Matt Romanowski

I wanted to share some cool data I collected two weeks ago. We were at Palmer and I could feel the car "hopping" a bit in turn 10. Here is a screen shot of what I was feeling.

You can see the suspension moving a bit (about .25"). The car felt like it was moving more and I think it was the tires. What's really neat is you can see the tire temps vary with the suspension movement. You can also see the changes in the lateral G force as well.

Another cool things is the bump at about 8525'. The offset from the front suspension movement to the back suspension movement ends up right at 8', which is the car wheel base!

For anyone who is into suspension tuning, you've probably heard the terms tire load variation. This is a great example of that and shows how the suspension movement and variation in tire load (about 8-10 lbs here) can change the tire temp and grip available. This is the variation that you are trying to tune out with great shock valving and tuning. it's also why tuning the suspension with consideration to the tire is important, as the tire is another spring (and undampened at that).

The setup to do this is nothing too wild. I did it with an AiM MXL2, shock pots (roughly $275 each) and tire temp sensors ($100 each).

ProCoach

Good stuff. I like the wheelbase calculation!

Are you using one temp sensor per corner for the tires?

Matt Romanowski

The wheelbase was an interesting find. I was first wondering why the bump was offset, then realized the front has to hit it first (duh). Using the delta function, the difference matched the wheelbase. Pretty cool.

I have a lot of IR sensors on this car. 12 sensors total from 3 manufacturers, creating 27 channels of data. There are over 66 total channels logged. Then a few math channels....

ShakeNBake

Oh man, that is really cool!