M758

I have a couple ideas for PCA Club Race Rule Changes. I would like some feedback before I submit to PCA.

Here is my concept for 10% weight reduction as special prepared mod.

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Rule Change Proposal

Prepared Cars
7.0 - Cars make may run 10% under their stock class weight as a prepared modification. Weight reduction may be by means of interior removal (all carpet and seats, dash must remain intact), removal of non essential components such as air conditioning and heaters and all related systems. Lightweight panels may replace steel and or glass panels provide they meet stock shapes and dimension unless these panels are free in per stock class rules. Cars that are otherwise stock may move up one class from their stock class. Cars that have any other prepare modifications must move up an additional class. Any progression that results in class beyond A will be moved to the appropriate GT class.


Reasoning
The gap between Stock and GT is vast and little exists in between for racers who want to go faster, but are not able to develop a GT that will run at a reasonable pace for the class. Currently racers must either race a full weight or race in GT where anything goes. Allowing car that stock, but at a reduce weight is great way to give racers something in between Stock and GT. This is especially attractive to owners of older cars. These cars have benefits of low acquisition costs, but can also be quite slow. A very simple and cost effective way to increase speed can not be danger on track to the newer faster cars is to reduce the weight of the car. The car goes a bit faster and puts less stress on its components.

A 10% reduction in weight is often achieved simply by removing the interior of the car. While a number of PCA stock class cars are street legal few are street driven on a regular basis. The vast majority see the bulk of their miles on the track. Thus allowing many racers to remove their interior will not take away from the functionally of their cars since most are dedicated track cars anyway. In any case stock class rules can still feature dual use cars.

The current stock class power/weight ratios can accommodate a reduction weight of 10% if the car is moved the next higher class. In nearly all cases the weight reduced car will have power/weight ratio that fits well in the established power/weight range of the next class up. Therefore there should be no impact of the competitiveness of any existing stock class car. In other words there will be no overdogs created with a 1 class increase for a 10% weight reduction.

There are already a few cases were the factory produce lighter versions of cars. These cars are about 9% lighter and classed one higher than the full weight version of the car sometimes will more powerful engines. Examples are the 95-97 911 RS at 2794 in C and 95-98 911 in D at 3064 (weight 8.8% reduction, with increase in power), 911 RS America in D 2760 and 911 C2 in 3031 (8.9% weight reduction).

Here is listing of the current class power/weight ratios and how a 10% reduction would impact the next class higher. In most cases the weight reduced car will have a power/weight ratio worse than the existing average power/weight ratio. In few cases (showed by numbers it the 10% weight reduced car will be better than the current power/weight ratio average. Only in the case of the 928 GTS in E, 69-73 911S in G and the 69 911E in I would a weight reduced car have the best power/weight in the next class above.

Link to Spreadsheet with data showing impact on power/weight ratios

http://members.rennlist.com/m758/StockClassWeights.xls

mark kibort

Ive often wondered about why as well???? there should be a place to run a porsche, as it came from the factory, with some bolt on mods and just lightened! Thank god you dont have a 928. then, YOU NEED to replace the engine with a 6.5 liter to ever be competitive with the super lightweight 911s as Mark Anderson has done. a stock engined 928 is about 5 seconds off the pace of a GT2,3 and 4 no matter what the weight. the rule makers forgot that abolute weight is MORE important than HP to weight. braking and cornering time helped by lighter weight, is usually more per lap than just full throttle!

MK

hacker-pschorr

I would like to see PCA catch up to speed with the rest of the world on safety devices.

I guess PCA knows better than Schroth and the FIA that 2" lap belts are unsafe when compared to a 3" lap belt.

Alan C.

Not a bad idea but an 88 Turbo S without the cat and a free flow exhaust makes about as much power as a 95 993. Shave 10% and move it to D would no doubt make the Turbo S driver happy. But then you have the 95 993 driver .........

While we are on the weight kick why not power/weight egaulaize each class?

As to interior I have never liked the thought of a fire and all that wonderful carpet and plastic burning around me. Not long ago a national person stated 'How many of you really drive your car to the track or on the streets? You should look into a full cage and not just a roll bar.' So why not get rid of the interior. It can be done in a pleasing fashion if the look of the car's interior is that important.

38D

Great idea. I might slightly change it so that the power to weight cannot exceed the lowest number for the class that the car is moving to.

jim3

Bill, your dreaming. Take a 944 I class car, take 277 Lbs out, move it up to H and race it against my stock H class 944S. It will kill the S, absolutely kill it, I mean really run away and hide. In addition, as a prepared car you can run Turbo brakes, chip, lightened flywheel. I don't think you can expect the rules makers to try and evaluate all the possibilities. The rules have stood for 13 years with some minor tweaking. Just came back from the Glen race, we had 65 cars in our race group including 32 F cars! But if you took 250 lbs out of the faster G cars they'll kill the F cars.

JCP911S

I think the proposal is to allow the weight reduction in lieu of the other mods... e.g. the car is in stock I class trim except for the weight.... I tend to think allowing both would be too much advantage.

