97C2s911

I'm trying to figure out how the new weight to power has made an improvement . In the old GT3 class it was pretty standard that the 3.4 was a good motor to run now it appears that will not be competitive particularly in a 911 . At 2450 total wgt and an actual 87 hp/ liter I am now at the fat end of the class.

38D

In the old GT3, a 3.4L 911 has zero chance against a 951 or the whacky small displacement 911 turbos. You also couldn't do anything about it. Now you can add ballast and move down 1 class.

A.Wayne

Positively the new rules make your 3.4 L more competitive in GT3 .

97C2s911

that kind of goes against what I've been trying to work toward . It feels like going backwards

97C2s911

in doing the math I can have a 3.8 that weighs nearly the same as mine

Larry Herman

You must be doing the math wrong. A 3.8 with a 110 hp multiplier would have to weigh no less than 2305 to be right at the top of GT3. Your 3.4 could weigh as little as 2060, or you could run in GT4 at 2530 and be right at the top of that class.

97C2s911

I guess I don't understand where these rules have made at least GT3 any better. It seems like to go to either the extreme for power or weight is a $ factor and it seems as the rules are realigning cars from the group that was running with 3.4 's to who wants to spend the right amount of money to be at the top of their class I felt like I did that once.

BBailey

The new rules require you to spend money on your engine if you want to be competitive.

The old rules, at least with the 911's, allowed you to spend money on being really, really light as another way to be competitive. That doesn't work any longer.

The days are over of racing a relatively low strung engine competitively in the PCA GT classes and relying on a super lightweight chassis to keep you competitive.

Geoffrey

The rules were changed for a number of reasons and were not specific to addressing issues in one particular class. There has been a reduced participation in some classes like GT2 where people who owned those cars have moved up to a 996/997 cup car with a perceived better value for dollars spent. There has been an inequity in the turbo multiplier, and at 1.3 gave ALL turbocharged cars an advantage. This is mainly seen by the 944Turbos in GT3, however, this was not targeted specifically. There were other issues with 2.1ltt 911s in GT4 and 2.6ltt in GT3. It does appear that GT3 is the class that has been affected the most, however, it is probably the class with the most participation.

The GT class rules also allow for adjustment for individual engine types if performance equity of a particular engine type is not found. In the old structure, you could overcome a deficiency in engine performance by running lighter weight, although the front running cars were generall the lightest with the best engine, and with lots of dollars spent. In the new class structure, there is more flexibility, and you may not need the best engine or the lightest weight. For instance, you could take a 964 Cup car, add a good 3.8l engine and race down in GT4.

To answer your specific question about the 3.4l engine, as pointed out, you'll be able to race your 3.4l engine in a very lightweight car 1800 without driver, against a 3.8l RSR type car, and with a 944 Turbo at a heavier weight than before. The competition between those cars should be similar.

The comments posted here are my opinion, and don't necessarily reflect the opinions of the GT Study committee.

Larry Herman

To add to what Geoffrey said, with the new rules, you do not have to go crazy lightening your car to be competitive. You actually may find it beneficial to add a little weight and move down a class. Yes, you still need a strong motor, but that has always been the case in the GT classes that have had real competition.

M758

Yep,
I think that factor is one of the most important added into the GT rules along with a factor for weight. In the past the only 944 type car that could do well was the 944 Turbo. All NA 944 types simply could not get the same hp/liter as the 911 motors and then were also stuck with a heavier chassis. Now those heavier chassis get taken into accout and also the lower hp capacity of the 944 based NA motors gets noticed. I think the 16v 944 motors are getting shaft on their factor, but I believe that this new system may take a few years to shake out. I would expect to see some adjustments in the multipliers and possibly in the class cut offs once PCA starts to see what the competition level is like.

The thing I would hate to see is PCA to never revise or re-look the class cut offs and factors as we may just be trading one problem for another. I would hope that PCA give the current system 2 years to shake out and then keeping the same concept adjust the numbers for the 2010 season based on what has been learned about 2008 and 2009.

John H

I did the math wrong too. I am glad this came up again as I signed up for the wrong class at Sebring. Won't that be a jolly tech session!

Lemming

The new system works well for me. Because of my engine swap, I would have been stuck in GT3 by the old rules. With the new rules the car will be near the top of GT4

John H

If I had a vinyl cutter and some vinyl, I'd bring it along. Can you imagine the number of class changes there will be?

97C2s911

you're right it is good that pca continues to evolve however it seems fairly apparent by the amount of cars at sebring in the gt class that 3S is a class that has better participation than the others so people have been in it awhile and have made the improvements that have placed them where they would like to be with minimal unkowns ( how much they weigh total hp ) so you could sort of gauge any improvements that are occuring by comparing times with some confidence.
My concern is how you perceive you're doing is now going to have many more variables , so I was just thinking why not at least designate liters on the car as well so if you're running against the same cars as before that someone doesn't drop a larger motor in the same car and then the largest unknown is shown