E92 M3 ZCP in SCCA Solo F Street

[Golddots]

I think I asked before, but what pressures are you guys running on re71r?

Someone recommended starting at 35 cold. Is that all around?

What pressures should I aim for hot?

Is no one spraying the re71r? My ad08r loved heat last year and I never needed to spray.

I bought a sprayer as a precaution.

Thanks

[chono]

Originally Posted by 414hpbabyshuttle

I think I asked before, but what pressures are you guys running on re71r?

Someone recommended starting at 35 cold. Is that all around?

What pressures should I aim for hot?

Is no one spraying the re71r? My ad08r loved heat last year and I never needed to spray.

I bought a sprayer as a precaution.

Thanks

What size are you running?
With 275 square on concrete I run pretty low -- ~34 front / ~32 rear *hot*

I bring my sprayers to each event and haven't used them yet. Maybe I'll need to when the weather gets hotter, but at this point it sure doesn't seem that it will be necessary.


-'chono'

[CSBM5]

Looks like it's going to be an interesting year in tires; perhaps it's down to two new ones, RE-71R and Rival S (with "older" tires not even close)? interesting podcast about latest GRM testing.

[CSBM5]

Originally Posted by CSBM5

Looks like it's going to be an interesting year in tires; perhaps it's down to two new ones, RE-71R and Rival S (with "older" tires not even close)? interesting podcast about latest GRM testing.

After reading the actual GRM mag test results, it looks like the Rival S is going to be the tire to beat. It is way ahead of the original Rival (they use it as the control tire through the testing) and a good bit ahead of the RE-71R on their STR Miata.

The average run for their expert driver went 48.5, 48.6, 47.6 for the ZII*, RE-71R, and Rival S respectively. It will be interesting to see test results from Tire Rack eventually on their 328i as car, car setup, etc, can likely flip flop results around, but at first look the Rival S appears to be a strong contender for this year. Hard to fathom it will be that much faster on other platforms, but if it is, then why bother showing up with those other tires?

[Richbot]

Did GRM have V720's in time to do their test? They juuuust made the rules cutoff

[CSBM5]

Originally Posted by Richbot

Did GRM have V720's in time to do their test? They juuuust made the rules cutoff

No, it wasn't part of the test.

[Rexpelagi]

Originally Posted by CSBM5

After reading the actual GRM mag test results, it looks like the Rival S is going to be the tire to beat. It is way ahead of the original Rival (they use it as the control tire through the testing) and a good bit ahead of the RE-71R on their STR Miata.

The average run for their expert driver went 48.5, 48.6, 47.6 for the ZII*, RE-71R, and Rival S respectively. It will be interesting to see test results from Tire Rack eventually on their 328i as car, car setup, etc, can likely flip flop results around, but at first look the Rival S appears to be a strong contender for this year. Hard to fathom it will be that much faster on other platforms, but if it is, then why bother showing up with those other tires?

Just a few things to keep in mind...

Caveat 1:

Andy Hollis was much closer on the Rival S and 71R - within .1s. He was also much faster on both than last year's tires (>1s). This result is consistent with all the test data I've seen, and consistent with my own testing.

I don't know what was up with David's runs. The data I've seen on multiple vehicles suggests the 71R should be faster than the ZII*, but it didn't end up that way in his test. Also, he was way faster than Hollis on the S.

I'm not sure if the car being setup for Toyos (which are similar to the Rival S's for balance) by David had something to do with his ultimate pace on that tire combination. Or, if the tires really are that fast but Andy wasn't able to achieve that delta in a brief few runs in the car.

Caveat 2:

I believe there was a comment that the 71R had the best longitudinal grip of the group. This will be amplified on our cars.

That said, I'm sure both tires are very good, and I don't honestly know which is faster for us. I'd be interested to drive the Rival S, as I haven't yet. If anyone does a comparison be sure to post it up!

[CSBM5]

Thanks John, excellent points. It would be great to test the RE-71R and the Rival S on the M3. From what's been said, it would appear that driver accommodation for the significant difference in the two tires' slip angle vs grip curve shape would be a big part of the learning experience when swapping between the two tires. Given that aspect of the two, it almost makes one wonder if having both sets available and then try one on the front and the other on the rear -- perhaps *that* combo could even be very useful on certain courses.

Regards,
Chuck

[chono]

Hey All,

I've been looking for the lightest wheel for the car and think I've found it -- Volk ZE40.
Should be about 4 lbs lighter than the wheel that I'm running now (PS7).

