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Old 09-11-2013, 05:21 PM   #3151
Splash
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The only flaw in the theory that Rick's accounting of asphalt and concrete is the reason STU's index is nuts, is in noting that applying RT's tire factor to SM gets you an index that is lower than STU. That's a good indication that SM and STU are too close. (and never mind more recent testing that shows the RT factor to be closer to 0.95 instead of 0.975.)

While I do agree that there is a difference between asphalt and concrete for AWD, I think it's that street tires are relatively less effective on concrete that makes up more of that difference. But still, if the PAX data samples really are showing that kind of difference, then they contain a lot of bad asphalt or cold temp events, where the R-tires are not much, if any, better.
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Old 09-11-2013, 06:35 PM   #3152
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Question regarding pax index and st classes. Are only national events included in the math? I ask only because if it is only national level events I would assume that ST classes would have better values.
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Old 09-11-2013, 07:30 PM   #3153
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Quote:
Originally Posted by piknockout View Post
But even at that, if you look at Geoff's Day 2, he couldn't get close to that first run time. Meanwhile I pulled out a 56.4, a 56.5 (dirty), and a 56.8 that had a huge mistake through part of it... ...Then again he did continue to drop time on Day 1, but then again you could drop a ton of time on that East course just by improving your braking zones and nailing those apexes. Hard to tell.
My Day 2 was all over the place due to my errors 1st run felt/was good, 2nd run I hit cones near the start and just put it into 3rd gear and just drove around the track at a constant throttle - not really staying on line and thats why my 3rd run was so loose - picked up a whole bunch of fine OPR on rear tires - should have been driving hard during 2nd run to keep them clean! So my 3rd run was very loose and I could feel I was slower in very corner

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I wouldn't read too much into it (personally). The two tires are definitely very different and require somewhat significant setup changes (on an EVO anyways), but imho, one isn't necessarily faster than the other... one is
disconcertingly loud and less percise, the other can't handle heat... pick your poison
What's odd is people pick less precise tires for autox, blows my mind, autox is ALL about precision, every single element has turn-in - precisely where the bfgs suck.... thats all I have to say about tires.

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I did not know of it, but it's not the first time that STU has turned away from rules infractions (heat shields, boost, excessive fender rolling, etc). Was the boost really that much higher than what is possible through boost creep?
Running the 3bar sensor is ONLY for running/tuning high boost. His boost levels are not easy to check/protest but the fact that he has an aftermarket MAP and a couple bypassed OEM sensors is very protestable. I didn't even see the 3bar tucked under the strut bar till later when I pointed out the bypassed FPR solenoid to someone.
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Old 09-11-2013, 07:53 PM   #3154
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At this rate, we'll have ALL of the STU EVO folks over here... <grin>
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Old 09-13-2013, 10:27 PM   #3155
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I was reading thru the August Fastrack again and found this.

#11154 STF/STC/STS E-Diff Clarification Change the second portion of 14.10.K as follows: “STX, STU, STR – Only standard (as defined in Section 12.4) limited slip differentials (LSD) are allowed on AWD vehicles. For AWD vehicles that did not come with any type of limited slip differential (including center differential or transfer case), a single aftermarket mechanical LSD may be added. 2WD vehicles may use any mechanical LSD unit.” Note: This clarifies that the ST LSD rules apply to mechanical differentials only. The original rule did not specify “mechanical” as electronic differentials were not in common use when it was written.


Does this mean people with WRX's in STU can upgrade to a limited slip for front OR rear?
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Old 09-13-2013, 10:43 PM   #3156
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Neither. WRXs came with center diffs. The infamous "box of goo".

The only diff-less AWD car that comes to my mind is the old Mazda 323 GTX.

Last edited by Splash; 09-13-2013 at 11:00 PM.
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Old 09-13-2013, 10:48 PM   #3157
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The center diff on the WRX is a mechanical system (e-diffs are really just fancy breaking algorithms that use abs to brake individual wheels to fake a diff), so no we don't get to add a front or rear diff. At least that has always been my understanding.
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Old 09-13-2013, 10:59 PM   #3158
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Quote:
Originally Posted by CopperTopNWOR View Post
Question regarding pax index and st classes. Are only national events included in the math? I ask only because if it is only national level events I would assume that ST classes would have better values.
No, actually there are events counted from larger regions, some divisionals, and certainly Tours and Nationals.

I'm sure this has a little to do with why ST indexes suck, but it's equally clear that he's never been raw-timed by a Civic. You know it's bad when the fastest STC car (one that's been consistently stupid fast for years) can't break the top-100 in PAX at Nationals. I'm not sure having some asphalt events in the data sample accounts for that. You could say that maybe the other ST classes are soft, but then why would their indexes be so rough? Besides, since when are Peters, Whitener, and Clark soft? As fast as Clark was, he only PAX'd 184th (8th place SM PAX'd 183). I know street tires don't do as well there, but jeez.

Last edited by Splash; 09-13-2013 at 11:16 PM.
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Old 09-13-2013, 11:29 PM   #3159
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Nationals are wierd in that respect though. Jack burns was 298, Alex Jones was 81 in pax. Rtf hs and FP respectively. At Toledo this year I think Alex has beaten jack maybe once. That is just our little region but still. It does seem that nationals is particularly rough on street tire cars.

