACK View Post
Typical street tires, worn out rubber has a lot more grip than fresh rubber. GRM (grassroot motorsport) did an article trying to get to the magical 1G barrier on street tires (on a Subaru Impreza WRX), and they've found that a nearly worn out OEM Bridgestone had more grip (and significantly more grip) than a set of fresh (and wider) Nitto NT05s.

As street tire wear closer and closer to the wear bar, the tread block becomes shorter and wider, therefore providing more grip and consistent traction. Just right before it cords is when a set of street tires are at its best grip. That's why you'll see racers where lap time matters actually SHAVE off most of the treads before they use their tires.
I'd say that's more the exception than the rule. My contis were slippery as hell when I was approaching the wear bars...
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      05-05-2009, 02:20 PM   #8
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Quote:
Originally Posted by Dammmittt View Post
I'd say that's more the exception than the rule. My contis were slippery as hell when I was approaching the wear bars...
The Contis are the exception to the rule, since there's 2 layers of compound in the CSC, a top layer that's very soft and wears away very quickly, and a rock-hard layer underneath that might as well be hocky pucks. The CSCs designed for the M3 (stock on MZ4) will wear away the first layer in about 8,000 miles of street driving, and the secondary layer may take another 20,000 miles to wear away.

My experience with nearly worn out Toyo T1-R, Bridgestone S-03, Bridgestone Turanza RE750, Pirelli P-Zero Nero, and Pirelli P6000 were consistent with GRM finding (that street tires near the end of its usable life were grippier than brand new tires, except in the wet of course).
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      05-05-2009, 02:35 PM   #9
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In the latest edition of GRM....Kumho Ecsta XS were tops....at least on their little Autox test...
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      05-05-2009, 10:25 PM   #10
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Quote:
Originally Posted by The HACK View Post
The Contis are the exception to the rule, since there's 2 layers of compound in the CSC, a top layer that's very soft and wears away very quickly, and a rock-hard layer underneath that might as well be hocky pucks.
I have a set of CSC's on the front end right now (an emergency set after my PS2's chunked on me during an event). I will let you guys know at what point they start to crap out.
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      07-25-2009, 11:02 PM   #11
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Kind of an interesting development with the emergency Conti Sport Contacts mentioned above.

They actually seem to be performing quite well...at least they did during my last event. I suspect that the harder compound when in high heat conditions (140+ degree asphalt) softens up enough to provide a decent amount of grip without coming apart like the PS2s did.

I am no expert...just my observation...maybe some of you guys with more experience can provide a bit of perspective.
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      07-27-2009, 04:43 PM   #12
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I got the Advan AD08's after doing some research on them and the RE11's... those were the only sizes avail at tirerack for this type / caliber of tire.

Sizes :

245/35/19 front
275/30/19 rears

Both have treadwear of 180

Advans are 2 pounds lighter a tire for the fronts, 1 pound lighter on the rear.
Some other minor section width differences. Nothing too major tho...

That said, the Advan's are INSANELY sticky... ran them at an AX this weekend and I'd highly recommend them. Made my car push more than it used to from more grip, but I'm working on that now....

If Kumho had the XS in these sizes... I might have gotten those as they're great, and cheaper.
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      07-27-2009, 07:59 PM   #13
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Quote:
Originally Posted by bkz4mc View Post
I got the Advan AD08's after doing some research on them and the RE11's... those were the only sizes avail at tirerack for this type / caliber of tire.

Sizes :

245/35/19 front
275/30/19 rears

Both have treadwear of 180

Advans are 2 pounds lighter a tire for the fronts, 1 pound lighter on the rear.
Some other minor section width differences. Nothing too major tho...

That said, the Advan's are INSANELY sticky... ran them at an AX this weekend and I'd highly recommend them. Made my car push more than it used to from more grip, but I'm working on that now....

If Kumho had the XS in these sizes... I might have gotten those as they're great, and cheaper.
Darn...I was hoping that Kuhmo would have those exact sizes too ! Double darn !

Oh...I rode in a Miata early in the morning out at El Toro and YES....the entry speeds and late braking for those cars is killer. So low to the ground and nimble. My co-worker has a few of them and I always mention them as his Bitch rides,lol...just to rib him.
He knows I know he'd beat me around the A-X.
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      07-27-2009, 10:23 PM   #14
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Damn, that sucks you were there in the am... my races were in the pm. I did pretty good in Novice ( 26 drivers ) and got a 5th overall ( even though I had the fastest time by a couple thousands of a sec ) with the PAX system tho, I get screwed... hahaha

There's a practice out there on the 8th that there's still opening for. You should come out man... $60 plus temp membership for the day if you're not an scca member.
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      08-02-2009, 01:16 AM   #15
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Try the Federal 595 RSR. Cheap tires that have phenomenal grip. One of the stickies dry weather tire I have tried.

I'm currently running 255/35/18 front and 265/35/18 rear.

Compound is pretty soft. Tread wear is 140. I don't expect them to last very long but at $170/tire who cares.

I got them from here.

http://www.citytireonline.com/Federal595RS.htm
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      08-02-2009, 03:14 AM   #16
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255s in front! Now that's a nice development...
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      08-02-2009, 09:54 PM   #17
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Quote:
Originally Posted by kojikoji View Post
255s in front! Now that's a nice development...

Not with stock wheels or suspension.

I'm running custom valved Single adjustable Koni coilovers on the front with 8.5x18 +38 wheels. The spring and spring perch on the coilovers are narrower than stock. Also the tire is 35 series which is a smaller diameter. This lets me fit 255 tires on the front with -2.7 degrees of camber.
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