A fellow autocrosser (and friend) can get Rays to build a set for us in our ZCP M3 FS legal size:
5x120 bolt pattern
72.53 center bore
18x9, ET31
18x10, ET25

Only catch.. since they're a custom size we need to order 10 sets. I don't know if there are 10 srzbzns autocrossers, but I hope that there are!

Let me know if you want more details.



-'chono'

[z3papa]

So these wheels will weigh in at how much and cost what if you get 10 people to buy? Seems pretty impressive you can get down to 16-17 lbs. The ARC-8's are a bit lighter than the PC7's but need a spacer up front to get the right offset and would not be as strong.

[chono]

Originally Posted by z3papa

So these wheels will weigh in at how much and cost what if you get 10 people to buy? Seems pretty impressive you can get down to 16-17 lbs. The ARC-8's are a bit lighter than the PC7's but need a spacer up front to get the right offset and would not be as strong.

The wheels weigh in the mid-18s. (My PS7s weigh in at ~22)
I'll PM you the details.

http://www.mackin-ind.com/portfolio/volk-racing-ze40/
http://www.rayswheels.co.jp/products...hp?wheel=ZE40&








-'chono'

[thasuperdude]

I'd jump on this, but I have to stay with non-zpc sizes being an '09
Good luck!

[UNCbigM]

Yes, interesting, but non-ZCP sizing needed too.

[CSBM5]

Back to tires...looks like trying out the Rival S isn't going to happen easily for a while. I see now that they are simply listed as backordered on TireRack's web site. I suppose many will simply go with the RE-71R given they are immediately available.

[CSBM5]

Congrats John for nailing down 1st in F-Street this weekend in the Wilmington ProSolo (and PAXing overall very high)! What happened in the bracket challenge? I can't seem to find anything online.

Regards,
Chuck

[chono]

Originally Posted by CSBM5

Congrats John for nailing down 1st in F-Street this weekend in the Wilmington ProSolo (and PAXing overall very high)! What happened in the bracket challenge? I can't seem to find anything online.

Regards,
Chuck

I hear that John made it to the final round of the challenge .. ended up 2nd overall.

Nice driving John.

[z3papa]

My most recent event video. Dinan sway bar coming this week and Bridgestones will be here in three weeks since they are backordered.

Right now I'm on RS3's (255/285) and was 1.5 seconds up on a guy who has trophied 3 of 4 years at Nat's.

[z3papa]

Originally Posted by chono

I hear that John made it to the final round of the challenge .. ended up 2nd overall.

Nice driving John.

Excellent. I'm going to have to work on my speed typing skills on 6/3 to see if I can get into the Wilmington Pro in August.

[Rexpelagi]

Thanks guys!

I had some solid runs during the main competition, although I'm still working to not try to chuck the car through slaloms (basically had to do that in the Shelby - slower steering and moar big). I kept getting better, but not where I need to be. Something to work on!

The challenge went well until I tried too hard to make a small gap in the final round - my good friend Kyle drove well all the way through though, and would have been tough to match regardless. All BMW final round - that was different.

Here are my fastest competition runs:

[Richbot]

lol, that's like watching some of my AS videos except add tire squeal. You can definitely tell where the diff is confused/slow to react, just like it was on the Hoosiers. Nice drive. This car looks tough this year, although it always has been, just needed people to drive it.

In my experience chucking this car in slaloms makes the car say "oh, fun, we're playing hoon, here's some oversteer...wait, what? Why are you mad at me? That's what you wanted right? Are you not entertained?" I suck hard at slaloms though.

[Rexpelagi]

Originally Posted by Richbot

lol, that's like watching some of my AS videos except add tire squeal. You can definitely tell where the diff is confused/slow to react, just like it was on the Hoosiers. Nice drive. This car looks tough this year, although it always has been, just needed people to drive it.

In my experience chucking this car in slaloms makes the car say "oh, fun, we're playing hoon, here's some oversteer...wait, what? Why are you mad at me? That's what you wanted right? Are you not entertained?" I suck hard at slaloms though.

Rich that is a very good description. Andrew Pallotta drove my car at a local and nailed the slalom perfectly, so I know it can be done, but man do you have to be careful.

For comparison, this is the video from Tom's fastest runs in 2nd place (E46 M3). These are really solid runs, he did a great job. I really need to get me and/or the car consistently slaloming like this:

[CSBM5]

Yeah Rich, that's hilarious and spot on. The combo of the diff locking up tight and the S65 hitting the sweet spot over 6500 is crazy...like the M3 saying "it's party time, have fun!"

Don't really have any significant slalom thoughts other than the typical focusing on that inside rear vs the cones and visualizing the path all the way through creating the exit condition needed for the following element.

Chuck