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Old 03-10-2012, 01:03 PM   #80
LOWDOWN
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Join Date: Apr 2009
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Take a look at these Weight Breaks, apply the specific Class...and you'll see 1,000 hp is NOT happenin'...the car would have to weigh a MINIMUM 6,000 POUNDS!


NHRA and IHRA Stock and Super Stock weight breaks
All classes, except where noted, have separate Stick and Automatic Classes. Some classes offer a weight break to the automatic, 5% or 250 pounds, whichever is LESS. Check the Rulebook for your class and sanctioning body.


All cars are pounds per NHRA or factory rated horsepower, unless noted All cars can move weight to go up or down a class from their natural class. Example, a car with a weight break that fits it into F/SA naturally, can also run E/SA and G/SA

NHRA Super Stock (IHRA are the same for these)
SS/AH 6.00 (NHRA, only 1968 Hemi Barracudas and Darts can run this class, and is their only class. Sticks and autos run together)
SS/A 6.00-6.49
SS/B 6.50-6.99
SS/C 7.00-7.49
SS/D 7.50-7.99
SS/E 8.00-8.49
SS/F 8.50-8.99
SS/G 9.00-9.49
SS/H 9.50-9.99
SS/I 10.00-10.99
SS/J 11.00-11.99
SS/K 12.00-12.99
SS/L 13.00-13.99
SS/M 14.00-14.99
SS/N 15.00-15.99
SS/O 16.00-16.99
SS/P 17.00 and more

NHRA SS/GT (IHRA are the same for these)
GT/A 8.00-8.49
GT/B 8.50-8.99
GT/C 9.00-9.49
GT/D 9.50-9.99
GT/E 10.00-10.49
GT/F 10.50-10.99
GT/G 11.00-11.49
GT/H 11.50-11.99
GT/I 12.00-12.49
GT/J 12.50-12.99
GT/K 13.00-13.49
GT/L 13.50-13.99
GT/M 14.00 and more

NHRA GT Truck (IHRA are the same)
Sticks and autos run together
GT/TA 9.50-10.49
GT/TB 10.50-11.49
GT/TC 11.50-12.49
GT/TD 12.50 and more

SS/Modified Stock (IHRA only goes to SS/DS)
Sticks and Autos run together
SS/AS 8.50-9.49 pounds per cid
SS/BS 9.50-10.49
SS/CS 10.50 or more
SS/DS 12 pounds or more; V6 only
SS/ES 15.50 or more, 4 cyl only, max 165 cid
SS/FS 16.50 or more, 155 cid max
SS/GS 18 pounds or more; 4 cly, FWD only, max 230 cid

SS/Modified Truck (IHRA are the same)
Four clases; sticks and autos run together
SS/TA through SS/TD weight breaks mirror SS/AS through SS/DS

Super Stock Modified (IHRA are the same)
Sticks and Autos run together
SS/AM 7.50-8.49 pounds per cid
SS/BM 8.50-9.49
SS/CM 9.50-10.49
SS/DM 10.50-11.49
SS/EM 11.50-12.49
SS/FM 12.50-13.49
SS/GM 10.50 or more pounds; non-supercharged inline 4 or 6 cylinder and straight 8
11.00 or more pounds, non-supercharged American factory controlled V6

Super Stock Modified X (IHRA are the same)
No V8's allowed in SS/MX; sticks and autos together
SS/AX 8.50-10.99 pounds per cid
SS/BX 11.00-12.49
SS/CX 12.50 or more
SS/DX 15.00 pounds or more; two turbochargers or OEM supercharger

