Geoffrey

I can see how the new rules may not help those who also run vintage series with other clubs.

97C2s911

Did anyone follow along during the process when pca made these rule changes? I am interested in what was the motivation for the big shakeup.
If it's not broke why fix it ?

Steward B.

"Did anyone follow along during the process when pca made these rule changes? I am interested in what was the motivation for the big shakeup.
If it's not broke why fix it ?"

A couple of quick comments from the chair of PCA club racing:

1) This was a two year process to review the GT classes and make a determination as to whether the classes needed to be restructured. Comments were solicited from a large group of class participants and engine builders, as well as our scrutineers and stewards. Proposals were posted during last year's rules change process, in the summer of 2006, and comments were received to those proposals.

After consideration, it was decided that we needed more time and more opportunity for comment. Donna Amico, the rules chair, stated that in her rules change report in November of 2006.

More comments were solicited from more class participants and engine builders after November of 2006, as well as from the same group as made comments in 2006.

As part of the rules change process this year, several proposals were posted. During the entire process, starting before 2006 and continuing up to today, the comments received were that we needed to review the GT classes and consider changes in order to keep it viable.

In addition, we have received a number of comments from racers running in other sanctioning bodies, specifically vintage groups, asking for us to consider changes to the rules so as to allow them to have somewhat competitive cars.

Almost to a person the comments from the racers this year was that we needed to change GT. The only discussion was which of the two proposals made the most sense. The vast majority of comments were in favor of the rules change that have now been adopted.

It's been a two year process.

We've been told over and over that the GT classes need to be revised.

Clearly we are losing participation in the GT classes. Unfortunately, with the factory continuing to produce ever more cup cars, we anticipate that we are likely to lose more participation in the GT classes.

The rules changes are an attempt to slow the loss of participants and also to level the playing field. However, in racing, the playing field is never level, for a variety of reasons, with MONEY being the largest one.

Let's see how these rules work. I can guarantee you that we are not going to change them for at least several years but if they prove to be a bust, after several years we will look at them.

Merry Christmas to all,
Bruce Boeder
Chair PCA club racing

MJHanna

It sure did not help any vintage 911 cars that run to the 72 SCCA rules.

kurt M

Many well put posts. I might not like it but I see the reasoning for the shake up. One was to get more cars in GT which I think it will. Got the half baked DE car that is too much for a letter class? Run in GT for giggles after tweeking the weight. I also see some down sides. One is the new rules don't seem to line up with other venues rules and they jack up some of the existing cars that were carefully built to the rules.

I am just mad as I am in the middle of a GT build and the rule change tossed my plans right in the fire. As was said if you are a bit handy light can be done on the cheap. I spent some real time grinding and cutting off a lot of unneeded weight and instaling tubing. Not ready to fess up to any numbers so lets just say 2 guys can pick up and carry my fully caged but still raw tub around. Light is also a one time cost. High power per displacment is over and over.

A true power to weight might be fun. The fixed HP numbers is where the rub might be. I also understand the problems with dynos and the temptation of cheating

I plan to finish the build, weigh it and then see what motor options are best. In the mean time I am done grousing. Thanks to all that spent many an hour working on this.

M758

When it comes to cost for hp vs cost for light weight it depends on where you are.

Take any street car. Losing 200 to 500lbs is often times pretty easy depending on what you start with. In most cases it can be done for cheap since all you do is rip out the crap you don't need. 944 spec cars run at 2400-2450lbs or so without driver. That is about 350lbs less than an I stock car and that weight is cheap and easy to achieve as it will all stock steel and glass. The issue is that beyond this point the costs and effort begin to really ramp up. Getting 944 NA race car down below 2400lbs starts taking alot more time and money. You need to look at dipping the entire chassis, replacing glass with lexan, and steel with fiberglass. At this point you are at may be 2200lbs without driver and very simple cage. The problem is that in the old GT class that still would not help much as the similar effort in a 911 or 914 may get you to 1800 or 1900 lbs. The issue is that going lower in 944 body means you will need to start cutting structure and possibly make the car more flimsy in the process. How many 2200lbs 500 hp 944 trubo's do you see? Not many since the running gear needed to support 500 hp will add more weight in 944 body shell. Do you run small lightweight suspension arms to save 30lbs and risk breaking them or replaceing them every 2-3 races? Or do you go with beeffy parts that add weight, but are cheaper and will last for a long time?

Now clearly the samething applies to hp. The first 10-25% hp gain may be easy to get. Maybe it is a chip, header or a cam. Turbo cars often have the first 40% gain in hp to be quite easy. Even so you still hit a limit where hp gets expensive.

Why put a director factor on weight, but not hp? It is easy to measure weight, but hp is not. Displacement is realtivly easy to measure so having fully sliding displacement scale with and assume hp/liter potential for various engine type makes alot of sense.

Now if I had been building a car for GT this sure would throw a monkey wrench into those plans. However it does not mean you would be screwed. You may in fact turn out much better, but you will need to adjust your thinking to beable to maximize the speed potential given the new structure.

Kurt, You still would want to build the lightest tub & cage structure you can. Any dead weight that does not add to the structure of the car is still ripe for removal. Heavy weight is still the enemy and even in power/weight class running 8:1 with 300lbs less hp is still better then more hp at most tracks.

97C2s911

I want to thank you all particularly Bruce Boeder for paying attention to our questions and responses . Initailly I wondered if there would be enough like minded people to challenge this decision . After listening to our discussion and appreciating how enjoyable pca is and must continue to be I now feel as there is a bit more of a direction for me,either continue on the weight loss program or simply add some weight and move a class .This decision being tempered by what other sanctioning bodies I want to race with . Receiving the reply from Bruce that this will be in place awhile has shown to me that this decision is in the best interest of gt classes and that is what ultimately works.
Scott Daiger GT3S

M758

I just worked up a little rough estimation on where most cars fall in the new GT classing system. The light green are possible classes given estimated acheiveable weights (remember these are with driver). Blue is where I would guess most cars would want to run. IE most would want to be closer to the min in class vs being on the heavy side of the next higher class.

Larry Herman

Nice chart Joe. Slow day at work?

M758

Well not many people around here the week before Christmas.

BBailey

I put a similar chart together when I started thinking about what to build.

You missed one thing though:

There are no minimum weights for GT1.

M758

I know, but it was easier to calcuate with a min weight. Simpler to keep from geting invalid numbers. So I just used PI of 250 for the min of GT1. For most all cars it just makes a ridiculous weight anyway. I did the same for the high side of GT6. It was easier that adding in a if statement to check for a zero limit when I ran the numbers.

Lemming

+1

Looks like I need to drop 25lbs. Hmm, a trim weight of 145lbs for me would do it

BBailey

I think the really interesting thing to look at would be some of the engine combo's that might pop up and suddenly be advantageous.

I think we'll start seeing some destroked engines in the near future as people try to wring more hp/L out of their cars.

I also see a potential need cropping up for custom 944/968 cranks that solve the oiling and bearing issues that are known to exist.

Steward B.

With regard to cars running to the 1972 SCCA rules, we did have a rules proposal up for comment this year about adding a "vintage 911" class, which would have done just that, run as set up to 1972 SCCA rules.

To our surprise I believe we had two comments in favor of the new class.

PCA club racing currently has a lot of different classes. The rules committee didn't feel that the expression of interest by two racers for the new "vintage" class was sufficient to add another class. However, if there is more interest during this coming year, we will certainly look at adding another class.