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

[Obioban]

So you're running the stock R&T rear springs but 350/325 fronts? Did you have to revalve the front dampers or was there enough adjustability for them to handle the softer spring?

I’m running the stock ohlins spring on the rear right

Per Ohlins, the dampers are good for +-30%, which I’m in range of. Next winter I’m probably going to have them rebuilt/revalved for my specific corner weights and spring rates.

[liam821]

I'm running 350 front left, 325 front right, 700 rear left, 628 rear right (which results in the same frequencies left/right with just me in the car).

So you're running the stock R&T rear springs but 350/325 fronts? Did you have to revalve the front dampers or was there enough adjustability for them to handle the softer spring?

[Dxj]

Has anyone tried using FCM calcs with PSS10? Vorshlag offers linear spring conversion package with their camber plates ( 450/500 springs) and I’ve heard of folks swapping out springs on PSS but not sure if anyone used FCM math to get to a right place.
Also, does anyone know what the springs rates are for PSS10? I feel that I used to be able to find it online before but I can’t any more.

[Andrew 06M3Cab]

Thanks, that's a great help. I do have US kingpins. The 3dm motorsports spacers look interesting, and solution until/if I change to the CSL kingpins.. I'll call Barry - that's where I purchased the Ohlins from. He was a fantastic help.

[Obioban]

Ian, what springs and rates are you using with your Ohlins R/T? And what ride height do you have? I installed about mine a month ago (with the Ohlins springs in the kit), haven't driven it very much at all, and now that it has settled (and i'm getting my second alignment tomorrow), I am paying a bit more attention to the set up. My ride height is just over 13.25" in the front and 12.75" in the rear. There is some adjustment available but I am wondering if I should really be going with different springs. IIRC you had some custom perches made, Just curious to know what springs you're running though.

I'm running 350 front left, 325 front right, 700 rear left, 628 rear right (which results in the same frequencies left/right with just me in the car).

The Ohlins don't have much travel up front-- you should set your ride height solely by bump/droop ratio, to make the most of it. They have 92mm of total travel, so I like to set the ride height at 32mm of droop (giving 60mm of bump travel). If you have US spec kingpins, combined with pretty much any camber plate on the market, that's going to put you low (too low for optimal handling). When I had US kingpins, I was running spacers on the shock mount to get the car sufficiently high. Now that I'm on CSL kingpins, they're no longer necessary. (side note: 3DM now sells spacers for this purpose).

My guess is that Ohlins developed their setup with Euro kingpins, which have the same shock mounting location as the Euro ones... but the US ones are different. Or designed without consideration for camber plates. Either way, non US Kingpins or the spacers above or the spacers I designed all address the issue.

Because I'm still running spacers of my own design (just now milled down further, since I got the CSL kingpins), I tweaked them so my 32mm of drop travel happens and exactly 13.5" up front. Rear is 13", and the the Ohlins have plenty of rear travel and let you set the bump/droop travel independently of ride height-- so I'm at 60% bump, 40% droop (143.5mm of total rear shock travel).

[Andrew 06M3Cab]

Ian, what springs and rates are you using with your Ohlins R/T? And what ride height do you have? I installed about mine a month ago (with the Ohlins springs in the kit), haven't driven it very much at all, and now that it has settled (and i'm getting my second alignment tomorrow), I am paying a bit more attention to the set up. My ride height is just over 13.25" in the front and 12.75" in the rear. There is some adjustment available but I am wondering if I should really be going with different springs. IIRC you had some custom perches made, Just curious to know what springs you're running though.

[Radekxpl]

I feel like street testing is better now than ever, with the pandemic going on!

In a sense that is totally true, there hardly anyone driving now specially on nice twisty back roads, can really stretch cars legs hehe 😉

[Obioban]

I actually was was running that setup last season along with, 700 rear springs Hotchkis front sway on med and no rear bar felt really good had rear csl but removed it, car feel more plated mid corner, can get quicker on the gas vs when I had rear csl, this year wanted to experiment a bit and trying out 396 front with 750 rear, would prefer 800 rear but ohlins can only max about 750 in the back before needs revalve, so far no complaints on the street but due to this pandemic, could not really give it fair test at the track time will tell.

