weight /class questions

Rory McNeil · 03-07-2011, 12:20 PM

Tom, also keep in mind that you don`t neccasarily go by the weight listed on your cars registration papers, or owners manual, sales brochure etc, you have to use the weight per horsepower factor as listed in the NHRA "Stock car classification guide". There will be various factors based on different trim levels, body styles, and engines. For example, say that the model you are trying to determine has a factor of 14.38 lbs per HP, which would give a shipping weight of 2876 lbs. You can either "round it off" to the "top" of M/S, which is 14.00 lbs per HP, for a min weight of 2800 lbs, or round it off to the top of "N",(14.50) which would give a min. weight of 2900 lbs. After that, you add the 170 lbs for the drivers weight. So now the minimum for "M" is 2970, and for "N" it`s 3070. Those are the min. weights that you need to be at the scales after a run. Years ago, you were not permitted to round off the class factors, so my example of a 14.38 factor would have meant that the car & driver combo had to weigh 2876+170 for a min weight of 3046lbs. That is the reason that there were so many oddball combinations, as a 4 door sedan may have fit the class better than a 2 door, or a wagon fit better than a convertible.

Jim Wahl · 03-07-2011, 12:25 PM

Quote:

Originally Posted by Rory McNeil

Tom, also keep in mind that you don`t neccasarily go by the weight listed on your cars registration papers, or owners manual, sales brochure etc, you have to use the weight per horsepower factor as listed in the NHRA "Stock car classification guide". There will be various factors based on different trim levels, body styles, and engines. For example, say that the model you are trying to determine has a factor of 14.38 lbs per HP, which would give a shipping weight of 2876 lbs. You can either "round it off" to the "top" of M/S, which is 14.00 lbs per HP, for a min weight of 2800 lbs, or round it off to the top of "N",(14.50) which would give a min. weight of 2900 lbs. After that, you add the 170 lbs for the drivers weight. So now the minimum for "M" is 2970, and for "N" it`s 3070. Those are the min. weights that you need to be at the scales after a run. Years ago, you were not permitted to round off the class factors, so my example of a 14.38 factor would have meant that the car & driver combo had to weigh 2876+170 for a min weight of 3046lbs. That is the reason that there were so many oddball combinations, as a 4 door sedan may have fit the class better than a 2 door, or a wagon fit better than a convertible.

This is a good and simple answer to the question! Very good examples and to the point. This should be posted every time someone asks this question. Nice job Rory! Jim

Jeff Lee · 03-07-2011, 06:24 PM

When I first started class racing I was confused when I heard "top" or "bottom" of class. Finally I realized it is alphabetical on a vertical chart instead of a horizontal chart. "A" is on the top and "Z" is on the bottom of the chart.

Although you may not even need the NHRA shipping weight, if you want it NHRA almost has it hidden from view in the class guides posted by NHRA. You have to scroll all the way to the right away from black text over white background to the area that is black text over a grey background.

Tom keedle · 03-07-2011, 09:14 PM

guys, i've got the weight stuff from nhra figured out as far as classification, i just wasn't sure about how the drivers weight figured into it (i ALSO thought it might help some other new guy out,too)

well, at least i don't have to quit eating

thanks for the help,guys!

03-07-2011, 12:20 PM	#1
Rory McNeil VIP Member Join Date: Jun 2007 Location: from Vancouver BC Canada, now in Nova Scotia Posts: 1,311 Likes: 319 Liked 1,106 Times in 303 Posts	Re: weight /class questions Tom, also keep in mind that you don`t neccasarily go by the weight listed on your cars registration papers, or owners manual, sales brochure etc, you have to use the weight per horsepower factor as listed in the NHRA "Stock car classification guide". There will be various factors based on different trim levels, body styles, and engines. For example, say that the model you are trying to determine has a factor of 14.38 lbs per HP, which would give a shipping weight of 2876 lbs. You can either "round it off" to the "top" of M/S, which is 14.00 lbs per HP, for a min weight of 2800 lbs, or round it off to the top of "N",(14.50) which would give a min. weight of 2900 lbs. After that, you add the 170 lbs for the drivers weight. So now the minimum for "M" is 2970, and for "N" it`s 3070. Those are the min. weights that you need to be at the scales after a run. Years ago, you were not permitted to round off the class factors, so my example of a 14.38 factor would have meant that the car & driver combo had to weigh 2876+170 for a min weight of 3046lbs. That is the reason that there were so many oddball combinations, as a 4 door sedan may have fit the class better than a 2 door, or a wagon fit better than a convertible. __________________ NHRA 6390 STK M/S 85 Mustang

03-07-2011, 06:24 PM	#3
Jeff Lee VIP Member Join Date: Jul 2007 Location: Anthem, Arizona Posts: 2,766 Likes: 0 Liked 3 Times in 3 Posts	Re: weight /class questions When I first started class racing I was confused when I heard "top" or "bottom" of class. Finally I realized it is alphabetical on a vertical chart instead of a horizontal chart. "A" is on the top and "Z" is on the bottom of the chart. Although you may not even need the NHRA shipping weight, if you want it NHRA almost has it hidden from view in the class guides posted by NHRA. You have to scroll all the way to the right away from black text over white background to the area that is black text over a grey background. __________________ Jeff Lee 7494 D/S '70 AMX

03-07-2011, 09:14 PM	#4
Tom keedle Senior Member Join Date: Dec 2008 Location: Berthoud, Coloraduh Posts: 695 Likes: 13 Liked 8 Times in 7 Posts	Re: weight /class questions guys, i've got the weight stuff from nhra figured out as far as classification, i just wasn't sure about how the drivers weight figured into it (i ALSO thought it might help some other new guy out,too) well, at least i don't have to quit eating thanks for the help,guys!