Chris White

You may be able to calculate the best ‘theoretical’ spring rate…but that does not equate to the best spring rate in the ‘real’ world. I know that some of the readers get all bent out of shape when I say that, but the ‘real’ world has to take into account track conditions, weather conditions, driver style and other intangibles that are not in the theoretical world.

If there existed a track that was as smooth as a pool table with absolutely no imperfections I would set a 944 up with very high spring rates. The 944 is a street production car and as such has a suspension that displays unwanted (for the track) characteristics through its range of movement.

If the track is very rough (like Bridgehampton before it closed) you need a much softer spring rate to avoid skipping down the track! Braking into the heal of the boot at Watkins Glen does not work well with a very stiff suspension – and it can’t be fixed by just tweaking the shocks!

Dry vs rain….big difference in spring rates.

Driver style – smooth vs overly aggressive, trail braker vs hard turn in….

Tires – brand new Hoosiers or 30 heat cycle Victoracers.

Suspension components – solid vs rubber bushings.

Way, way too many factors in the ‘real’ world to be able to calculate the one best spring rate. You can calculate a good starting point but that’s about it – or you can see what has been working for other successful drivers/teams and start with that set up and fine tune it to your needs.

ausgeflippt951

Hey I never said to assume a perfectly flat pool table!

It is possible to calculate it. Everything's possible... F1 has been capable of doing this kind of extremely sophisticated simulation for years.


Semantic argument aside, I was agreeing with you: whatever calculations you perform will only provide you with a baseline. Once you get to the track and can actually experience the track surface, you will inevitably require fine-tuning adjustments. Even F1 can't wholly predict that.

mikey_audiogeek

I enjoy calculating this sort of thing. I'm an engineer, after all! And I also have a variety of spreadsheets and dynamic simulation software. So why do I keep getting reminded of the quote from Carroll Smith (Engineer to Win)?:

"Some ideas look good on paper. But remember, paper doesn't make much of a crash barrier..."



Cheers,
Mike

Chris White

Ah yes, the ubiquitous* Carroll Smith…*(that’s his favorite word!).

Anybody that lays a wrench on a track car should have all of Carroll’s books. Just the right mixture of serious engineering and common sense. One of the first things I picked up from his books is when using a nut and bolt to attach something to a race car have the nut facing down or back – that way if it does loosen and fall off you will have a chance that the bolt will stay in place if you are lucky! This also goes along with the idea that bolts should only be used in shear fashion (where ever possible).

Look up these books and buy them today…..!!