BMR relocation brackets

[KEVINS]

Thats a good point but you can only move the instant center back so far with relocation brackets. In lifting the body you are also transfering weight towards the rear of the car which helps plant the tires. A car will 60' better with the instant center moved rearward. It is possible to go to far rearward with your instant center adjustment. Every car reacts different. Thats why we have several different holes to use in our brackets.

You are NOT "transfering weight" when lifting the body to plant the tires. There is a huge difference in "transfering weight" and "Loading the tires" due to lifting the body. What the drop down brackets do is cause a higher Anti-Squat Value to separate the rearend from the body thus planting the tires into the ground. Yes, this Loads the tires but this is NOT weight "transfer". Weight transfer happens due to acceleration which happens afterwards due to the car moving forward.
The rearend separating is mearly a way to get traction to get the car moving thus start the weight transfer.

Weight transfer can also be hurt b/c the body is lifting too much. If the rear of the body is lifting UP (b/c the rearend is being planted into the ground) then this also pushes the front of the car down pivoting around the CG, thus hurting weight transfer. So MORE body separation to plant the tires even harder due to a really high AS value is only going to push the nose of the car down even more. This affect causes the car to leap frog off the starting. The more the tires are planted does not mean more weight transfer. These are two totally different ideas and definitions.

You can also have weight transfer by having the car squat b/c weight transfer happens after the car moves. It has nothing to do with what the rearend is doing compared to the body of the car.
KS

 

[Betcha618]

Thats a good point but you can only move the instant center back so far with relocation brackets. In lifting the body you are also transfering weight towards the rear of the car which helps plant the tires. A car will 60' better with the instant center moved rearward. It is possible to go to far rearward with your instant center adjustment. Every car reacts different. Thats why we have several different holes to use in our brackets.

You are NOT "transfering weight" when lifting the body to plant the tires. There is a huge difference in "transfering weight" and "Loading the tires" due to lifting the body. What the drop down brackets do is cause a higher Anti-Squat Value to separate the rearend from the body thus planting the tires into the ground. Yes, this Loads the tires but this is NOT weight "transfer". Weight transfer happens due to acceleration which happens afterwards due to the car moving forward.
The rearend separating is mearly a way to get traction to get the car moving thus start the weight transfer.

Weight transfer can also be hurt b/c the body is lifting too much. If the rear of the body is lifting UP (b/c the rearend is being planted into the ground) then this also pushes the front of the car down pivoting around the CG, thus hurting weight transfer. So MORE body separation to plant the tires even harder due to a really high AS value is only going to push the nose of the car down even more. This affect causes the car to leap frog off the starting. The more the tires are planted does not mean more weight transfer. These are two totally different ideas and definitions.

You can also have weight transfer by having the car squat b/c weight transfer happens after the car moves. It has nothing to do with what the rearend is doing compared to the body of the car.
KS

What your saying is 1/2 true. If your car is set up right it works. I have the brackets on my car and on launch it hangs the front wheels about 2 inches above the track. so i am getting the maximum usable down force on my rear tires, with out the resistance of a high wheelie (which hurts your e.t.) . Yes, my car lifts the back of the body off the frame on launch but the front comes up higher, thus still having weight transfer when the front tires hit the track again. You have to find a happy medium when setting up your susp.

 

[KEVINS]

What your saying is 1/2 true. If your car is set up right it works. I have the brackets on my car and on launch it hangs the front wheels about 2 inches above the track. so i am getting the maximum usable down force on my rear tires, with out the resistance of a high wheelie (which hurts your e.t.) . Yes, my car lifts the back of the body off the frame on launch but the front comes up higher, thus still having weight transfer when the front tires hit the track again. You have to find a happy medium when setting up your susp.

His definition of Weight Transfer is wrong and I wanted to clarify what it is.
What I say is 100% true. I simply tried to explain the dynamics of what is going on. As you described if someone can use this to go quicker, GREAT!

In my experience if the car is set up right you don't need to plant the tires (maybe a little depending on the car) and the rearend stays neutral or fairly neutral. This saves energy to help propel the car forward instead if wasting energy to plant the rearend. If it's going up then it's not going forward.

BUT this is determined by what the CAR wants which is figured out by trial and error with suspension geometry, different shocks, springs, tires, weight distribution, torque converter, etc and can be costly b/c some parts may need to be replaced in order to go quicker. Slower cars may need more "hit" (higher AS value) than faster cars but again it's all figured out by trial and error.

Simetimes a "better" launching car may be one that 60's a tad slower but is more managable down track where the power can really be applied.

I don't like to look for happy mediums when setting up / designing a suspension but, yes, sometimes you do if someone is on a budget. There is sooo much that goes into setting up a car and it all depends on what the car wants not what the owner/chassis guy want's to do. Every chassis guy will have a baseline setup that he uses for the majority of cars then he adjusts from there and sometimes a car wants something weird and that's the setup that is used..
My main goal is to get the desired AS and IC values for the application and I use whatever is necessary to do that.

Don't stop testing and trying things out sometimes a simple shock change can make a huge difference or altering the ride height 1" or different frontend travel, etc. Just keep testing to fine tune the car, you may be surprised! cool.gif

ks

 

[BMR Sales]

Thanks for clarifying that. As i stated every car is different.

 

[fast eddie]

you say if its going up its not going forward

what about super stockers that"PITCH ROTATE" actually propelling
them forward, can anyone chime in here?

 

[KEVINS]

you say if its going up its not going forward

what about super stockers that"PITCH ROTATE" actually propelling
them forward, can anyone chime in here?

Sure.. Sometimes you have to compromise and need it to go up.. It's more efficient to keep the nose on the ground if the car will like it but if it doesn't hook up then that is no good either..

ks