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Author Topic:   WEIGHT AFTER RACE
viper3244
Dirt Full Roller

Total posts: 57
posted September 14, 2005 08:46 PM  
Ok on our weekley show we run 18 laps in the main our weight rule is 2400#'s We have a big race (special) this weekend that is at a different track and is a 30 lap main that we can excpect alot of cautions, and the weight rule is 2450. Normally I start with 28 gallons of fuel and after the feature the car with driver weighs around 2460 and generally uses about 12 gallons of fuel. Any suggestions on How much weight I should add?
And where? currently run a semi banked 1/2 and this track will be 1/2 mile but longer straights and tighter turns. I am guessing high right, or as close to center of the car s I can get it. I hate to mess with my set cause it works pretty **** good, just worried about being light. Can you add weight to just make the car heavier with out effecting the set up? I am open to any suggestions. Thanks

joeltjen
Dirt Maniac

Total posts: 182
posted September 14, 2005 09:32 PM  
interesting reading.

http://www.jimmyjudd.com/Tech/body_tech.html

rocket36
Dirt Freak

Total posts: 209
posted September 14, 2005 09:33 PM  
if your burning around 12 gallons per 18 laps now, and making weight by 60 lbs, you should be able to run 30 laps and not have to add much more weight than you normally start with.
you will likely burn twice as much fuel as normal (18 laps x 2 = 36/per 12 gallons) and this will allow for some extra cautions too.
you should try this on the scales first with 24-30 gallons of fuel - see how much the car weighs, then drain 24 gallons and see if it still makes weight, if not, add the difference in ballast.
you can add ballast to the estimated centre of gravity point in your car to have minimal effect on handling. centre of gravity is the invisble point at which you could theoretically suspend the car in the air by a hook and have it balance perfectly.
unfortunatley its a little hard to find, but if you have a car with a lift arm, place the ballast on the bar that the shock mounts to the frame on, this will be very close and you should be able to just slide in back and forth (while car is on scales) to find the point where all the wheel weights increase by the same amount and percentages should not alter.
if you don't have a lift arm, a good estimate for most cars is at the hieght as the camshaft, in line with the camshaft and a few inches behind the wheelbase centre (assuming you've got more than 50% rear weight). thats a bit of an educated guess, but it should get you close, and if you've got access to scales, then use them for things like this.

scanner
Dirt Roller

Total posts: 16
posted September 15, 2005 05:46 AM  
We mounted some lead to the center of our car right on the cross braces, & it didn't change the setup at all.

PinThunderStang
Dirt Forum Racer

Total posts: 89
posted September 15, 2005 02:08 PM  
If you are running gas keep in mind one gallon weighs about 6 pounds(6.xxx). what size fuel cell are you running? I would just fill it up with however much you need and be done with it.

autoshop
Dirt Freak

Total posts: 298
posted September 15, 2005 04:38 PM  
or you can change nothing and after the race go up on the cushion and spin the tires a few times and add weight that way too.

viper3244
Dirt Full Roller

Total posts: 57
posted September 15, 2005 05:35 PM  
Well I have to qualify on friday night so I will let you guys know how it works out. It is a ten lap heat but should give me a good idea what to excpect for fuel usage per lap. I plan on topping the 32 gallon cell (I am guessing I will need that tail weight for handling also) just what does a gallon of alky weigh???

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