Weight placement on metric

[3dinter]

Just scaled the car LF 797, RF 810, LR 802, RR 701..Rear 48.3...Left side 51.4...right side 48.6...RF/LR 51.8 ...total weight 3111 with our driver. The car has the lead in the rear above the axle
As the car is right now i am Tight going in, Push in the middle and Lose on exit of the 3/8 slightly banked track i run.
What does these readings tell me and where should I need more / less weight at or move weight too ?

[DANNY]

Why so heavy up front? 3111 with driver sounds like the problem I had with my car before I put it on a diet it was 3450 to get the % right...

[3dinter]

Why so heavy up front? 3111 with driver sounds like the problem I had with my car before I put it on a diet it was 3450 to get the % right...

Everything is hulled out up front, the car still has minimal factory fenders and hood. Maybe a 50 lb square bumper, that's the most heaviest thing in front of motor. I'm confused too..with as much weight I have over the rear, I would of assumed at least 51% for the rear.
So it took your car to be 3450 to get the % right ?

[DANNY]

You should pull that bumper off and see what happens to your % a 50 lb bumper up front is way too much lol

[racingford]

not sure of your rules but set seat as far back to the center of the axle as the rules will allow. if the cage wont allow you to do so than your barking up the wrong tree with the car you are working with. if you do take that 50lb bumper oft the front it will be 100lb lighter at the same rear percentage . do not go to any track with at least 50- 51% rear or stay home.With that being said the more rear will likely make it tighter in, i would put more bite in the left rear get some of that weight off the left front or more rear brake even if that means bigger caliper or differnt master cylinder on rear or just throw it in harder.......... try this make the left and right front and right rear as close to the same weight and the left rear to make up the difffence... just my thoughts works for me

[3dinter]

You should pull that bumper off and see what happens to your % a 50 lb bumper up front is way too much lol

Yeah that is probably a Lil overkill when we was building the car, guess I could try the limited type front bumper.

[3dinter]

not sure of your rules but set seat as far back to the center of the axle as the rules will allow. if the cage wont allow you to do so than your barking up the wrong tree with the car you are working with. if you do take that 50lb bumper oft the front it will be 100lb lighter at the same rear percentage . do not go to any track with at least 50- 51% rear or stay home.With that being said the more rear will likely make it tighter in, i would put more bite in the left rear get some of that weight off the left front or more rear brake even if that means bigger caliper or differnt master cylinder on rear or just throw it in harder.......... try this make the left and right front and right rear as close to the same weight and the left rear to make up the difffence... just my thoughts works for me

The seat, cage and dash is far back as our rules allow, maybe put in a larger fuel cell, but I do understand the at least 50 or more% rear.

[racingford]

the trend with most is less capacity for less moving weight and replaced with lead you can put laed over the rearend but you cant put fuel over the rearend. but these chassis are not dealing with the nose weight. i have a 22 gallon cell real close to rearend with aprox 150 to 160lb lead mounted high in front of cell but still behind reaend,run 3/4 to 1/2 in cell and no less than 53% rear in a class at 2950 rules and weigh in 3200lb

[DANNY]

Yeah that is probably a Lil overkill when we was building the car, guess I could try the limited type front bumper.

Theres still alot of weight that I can shave off but a good start is if you dont have to run the steel body go with alum. then look at all the little things I still have to redo the driver area as its real thick steel still and then its goes to some of the parts on the car ie steering and trans need to get rid of the heavy saginaw lol... but in all right now it prob weighs with no lead just fuel around 2600... add me (270) and a bunch of lead and right now I can range it form 3100-3200 depending on how much rear % I want... That puts me from 54-56% rear...

When I started the "diet" someone told me, "For every pound I take off the front, its like adding 2 pounds to the rear!!!"

food for thought

[3dinter]

the trend with most is less capacity for less moving weight and replaced with lead you can put laed over the rearend but you cant put fuel over the rearend. but these chassis are not dealing with the nose weight. i have a 22 gallon cell real close to rearend with aprox 150 to 160lb lead mounted high in front of cell but still behind reaend,run 3/4 to 1/2 in cell and no less than 53% rear in a class at 2950 rules and weigh in 3200lb

i might have to go to a bigger fuel cell, i have a 12 gal in it right now, a lil here and there should help out.

