E92 M3 ZCP in SCCA Solo F Street

[Rexpelagi]

Originally Posted by CSBM5

I'm not so sure the F80 will be quicker on "most" typical autox courses than the E90. It's wider, longer, and has a FAT low to mid range torque curve. On street tires, it will take great patience and skill managing rear tire grip coming off elements, making minor throttle changes when loaded up, etc. The S65 flat torque curve really allows the E90 to hook up coming off elements, upshifting from 1-2 in the middle of an element, etc.

I'm contrasting it to my E39 M5 which has just a tad less peak power than the E90 M3, but has a fat, explosive mid-range with 74 ft-lbs more peak torque than the S65. That car just wants to spin its rears any place, any time, any chance you'll allow it to on course. The first time I autocrossed the M3, there was an offset gate right in the middle of the acceleration run from the start toward a Chicago box. The 1-2 upshift needed to occur right in the middle of that offset movement, and I continually amazed myself how I could pop a 1-2 there with just a bit of wheelspin and then quickly hook up the rears (using Rivals btw). If that was the M5, I would have instantly spun doing a maneuver like that, so I would have had to carefully manage that shift, be much smoother on the throttle/clutch, etc.

I'm guessing with the explosive torque of the S55, it won't be a cake-walk managing getting it to the ground effectively on most autox courses.

EDIT: lol, just read this thread in the F80 section about AWD option. Interesting to hear some of the comments about not being able to put down the power...

You may have a point with that - I generally don't factor that in. I've never really had any difficulty putting power down, so it's hard for me to relate. I've autocrossed an E60 M5 and a C6Z06 on streets (not even the 'good' streets) and while you had to be aware of the power if driven with care it wasn't an issue. Given that those are NA vs. the F80 boosted torque curve I don't know how they compare.

Still, there is very little upside to placing a 70k+ new car that has potential to be an overdog in a decently-subscribed class where 25-35k cars are running competitively.

[Richbot]

We're such nerds.

[UNCbigM]

And?

[Rexpelagi]

FYI - Apex is offering $50 off per wheel on the PS-7's starting on Friday.

[UNCbigM]

Saw that as well.

I have a set of ZCPs on the way and the Dinan bar. ZCPs will be for street and OEM 18s will see autocross duty. Before I order tires for those wheels in the next couple of months before next season, I need to determine whether to go square or not and what tire to go with. I have nene a big fan of the ZI/ZII on my STR Miata that goes bye bye tomorrow. I liked the crisp response and rewards for precise driving as opposed of lots of slip angle. Something tells me I need to get more comfortable with slip angle with this car...

Any thoughts on tire choices with the 18s? Also, what sort of pressures do you run? I'll get to play in the cold in two weeks at our last event for the season on what I have left on the PS2s on the car now.

[z3papa]

R-S3's love slip angle but want more camber which we can't get in FS in order to make up for the softer sidewall. For me, up front the tire of choice will be the Dunlop since they are very stiff and I don't like the absence of wet traction the Rivals have.

[CSBM5]

The "problems" for 2015 are the wild cards lying out there with no specificity yet: (1) new compound Rival possibility, (2) the report from a Monterey Michelin talk where it was claimed they said the Pilot Sport Cup 2 tire was going to be TW200 in 2015 along with a large number of sizes available, and Michelin was targeting street tire class.

In any event, who wants to bet that *prices* for these ultra-high-end street tires will easily reach $400/tire and more in short order?

[z3papa]

In all honesty, I bought the Pilot Super Sports to run on the street and to serve as my competition wet tire when the TR tests came out stating it was the tire to have over the Conti DW. I can state that while the tire was a "good" street tire, it was way over-rated in terms of uhp performance. I'm just not feeling the next gen being that great unless pigs fly.

[CSBM5]

Originally Posted by z3papa

In all honesty, I bought the Pilot Super Sports to run on the street and to serve as my competition wet tire when the TR tests came out stating it was the tire to have over the Conti DW. I can state that while the tire was a "good" street tire, it was way over-rated in terms of uhp performance. I'm just not feeling the next gen being that great unless pigs fly.

