Latest on racing class allowing boost if 4.5L 928?
11-21-2007, 08:55 PM
#1
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Latest on racing class allowing boost if 4.5L 928?
Where did I see that? What did it mean?
Is it still happening?
Is it still happening?
11-21-2007, 10:29 PM
#4
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Thread Starter
So it exists then Mark? What would be the limit on power within the rules then? Because you could get 700-800 if you sleeved the engine to original bore and used forged pistons and aftermarket EFI. The heads could get special treatment, and it could be an 8k rpm motor very easily.
11-21-2007, 10:50 PM
#5
Rennlist Member
It has always existed in SCCA ITE, but i think someone was referring to PCA rules, but i have a hard time believing that! 
The other racing organizations that would allow a blown 928 would be GTS series with NASA which is based on rwhp dyno numbers and weight ratios.
mk
The other racing organizations that would allow a blown 928 would be GTS series with NASA which is based on rwhp dyno numbers and weight ratios.
mk
So it exists then Mark? What would be the limit on power within the rules then? Because you could get 700-800 if you sleeved the engine to original bore and used forged pistons and aftermarket EFI. The heads could get special treatment, and it could be an 8k rpm motor very easily.
11-22-2007, 08:18 AM
#6
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Are you going for a race license next year?
The rule that was approved is as follows:
GT cars will be classified by calculating a “performance index.” The performance index applies the same principle of classification as used for the stock classes, which is weight/horsepower. The formula is:
Performance Index = (Weight/[Displacement x Horsepower/Liter for engine type]) x 100
The weight in the formula includes driver and driver gear.
The table below provides the HP/L for your type to calculate the Performance Index for your car:
Engine Type
HP/L
8 cyl 2 valve 90
8 cyl 2 valve turbo 145
8 cyl 4 valve 100
8 cyl 4 valve turbo 165
Classification is proposed as follows:
Performance Index Class
425 and below GT1
426 to 550 GT2
551 to 675 GT3
676 to 825 GT4
826 to 975 GT5
976 and above GT6
The weight in the formula is the actual weight of the car including driver and all gear. It is permissible to add ballast to change one class only. Ballast is defined as removable weight bolted into the car solely to achieve a target weigh.
So a turbo/supercharged 4.5l 928 at a 2900lbs weight runs GT2, not GT1.
The rule that was approved is as follows:
GT cars will be classified by calculating a “performance index.” The performance index applies the same principle of classification as used for the stock classes, which is weight/horsepower. The formula is:
Performance Index = (Weight/[Displacement x Horsepower/Liter for engine type]) x 100
The weight in the formula includes driver and driver gear.
The table below provides the HP/L for your type to calculate the Performance Index for your car:
Engine Type
HP/L
8 cyl 2 valve 90
8 cyl 2 valve turbo 145
8 cyl 4 valve 100
8 cyl 4 valve turbo 165
Classification is proposed as follows:
Performance Index Class
425 and below GT1
426 to 550 GT2
551 to 675 GT3
676 to 825 GT4
826 to 975 GT5
976 and above GT6
The weight in the formula is the actual weight of the car including driver and all gear. It is permissible to add ballast to change one class only. Ballast is defined as removable weight bolted into the car solely to achieve a target weigh.
So a turbo/supercharged 4.5l 928 at a 2900lbs weight runs GT2, not GT1.
