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I just added the BMW M2 to the list. Such a number skews everything so bad I think it renders the method unusable.
Here's a test case -- plug the FS E92 M3 and Mustang GT into your formula and see how they shake out. Both are known to be slower than BS, so if your formula shows them to be comparable or better, that's an indication that it's weighting power too heavily. Conversely, if it shows them to be distinctly worse than BS, then the class is doomed.
Originally Posted by mopar bob
look at nationals almost none of these cars come out any more. This is a big market that no longer comes out to run.
More correctly, this is a small market that has *never* come out to run. Porsches have been classed very competitively many, many times in Stock and now Street. Despite that, never in modern history (probably never, but my knowledge only goes back to the late '90s) has a Nationals field been composed primarily, or even significantly, of Porsches.
Also, SS has been one the smallest Street classes every year since its inception. Splitting it in half would make that already bad situation even worse.
Here's a test case -- plug the FS E92 M3 and Mustang GT into your formula and see how they shake out. Both are known to be slower than BS, so if your formula shows them to be comparable or better, that's an indication that it's weighting power too heavily. Conversely, if it shows them to be distinctly worse than BS, then the class is doomed.
Challenge accepted.
I got some better data on weights plus found a formatting error in the BS spreadsheet, so take a look at the new numbers in the earlier list in post 25.
E92 M3 gets a rating of 98.6 It's 2nd gear thrust is a little better than the Corvettes, but the grip is much worse. It's usefully narrower.
2015 Mustang GT PP gets 101.8 Again, Like the M2, it's crazy high 2nd gear thrust is to blame, making it look overall comparable to the Corvette when its grip rating is horrible, plus it's very wide.
So, I think the lesson to be learned is that with any such very simple, 3 factor system, a car with one factor way out of bounds compared to the others can lead to poor results. (Kinda like the way we class wildly different cars within a single class these days.)
Update: here's the list with thrust reduced to a 50% factor. When I first started doing this I used 50% for thrust, but later went to 70%, maybe because of the differences in local vs. national courses. Still shows M2 dominant, E92 slower than B-Street, and Mustang faster than it really is. The mustang would drop to 98.2 with the 3.55 final drive instead of 3.73 I don't know what people really run. The system doesn't correct for cars that have super short 2nd gears, but need to shift to 3rd on any national course. Real people take things like that into account, of course.
This makes the 987.1 CS look even better compared to the Corvettes and would indicate that a 2008 Cayman would also be competitive on a sweeping/transient course without deep digs.
You also need to spit SS when you have a 997.1 base or even an 997.1 S and 991 GT3 in the same class. They are not even in the same zip code with a GT3. There still should be a class for cars like the GT3 or the GTR to run in street. look at nationals almost none of these cars come out any more. Does any body think that a 2011 Boxster Spyder can run with a GT3? This is a big market that no longer comes out to run. I know that you have to fill classes but Porsche is not the only make that this effects.
Nobody thinks the Spyder can run with the GT3. It's just (possibly) too fast but mostly too rare for AS.
997s never came out to autocross that I've ever seen. True, they were not competitively classed, but the fact is few owners of late-model 911s are interested in competition. The cars have moved too far upscale. Do you think they would add numbers to AS if moved down? I've never put them into my AS ratings. Maybe I should.
Frankly, I'm on record as predicting that the entire SS class would be dead and gone by now. The class has struggled, but there were 26 drivers at Nats last year, the majority of which were GT3s and GT4s, cars which attract the competitively minded. So, I'm happy to have been wrong. And I just re-read The Black Swan, so I'm going to stop making predictions.
I don't hear people suggest there's too few classes very often. I'm fairly good with Street with the exception of a big group of late model enthusiast cars buried in AS under the old z06s. Almost needs to be something between AS and BS, or break out the C5z and C6z to a SSC-like spec class, as that's what AS is now. I *think* there would be enough Porsches / GT350s / 1LEs / M4s / C7s to fill grids.
I do think all of SP/P/SM could be partitioned into 6-8 classes total instead of 16 though.
You must spend too much time on SRS BZNS forums. It's not just performance potential, but course and condition dependencies. There is no reason we should ever put S2000, Cayman S, C5 Corvette, M2, Focus RS, and Shelby Cobra in the same class. It ceases to be about skill and becomes all about luck in course design, surface, tire availability, etc: someone is ALWAYS going to get screwed.
Incidentally, I like the way SCCA is doing the ProSolo bump classes this year; if we stick with that model (grouping like with like and indexing for potential), we could double the number of classes yet still end up with fewer classes overall.
FWIW, I like the wildcard classes. I DON'T like having a fwd DS car at Pros (which is worse for 2018 getting lumped in with STH,) but I like my chances with the lightest car in the class most other times. I also really enjoy having something different than everyone else in grid.
If you are SRSBZNS, and have to know you have the best car in the class, or at least narrow it down to two, you can run AS, CS, ES, GS, or HS. Locally, the classes are close enough as is to be within driver noise.
I haven't tried to rate the 718, but, as I said, I think it would rate slightly higher than the 987.2CS, assuming you can get 8.5's and 10's. It has slightly higher peak torque, slightly less weight, same width. (If wider wheels are available that would create a big increase for the 718.) As usual, the actual dimensions of the optional wheels seems very difficult to figure out and Porsche has a history of publishing figures that differ from what is actually delivered. According to the build page, you can order 911 turbo wheels for a 718, but do you just get things that look the same or do you get the same widths? In the past, you just got the look.
