Zeus

Theres an article in the December issue of Car Craft about traction. I grew up with the general rule of thumb that every 100lbs weight savings is worth a tenth in your ET due to their being less mass to push down the track.

In the article, they interview Jimmy Byrne and he says if you want your car to go faster, add more weight. That's the basic jist of the section. There was one guy who was gutting his interior to get a lighter race weight, and Jimmy told him not only to put all the interior back in, but add 100lbs ballast to the rear. This is a total paradigm shift for me. What do you guys think about it?

I realize that increasing the weight in the rear increases the normal force on the wheels and hence traction, but you still have to pay a price for this during the other 90% of the race. Is it that in traction limited vehicles, the decrease in 60' times would be far greater than the small addition to the time over the next 1260'?

As an offshoot, what would be better, shaving 50lbs off the front by using lightweight suspension components, adding 50lbs to the rear without any new suspension parts, or adding the lightweight parts and the ballast?

Normally I wouldn't trust anything car magazines publish, but this guy runs 8.30's on a regular basis so I figure he knows just a teeny bit more than me when it comes to going fast.

Shon Herron

iTrader: (25)

no comment....considering I cant run 8.30s but my timeslips tell me to remove as much weight as possible and make the suspension work as it should.

With alot less weight we have improved in all aspects of the track....

Hugger

iTrader: (21)

I read that same article and left feeling the same way you do. I really don't know what to think about his theories but they are definitely interesting. I feel like I always run best when I am as light as possible. Although I have never experimented with adding weight to the rear. The article definitely made me undecisive about subtracting weight. I don't remember the total weight of the author's car. Does anyone remember?

Zeus

I don't think it mentioned it.

SUX2BU

iTrader: (14)

if you're not traction limited taking out weight WILL make you ET better.

aram

iTrader: (7)

I don't really think that applies to lower power street cars. I wouldn't trade my 2875 # raceweight for anything. I was able to cut 1.6 60fts with 300 rwhp and a dead stock (1991 original including shocks) mazda IRS suspension at a less than optimal track.

Ben R

What he's trying to show you is that having the correct weight bias in a car can be more important than saving a few pounds.

Shon Herron

iTrader: (25)

But you would first pull all the weight and add it back in (where it is needed)...the way the NMRA cars are done!!! (Just naming that b/c I am familiar with some of those set ups)

The Juggernaut

iTrader: (7)

in a car that fast they can haze the tires down the track.
Traction being equal, that statement makes no sense.

ONEBADWS6

iTrader: (22)

What he said!

rozzyroz

jugg and onebadws6... i thought you guys had the same cars there for a second there was even a car in the background in your sig pics that was the same

Ed Wright

iTrader: (1)

That old adage of 100 lbs = 1/10th is close on a lower hp car. With mine it is closer to .006 sec. I was talking about that with Jim Hayter, long time NHRA Pro Stock and Comp Eliminator crew chief, and with the Comp cars he is working with right now (mid-to-low 7 second small blocks) they see about .005 sec per 100 lbs when they juggle ballast to change classes. Years ago, my old Stock Eliminator cars saw right at 1/10th per 100. I have never added weight to a car that hooked correctly, and failed to slow it down. Pounds are the same as hp. Weight BIAS is very important.

Ed

Bitemark46

I disagree with his comments. More weight = more energy spent to produce the same results. BUT putting the weight in the rear of the car would help. Of course traction needs to be determined if it is a factor or not. When removing weight as long as your CG (Center of Gravity) moves to the rear of the car, it benefits you. -Mark

black_z

iTrader: (4)

His argument does hold water, but not to the normal enthusiast. There is a point of diminishing returns when it comes to weight in relation to traction.