PedroNole

You're assuming that one car is a factory based race car and one is a street-based race car when they are actually both (in this instance) street based race cars.

karlooz

it was a response to what ed newman posted.
i thought i would be able to run in gt3. since gtb is so new there won't be many cars (around here at least) for a while.

38D

If his base car without ballast would be in GT3, then yes, he can add ballast to move to GT4.


I don't think that is correct. GTB is intended for ex-Grand Am 996s/997s. We had quite a few of those cars attempting to run in C last year. This gives them a class to run in.

Geoffrey

To be clear, any 986 type engine 2.5l, 2.7l, 3.2l, 3.4l, 3.6l, 3.8l installed in any chassis 911, boxster, cayman is able to run in GT classes with a performance factor of 135.

Ed Newman

I was one of the ones suggesting it. The rules stated that water cooled 911's modified beyond prepared go into GTA. That was not fair so GTB offers a place for street cars (not cup or RSR) to run. It is for much more than just Grand Am. The Synergy cars, and card like Jim and mine if we choose to make a few more mods, now have a place where we can go.

Ed Newman

I think you mean Mxx (M86, M96, M97, etc) based engines. On what do you base than they can run open in GT classes?

GTA Class (from the rule book)... "996 or later 911 model-based factory race cars and other 996 or later 911 model-based cars not meeting the equirements of the Stock, Prepared or GTC Classes. Maximum displacement is 3.6 liters,
normally aspirated. Tires are free. Minimum weight for this class shall be 2700 pounds including driver."

Boxster is ok in GTx... "Must retain a Porsche OEM engine block or case. Other changes or modifications are free. Non-996 or later 911- based cars with water-cooled 911 engines, except the Boxster, shall be classified in GTP by displacement. The turbo multiplier shall be applied as necessary."

And then we added GTB this year..."Create GTB Category for “street” 996s and 997s modified beyond stock or prepared class. A description of GTB will be included in the rules; GTB is intended for cars that were prepared to Grand Am Cup or Koni Challenge rules or are otherwise consistent with those rules."

Ed Newman

I believe this is from the days of a 986 with a 2.5l vs a 996 with a 3.4l. Someone transplants the 3.4l from the 996 into 986 it is more of a true "GT" car as it is a custom built car. That and somethign about concern byt the aircooled guys that the water pumpers were going to be faster. Personally, I think it is silly. BUT the problem between 996 3.6l Cup and 996 3.6l street still exists if you go to all cars are allowed in GT classes.

The new rules are a quantum leap forward, but we may still need some adjustements. Lets go race this year, have fun and see what happens. :-)

Geoffrey

I was one of the GT Study people for PCA who helped draft the rules and continue to have dialogue with Donna on this subject. There is a big difference in performance capability between the 986 type engines and the GT1 derived watercooled engines. If you allowed the GT1 engines into the GT classes, a 997RSR would most likely slot into GT3 given its weight and displacement.

bobt993

Geoffrey, Just curious why they did not just adapt the dyno rules that NASA is using. It just seems alot more affordable to adapt what you have to a class.

Geoffrey

That was not one of the proposals and it has its own challenges. I'm really not the right one to ask that question to.