CSG and RCE tag-team suspension Q&A thread! Ask us anything!

[karlsson]

I am wondering about the difference in camber front to back. I know that rear camber should be lower than in the front to make the car corner better. But by how much?
My car is my only car so I don't want to go crazy on front camber. But what is considered not going crazy? 1.5, 1.7? 2 is a bit too much, I think. So if I went with 1.5 or 1.7 up front and zero toe front and zero or a hair positive toe rear, how much camber should I try rear?
I am on Advan Neova 08-Rs in 215/45 r17, and I am 15mm lowered on Ohlins.

[gramicci101]

Do you have any kind of camber adjustment in the rear, such as upper or lower control arms or camber bushings?

If not, you're limited to the camber gained from the lowering springs, so the question is kind of moot.

[karlsson]

I have bushings that supposedly allow for an additional 1 degree of adjustability.

[lbejosano]

This is directed to both @Racecomp Engineering and @CSG Mike. I am planning on upgrading to Michelin Pilot Super Sports on stock wheels. Which is a better size between 225 and 215 width for optimal performance? Only other suspension modifications right now are RS*R SuperDown springs and Whiteline Camber bolts. Alignment is set to -1.5F and -2.0R for camber and factory toe.

[JustDoItMikey]

@Racecomp Engineering

Talk spring rates with me. I am building my FR-S to run NASA TT and am wondering which spring rate would fit my application best as you offer multiple options on the Tarmac II. This car is mostly track driven but I do on occasion drive it on the street so performance>ride comfort. I plan to run DOT approved R compounds such as Toyo RR or similar for the track in a 225-245 width (undecided as of yet) and will likely have a street setup using something like the BFG Rivals. I have not done any research on the need of beefier swaybars for coilovers in general but I intend to run stock sways to save on the points.

All this considered is there any reason I need to run 500 or 600 springs? What track benefits would I see running the higher spring rates? What downsides are there to running higher spring rates (besides comfort)? Is running a coilover, at any spring rate, without upgrading the sways going to be a problem?

Thanks

[CSG Mike]

Originally Posted by lbejosano

This is directed to both @Racecomp Engineering and @CSG Mike. I am planning on upgrading to Michelin Pilot Super Sports on stock wheels. Which is a better size between 225 and 215 width for optimal performance? Only other suspension modifications right now are RS*R SuperDown springs and Whiteline Camber bolts. Alignment is set to -1.5F and -2.0R for camber and factory toe.

I'd recommend sticking to 215; the car will feel sloppy on 225 with stock wheels.

[Ashikabi]

Curious what you guys' opinion on a aluminum rear subframe is? How much weight would be saved? Is it safe? Would it be strong enough?

[the new guy]

Originally Posted by CSG Mike

I'd recommend sticking to 215; the car will feel sloppy on 225 with stock wheels.

Would you clarify? I thought I've always read that 225 is a performance bump from the grip in spirited driving/tracking the car.

[CSG Mike]

Originally Posted by the new guy

Would you clarify? I thought I've always read that 225 is a performance bump from the grip in spirited driving/tracking the car.

Yes, but that is with 17x8 wheels, not 17x7.

225mm is about 8.86 inches. Do you really want to mount a tire that wide on a 7 inch width rim?

[solidONE]

Originally Posted by Ashikabi

Curious what you guys' opinion on a aluminum rear subframe is? How much weight would be saved? Is it safe? Would it be strong enough?

And who makes this? With enough material used in the right way Al can be very strong, but it also can cost a lot to make. IIRC, the G35, G37, and newer Z's use extra beefy aluminum rear subframes out of the box.

[Ashikabi]

No one makes one as far as I know. That's why I'm curious. It's possible I have the facilities available to me to try to make it happen.

[solidONE]

Putting something together with the same pick up and mounting points out if al is one thing. Designing and making one that is strong enough yet still light enough to not defeat the purpose is yet another. If you know someone who knows what they're doing making it for you, and you want to put that money and effort into it just to shave some weight, go for it. Otherwise I'd think spending it on something that will actually make a noticeable impact and improvement in performance would be a better bet.

[Ashikabi]

That's why I'm asking. I expect making a one off at my work wouldn't cost near as much as contracting it out. But I'm not an engineer. However having the only aluminum subframe would be pretty darn cool. What thickness tube do you think I'd need too use for the same strength?

[Lawnik]

@CSG Mike

Your thoughts on roll center and bump steer correction kits? At what ride height do they become nessesary if any?

Thanks for the help