Having swapped out DWs for PSS for my street tires, they sure are a lot better in the dry than the Contis. My Contis were horrid in terms of uniformity also...continual issues even after multiple roadforce balancing attempts. I have a similar issue on my S4 with the DWS' just not as bad.

Check out how the PSC2 are performing on the latest cars using them such as the GT3 and C7 Z06 along with the feedback from those that have driven them. Record levels of lateral grip and braking distances on these tires have been established for street cars in the past few months. Granted they're great cars, but the tires play a large role in the outcome.

[GTB/ZR-1]

Originally Posted by CSBM5

In any event, who wants to bet that *prices* for these ultra-high-end street tires will easily reach $400/tire and more in short order?

They seem to have us by the short hairs...

Also, the (quickly becoming) new conundrum is that a lot of people are either trailering or changing tires @ events (even locally!) w/ the new Hi-Po streeties; since these tires are heat-cycling out faster & faster w/ each new iteration--back to square 1... lol

[CSBM5]

Originally Posted by GTB/ZR-1

They seem to have us by the short hairs...

Also, the (quickly becoming) new conundrum is that a lot of people are either trailering or changing tires @ events (even locally!) w/ the new Hi-Po streeties; since these tires are heat-cycling out faster & faster w/ each new iteration--back to square 1... lol

Yep, exactly. I change mine at home prior to driving to an event though...too old/lazy/sick-as-heck-of-99F-heat-index-tire-changing-heatstroke-days to fool with them at events anymore. Just a local club hack anyway.

It's only a matter of time until Hoosier enters this ballgame it would seem. They'll probably rework the A7 carcass a bit for toughness, etc, then lay down a dual compound treadface where the outer layer that is worn in the treadwear rating tests is hard, but shave them to 4/32s and *surprise* A7 compound is sitting there waiting.

[z3papa]

Originally Posted by CSBM5

Having swapped out DWs for PSS for my street tires, they sure are a lot better in the dry than the Contis. My Contis were horrid in terms of uniformity also...continual issues even after multiple roadforce balancing attempts. I have a similar issue on my S4 with the DWS' just not as bad.

Check out how the PSC2 are performing on the latest cars using them such as the GT3 and C7 Z06 along with the feedback from those that have driven them. Record levels of lateral grip and braking distances on these tires have been established for street cars in the past few months. Granted they're great cars, but the tires play a large role in the outcome.

I'm not saying that DW's are better dry or even overall tires that Super Sports but DW's were better wet tires. As for Sport Cup 2's and what they are doing on track, that very well may be a different story. If you have any links, I'd appreciate. My overall feeling is Michelin tends to go conservative on sidewall stiffness for sound and comfort. Autocross on stock/street setups (modest camber and spring rates) will likely reward that stiffness.

[z3papa]

Originally Posted by CSBM5

Yep, exactly. I change mine at home prior to driving to an event though...too old/lazy/sick-as-heck-of-99F-heat-index-tire-changing-heatstroke-days to fool with them at events anymore. Just a local club hack anyway.

It's only a matter of time until Hoosier enters this ballgame it would seem. They'll probably rework the A7 carcass a bit for toughness, etc, then lay down a dual compound treadface where the outer layer that is worn in the treadwear rating tests is hard, but shave them to 4/32s and *surprise* A7 compound is sitting there waiting.

Sounds like a tootsie pop. Be expensive as hell and immediate put on the exclusion list.

[CSBM5]

Originally Posted by z3papa

If you have any links, I'd appreciate.

Originally Posted by Car and Driver C7 Z06 test

scorched the skidpad with 1.19 g’s of grip, and stopped from 70 in an astonishing 128 feet, the latter two figures setting C/D records for a production car.

C7 Z06 Car and Driver test.

Originally Posted by Car and Driver GT3 test

The GT3 doesn’t give up grip willingly, though. The Michelin Pilot Sport Cup 2 tires are tenacious, and the GT3’s balance is impeccable. We recorded 1.12 g on the skidpad and stopped from 70 mph in 135 feet

C&D GT3 test.

Don't know how these PSC2s would/will work out, but I'd sure like to take a crack at them sometime.... It's a bit hilarious that the PSC2s on the Vette are ZP tires too (run flats).

