Spring Rate for Autocross

[Wolverine]

Looking to upgrade springs and dampers on my 2017 GTPP for CAM-C class. Currently on stock suspension other than BMR CB005 cradle lockout and Steeda camber plates. Car will be running 19x11” squared with 305/30R19 Bridgestone RE71R tire’s (seems to be the hot shoe in AX).

Full weight GT Premium PP. Rear seat delete may have lost some, but I gained right back with a hitch. Added fiberglass wing and APR splitter too so we’re sitting heavy. Probably 3,700 range give or take.

I’m really interested in the Steeda Competition Dual Rate springs (220-350 front, 800-1200 rear) but my concern is that they’ll be TOO STIFF and I’ll lose grip because of it. Generally speaking the softer spring rates yield more mechanical grip since the weight can transition into the tire’s contact patch smoother than a super stiff setup which could shock-load the tire and cause it to slide. The other springs I’m considering are Steeda Sport Linear, Ultralite Linear, and Sport Progressive (all of these are roughly 150-200 front, 800-900 rear). The dampers will be Steeda adjustables. Car is a daily driver but Autocross performance is equally/more important than a cushy ride.

Suggestions?

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[BmacIL]

BMR SP083 handling springs. They were amazing for me on RE71Rs with Ford Racing track dampers the weekend before last. They are 250/980 front/rear linear springs. I was ~1 seconds off competitive Corvette AS times. That was on 275 square, 305 would be another step on that! I'll probably be looking at stiffer bars in the future.

 

[tj@steeda]

Steeda Tech can provide some incredible data - private message him for some real-world testing & feedback.

Best Regards,

TJ

 

[Wolverine]

[MENTION=25806]SteedaTech[/MENTION] - I’ll send PM here shortly.

BmacIL: those BMR Handling springs are 250/980 linear. Seem like decent rates, but they don’t list how much they lower the car on their site. Do you know? Not looking to any more than 1” to 1.125” lower than stock.

 

[tj@steeda]

[MENTION=25806]SteedaTech[/MENTION] - I’ll send PM here shortly.

BmacIL: those BMR Handling springs are 250/980 linear. Seem like decent rates, but they don’t list how much they lower the car on their site. Do you know? Not looking to any more than 1” to 1.125” lower than stock.

Sounds good - you won't be disappointed!

 

[BmacIL]

[MENTION=25806]SteedaTech[/MENTION] - I’ll send PM here shortly.

BmacIL: those BMR Handling springs are 250/980 linear. Seem like decent rates, but they don’t list how much they lower the car on their site. Do you know? Not looking to any more than 1” to 1.125” lower than stock.

0.875" front, 0.75" rear.

 

[Wolverine]

Follow up... got in touch with SteedaTech and got it sorted out. Went with the dual rates like I originally was interested in. Can't wait for them to arrive now!

Thanks Steeda!

 

[Performance nut]

Follow up... got in touch with SteedaTech and got it sorted out. Went with the dual rates like I originally was interested in. Can't wait for them to arrive now!

Thanks Steeda!

It's what I got. Hope you got their adjustable shocks, they really compliment it well.

 

[BmacIL]

Nice. Looking forward to seeing what you think.

 

[tj@steeda]

Wanted to share a great video of our VP of Operations, talking about the dual rate springs & their performance on & off the track - enjoy!

[ame="[MEDIA=youtube]t6DPnBUFCxw[/MEDIA]"]

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