I think there is nothing wrong with this idea except that, like any major rule change, it upsets the apple cart.... people know which cars are competitive and can buy a car accordingly... speaking purely selfishly, I'd hate to see my currently competitive car suddenly rendered second rate by a lightened H car. Not that this is guaranteed to happen, but as Jim points out, it certainly is a possibility

JCP911S

Of course if the lightened SC would kill the F cars.... then I'm all for it!!!!!

M758

Yep,
My intent was to allow weight in lieu of normal prepared mods. If you have I class 944 and weight reduce it. It goes to H. Do any prepared mods and that weight reduced 944 goes to G.

The intent is not to upset the apple cart. At least not too much. It however tough to not change something in at least one class. There are also those that simply "fear" change and other cars.

They assume that this car will KILL my car because it lighter yet forget that their exisitig car is faster for a reason. Really 10% is not that much weight and given the power/weight ratios in the next higher classes are in general 10% better.

Seems like from the feedback I have gotten that I will sumbit this change to PCA. I have my thiughts on how it will be recieved there, but I think someone needs to try given the generally postive response here.

38D

Maybe a 5% reduction instead?

JCP911S

Definately submit it... it is a totally valid idea... worst than can happen is it is rejected.

Plus it is a relatively cheap way to move up a class. For me to do a full "prepared" treatment to my car under current rules would easily cost $6-10K.... just not economically feasible. But a weight adjustment is both fairly inexpensive and easily reversable.

Frankly, with all the 996 Carrara Cup derivatives coming into the higher groups (and the faster street P-Cars coming in every year), the lower stock groups are forced to consolidate... both Mid Ohio and Glen, the F cars were moved to Group 1, and I suspect this is a trend... in this scenario more cars in fewer groups would mean more meaningful battles for position and make for better racing... a weight formula would be a way to accomplish that without forcing folks to spend alot of money.

I loved racing with the F cars... I hated that it didn;t really "count"

Just a thought...

M758

My reason for 10% is two fold.

1) It seems that with most of the more modern cars (Late 70's early 80 and newer). 10% about the weight of the interior and other non essential items. This means it is meaningful and would have an impact on most folks. lets say take off 50 to 100 lbs is rather meaningless since it is not that much, but still something. Sort of inbetween, were as 10% is large enough to "feel" like something.

2) 10% is easy calculate on the fly. Take the Current book weight drop the last number and subtract from the original.

jim3

Bill, when I said a lightened I car would kill my H car, I wasn't even thinking about other mods. The 277 lbs would do more than a chip, bigger brakes, flywheel and everything else you can do in prepared. If I was running prepared, I'd give all that stuff back to be 270+ pounds lighter. As you mention, you think you know what the answer will be. I suspect you're right.

mark kibort

keep in mind the weight of 225lbs is substantial, but in World Challenge pro racing, it doesnt do as much as folks think. there are tremedously fast cars that have "rewards" weight added to them. even though ive said over and over, dont just look at the HP to weight, but look at the absolute weight too, as it is 2/3s as important. (hp is just accel, while absolute weight is handling and braking).

for those of you that know times at tracks. Speed GT Audis ran 2:14.5 at road america with 275lbs EXTRA!!! (with less than show room boost levels, but an engine built by cosworth!) at sears, some BMWs in Touring class ran 1:46ish with the extra weight too! (also 2:28 at road america)

Point is, the problem with parity is the complete formula. we need to look at top driver potential in the cars we are talking about. There are Miatas on Toyos (bone stock) that run 1:48s at Laguna seca with some top drivers. Go look at the stock classes in Porsche when PCA was there for the race groups.. times were all over the map.

what i can say, is when we do get a bench mark , like we have in the 928 at different levels of prep, we need to use that information to help in the prep. In C class for example, we can see what Chris Cervelli had done with his "best of everything " 993 racer.

I really like the idea of changing the entire system to HP to weight, with a absolute weight factor. NASA is doing this for an interesting class for anything goes production basd cars.

this whole thing is kind of tough for PCA as there are already a ton of classes, and usually only a few per group, unless you are talking GT2 or the GTC class. in the stocker classes, this is where the fairness really comes out , and i think the only issues are really with the 928s and 944s.. the 911s seem to be classed fairly well. My real issue is the PCA based rules of POC, where a 3500lb 928 has to compete against a 320hp 996 at 2950lbs. (ie 500lbs less) in the R5 race group.

its a good and worthy discussion.

mk

JCP911S

The beauty of a weight formula is that if one car combo is clearly dominating, the weight can be adjusted to level the playing field a bit. I'm not talking about "reward" weight, just a way to balance the competitiveness of different cars. Ballasting imposes little finaincial burdon on the competitors.

I just see the writing on the wall.... as the newer cars enter the series, you can't just keep creating more and more classes and having more and more different classes run together in a single group... what's next? Having E, F, G, H, I, and J in the same group?

I just see some emerging need to start consolidating classes