[3dinter]

Theres still alot of weight that I can shave off but a good start is if you dont have to run the steel body go with alum. then look at all the little things I still have to redo the driver area as its real thick steel still and then its goes to some of the parts on the car ie steering and trans need to get rid of the heavy saginaw lol... but in all right now it prob weighs with no lead just fuel around 2600... add me (270) and a bunch of lead and right now I can range it form 3100-3200 depending on how much rear % I want... That puts me from 54-56% rear...

When I started the "diet" someone told me, "For every pound I take off the front, its like adding 2 pounds to the rear!!!"

food for thought

Definately a DIET for the front end...and i guess im to the point all the LIL things matter now.

[DaveBauerSS6]

Just scaled the car LF 797, RF 810, LR 802, RR 701..Rear 48.3...Left side 51.4...right side 48.6...RF/LR 51.8 ...total weight 3111 with our driver. The car has the lead in the rear above the axle
As the car is right now i am Tight going in, Push in the middle and Lose on exit of the 3/8 slightly banked track i run.
What does these readings tell me and where should I need more / less weight at or move weight too ?

I would not correct a tight in with weight in a stock car. Correct your front springs. I have 8 cars I crew for with less than 50% rear and they all turn in well. The one with 46.8% is the fastest car. Diets are for forward bite. If you are not sure, add 100# in the rear and see if it changes the entry.

[3dinter]

I would not correct a tight in with weight in a stock car. Correct your front springs. I have 8 cars I crew for with less than 50% rear and they all turn in well. The one with 46.8% is the fastest car. Diets are for forward bite. If you are not sure, add 100# in the rear and see if it changes the entry.

the fronts are R 1000 lb, 5.5x11.....L 1100 5.5x11 i have been reading and thinking of going to lower rates on the front, maybe something like a L 800 R 900 or vice versa...

[DaveBauerSS6]

I have a metric IMCA stock car and am running 800 lf and 850 rf with 50.5 % rear.

I have had the fronts at 1050 and the rear % at 55.2. I put my car on a diet I think as good as anyone could and added 345# of lead over the rear end to make minimum weight.

Too heavy front springs will NOT allow as much weight to transfer forward when going into the corner. Too heavy springs will make rough tracks worse to drive on.

Swing weight, ( any ballast positioned rear of the rear axle ) will take a loose condition and make it worse. Tight tracks with a lot of stop and go racing cant handle swing weight.

We yank their teeth out of the corners with the lower rear %. And when the track dries out, it stays under the driver.

To answer your question, Tune your entry with the front springs. Light is better for the above reasons, but you select the RF spring and shock so it will not bottom the frame ( most of the time), then tune the entry with the LF spring. As said in other posts roll center and how hard the driver enters the corner will play a factor in the exact choice for the spring. You may end up with a heavy spring on the LF; that's OK as long as the car turns well.

Good luck.


BTW I have a crew of mid 80's caddys that run a no ballest, no minimun weight class with open rear ends. We run against full montes and malibus that have 50 to 51 rear. We are 4 to 5% less and out handle and kick their butts every nite.

[3dinter]

I have a metric IMCA stock car and am running 800 lf and 850 rf with 50.5 % rear.

I have had the fronts at 1050 and the rear % at 55.2. I put my car on a diet I think as good as anyone could and added 345# of lead over the rear end to make minimum weight.

Too heavy front springs will NOT allow as much weight to transfer forward when going into the corner. Too heavy springs will make rough tracks worse to drive on.

Swing weight, ( any ballast positioned rear of the rear axle ) will take a loose condition and make it worse. Tight tracks with a lot of stop and go racing cant handle swing weight.

We yank their teeth out of the corners with the lower rear %. And when the track dries out, it stays under the driver.

To answer your question, Tune your entry with the front springs. Light is better for the above reasons, but you select the RF spring and shock so it will not bottom the frame ( most of the time), then tune the entry with the LF spring. As said in other posts roll center and how hard the driver enters the corner will play a factor in the exact choice for the spring. You may end up with a heavy spring on the LF; that's OK as long as the car turns well.

Good luck.


BTW I have a crew of mid 80's caddys that run a no ballest, no minimun weight class with open rear ends. We run against full montes and malibus that have 50 to 51 rear. We are 4 to 5% less and out handle and kick their butts every nite.

Right now i have about 275# over the rear "no swing weight" just to get the 48.3 %, and i order some lower springs to try them as well. appreciate the help. Our season is about to start, so ill get back to trying new things each week.