NHRA Stock Eliminator (IHRA is the same, except where noted)
AA/S 7.50-7.99 (IHRA is 7.00-7.99)
A/S 8.00-8.49
B/S 8.50-8.99
C/S 9.00-9.49
D/S 9.50-9.99
E/S 10.00-10.49
F/S 10.50-10.99
G/S 11.00-11.49
H/S 11.50-11.99
I/S 12.00-12.49
J/S 12.50-12.99
K/S 13.00-13.49
L/S 13.50-13.99
M/S 14.00-14.49
N/S 14.50-14.99
O/S 15.00-15.99
P/S 16.00-16.00
Q/S 17.00-17.99
R/S 18.00-18.99
T/S 19.00-19.99
U/S 20.00 or more (IHRA 20.00-21.99)
V/S 22.00 or more (NHRA, only 4 and 6 cylinder cars are eligible)
W/S 24.00 or more (NHRA, only 4 cylinder cars are eligible
AF/S 13.00-15.99
BF/S 16.00-17.49
CF/S 17.50-18.99
DF/S 19.00-24.99
EF/S 25.oo or more
(sticks and autos run together; stick shift carries a 100 pound penalty in NHRA FWD Stock)
IHRA Weight breaks, for IHRA-only Classes

Super Stock Production (either a single 4 bbl or single 2 bbl carb is permitted)
SS/PA 7.00-7.49 pounds per cid
SS/PB 7.50-7.99
SS/PC 8.00-8.49
SS/PD 8.50-8.99
SS/PE 9.00-9.49
SS/PF 9.50-9.99
SS/PG 10.00-10.99
SS/PH 11.00-11.99
SS/PI 12.00-12.99
SS/PJ 13.00 or more

SS/Modified Compact
Sticks and autos run together
SS/AC 15.00-16.49 pounds per cid; includes rotary engines
SS/BC16.50 or more
SS/CC 18.50 or more; American production front engine
SS/DC 15.00-17.99; 4 or 6 cylinder FWD
SS/EC 18.00 or more; 4 cyl FWD only
SS/FC 4 cyl, 165 cid or less; 2400 pounds auto, 2500 pounds stick

SS/Fuel Injected Modified
Sticks and Autos run together
SS/AFI 7.50-8.49 pounds per cid
SS/BFI 8.50-9.49
SS/CFI 9.50-10.49

Stock FWD
Sticks and autos have their own classes in IHRA
AF/S 13.00-15.99
BF/S 16.00-16.99
CF/S 17.00-17.99
DF/S 18.00-18.99
EF/S 19.00-19.99
FF/S 20.00-23.49
GF/S 23.50-27.49
HF/S 27.50 or more

Stock FI
AA/FI 7.50-7.99 Only 2008 and newer factory muscle cars are eligible.
A/FI 8.00-8.99
B/FI 9.00-9.99
C/FI 10.00-10.99
DF/I 11.00-11.99
EF/I 12.00-12.99
FF/I 13.00-13.99
G/FI 14.00-14.99
H/FI 15.00-15.99
I/FI 16.00-17.99
J/FI 18.00-19.99
K/FI 20.00-21.99
L/FI 22.00-23.99
M/FI 24.00

Stock Trucks
1980 and newer, 1/2 ton or mini trucks only. Four wheel drive combinations prohibited. Class A and B restricted to all wheel drive. Classes C through J restricted to two wheel drive. Class J restricted to 4 cylinders only. Kind of sounds like two different things--no 4 wheel drives, but the class is restricted to all wheel drive?? It's in the rulebook.
AT/S 12.00-12.99
BT/S 13.00-13.99
CT/S 12.00-12.99
DT/S 13.00-13.99
ET/S 14.00-14.99
FT/S 15.00-15.99
GT/S 16.00-17.99
HT/S 18.00 or more
IT/S 20.00-21.99
JT/S 22.00 or more

Stock GT
1980 and newer cars, with engines from 1955-1979; sticks and auto's run together
S/GTA 8.00-8.99
S/GTB 9.00-9.99
S/GTC 10.00-10.99
S/GTD 11.00-11.99
S/GTE 12.00-12.99
S/GTF 13.00-13.99
S/GTG 14.00 or more