[z3papa]

Big thanks for the link. I'd have to wonder how the ZII Starspec compares since their comparison was the Super Sports which IMO are a full 1-1.5 sec off top UHP's on a 50-60 sec. course. Regardless, they sound very impressive.

[CSBM5]

Originally Posted by z3papa

Big thanks for the link. I'd have to wonder how the ZII Starspec compares since their comparison was the Super Sports which IMO are a full 1-1.5 sec off top UHP's on a 50-60 sec. course. Regardless, they sound very impressive.

It's not real useful to compare the Pilot Super Sport and the Pilot Sport Cup 2 -- two totally different tires/design/compounding/target end users/etc. The PSC has always been Michelin's track R-comp DOT tire line, and the PSC2 is the latest version with updated carcass and new compounding. My understanding is that advancements in compounding they used in creating the PSS and other recent tires allowed them to formulate a DOT R-comp tire, the PSC2, with a *much* longer wear life than the prior PSC while at the same time significantly improving grip. That is an amazingly tall order to achieve in tire design...hence the reason my hat's off to them.

If they weren't currently TW180, I'd buy a 19" set to try them out. I actually don't believe they are going to make these into TW200 tires for 2015 and have a large range of sizes available regardless of that presentation. Something just doesn't seem right with that plan. I would instead expect them to come out with a Rival 2. That part would make sense as the Rival was designed and is built here in the USA whereas the PSC2 is a France product (not sure where it's built, but if Michelin has any hope of selling a wide range of sizes here, I would think they would have to start a line building them in the USA instead of France). All just gut feel stuff, but if I was running Michelin USA, I'd sure as heck put all my resources into the Rival perhaps even coming out with two different compound Rival IIs -- one for asphalt and one for concrete. (therein describes what's coming in the street tire wars ).


Regards,
Chuck

[Richbot]

What's old is new again...

[Rexpelagi]

Keep in mind that there are other tires expected on the market in the Spring that haven't been mentioned. It is too early to buy tires for next year IMO.

Another thing to consider is that OE tires may have complete, some, or no similarity to a replacement tire with regards to compounds, construction, etc. I wouldn't base much of anything on potentionally one-off OE tires.

[Gcode]

AutoX done wrong?

How does this sound:
- E93 with passenger
- 4300+ pounds
- Stock 219 wheels
- Cheap tires 255/40/18 - 275/40/18 (Sumitomo HTR Z III)
- Slide quite often

Like the video if you can be 3.3s faster than mustangs in FS and manage to get 1st place the whole season in a fat ass car.

[UNCbigM]

I autoxed my E90 for the first time on Saturday. I had a blast but definitely have a learning curve coming out of an STR Miata. With time I'll get used to more power and weight.

Power oversteer at will is nice for a change. The biggest thing I need to figure out is the massive understeer I experienced (to the point I had chatter coming from the front tires). I think there were three contributing factors:

1) Old PS2s - I probably ran incorrect pressures too.
2) Dinan bar set to full stiff (I'm thinking this was too stiff for the PS2s, and should hopefully improve with a better tire in a couple months. I may try the middle setting. I also did not disconnect the bar and reconnect once on the ground to remove preload, as not having a 4 post lift or ramps makes this particularly difficult.
3) The final contributing factor is my bad habit of driving too deep into a corner and not giving it up enough early enough. This hurts more than it did in the Miata due to the extra weight. I'm working on it...

Thoughts?

Otherwise I had a blast and can't wait to hit it again soon!

[Richbot]

Yeah patience in this car is key you can't take as much speed in as you might be used to. I had to relearn to drive too. Drive it on the back tire and get it to pivot before you need to apply power and you're golden otherwise you are waiting a while.

Agree the ps2's don't help.

[UNCbigM]

Originally Posted by Richbot

get it to pivot before you need to apply power

I like the sound of that! Just need to make it happen now...

Also, in a slightly related matter, I seem to be getting some noise from the front bar in street driving. I'm thinking not enough lube on the bushings. I was pleased to see that the Dinan mounts include a small port to add lubricant without removal. I just need to find a good lube and applicator.