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Hey guys, I've been racing now for only a couple of years on and off and I've had help from people about how to tune my car at the track but I still haven't gotten a clear picture in my mind as to what the suspension is doing in the turns. Specifically weight transfer on entry, through the center, and on exit.

(Maybe some can describe it in detail as the car rolls through the turns?)

I'm the kind of person that has to see it in my mind to really figure it out and I'm thinking if I can really get how the suspension works on the front and rear of the chassis then I can figure out on my own how to fine tune the car know matter what track I'm at.

My goal this year in racing is to figure out how the car works and tune it on my own, along with getting faster on the track. :thumbsup:

Would really like to gain knowledge from some of you more experienced DUDES!
 

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I think you have to start with the fundamental basics of knowing what the car is doing. Being able to determine if the car is loose or tight is a basic idea that you HAVE to know.

A loose car is always fast, but is the car loose or is it pushing so much that it is breaking loose?? Big difference there. Where are the other guys beating you on the track? Are they beating you off the corners, down the straights? Knowing this can help with figuring out if you lack drive off of the corner or speed down the straights.

I can't speak about front suspension and what it is doing in the corner per se, because I honestly am not that knowledgeable about it. I know how I want my car to feel and I can gauge my performance off of those on the track with me. One rule I always follow is this.....

If the car is loose, work on the rear end. If it is tight, work on the front end. Also, IMO, you should do very little work to the side shocks in order to cure an ill-handling car. Next, always, always be tweaking on your car and working on new things. If you are not tweaking something after each heat, you are getting beat.

Another good rule of thumb.....if your car feels really good and really smooth and is easy to drive, you are slow most likely. A good, fast car should be on the edge all the time. If your car don't make you pucker up just a bit when you are driving it, you are most likely leaving speed out on the track somewhere!:thumbsup:

There a few others here that can chime in and help you out much more than I can, but I think it is important to understand the basics before you kill yourself trying to figure out the minute details.

Good luck to ya this year.....
 

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I don't think he was looking for setup help,
it sounded more like he was interested in the physics aspect...

:confused:
 

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I don't think he was looking for setup help,
it sounded more like he was interested in the physics aspect...

:confused:
Yeah, I understand what he was asking. I am just saying that without the basics, knowing the physics of it does no good IMO.

He said is goal this year was to figure out how the car works and tune it on his own. In order to do that, I think you have to first know what the car is doing in terms of setup and handling. And maybe he already knows those things, which would be great. But if he don't, or for others that come along and read this thread, I was simply trying to point out what has helped me get better on the track.
 

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Handling guide....

This was copy/pasted from a thread over at 'dirtoval.com'. Hope it helps!

Phase 1 (going into the turn)

If the vehicle is loose at turn entry then..(needs more traction)

(1) Right front spring is to soft use a harder spring
(2) You need to add more crossweight - by adding a round to the right front spring (add weight to the left rear tire).
(3) Change left front spring to a softer spring.
(4) Lower chassis - keeping it level with the rear.
(5) Reduce front right caster (no less than 2 degree min.)

OR If the vehicle is pushing into the trun entry then..

(1) Right front spring needs to be softer.
(2) You need to reduce the crossweight - by taking out a round to the right front spring (add weight to the front left tire)
(3) Increasing right rear spring tension by one round
(4) Increase front right caster (6 degrees max.)

Phase 2 (the middle of the turn)

If the vehicle is loose in the middle of the turn then...(needs more traction)

(1) Increasing the crossweight by adding a round to the front right and left rear evenly (add weight to the left rear tire)
(2) Use a harder spring to the left rear
(3) The right rear spring needs to be decrease a round (less spring tension)

OR If the vehicle pushes in the middle of the turn then...(needs more steering)

(1) Decrease crossweight by taking out a round to the front right and left rear evenly
(2) Use a softer spring to the right rear
(3) The right rear spring needs to be increase a round (more spring tension)

Phase 3 (coming out of the turn..)

If the vehicle is loose coming out of the turn then..(needs more traction)

(1) Stagger needs to be decreased on the right side
(2) Increase crossweight by adding a round of spring tension to the right front and left rear evenly (add weight to the left rear tire)
(3) Check if right rear spring tension is to much - if it is then take a round out of spring.
(4) Decrease rear springs evenly to the right and left rear.
(5) Use a soft tire in the rear

OR If the vehicle pushes coming out of the turn then...(needs more steering)

(1) Stagger needs to be increased on the right side if present.
(2) Decrease crossweight by reducing a round of spring tension to the right front and left rear evenly (add weight to the front left tire)
(3) Increase right rear spring tension a round.
(4) Increase rear springs evenly to the right[/SIZE]
maybe this will help
 

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See if I can take a basic crack at that one...

First you have to break down where the car is at on track and break down what the suspension is doing at that point----for example: ON ENTRY, as the car begins a corner...two things happen, weight transfers DOWN on both front tires and weight also transfers from the LF tire to the RF tire (AGAIN, this is early entry and ONLY the front suspension). As the weight travels DOWN the nose of the chassis as well as the entire front suspension TRAVELS or compresses. It also ROLLS, usually from left to right and usually you will hear guys talk about ROLL-CENTER...which is essentially how far the Center of the front supsension moves from left to right as well as up and down FROM THE CENTER OF THE CHASSIS. How much usually varies on things such as a-arm location, spring rate, spring preload, Kingpin length as well as camber gain/loss and caster. You have to pay attention to both vertical movement (up and down) as well as Lateral movement (side to side) and think of them as one movement because they happen at the same time on entry.

