Generic theoretical springrate question

[heavy85]

From a very high level I need to get my head straight. I realize there are many variables to consider but would like to focus on one for now ... assuming everything else equal and that's spring rates. Some may remember from other threads that I did quite a bit of work to the chassis to stiffen up the front end while relatively little to the rear. So I would say the chassis is now relatively stiffer front to rear than it used to be. From a high level would I want stiffer springs in front to take advantage of the stiffer chassis or less stiff springs since the realized springrate is now higher relative to the rear and why? This is not a riddle I'm really trying to gain some understanding.

 

Thanks

Cameron

[tube80z]

The chassis torsion is just another spring. Even though you've stiffened the front it's hard to say if it really changed the overall chassis torsion. If that hasn't changed then you probably won't need a change. It's somewhat hard to say without some numbers to take a look at. But as a general guideline if the chassis becomes stiffer you can run softer wheel rates to get the same result. What you need to know is what is the lateral load transfer distribution on your car. In the spreadsheets at the top of this thread that's referred to as the magic number.

 

One option that I've found that works for me is to setup the suspension to try and get equal roll angles front and rear. This minimizes the need for chassis torsion. It has a side benefit of making the tires last longer and that's a big plus for me.

 

Cary

[johnc]

IMHO, a stiffer chassis allows a higher spring/wheel rate.

[EMWHYR0HEN]

Cameron,

 

If I remember correctly you running 200 ish lbs springs..?

 

It would make sense to me to increase your spring and shock rates to take advantage of the stiffer chassis.. Plus it might help reduce roll from the added weight of the V8.

[tube80z]

IMHO, a stiffer chassis allows a higher spring/wheel rate.

 

I totally agree, but what I was trying to get at and poorly worded as a flimsy chassis generally needs a lot more to see a change. Meaning you need to make larger jumps in bars or springs. Anyway, I think I'm digging a hole here ....

 

Cary

[heavy85]

I can say for a fact I improved the chassis overall torsional stiffness by the fact that it no longer sets on four jackstands. My garage is not perfectly level and it used to just sag and set on four stands anyway. Now it does not and ends up just sitting on three stands.

 

Since we're talking springrates here's another one. For a relatively high hp/torque car (LS1) would ... again in general terms ... you want a softer or stiffer rear than a lower powered car and why?

 

Thanks

Cameron

[JMortensen]

Stiffer so that you don't bottom out while accelerating would be a general rule and I think if you look you'll see posts similar to that regarding drag racing and limiting squat.

 

What's more important for your autoxer is to keep the car flat, limiting body roll and camber and toe change.

[johnc]

a flimsy chassis generally needs a lot more to see a change. Meaning you need to make larger jumps in bars or springs.

 

Quite true.