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993 c2s base points vs 992 c2 base points question

Posted: Wed Mar 31, 2010 5:23 pm
by petep
Hi all,

I was calculating my new classification and I noticed that the base points for a 993 c2s had gone up relative to a 993 c2.

993 c2 = 360
993 c4s = 370
993 c2s = 390

Why is a c2s any more than a c2 with wheel spacers and possibly flares?

The c2s is basically a c2 with the rear wheels spaced 1" further outboard.
Working against it is the additional aero drag of the rear wheels and the extra weight of the body.

Why is the 993 c4s 370? It has the wide body AND big brakes AND the sport suspension and 4 wheel drive.
Yes, it weighs more. The brakes should help stop it and the 4wd should help stabilize it though.

thanks,
Pete

Re: 993 c2s base points vs 992 c2 base points question

Posted: Thu Apr 01, 2010 3:18 pm
by Zone7Rep(Larry Sharp)
the cars are overall closely classed .. if they were all stock they would run in the same class.. but as you modify the car more .. a C2S has more potential ..

Re: 993 c2s base points vs 992 c2 base points question

Posted: Thu Apr 01, 2010 4:28 pm
by petep
My point is that it doesn't have any more potential. Same engine, same suspension, same brakes. It is a c2 with 1" spacers in the rear and rear flares and cosmetics. I guess there is the additional 50 pounds...

Actually, the wheels just have different offsets, so technically that doesn't have a cost with the current rules. I could put the c2s wheels on a c2 without penalty if I had the clearance.

Re: 993 c2s base points vs 992 c2 base points question

Posted: Thu Apr 01, 2010 5:18 pm
by Zone7Rep(Larry Sharp)
the S models are more powerful and have larger rims and track width in stock condition compared to a normal 993 .. a two wheel drive car is better at track work than a 4 wheel drive and weighs less.. Soo a C2S is better just a little better than a C4S, hench it has slightly more points.. and they both have slightly more points than a normal 993.. But in stock condition they are in the same class.

Re: 993 c2s base points vs 992 c2 base points question

Posted: Thu Apr 01, 2010 5:44 pm
by petep
Hi Larry,

Thanks for humoring me. :)

The S model is not more powerful than the same year c2. All the USA 96-98 993 cars have vario ram, c2, c2s and c4s.

If you want to break out the non vario 95 c2 as a different base model , that might make sense, but that is not the way it is now. (If you head in that direction, perhaps we should look into the cars with cam timing as well.)

I assert that the c2s is a c2 with rear flares and 1" less offset on the rear wheels and nice cosmetics. Flares are 10 points, wheel spacers are 5.

I suspect that the c2s should be the c2 value + 15. Perhaps I'll propose that to the committee next year...

Pete

Re: 993 c2s base points vs 992 c2 base points question

Posted: Thu Apr 08, 2010 11:01 pm
by johntavernetti
Pete,

The 2010 base points are calculated on a purely mathematical basis using data in GGR's model info database. The formula is in the 2010 rule book (see Appendix G) available online. I just checked the db and it appears we have a factory curb weight for the 993C2S car of 3,064 lbs, which curiously is the same figure we show for the '96-'98 993C2 n/b. So, if you can provide factory documentation (like a scan of your C2S owners manual's specifications page) showing that the C2S was in fact 50lbs heavier than the n/b C2, then you indeed have good grounds to ask for an amendment in the next cycle of rule changes.

As it stands, the points are slightly higher for the C2S because the stock wheels for that model (again according to the GGR db) were 8 & 10 " wide vs the n/b 993's stock 7 & 9 ' wheel widths. Also, as you noted, all the n/b C2 years are lumped together so there is some averaging happening between the '95 272hp cars and the '96-98 282hp cars, bringing down the basepoints ever so slightly for the n/b 993 compared to the C2S which was only ever made with the later more powerful motor. Unaccounted for in the formula, but arguably working in the C2S's favor is the fact that the C2S came stock with a sport suspension which would normally be a 15 point mod on a n/b 993 C2. So maybe it's a wash.