We do use the .975 multiplier for rt class cars on the pax if I recall though.
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Old 09-14-2013, 01:51 AM   #3160
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Quote:
Originally Posted by CopperTopNWOR View Post
Nationals are wierd in that respect though. Jack burns was 298, Alex Jones was 81 in pax. Rtf hs and FP respectively. At Toledo this year I think Alex has beaten jack maybe once. That is just our little region but still. It does seem that nationals is particularly rough on street tire cars.

We do use the .975 multiplier for rt class cars on the pax if I recall though.
And that again shows how wrong the pax is. It's pretty bad that I could go and run my SM car on z2's on the smaller events to save Hoosiers and have a pax slightly better then a STU car.
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Old 09-14-2013, 07:34 AM   #3161
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Quote:
Originally Posted by Splash View Post
Neither. WRXs came with center diffs. The infamous "box of goo".

The only diff-less AWD car that comes to my mind is the old Mazda 323 GTX.
I think some Mercedes systems are ediff only too.
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Old 09-16-2013, 11:08 PM   #3162
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I'm confused. It basically says if your AWD car didn't come with a limited slip diff that you CAN add ONE. The WRX does NOT come with a limited slip. So what if the center diff is mechanical, it's still not a limited slip diff.
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Old 09-17-2013, 12:57 AM   #3163
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Yes, the WRX does come with one, it's the center diff. It is a limited slip diff in the same way the viscous rear on the older WRX is.

Think about it, if the WRX center diff did not slip, you could never turn the car on asphalt. If the center diff was open, you wouldn't really have AWD, would you?

Old Mazda 323 GTX's had open center diffs and the only time they were really AWD was when all 4 wheels were down and the weight was evenly distributed. Rev it up, pop the clutch, when the weight shifted back the front wheels would light up like a drift king and stay that way. A WRX starts to spin the fronts, then the center diff kicks in and tries to lock the front and rear driveshafts to the same speed. In fact, a WRX ALWAYS tries to keep the shafts at the same speed. However, it's lock isn't so tight that it can always do it. fortunately, it lets the speeds differ somewhat so the driver can turn the car (where the front shaft turns faster than the rear shaft).

A stock WRX center diff is actually rated at 4kgf/m. There is a rally part available that is rated at 20kgf/m. Obviously, it has 5 times the locking power. The problem is, it's meant for loose surfaces. When used on tarmac, it doesn't want to let the car turn, which is a problem enough as it is.
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Old 09-17-2013, 08:03 AM   #3164
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Oh ok I see now. Thanks for explaining it.
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Old 09-22-2013, 06:26 PM   #3165
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Corvette nonZ06 c5 and 350z approved for STU. Discussed.
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Old 09-22-2013, 11:45 PM   #3166
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I have never bought the "bad gearing" argument for the C5 being in STU. Sure, it's bad for the manual, but the automatic can do 57mph in 1st. The STIs do 56mph in 2nd. Doesn't look like that gearing will hold it back to me.

Not really scared of a STR-winning 350Z with 30mm more tire, though they won't need as much course dependency for them to win as the E36 M3 does.

I still do not get their logic behind not allowing oil coolers either.
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Old 09-23-2013, 10:00 AM   #3167
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Some dumb rules. It will be fun to have a wider variety of competition though.

Doubtful I'll be back in Austin's car next year, he's unsure of his plans. Guess we'll see what happens this winter.
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Old 09-24-2013, 10:27 PM   #3168
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Should be fun next year with the new additions. Hopefully they make the class that much more competitive.
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Old 09-29-2013, 11:05 PM   #3169
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Welp, it finally happened. 4 years on OE engine mounts and one let go. So, given that we're not limited to OE or Group-N mounts anymore, what has everyone been using?

Are the MSI all-aluminum ones bad for vibration compared to the stiff poly or rubber solutions (Torque Solutions, Cusco, Perrin, etc)?

I'll likely just do the whole set of mounts because, after 188K miles, if one let go they all will soon.
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Old 09-30-2013, 01:28 AM   #3170
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Due to lowering the Engine 7mm and being possibly lighter than stock the MSI mounts as sold are illegal, . Neither of these issues is a dealbreaker, just be aware. There was a rumor of stock height ones but TiC couldn't confirm it for me.
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Old 09-30-2013, 08:56 AM   #3171
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Sidenote. Yazel told me last night that the MSI now have poly bushings in the middle to help with vibration. Safe to assume that's info from TiC.
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Old 09-30-2013, 09:23 AM   #3172
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I've been using the Cusco mounts, vibrations seem to not be too bad. No complaints with the setup so far.
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Old 09-30-2013, 10:11 AM   #3173
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Good to know... Anyone on Torque Solution or Perrin mounts?
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Old 09-30-2013, 11:51 AM   #3174
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I also use the Cusco mounts for engine and trans. Good stuffs IMO. Came from the Group-N mounts and it was pretty noticeable in terms of firming up the movement.
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Old 09-30-2013, 02:22 PM   #3175
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Torque Solutions here. You have to add a little weight to make them legal, which is much simpler prior to install.

The increased NVH might be a bit much for those that DD their car, but I'm okay with it (trailer queen ).
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