I’d like to take a little time to describe what is going on in dirt late model racing lately. Actually, I think it’s been going on for a couple of years now.
I now I’ve been working with this for at least five years now, but it has not been popular with local racers.
It seems if it’s not well known or it’s not being done widely on the national scene, local racers dismiss it as being ill relevant.
And that is setting up your car in a dynamic state as opposed to a static state.
Anyone who has read my book know this is how I prefer to think about things.
Actually I believe if you are scaling your car, like we traditionally do it, you are kind of guessing at what the car actually needs in a dynamic state on the track.
I continually get asked the question about how much wedge is “right”. I sometimes feel like banging my head against the wall.
There are too many things that affect wedge in a dynamic state that it’s really impossible for me to answer that question.
This why I’m going to talk about the next step in setting up your car in a dynamic state. I’m pretty sure that Bloomquist guy has been doing this for years.
And, have been told through a reliable source that “everyone” is doing that now.
I first was hip to it by a guy named Bubba Gale who created a spring loading machine to set up corner spring loads on coil-overs without scaling a car.
This is the closest you can come to setting up your car in a dynamic state as you will come.
First through, you need to create a base line and gather some information about your car before you can really begin cracking away at setups and making your car better.
I don’t know the experience level of all my readers, so I will lay down some basics that will hopefully level the playing field for everyone.
Your car redistributes its weight as it rolls around the track. The numbers you recorded on your scales would look much different if you could pick your car up and set it on scales in the middle of the corner.
The transferring of weight will cause the springs to compress more on some shocks and less on others. We see this thought ride height change on each corners of your car.
For instance if your right front spring compresses 3” because of weight transfer the load on that spring will be different, obviously.
If we take a 300 lb. spring and compress it 3 inches it will have a load close to 900 lbs. (I say close because as you compress a coil spring the coils begin to close up and the rate per inch will increase slightly)
If you scale your car, your right front spring will have a static load. Let’s pretend it’s 500 lbs.
It will also have a certain ride height. We will need to measure eye to eye on the shock and record it.
Then take out the right front spring and shock and put it into one of these load machines and compress it to that ride height. The load will read 500 lbs.
If we compress it now 3 inches the machine will read 1,400 lbs.
So, we know that in the corner if the spring compresses 3 inches, it will take 1,400 lbs of load.
If we want to lower the right front corner of the car an extra inch to 4 inches, we will need to figure out either a spring combination to accept 1,400 lbs of load at 4 inches of compression or we will need to increase weight transfer to increase the load on the right front to 1,700 lbs.
Usually this is done mostly with springs. Maybe a little with weight transfer.
A common trend is to use soft springs to get the right front loaded and the use a stiff bump stop or bump spring to set the final ride height.
This is a topic though for another day.
What I’m saying with all this is, if you know what you running ride heights are at each corner, you can set your car up using the wheel load machine without ever touching the scales.
You will need to first collect some data to do this.
You will also need a load machine to see what your wheel loads are on each corner.
First, I would recommend getting some accurate way to measure shock compression at each corner as the car travels around the track. Data acquisition is the best way, but it is expensive and mostly illegal everywhere.
Allstar sells a kit to measure this. This and some visual clues is my method of choice.
Second, I would take a measurement of the center to center on each shock on the car at ride height.
Third, take off each corner shock and spring and put it into the machine and figure out what load is on each corner at ride height and dynamically on the track.
After you have all this data recorded, the fun begins.
Tuning your car in a dynamic state.
Tim next time,