[Footloose]

Does anyone know where I can find the specs on 2009 Sedan center of gravity and also front and rear roll center. I have been doing
some performance driving and want to work out tire pressures.

 

[AAIIIC]

How are you going to work out tire pressures with those numbers? Even professional race teams that have every dimension and specification available to them use pyrometers to analyze tire temperatures and determine tire pressures based on that.

 

[V Wagon]

You can measure them but you'll need a drive on hoist to get under the car to get the measurements with the wheels on the ground. Get a Faro arm and put it on a drive on hoist to measure suspension points to determine roll centers (this would be an expensive option but you'll have a sweet toy). Or if you don't need to be that exact you could just do some measurements with a tape to find the points, draw it out, and get the roll centers. You can find the center of gravity with corner scales. Check corner weights with car on flat ground. Then do it with the car tilted, going to need the drive n hoist again, leave one end of the car on the ground and raise the other end slightly with the hoist. Measure the angle of tilt, see what the weights are when tilted, you can find the CG from there.

But I agree that none of this is going to help you find the optimal tire pressure.

 

[Footloose]

Thanks for the reply, I can do the work to find center of gravity, but I was hoping some had already done it. I am working toward the maximum contact patch, I know the max G's in turning left and right. With the center of gravity and the motion ratio I can calculate the loading on the tires. This should give me a good start on tire pressures.

The driving I have done, by the time a get parked a pyrometer is a waste of time unless you have a real problem.

 

[AAIIIC]

Does the track you're running at not have hot pits?

 

[Footloose]

The latest performance driving experience they aren't happy stopping in the hot pits and doing tire pressure. We are not racers we are guys trying to learn the
limits of our cars with out getting an ticket or maybe impounded.