53--47 weight bias

Tintoy35 · Dec 23, 2020

Scaled the car before taking it apart. Have 53% front and 47% rear weight bias . Didn't have the time to try placement of weight. Put about 100 lbs to the very back of the trunk and got a 50 50. 1st question would you add weight having 53--47 . 2nd question would it be better to add some weight to the frame rails or just spread it out across the rear of the car or best weight placement. Not going to add 100 lbs and nothing to change up front. Fiberglass bumpers. Thanks 2910 lbs race ready without me.

Darter6 · Dec 23, 2020

All I know is guys do both methods. My neighbor runs a F stock Duster.We made 3''x3'' square tube about 12''-14''and filled with lead melted down from wheel weights the local tire shop gave us. He mounted them to the rear frame rails. The Sox&Martin 68 SS/B Cuda had the weights in the trunk next to the tail panel.

Cranky · Dec 23, 2020

Well, if you place weight in the very back, that can slow down your pitch rotation and sometimes mess up the launch. Experimentation is key so don't do something too permanent without seeing how it acts. Btw, how heavy are you? I took 35 lbs off of my butt several years ago but haven't been back racing

Tintoy35 · Dec 23, 2020

Cranky said:
Well, if you place weight in the very back, that can slow down your pitch rotation and sometimes mess up the launch. Experimentation is key so don't do something too permanent without seeing how it acts. Btw, how heavy are you? I took 35 lbs off of my butt several years ago but haven't been back racing

Old and fat but still learning . 225 and trying to lose some weight but not 100 lbs. Lol. When I sat in the car it didn't change any %. A friend of mine put some weight under the fuel cell in the trunk of his Challenger.

66Satellite47 · Dec 23, 2020

My '65 Coronet was 3350# w/o me, plastic side windows, gutted doors & dash, lots of misc metal removed, all steel front, Dana, iron head 440, 125# 8D battery in the trunk. It was 50/50.

Cranky · Dec 23, 2020

Tintoy35 said:
Old and fat but still learning . 225 and trying to lose some weight but not 100 lbs. Lol. When I sat in the car it didn't change any %. A friend of mine put some weight under the fuel cell in the trunk.

I hit 235 and at 5'9", that didn't feel too good. Got down to the low 190's and put some back on when this pandemic hit and having a hard time getting back to it and have been steady at 200. Still, that's too heavy for my liking. Still, taking weight off the car is always a good thing no matter what part loses it lol

6PKRTSE · Dec 23, 2020

With today's bigger horsepower combo's what you have is not that bad. My car is currently 54.4% on the nose. More and more of my buddies whos engines we have set back over the last 20 years are now all moving back them back up to factory locations to help keep the nose down.

Cranky · Dec 23, 2020

6PKRTSE said:
With today's bigger horsepower combo's what you have is not that bad. My car is currently 54.4% on the nose. More and more of my buddies whos engines we have set back over the last 20 years are now all moving back them back up to factory locations to help keep the nose down.

Must have some pretty good traction then.....

33 IMP · Dec 23, 2020

Cranky said:
Must have some pretty good traction then.....

Yes but it is the down-track wheelstands that are the problem. With the power the cars are making now, and the self-imposed handicap of "small tires" the cars are leaving the starting line with power turned way down, and then having to control a wheelstand two or three hundred feet down track. More front end weight helps when the extra thousand horspower shows up!

Cranky · Dec 23, 2020

33 IMP said:
Yes but it is the down-track wheelstands that are the problem. With the power the cars are making now, and the self-imposed handicap of "small tires" the cars are leaving the starting line with power turned way down, and then having to control a wheelstand two or three hundred feet down track. More front end weight helps when the extra thousand horspower shows up!

What kind of rear suspension does the car have and what kind of ET's are being turned?

33 IMP · Dec 23, 2020

Cranky said:
What kind of rear suspension does the car have and what kind of ET's are being turned?

Most that i have seen use four link, or ladder bars, but some (primarily g-body gm's and fox body mustangs) use very modified factory unequal four links. My old racing buddy with a stroker LS with a turbo, uses a nine inch hung on the factory unequal fourlink. He leaves with somewhere around 400hp, then the next eight hundred ramps in. His next car, the one with the procharged tall deck aluminum solid block KB, is a promod with a real four link. (He is way, WAY faster than i want to be!)