CENTER: As the car lands or set's, the suspension stops traveling and the forces balance out and maintain a certain ride height and the suspension tends to maintain that ride height for a moment as the car travels into the center and through the center where the amount of force being applied down as well as laterally are at their highest...

Center/Early Exit: As the car begins to travel just past the center or APEX of the corner...the suspension begins to Unload as a result of the forces being applied to it begining to lessen---the springs begin to cause the chassis's ride height to rise as weight is now begining to transfer off the front tires towards the rear of the car and back off the rf of the car and towards the center of the chassis

Exit: This is essentially where the rear of the car begins to take control of the car under acceleration and the weight is transfered from the Front tires to the Rear tires. REMEMBER: BOTH FORCES (VERTICAL and LATERAL) are still working together so as weight transfers from the front to rear it also transfers from the right side back towards the left!

Hope this is close to what you were looking for...

-Robbie Burgess
 

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Yeah, I understand what he was asking. I am just saying that without the basics, knowing the physics of it does no good IMO.
And I understand what you are saying, but to be honest, it sounds
like he is pretty clear on tight/push... loose/goose.

He specifically asked about weight transfer and the like...
He's asking about weight transfer through each segment of the corner.
So imo, looks like he is seeking more advanced info..

In other words, for example, when the car goes into the turn,
what happens to the weight?
It goes to the right front..
Midway it balances out the right side, and exit, it goes to the right rear.

(reader's digest version of what Robbie said)

Camber gain... caster stagger... not just 'use a stiffer spring' but 'why'? maybe??
I'm sure he'll let us know :thumbsup:
 

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IMHO.......

Weight is transfered diagonaly from one corner to the opposite corner. "X"

Grab yourself a 4 scale set-up board and you can learn quite a bit of the "physics" of things.
 

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Discussion Starter #10
Guys thanks for the input I really appreciate all f the help. Robbie you h. The nail on the head with what I was really looking for even though I really appreciated Corys comments.

I guess some more info would help as well like what is the difference in suspension geometry between flat tracks and banked tracks.

With so many solutions to the same loose/push problem I'm looking to become a student of suspension dynamics so that I can come up with a more consistent setup.

Thanks again... all of the advise is well received.
Bill
 

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Weight never goes to one corner and stayes there. What the weight is actually doing in the corner is very complicated and depends on more than just suspension. Static weight VS. dynamic, tires, front and rear roll center, ect. That's why nasar teams use "shaker" rigs to test suspension, as through the corners the car is "oscillating" on all 4 corners. a general rule is RF in, right side center, RR off, but it is much more complicated than that. I always remember that getting into the corner you adjust the Left side of the car, and getting off I adjust the right side, through the center I adjust camber, caster, center shock, or lead on the LF tire. Doing some basic research on suspensions geometry design on the internet would be a big help as there are some articles out there that cover it in great detail.
 

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Danny Bs Black book has everything you are looking for ....If you go back a couple of years on this site theres a link somewhere on here ... SRM
 

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Tune To Win

say man,
if you wanna learn chassis go and pick yourself up a copy of Carrol Smith's Tune to Win. its a good book that covers quite well the basics of chassis dynamics and tuning, lots of diagrams and pictures and not very math intensive. obviously its about big cars but chassis dynamics is chassis dynamics.......fore the most part;)
good luck
chris
 

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This was copy/pasted from a thread over at 'dirtoval.com'. Hope it helps!

Phase 1 (going into the turn)

If the vehicle is loose at turn entry then..(needs more traction)

(1) Right front spring is to soft use a harder spring
(2) You need to add more crossweight - by adding a round to the right front spring (add weight to the left rear tire).
(3) Change left front spring to a softer spring.
(4) Lower chassis - keeping it level with the rear.
(5) Reduce front right caster (no less than 2 degree min.)

OR If the vehicle is pushing into the trun entry then..

(1) Right front spring needs to be softer.
(2) You need to reduce the crossweight - by taking out a round to the right front spring (add weight to the front left tire)
(3) Increasing right rear spring tension by one round
(4) Increase front right caster (6 degrees max.)

Phase 2 (the middle of the turn)

If the vehicle is loose in the middle of the turn then...(needs more traction)

(1) Increasing the crossweight by adding a round to the front right and left rear evenly (add weight to the left rear tire)
(2) Use a harder spring to the left rear
(3) The right rear spring needs to be decrease a round (less spring tension)

OR If the vehicle pushes in the middle of the turn then...(needs more steering)

(1) Decrease crossweight by taking out a round to the front right and left rear evenly
(2) Use a softer spring to the right rear
(3) The right rear spring needs to be increase a round (more spring tension)

Phase 3 (coming out of the turn..)

If the vehicle is loose coming out of the turn then..(needs more traction)

(1) Stagger needs to be decreased on the right side
(2) Increase crossweight by adding a round of spring tension to the right front and left rear evenly (add weight to the left rear tire)
(3) Check if right rear spring tension is to much - if it is then take a round out of spring.
(4) Decrease rear springs evenly to the right and left rear.
(5) Use a soft tire in the rear

OR If the vehicle pushes coming out of the turn then...(needs more steering)

(1) Stagger needs to be increased on the right side if present.
(2) Decrease crossweight by reducing a round of spring tension to the right front and left rear evenly (add weight to the front left tire)
(3) Increase right rear spring tension a round.
(4) Increase rear springs evenly to the right[/SIZE]
maybe this will help
Glad to see this is still around.
This was copied from www.nascart.com web page years ago.
 
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