Downforce Pro Mod

Roughly, how much rear areo downforce are people generating with Outlaw PM's these days? Either through body work or through wings/spoilers? As the ET's drop and the speeds increase, I would assume lots. Don't need exact numbers, but some ballpark numbers for figuring out a couple of things would be appreciated.

As always, thanks for any feedback either on or off line.

 

just as rough numbers go : from the stuff iv be apart of running 240-250 in the 1/4 we see around 900lbs, these numbers are pulled from the shock sensors, for easy numbers if we know are spring rate is 150lbs. Then we look at the shock sensors and see that they are being compressed 3 inches from static right height that would tell us 3x150=450, 450x2 due to having 2 shocks gives us 900lbs of force making the shocks move.
I recently read some stuff regarding this and the only way to get a true awsner it seems is to add the use of a ride height sensor. Due to the tires gaining size , or growing as they gain speed its hard to actually determine if the shocks are being compressed from downforce, tire growth, or what is probably the real deal, both of the forces together.
The numbers i put up are just simple math stuff and every car would be different of course, and this is only the rear shocks, im sure if you could measure all 4 tires together you would get a higher number

 

Thanks Guys. So at what part of the run does downforce really start to play a critical role in a typical Pro Mod? Mid track and beyond for a 1/4 run, or mainly just for the top end charge and stability? Obviously the downforce is going to grow as a function of the vehicle speed.

For those who have played around with dedicated wings with struts on a PM, versus a big "picnic table" like extension with spill plates, do you see much difference between the two in terms of vehicle performance or vehicle stability assuming that both are somewhat optimised?

 

you miss understood, Obviously the shock sensor will only record the travel of the shock in relation to the frame ( or whatever the other end is mounted to ).As the tires gains speed it also grows vertically in size. This will lift the rear end of the car and push up on the chassis through the shocks. The point of having a ride height sensor would be to determine if the tire growth is compressing the shocks in an upward motion at the same time the shocks are being depressed downward from the weight of down force.

You can never have to much data and in a situation like this when you have two opposing forces it would help figure out the OP's first question, Maybe the tire growth isnt enough to overcome the shocks spring and all measured data from the shock sensors are correct. Maybe not. I dont have the data to prove one way or the other but hopefully somebody does.

 

Would you be able/willing to share a screen shot of a graph with shocks and ride height? Im curious as to what it shows as iv never seen it before and it may help the OP with his questions to boot.

 

thanks for the pics mike. Still didnt tell me what i was wondering but nice to see the info non the less. Im not sure il be able to get the data i was actually wanted to see regardless of sensors