[quote=“westwest888,post:60,topic:7020”]
At the end of this season, I’m going to do the differential oil service. I’ll have about 50k miles on the clock. Probably the most useful thing ever posted on Audizine. Thanks, @Jake. Redline 75w90 should do it.
I like and have used Motul Gear 300, Redline should be fine for the rear diff, but if you do the trans as well you might get shifter notchiness
I’m a 6MT. It got new fluid when JHM put in the single mass flywheel and new hybrid clutch (organic/ceramic on either side).
Had to order a new set of tires after I trashed the fronts at Thunderhill on the last outing. My 235/35 19" Pilot Sport Cup 2 lasted 8 track days and < 5000 miles of street driving over 12 months. I’ll size up to the proper 96Y rated tire, now that it is available. The rears were in pretty good shape. I may save one of them as a full size spare for emergencies.
255/35ZR19 Michelin Pilot Sport Cup 2
$1,807.56 heat cycled and delivered
Nice, I am hoping to get 8 days out of my Cup 2’s also. Did you or have you considered rotating them between events? I’ve found the fronts wear much faster than the rears and plan to rotate between events now. Probably going with Option A:
http://www.tirerack.com/images/tires/tiretech/tire_rotation_abc.jpg
Cup 2’s, so good! Anyone else running these?
How much experience do you guys have in DE’s? I’m kind of apprehensive to go r-comp since I’m still learning the basics of car control and limit handling. The street tires just love to sing when you push them.
I went to the Belle Isle Grand Prix last weekend and you couldn’t hear any tire noise from the cars, except maybe the Mazda diesel protypes in the IMSA race. Which on a side note, if you guys can attend one of these events, it’s wicked cool. Just remember to bring some ear plugs because those 911 GT3R’s are loud as @#$!
PSC2 really are an R-comp light. Versus a PSS, you’re trading off wear life, tire noise, comfort over rough roads. You’re getting back grip, road feel, tire lightness, and tolerance for heat and high pressure. These tires have no issue with 50 PSI at 165 F on the surface - they grip for days. It lets you do a consistent 25 minute session without the tire changing personality half way through. The PSS goes terminally non-linear at the temp and pressure I mentioned.
On the streets for DD it operates just like a PSS would.
You are probably ok to transition if you are thinking about it now.
Considering the fact that you drive on Z2’s and are ok with them, you’ll be fine on r comps.
z2 break away characteristics are very similar to an r comp (that is, they are not very progressive). Also, they dont exhibit much noise at the limit compared to many other tires–so you cannot rely on audible feedback to know how close you are to the limit of adhesion.
That said, if you are going to go R comp, pick something that is VERY good with heat, as these heavy + understeering cars will bake the tires real quick. PSC2 is a great tire, if it is within your budget. The RA1 is good, and the NT01 wears like iron (though not as grippy). R1 also good (BFG).
I would concur with West’s assessment of the PSC2’s but add that I think they are a bit louder and a bit less compliant on the street than PSS. I run PSS as my street set and love them for that purpose. Also, I felt a bit less confident on the street in the rain with the PSC2’s on but perhaps that was just my paranoia as that was also when the tires were very new and I hadn’t had much time on them yet. I left them on in the rain at the track (2 wet sessions) and absolutely loved them for that. I was lapping every other non-AWD car out there and pushing the car slide through turns, it was a hoot. I do think the PSS’s would grip better in the rain but I don’t think it would be worth swapping tires (if you are running PSC2’s w/ quattro).
The grip at the track vs my OEM ContiSports was night and day, so I highly recommend them (or any upgraded compound tire) from that perspective. Also, they do still talk to you a bit. I’ll pay more attention to this the next time I go out but I was getting some tire noise when pushing them through turns. The Conti’s were louder in that regard but I also corded them in 4 track days which is unacceptable (both the front and rears were chunking as well). The PSC2’s look to be wearing much much better (no chunking and even wear) and also I am planning to rotate them between events so perhaps I’ll get a little more life out of them, hoping for 8 track days which is 4 weekends for me (I usually do two day events).
Then in terms of experience I’ve only done maybe 6 two-day events (12 track days) so far. I am planning to go full traction control off at my next event and that may change my opinion after that, we’ll see. I was running w/ traction control on in the rain and it was intervening but not through every turn, was fun nonetheless.
I should also add that in addition to driving I typically do about 4 ride-alongs in a weekend with instructors or advanced students, this extra “free” seat time has been invaluable to me.
And your advice is well received, I’m hoping to make it to this race in September:
http://www.imsa.com/races/lone-star-le-mans
If I look at it as: $200-$250 per track day for tires, then it sounds expensive.
I’ve considered the expense, and it is pricey but I also don’t make it to the track as much as I’d like to, so why not make it count when I do!
That said I may try Bridgestone Potenza RE-71R’s next time just to try them out (though I really do love the PSC2’s). Will wait to hear a few reviews on those first before deciding.
RE71R is not an r compound tire, but that said, I am a huge proponent of the extreme performance tire category.
Anything at that level will pretty much rival an r compound. And for cars that eat rubber as quickly as ours does, it’s good enough. We’re talking about probably 0.5sec lap time differences in most cases between an extreme tire and an r comp.
So here’s a question for the guys running decent negative camber at the track. Are you noticing threshold straight line braking to be somewhat squirrelly? I was having this sensation at the end of the main straight at mid-ohio. Not sure if it could be attributed to running xp20’s on the front and xp8’s in the rear. I’ve read the xp8’s might actually have a higher coefficient of friction, but less thermally stable than the 20’s.
I was running ESC in sport mode (single press, but not long press), and wondering if ESC was saving me on this. I know stoptech tends to keep the brake bias pretty close to factory or even slightly more aggressive than stock (pushing bias rearward to improve performance).
Just wondering if some of this could be attributed to the ~2.5 deg of negative camber. BTW - tires are wearing wonderfully at this camber setting. Running 40 psi hot and the wear mark is right where the triangle tip is on the sidewall. After 2 DE’s, still have tons of tread left. Measured it and it’s around 7/32’s in the middle with plenty of sidewall to spare.
Here’s a shot right before I gave this turbo a point bye ;D
Camber in the -2 range shouldn’t be a problem with braking; at -4 it can be. Toe could be the issue.
More likely the track just has grooves in it where everyone brakes. I try to move my braking zone back a car length or over slightly to avoid this.
It’s the rear pads. I’m running XP12 in the rear and it’s solved all issues of the twitchyness under heavy braking. I’m using XP24s in the front.
I initially had XP24 at the front and XP10 in the rear but man when I hit the brakes hard at the end of the straight, I had to fight to keep the car straight. Now it’s more stable.
I’m running -2 degrees all around. Might change it to -2.1 (pretty happy that I’m not rolling sidewalls). That and I’ll be increasing the spring rate by 50 lbs as well (I bottomed out on the track lol)
PsYkHoTiK, noticed you have the 034 rear diff mount, have you tried it out at the track yet? Any thoughts?
Perfect, exactly the feedback I was looking for…+ karma
Totally makes sense about the brake bias, were you ever feeling anything dicey while trail braking? I wonder how it would feel if I fully disabled ESC, hopefully not sliding the ass out :o
Good luck with the spring rates…bottoming out (I assume you mean hitting bump stop?) on track sounds not good :-\
If by bump stops you mean the car’s body and frame, then yes. 
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