6PKRTSE · Dec 23, 2020

Mine car is Cal Trac, split mono's. 29.5 x 10.5 or 315 D.R.'s. My buddies GM G Body with stock suspension has gone best of 8.24 on 28 x 10.5's with a stock block BBC and 2 kits. Yes, they have traction. He has pictures of all 4 tires off the ground on the back bumper many times. The whole small tire no wheelie bar rules usually becomes the issue....

dvw · Dec 24, 2020

Mine is 54.5F/45.5R without ballast. Any ballast added slows it down. Running Index we regularly add ballast. Can be up to 200lbs. Placing it on the floor right around the main hoop doesn't change anything but ET. R/T stays the same. Just slows the car. Adding to rear will slow the car but sometimes not as linear. High has similar results to rear placement. The further away weight is placed from the CG, the greater the changes to distribution. This also increases polar moment of inertia. In layman's terms: Chassis will resist rotation and continue to rotate when it is moving, but the initial movement will be slower. The bottom line is the more power the less chassis rotation and housing separation you need. Power will plant the tire. Most cars being discussed here have way more power than any of us. To be honest I'd like to knock a 100lbs of the nose. (currently 1810F/1510R). Marginal tracks or even normal bracket prep with10.5 tires is not the same as 1500+hp on radial prep.
Doug

Tintoy35 · Dec 24, 2020

Thanks everyone !!!!! This was my first year trying to compete at age 66. In the past I usually did mostly test and tune and didn't concentrate so much on the lights. So I went 6.50 racing this year. Like Doug said I don't have the extra hp. Just trying to find anything to help with the 60 ft. Like I said earlier getting old but still wanting to learn. Thanks again. Rick

Darter6 · Dec 25, 2020

Thanks Tintoy, You give me hope that I'm not too old yet. :thumbsup:

dvw · Dec 25, 2020

Join the club guys. I’m 66 as well. Age has little to do with it. Desire and attention to detail.
Doug

Dodge 330 · Dec 27, 2020

Tintoy35 said:
Thanks everyone !!!!! This was my first year trying to compete at age 66. In the past I usually did mostly test and tune and didn't concentrate so much on the lights. So I went 6.50 racing this year. Like Doug said I don't have the extra hp. Just trying to find anything to help with the 60 ft. Like I said earlier getting old but still wanting to learn. Thanks again. Rick

6.50 index is my favorite. I scaled the car recently and it was over 3,700 lbs. as raced last. I would really love to scale the four corners to see where I'm at but so far it's workin fine. I usually have 55 lbs. of ballast in the rear of the trunk but honestly haven't tried it without. Battery up front, all steel, full interior. It has been a 1.36 60 ft. with leafsprings so I must be doing something right. LOL!

66Satellite47 · Jan 3, 2021

That's an impressive 60'. Do you use a brake?

Dodge 330 · Jan 3, 2021

66Satellite47 said:
That's an impressive 60'. Do you use a brake?

Nope, no transbrake.

sam65 · Jan 9, 2021

Dodge 330 said:
6.50 index is my favorite. I scaled the car recently and it was over 3,700 lbs. as raced last. I would really love to scale the four corners to see where I'm at but so far it's workin fine. I usually have 55 lbs. of ballast in the rear of the trunk but honestly haven't tried it without. Battery up front, all steel, full interior. It has been a 1.36 60 ft. with leafsprings so I must be doing something right. LOL!

1.36 n/a ?

53--47 weight bias

Well-Known Member

Well-Known Member

Banned Henchman #27

Well-Known Member

Well-Known Member

Banned Henchman #27

Well-Known Member

Banned Henchman #27

FBBO Gold Member

Banned Henchman #27

FBBO Gold Member

Well-Known Member

FBBO Gold Member

Well-Known Member

Well-Known Member

FBBO Gold Member

Well-Known Member

Well-Known Member

Well-Known Member

Well-Known Member

Similar threads