In the end all these cars are pretty close points-wise so even if there is a correction necessary due to a curb weight error, it's unlikely to be huge.

Let us know what you find. Thanks for scrutinizing this stuff.... it's the only way it'll ever be optimized (and I use that term here VERY loosely).

Cheers,
JT

Re: 993 c2s base points vs 992 c2 base points question

Posted: Fri Apr 09, 2010 7:35 am
by petep
Hi John.

Thanks. A few answers to your points.

The 98 Owners Manual reports curb weight for a Carrera as 3064 lbs and a CarreraS as 3086 lbs. This is a 22 lbs difference.

c2s came stock with the same 7" and 9" wheels as the c2. The 18s were options. (as in the manual)

c2s came stock with the same suspension as the c2. Mine certainly had the stock suspension.

Not huge, just a level playing field...

Thanks,
Pete

Re: 993 c2s base points vs 992 c2 base points question

Posted: Fri Apr 09, 2010 1:21 pm
by psmith
To to add a few thoughts here for future rules:

We still currently do nothing in the rules for AWD... quite often the extra weight of this results in the AWD versions actually coming in with less points! There should be an added 10 points or so for AWD. That covers the C4S in this case...

If you were to classify the car as a 993 C2 and consider the "S" modifications as non-factory... you'd start with 360 points, +10 points for the spacers and +10 for the fenders. Given that these are relatively small differences from the "normal" 993, should this actually be considered a different model? I'd suggest a small change in some of the modification points wording (ie, "non-stock spacers" would become "optional or non-stock spacers"), and this would also have the added bonus of making things a little more steamlined in the long run.

And one last note too with regards to the wheels... as to what was "standard," it is possible that the manual does list the standard wheel and 7x17 and 9x17, but also very possible that no such configurations were ordered by PCNA as this has happened for other US versions in the past. But in either case, the wheels are handled pretty much outside of the base points now.

Re: 993 c2s base points vs 992 c2 base points question

Posted: Mon Apr 12, 2010 5:44 am
by C4sport
I was curious why you beleive the AWD C4S should be assessed 10 Pts. I don't see an addvantage in AX as it is more prone to on throtle understeer. The C4s does pull out of the hole well once pointed straight perhaps due as much to it's standard LSD than AWD & the associated 30 pts hit. I'm not going to quibble over 10 pts I'm assessed over the C2, even though the US version has the exact same bumper height driven US spec suspension. As Paul points out wider fenders and larger rear wheel offset/spacers good for 20pts.

Re: 993 c2s base points vs 992 c2 base points question

Posted: Mon Apr 12, 2010 10:32 am
by johntavernetti
Re: AWD. It's not true that we "do nothing for AWD." Each 4wd model is given a distinct base point assignment seperate from its 2wd cousin. So at least it's higher curb weight (and, where applicable, wider wheels) are taken into account. However, if what you meant to say is that there is nothing in the formula to adjust for the pros/cons of AWD as a system, then that's true. To do so would be tough: Consider that the 4wd system on a 964C4 is probably a performance handicap whereas the recent 4wd systems (esp. on the '09+ cars) is most likely a significant performance benefit. How could we write a formula to account for such disparate outcomes? Tricky... and ultimately perhaps not a good use of our limited appetite for rule-complexity.

BTW: The fact that many of the 4wd cars include a stock LSD is already accounted for. The LSD item (#33 on the Modifications list) requires that participants take the points hit for the LSD even if it was stock. So all GT3's, GT2's, Turbos, and any 4wd cars that came stock with a LSD are supposed to select this item which raises their points total by +15 for TT and +30 for AX. In general this will more than offset the slight basepoint discount 4wd cars received as a result of their higher curb weight. Unfortunately, people forget to check this option (this is probably the most common mistake I've seen in the online classifications) so this corrective effect is somewhat blunted.

I'm all in favor of improvements though... if you've got good ideas on how to better solve these puzzles, keep 'em coming.
JT