From my research, the max wheel width for the 718s are 8.5 front and 10.5 rear. This could allow up to a 305 rear tire, if needed. I'm going to start out running 255/285s on my 718. I may even try to put 265 on the fronts, but I'm not sure it's going to make much of a difference. In addition, I'm skipping the GT3 front bar for the time being, and think I may want to consider an adjustable rear bar if I move to 305/30r19s in the rear.
From my research, the max wheel width for the 718s are 8.5 front and 10.5 rear. This could allow up to a 305 rear tire, if needed. I'm going to start out running 255/285s on my 718. I may even try to put 265 on the fronts, but I'm not sure it's going to make much of a difference. In addition, I'm skipping the GT3 front bar for the time being, and think I may want to consider an adjustable rear bar if I move to 305/30r19s in the rear.
In general, the mid-engined Porsches have more weight per inch of wheel in the rear than the front, but are close to equal front to rear, making them balanced in a sweeper. So, a 10.5" rear wheel with a 305 should swap that and make the rear more lightly loaded than the front. This makes me think that more front tire would be a good thing. It also makes it at least theoretically possible, as you seem to suggest, that you might want to attract more load toward the rear with a stiffer bar to improve sweeping. Who knows?
P.S. It doesn't work with Corvettes, which have way less loading on the rear than the front. The stiffer front bar both limits roll and thus limit camber loss and keeps the rear end from lifting an inside rear tire on corner entry. But, the front end has more static weight (except for the C6Z06 which is 50/50) while the opposite is true of the Porsche.
Wow! Fingers crossed! Now if the 718 would just follow suit...
Fastrack News – February 2018: Street
#22275 981 Cayman (non-GT4, non-GTS, nonR, non-S) (2013-16) to B Street
The SAC is requesting member feedback on the following proposal:
Move from AS to BS
Porsche
Boxster (non-GTS, non-S, non-Spyder) (2013-16)
Cayman (non-GT4, non-GTS, non-R, non-S) (2013-16)
#23593 Moving Porsche Cayman S & GTS
The SAC would like member feedback on the following change to Appendix A:
Move from SS to AS
Porsche
Boxster S, GTS (981 chassis) (2013-16)
Cayman S, GTS (981 chassis) (2013-16)
Quick look and a base 981.1 could get PTV and PCCB, and biggest factory option wheel was 20x8.5/20x10, sound correct?
Yes. I believe the best 981.1 BS setup would include X73, PTV, PCCB, Sport Chrono, with 19x8.5/19x10s. I honesty think the GTS could be a contender in AS, with all of these goodies.
Edit: The main issue would be finding a base 981 with all of these goodies. My base 981 had X73, but no PTV. Finding one with PCCB and PTV would be like finding a unicorn. The S/GTS would be much easier to find with these options.
My car is finally ready for the 2018 season! Just mounted new 255/285 RE71Rs on my 19x8.5/10 Forgeline GA1R Open Lug Cap wheels (that came off of my 981). Note: Had to get new TPMS sensors programmed for the 718. I also got an alignment, and was able to -1.5 degrees of camber up front and -1.8 degrees in the rear. This is with the 10mm lower PASM on the base 718 Cayman. Can’t wait to try it out in just a few weeks!
My car is finally ready for the 2018 season! Just mounted new 255/285 RE71Rs on my 19x8.5/10 Forgeline GA1R Open Lug Cap wheels (that came off of my 981). Note: Had to get new TPMS sensors programmed for the 718. I also got an alignment, and was able to -1.5 degrees of camber up front and -1.8 degrees in the rear. This is with the 10mm lower PASM on the base 718 Cayman. Can’t wait to try it out in just a few weeks!
I think I am going to pick up a base 718 with a manual and sport seats + and try to autocross it now and then as a supplement to my WRX. They are both 4 cylinders !
BTW.......not sure if combining 8.5 front with 10 rear is technically legal for AS. As the 8.5 front has to be paired with the 10.5 rear I think.
I would also like to run the 8.5 front but would have to pair it with a 10.5 rear.
Alignment looks good !
i think I’m just going to throw on 245/19 front and 265/19 rear as I had these left over tires from my 911 which I had to sell because of my divorce. Cayman coming is a divorce celebration present !
I think I am going to pick up a base 718 with a manual and sport seats + and try to autocross it now and then as a supplement to my WRX. They are both 4 cylinders !
BTW.......not sure if combining 8.5 front with 10 rear is technically legal for AS. As the 8.5 front has to be paired with the 10.5 rear I think.
I would also like to run the 8.5 front but would have to pair it with a 10.5 rear.
Alignment looks good !
i think I’m just going to throw on 245/19 front and 265/19 rear as I had these left over tires from my 911 which I had to sell because of my divorce. Cayman coming is a divorce celebration present !
You'll love it!
From my research, it is legal. The Vette guys do it regularly. You're allowed to go up 1 inch or down 1 inch in diameter on any axle, so if you take the 20x8.5 standard wheels the front and reduce them, then you can run 19x8.5 up front.
Here are a couple of pics from the NNJR SCCA autocross Saturday at MetLife Stadium. I was a bit rusty, but the car was a blast to drive. I think once I get more comfortable and back on my game, it will be a contender.
The going down 1” is totally good. The only thing that wouldn’t be kosher for national nit picky competition is combining a 8.5 front with a 10 rear.
8.5 front with a 10.5 rear is ok, but not 8.5 with 10 or 8 with 10.5
01-02-2018, 09:04 PM