I feel like street testing is better now than ever, with the pandemic going on!

[Radekxpl]

Hey Ian,
you have extensive knowledge with turner hybrid camber plates with ohlins dfv. I currently have ohlins with a csl rear bar and a hotchkis front on medium stiff. Car feels great but I want to experiment with flatride. If I got the turner hybrid camberplates 3ddm front strut spacer and 8inch 350 front 60mm springs would that be a good start? With the front strut spacer and the tuner plates I shouldn’t have any droop issues correct?

I actually was was running that setup last season along with, 700 rear springs Hotchkis front sway on med and no rear bar felt really good had rear csl but removed it, car feel more plated mid corner, can get quicker on the gas vs when I had rear csl, this year wanted to experiment a bit and trying out 396 front with 750 rear, would prefer 800 rear but ohlins can only max about 750 in the back before needs revalve, so far no complaints on the street but due to this pandemic, could not really give it fair test at the track time will tell.

[Obioban]

Hey Ian,
you have extensive knowledge with turner hybrid camber plates with ohlins dfv. I currently have ohlins with a csl rear bar and a hotchkis front on medium stiff. Car feels great but I want to experiment with flatride. If I got the turner hybrid camberplates 3ddm front strut spacer and 8inch 350 front 60mm springs would that be a good start? With the front strut spacer and the tuner plates I shouldn’t have any droop issues correct?

I've been running the Vogtland 7.5" springs. That lets me get the ride height adjuster higher, for the same ride height, so I can fit the tire under the adjuster instead of next to it. They have just enough travel to cover the Ohlins travel.

The turner hybrids will work nicely with the 3DM front strut spacers-- should address the bump issue entirely.

What's the flat ride ratio with the 350 fronts? going off intuition, it feels like that might not be enough to get you into the flat ride range (assuming you're keeping the stock 628 rears).
Vogtland also sells 325s, which is what I'm running on the passenger front side of my car (and the passenger rear is a stock Ohlins 628).

... I suspect you're going to want to go back to the M3 stock rear sway (instead of the CSL sway). But, again, I haven't run the numbers for your car, so just guesstimating.

[Grke46m3]

Which kingpins do you have installed?

Stock kingpins.

[Obioban]

If it feels great why mess with it? Does it have an uncomfortable pitching motion?

More comfortable, faster, easier to drive at the limit...

[T.J.]

Hey Ian,
you have extensive knowledge with turner hybrid camber plates with ohlins dfv. I currently have ohlins with a csl rear bar and a hotchkis front on medium stiff. Car feels great but I want to experiment with flatride. If I got the turner hybrid camberplates 3ddm front strut spacer and 8inch 350 front 60mm springs would that be a good start? With the front strut spacer and the tuner plates I shouldn’t have any droop issues correct?

If it feels great why mess with it? Does it have an uncomfortable pitching motion?

[Obioban]

Hey Ian,
you have extensive knowledge with turner hybrid camber plates with ohlins dfv. I currently have ohlins with a csl rear bar and a hotchkis front on medium stiff. Car feels great but I want to experiment with flatride. If I got the turner hybrid camberplates 3ddm front strut spacer and 8inch 350 front 60mm springs would that be a good start? With the front strut spacer and the tuner plates I shouldn’t have any droop issues correct?

Which kingpins do you have installed?

[Grke46m3]

Hey Ian,
you have extensive knowledge with turner hybrid camber plates with ohlins dfv. I currently have ohlins with a csl rear bar and a hotchkis front on medium stiff. Car feels great but I want to experiment with flatride. If I got the turner hybrid camberplates 3ddm front strut spacer and 8inch 350 front 60mm springs would that be a good start? With the front strut spacer and the tuner plates I shouldn’t have any droop issues correct?