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

[cobra]

40,000 miles is about 10yrs away for me. I didn't go this route to be "cheap" but rather to achieve maximum comfort without spending the next step up, which would be $5,000+

Price breakdown not including refreshing the OE hardware (links, shock mounts)
Hotckis Sway bars $630
B4 Dampers $450
Eibach Springs $300

So for roughly $1400, which is the cost of most trash "coilover" kits (think BC Racing, KW V1/2, ect.) I have a setup that performance wise is FASTER, and comfort wise is MUCH better. The next step up would be custom valved Billy's from Fat Cat and springs which would run $5,000. B8's are a downgrade in comfort which is HUGE to me. B8's marginally perform better than the B4's but significantly ride worse than b4's. You can send the b8's out Fat Cat, but at that point, they make less financial sense performance wise % than ordering a set of the pss10's and sending them to Shaik..

My ride is sublime in both comfort and performance and for 1/4 the price of a dedicated "track setup". Again, 40k mile interval rebuilds is awesome, easy enough to do and will take me a decade to get to.

Curious - How do you define comfort and performance objectively?

[Chas3n]

B4s are twin tube like koni and oe sachs and are pretty comfy and will dampen well enough if the spring rate isn't much higher than stock, like Eibach pro-kit.

B6s would be better, but harsher.

exactly this. Harsher is not what I wanted. Car spends most of its driving being a GT, and partial time me embarrasing locals on the canyon roads. Thing is, with flate ride, and ideal wheel/tire setup, even at the "cheap" flat ride setup, I can easily run away and have loads of confidence with the car.

[Chas3n]

Yes. I ran B4s with Eibach Pro-Kit springs on my E91, and I was doing dampers again in 50k miles. But the dampers were gone by 40k, I was just too busy to deal with it. Sometimes cheap is too cheap -- I put B8s on there this time, and I wish I had just done that the first time around.

40,000 miles is about 10yrs away for me. I didn't go this route to be "cheap" but rather to achieve maximum comfort without spending the next step up, which would be $5,000+

Price breakdown not including refreshing the OE hardware (links, shock mounts)
Hotckis Sway bars $630
B4 Dampers $450
Eibach Springs $300

So for roughly $1400, which is the cost of most trash "coilover" kits (think BC Racing, KW V1/2, ect.) I have a setup that performance wise is FASTER, and comfort wise is MUCH better. The next step up would be custom valved Billy's from Fat Cat and springs which would run $5,000. B8's are a downgrade in comfort which is HUGE to me. B8's marginally perform better than the B4's but significantly ride worse than b4's. You can send the b8's out Fat Cat, but at that point, they make less financial sense performance wise % than ordering a set of the pss10's and sending them to Shaik..

My ride is sublime in both comfort and performance and for 1/4 the price of a dedicated "track setup". Again, 40k mile interval rebuilds is awesome, easy enough to do and will take me a decade to get to.

[K-Dawg]

So pretty much B8's and Eibach springs are The B12 (pro-Kit)

Edit" seems they dont make B8's for our cars

The B12 kit is B6 dampers with Eibach Pro-Kit springs. No B8's for the E46M.

OE springs are also flat ride, but buying new would be quite a bit more expensive than Eibach or Dinan.

[Obioban]

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.

Yeah, eibach springs and Dinan springs, paired with Bilsteins or Konis, are the cheap ways to decent flat ride.

[Tbonem3]

B4s are twin tube like koni and oe sachs and are pretty comfy and will dampen well enough if the spring rate isn't much higher than stock, like Eibach pro-kit.

B6s would be better, but harsher.

[lvm3sm46]

So pretty much B8's and Eibach springs are The B12 (pro-Kit)

Edit" seems they dont make B8's for our cars

[r4dr]

Chas3n aren't the B4's just a OEM replacement?

Yes. I ran B4s with Eibach Pro-Kit springs on my E91, and I was doing dampers again in 50k miles. But the dampers were gone by 40k, I was just too busy to deal with it. Sometimes cheap is too cheap -- I put B8s on there this time, and I wish I had just done that the first time around.

[lvm3sm46]

Chas3n aren't the B4's just a OEM replacement?

[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.

[IamFODI]

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

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

[Obioban]

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

[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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[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

[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.