e46 M3 suspension setup, or how to not downgrade your car with suspension mods

[duracellttu]

My previous suspension was TCK SA and after talking with TC he recommended 400F/500R spring rates. Any idea why the spring rates are so much different than flat rides approach?

[Cronenberged]

Yes recommended by FCM, based on corner weights and dual use. Don't have have aero yet, but eventually.

[duracellttu]

Yes recommended by FCM, based on corner weights and dual use. Don't have have aero yet, but eventually.

Can you share your corner weights?

[mrgizmo04]

Per the spreadsheet, those spring rates give you a 1% flat ride.

Yeah that's set up for "flat" ride at like 300mph with those frequencies...

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[duracellttu]

Yeah that's set up for "flat" ride at like 300mph with those frequencies...

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Is the approach to aim between a 45-70 mph flat ride?

[mrgizmo04]

Is the approach to aim between a 45-70 mph flat ride?

Yeah, remember, it is somewhat "static", so you need to aim for avg cornering speeds on track. That will differ on a more technical/slow speed vs a more open higher speed, but 45-70 is a decent range.

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[mrgizmo04]

Yes recommended by FCM, based on corner weights and dual use. Don't have have aero yet, but eventually.

I guess I can see it if your car is rather stripped where you are carrying closer to 55-60% of weight in the front.

What are your FRC and hz ratio per FCM setup recommendations?

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[Cronenberged]

Can you share your corner weights?

Had me searching deep for the pic.

[duracellttu]

Had me searching deep for the pic.

Nice, looks like you have some significant weight reduction.

[Cronenberged]

I guess I can see it if your car is rather stripped where you are carrying closer to 55-60% of weight in the front.

What are your FRC and hz ratio per FCM setup recommendations?

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I had Shaihk run the numbers for me and I can't fully remember but I believe was right around where it needs to be.

[cobra]

To me it seems like a reasonably balanced ratio. It's just pretty stiff... 2.2Hz+ frequency. For track use this is ok but street use I would target closer to 1.7

[mrgizmo04]

Yeah with weight loss (mostly at the rear), those rates make more sense and result in some flat ride. Just getting readout of the rates without additional context seemed sacrilegious from FCM suggesting borderline pitchy setup, so ok there.

The only thing I'm still hung up on is adding so much front bar to those front rates, seems like a pushy setup with FRC over 80? Is that just driver preference, or some other context missing?

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[Obioban]

GC front bar comes in 3 different wall thicknesses and is adjustable.

[IamFODI]

GC front bar comes in 3 different wall thicknesses and is adjustable.

Thick, car-breakingly thick, and extra car-breakingly thick?

[Chas3n]

What are you spring rates? Also, did you measure corner weights?



Also curious if you measured your corner weights before FCM recommended spring rates? Were these spring rates aimed towards a sporty or more race focused setup?

The B4/Eibach pro kit/hotchkis setup is not height adjustable, so you’re not able to corner balance.

The point of the setup is budget flat ride. I wasn’t interested in spending $5,000+ to get a proper setup damper and spring rate conversion. Not saying it’s not worth it, but for how I drive my 46, the cost doesn’t add any more experience to the car.

My s2000 on the other hand I’ll be working with Shaik on dialing that in as it’s already purpose build to see track time.