Pure Stock
No supercharged or turbocharged cars permitted; sticks and autos run together
A/PS 8.00-8.99
B/PS 9.00-9.99
C/PS 10.00-10.99
D/PS 11.00-11.99
E/PS 12.00-12.99
F/PS 13.00-13.99
G/PS 14.00-14.99
H/PS 15.00-15.99
I/PS 16.00-16.99

Stock Crate Motor
1955 and newer cars and 1/2 ton trucks; sticks and autos run together
A/CM 6.00-6.49
B/CM 6.50-6.99
C/CM 7.00-7.49
D/CM 7.50-7.99
E/CM 8.00-8.49
F/CM 8.50-8.99
G/CM 9.00-9.49
H/CM 9.50-9.99
I/CM 10.00-10.49
J/CM 10.50-10.99
K/CM 11.00-11.49
L/CM 11.50-11.99
M/CM 12.00-12.49
A/FCM 9.00-9.99
B/FCM 10.00-10.99
C/FCM 11.00-11.99

How cars are classified:
The majority of Super Stock and Stock cars are classified by a horsepower to weight ratio. You divide the shipping weight of the car by the factory, or in some cases, NHRA/IHRA, horsepower.

As an example: Say you want to run a 396 cubic inch, 325 factory horsepower rated engine, with an automatic transmission, in a 1968 Camaro, with a factory shipping weight of 3,253. You divide the weight by the horsepower (3,253 divide by 325), and you will get 10.01. This will put you in the E/SA class, or SS/IA class. All cars are permitted to move up or down one class, so this car is also eligible for D/SA and F/SA in Stock, and SS/HA and SS/JA in Super Stock.

All cars are permitted to adjust weight to do this, and also to make the top of their natural class. To do this, you multiply the top weight break in each class by the HP rating of the engine. You then add 170 pounds, for driver, to arrive at the minimum weight for your car, in each class, that it must cross the scales at. All cars are weighed with driver.

So: E/SA = 10.00 pounds x 325 + 170 = 3,420 pound minimum weight with driver across the scales at the conclusion of the run. To run D/SA (9.5) or F/SA (10.5), you would use the top weight break in each class to determine the weight in that class the same way. From time to time, NHRA/IHRA will adjust the HP of the engine. This will at times adjust the class(es) the car can run. This is based on on-track performance and letters written by racers. Using the example above, if a number of racers using the '68 Camaro396/325 were running very fast, consistently, NHRA may adjust the HP of the engine to a rating of 340. This will change the class(es) the car can run.

So:3,253 divided by 340 = 9.56. Making this car a natural D/SA, that can run C/SA and E/SA in Stock. Minimum weight is still calculated the same, but now you will use 340 instead of 325. It works the same way if NHRA were to reduce the HP rating of the engine. If there were a number of cars running this combination that were not very fast, and sent letters to NHRA requested a HP decrease, it may happen. If NHRA were to decrease the rating of this motor to, say,305: 3,253 pounds divided by 305 = 10.66. This would make the car a natural F/SA, that can run E/SA and G/SA. Again, minimum weight calculation process is the same, except you use 305 instead of 325. NHRA updates their Stock Car Classification Guide (http://www.nhra.com/competition/classification.aspx ) weekly, so be sure to check periodically to see if any adjustments have been made. Only combinations listed in here are eligible for NHRA traditional Stock and Super Stock.

For other classes, such as Super Stock GT, GT Truck, Stock GT, and Crate Motor Stock, you divide the shipping weight of the body you want to use; divided by the performance rating of the engine you want to use, to determine the natural class of the car. From there, minimum weights and eligible classes are determined using the formula above. For Super Stock Modified, SS/Modified Stock, Modified Truck, Modified X, Modified Compact and SS/Production, they are classified by pounds per cubic inch. If your car weighs 2,800 pounds with driver and your engine is 280 cubic inches, your car will fit into the 10 pound class.
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