So I have been doing some research on adding a rear diffuser to my current setup when I ran across an article/blog on the Professional Awesome Racing website
https://professionalawesome.com. After read their article on aero and downforce I decide to shoot them an email to see if their splitter diffuser would be a good addition to my front aero. Long story longer we have exchange sever emails regarding my aero and suspension most significantly my spring rates and the owner Dan O'Donnell provide me with the following information:
So you have a “true type” rear, meaning the spring is directly on the damper body, not in the stock bucket. This has the effect of dramatically increasing the “wheel rate” or effective spring rate at the wheel, if you are using the same spring rate you use previously. If you are running 14k front 12k rear or 800lbs front 700lbs rear, the car will oversteer badly. I just had a long discussion with Savanna Little and Kevin Parlett. They are using a “true type” design as well on similar chassis designs and no suspension manufacture compensates properly for the change.
With your rear wing, I think you can safely add our diffusers and vents, but I would really, really want you to change spring rates to a proper setup. Your system is borderline unsafe in my opinion. Let me know if you want to do the calculations to get the right springs in there. Quick math is lettings me like if you have 14k front springs, you need to be around 5-6k in the rear.
So I am prepared to pay for the his consulting fee as this a steep learning curve for me and at my soon to be power level I don't want to be wadding my car up or possibly hurting anyone else. Here is where I need some help as he needs some information from me to dial the best spring rates for the rear coilovers. I need to provide him with corner weights for the car and obviously right now I have no way to do so. He doesn't need to have actual numbers but just need to be in the ballpark. My car weighs about 3440 with me in it and I am 210 lbs. If any of you have corner weight numbers and your car is of similar weight I would greatly appreciate you providing them to me.
Thank you in advance and go check out the Professional Awesome Racing!
Cheers,
Bob