Suspension advice please; 2,400 lbs., street legal

[LAP1DOUG]

Originally Posted by Hasbro

Fwiw, was comfortable with 2.35 - 2.5 hz. suspension and RA1s on last street project, could go a little bit higher with proper dampers.

Hasbro:

With the low weight that you are going to, you are looking at a corner weight of about 540 lb on each front wheel, and 660 lb on each rear wheel.

With these corner weights on the 986 suspension geometry, you only need about 330 lb/in springs in front for a 2.40 Hz frequency, and 430 lb/in rear springs for a 2.56 Hz frequency in the rear.

If you are going to autocross at AMS, I would not go much over a 2.5 Hz frequency as there are some surface changes where you need compliance to avoid upsetting the balance.

If you know what natural frequency you are going to run, you really don't need multi adjustable dampers. Just get some high quality single adjustable dampers set up at around 70% of critical damping force, and you are good to go.

That said, the biggest bang for your buck is going to be camber control. For that, you need either GT3 LCA's or camber plates (or both) along with an adjustable front bar. These McStrut suspensions have awful camber curves, and you must add front bar to stop the dynamic camber change that makes the stock configuration understeer like a pig.

Good luck.

[Hasbro]

Originally Posted by LAP1DOUG

Hasbro:

With the low weight that you are going to, you are looking at a corner weight of about 540 lb on each front wheel, and 660 lb on each rear wheel.

With these corner weights on the 986 suspension geometry, you only need about 330 lb/in springs in front for a 2.40 Hz frequency, and 430 lb/in rear springs for a 2.56 Hz frequency in the rear.

If you are going to autocross at AMS, I would not go much over a 2.5 Hz frequency as there are some surface changes where you need compliance to avoid upsetting the balance.

If you know what natural frequency you are going to run, you really don't need multi adjustable dampers. Just get some high quality single adjustable dampers set up at around 70% of critical damping force, and you are good to go.

That said, the biggest bang for your buck is going to be camber control. For that, you need either GT3 LCA's or camber plates (or both) along with an adjustable front bar. These McStrut suspensions have awful camber curves, and you must add front bar to stop the dynamic camber change that makes the stock configuration understeer like a pig.

Good luck.

Thanks, LAP1DOUG. In November I spoke with Chuck at Elephant re. their Vonn's non adjustable coilovers. With my budget requiring a drawn out time line I would have to save up for a good while. Not a horrible situation but it would delay some of my other concurrent projects such as bodywork and a ton of refreshing. An economical route would allow me to move on, however, down the line, higher quality parts would be desired. I guess I need to determine my priorities! Therein lies the rub.
I really like tinkering with suspension adjustments so with non adjustables there would still be adjustable bars front and rear?, tire pressure, yada, yada. Maybe go with even lighter springs?

I appreciate your weighing in. My last project involved struts and an engineer on that forum made a wonderful suspension program for that specific model. It was the best tool ever and it taught me a lot so I still want to think in Hertz for starters.