Super Stock Weight Breaks

Thanks for the info Buff Daddy, it is much apreciated!

[Bill Harris]

Here is a handy excel spreadsheet I made for figuring out which GT classes a particular chassis/engine combination can run. It calculates the minimum race weight for each class and shows the ET's for the class index, 0.8 under, 1.0 under and 1.2 under. It also does an estimation of the HP needed to achieve the ETs at the min race weight. You only need to enter the body style shipping weight and the NHRA factored HP for the engine you want to use, and if it is a stick or automatic. It will do all the calculations in any easy to read and print format.

Enjoy.

http://www.employees.org/~bhracing/g...ulator_1p1.xls

[Bench Racer]

Bill that is slick! Is there anyway to download or copy the spread sheet? thanks, Don Jackson

[Bill Harris]

Hey Don,
You need to have Microsoft Excel in order to use the spreadsheet and put in your own data. You can download the spreadsheet from the link in my original e-mail. If you click on the link it should ask you if you want to "open" or "save" the file. Alternately, you can "right click" on the link and select "Save target as" and put it on your local drive. If you save it and have Excel you can do anything you want to it. There is no protection implemented. If you don't have Excel, but you are able to see the spreadsheet, then you probably have the free Excel reader that lets you look at a spreadsheet and print it, but you cannot change any of the data.

Bill

Another question guys; How do I classify my car? I have a 1971 Ford Mustang, I am claiming it as a 2dr Fastback which is a lighter weight. If I choose to run the car in a traditional SS class the shipping weight for an 71 with the 280/305 engine at 10.65. When you do the math the car and driver shipping weight comes to 3418 lbs. If I claim the car as an 72 with 275/313 engine at 10.68 lbs the driver shipping weight comes to 3512 lbs. My question is If I want to run the car in SS/IA the weight break is 10.00-11.00 lbs. To run the car in this class what must the car weigh? Do I subtract 150 lbs from the shipping weight and this is the weight of the car or can I run the car at the bottom of the SS/IA weight break because the natural weight falls between the 10.00 to 11.00 weight? If someone has an clear answer on this please speak up, I called Glendora and of course they are on Holiday break so I couldn't get an answer there today.

Thanks guys!

[JRyan]

Terrance,

For SS/IA at 10.00 lbs. with the 280/305, simply multiply the NHRA factored HP x 10 = 3050 lbs. Add driver weight of 170, for a toal of 3220 lbs. minimum weight. I doubt you can get that car that light, so I'd suggest you run it in SS/JA at 11.00 lbs., or 3525 with driver.

With the 275/313 combo in SS/IA, it would weight 313 x 10 = 3130 + 170 lbs for driver ='s 3300 lbs. That might be achievable, but it'd be pretty light on the rear.

Hope this helps.

Jerry

Originally Posted by JRyan

Terrance,

For SS/IA at 10.00 lbs. with the 280/305, simply multiply the NHRA factored HP x 10 = 3050 lbs. Add driver weight of 170, for a toal of 3220 lbs. minimum weight. I doubt you can get that car that light, so I'd suggest you run it in SS/JA at 11.00 lbs., or 3525 with driver.

With the 275/313 combo in SS/IA, it would weight 313 x 10 = 3130 + 170 lbs for driver ='s 3300 lbs. That might be achievable, but it'd be pretty light on the rear.

Hope this helps.

Jerry

Jerry,
Thanks for the tip. Beleive it or not the car weighs 3020 lbs without me in it and the only thing that is not in it right now is the second seat. The car ran as a SS/I stick car back in 80's. So I guess what you're saying is that in traditional SS there is no weight amount that you have to play with like you have the 250lbs in GT.

Terrance

[Bill Harris]

You don't have a choice on shipping weight in the regular S/S classes. The NHRA classification guides tell you what the shipping weight is for a particular body style/engine combination, and that's that. You can run the "natural" class, or move up one class, or down one class, by juggling weight. That's it. If the car's natural class is, for example, SS/E, then you can run it in SS/D, SS/E or SS/F. Even if you could take out enough weight to get it into the SS/C territory, it wouldn't be legal.

So, on a '71 Mustang Fastback with a 351/280/305 shipping weight is 3249 lbs directly from the classification guide. That's a HP/weight of 10.65 (3249/305 = 10.65). That puts it in SS/I which is 10.00 to 10.99 lbs/hp. If the car was a Mach I the shipping weight for the 351/280/305 engine is 3296 straight from the classification guide. That is HP/weight of 10.84 (3296/305 = 10.84) which puts it in..... you guessed it.... SS/I. So it doesn't matter if you claim the car as a fastback or a Mach I, you'r still a natural SS/I.

So now you can run SS/I, or go up one class and run SS/J, or down one class and run SS/H. That's it.

At this point, the shipping weight of the car is totally irrelevant. All you need to know is that the shipping weight ALLOWS you to run SS/H, SS/I or SS/J. Now you can calculate the minimum weight for the car in each class. The shipping weight doesn't come into play anymore. The only thing that is important now is the factored HP and the class. For SS/H, the minimum HP/weight is 9.50. So at an NHRA factored HP of 305, the car has to weigh 9.50 x 305 = 2897.5 lbs..... but that's not all.... You ALWAYS have to add 170 lbs for the driver, so the race weight for SS/H will be 2897.5 + 170 = 3067.5 lbs. Using the same procedure, the minimum race weights (with you in the car) are:

SS/H: (9.50 x 305) + 170 = 3067.5 lbs
SS/I : (10.00 x 305) + 170 = 3220 lbs
SS/J: (11.00 x 305) + 170 = 3525 lbs

Those are the minimum weights that you have to weigh when you cross the scales after a run with you in the car. You can be heavier of course. However, you may get an argument from tech if you are claiming SS/H and you go across the scales at 3300 lbs (which is SS/I territory). They might not say anything.. and they might give you ****... hard to tell.

Now, just because a car is ALLOWED to run a particular class doesn't mean that it CAN. If you want to run at the bottom (lightest) of SS/H with the '71 you have to get the car down to 3068 lbs with you in it in a manner that is legal for S/S. Good luck with that.

Stock classes and weights are calculated exactly the same way but using the stock HP factors.

My '71 Mach I with a 429/375/360 runs D/SA at a minimum race weight of 3590 lbs.... (9.50 x 360) +170 = 3590. I could run C/SA at (9.0 x 360) + 170 = 3410 lbs, but it would be really hard to get 180 lbs out of my car legally. Anyway, it wouldn't hook if I could.

Hope that helps.

Originally Posted by Bill Harris

Here is a handy excel spreadsheet I made for figuring out which GT classes a particular chassis/engine combination can run. It calculates the minimum race weight for each class and shows the ET's for the class index, 0.8 under, 1.0 under and 1.2 under. It also does an estimation of the HP needed to achieve the ETs at the min race weight. You only need to enter the body style shipping weight and the NHRA factored HP for the engine you want to use, and if it is a stick or automatic. It will do all the calculations in any easy to read and print format.

The numbers that are in this copy are for a 2006 Chevy Cobalt 2-door LS coupe with a 1987 305/170/271engine with an automatic. Just change the numbers for your engine/body/trans choices.

Enjoy.

http://www.employees.org/~bhracing/g...calculator.xls

Bill,

This calculator really works great, I think it answered some of my questions. Do you know if there is one for traditional classes, I am in deseprate need of some answers.

Smitty