Ohlins R&T Spring/Sway Choice

[LSB4Me]

No noise with the e9x front spring? Think Barry is able to get these? Also what's the custom trimming look like? I love my ohlins but I always feel
Like the rear is so damn busy sometimes. Not uncomfortable but just busy.


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Yep—the busy feeling drove me crazy. The car still moves over undulations but it’s less of a disturbance now and feels
more composed.

Barry and I are connecting on Monday to discuss spring inventory. I will report back.

In terms of noise, I did notice a slight clunk or two when turning the wheels to parallel park last night. Not offensive and a trade off I’m more than willing to accept.

The trimming sounded minor, but my shop
handled it. They certainly didn’t complain about the job. I’ll ask about that as well and revert. Though I don’t think this was a custom, one-off tedious headache.

[Grke46m3]

Finally got back to the M3 this week.

Ohlins E9X front springs installed. The front upper rubber spring mounts was trimmed slightly and they went on without issue.

In short, the slightly softer e9X springs make a world of a difference. It was a game changer.

Disclaimer: I am (hyper) specific about suspension setup. I want things firm but compliant. I want to feel the road, but don't want to be disturbed by it. I also like to run higher rebound than others, data be damned. At 10f / 11r clicks off from full stiff with 500lb rear springs, the ride is sublime.

No noise with the e9x front spring? Think Barry is able to get these? Also what's the custom trimming look like? I love my ohlins but I always feel
Like the rear is so damn busy sometimes. Not uncomfortable but just busy.


Sent from my iPhone using Tapatalk Pro

[LSB4Me]

Interesting! Good feedback. That looks like a race track compared to many of the roads up here
The thing I've learned about going too stiff on springs is... you can't simply soften it up by softening your shocks, because you end up with a horrendously bouncy ride. With softer springs you have more room to play with adjusters, though I think "stiffening" it with damping is a good way to make it start riding harsh if you're not careful.

I was thinking of trying 350/550 or 300/475 next. It becomes increasingly hard to find springs with enough travel if you're running stock height.

I agree re bouncy ride with stiff springs. When on stock RT rates, I adjusted my dampers twice a day for weeks. It became really tiresome and I was never happy. Going softer in the rear conformed my fear—the RT rates were too high. The search for appropriate front springs was exceedingly tricky … until I got Barry at 3DM on the phone and discussed things at length.

You might want to try these front springs, Cobra. They are the same length as the springs on our e46 RT kit and they don’t require camber plates.

Regarding ride height, I’m enjoying comfortable compliance despite being rather low. I haven’t measured but it seems like 13.25 f / 13.0 r. Planning to go up a spline or two in the front, as my tech unilaterally reduced the front height when changing out the front springs this week.

[cobra]

Bumpy roads were my problem. For those of you that aren’t familiar with Los Angeles, the roads are truly awful. Think budget cuts meets warzone. At the Ohlins stock rates (400/630), my car was constantly in motion and absorbed nothing. Felt like I was on horseback.

Current rates are 342lb front (Ohlins stock spring off the E9x RT kit); 504lb rear (Swift, 6”). Stock sway bars.

And as mentioned above, on my new setup, I’m able to happily run the damper rebound setting where I like them—fairly firm. FWIW, soft springs and firm dampers are how GT3s come from the factory.

Interesting! Good feedback. That looks like a race track compared to many of the roads up here
The thing I've learned about going too stiff on springs is... you can't simply soften it up by softening your shocks, because you end up with a horrendously bouncy ride. With softer springs you have more room to play with adjusters, though I think "stiffening" it with damping is a good way to make it start riding harsh if you're not careful.

I was thinking of trying 350/550 or 300/475 next. It becomes increasingly hard to find springs with enough travel if you're running stock height.

[LSB4Me]

So what rates are you running now?

I am currently on 400/630 Ohlins rates and while incredible on a smooth road, it's too damn stiff for bumpy roads.

Bumpy roads were my problem. For those of you that aren’t familiar with Los Angeles, the roads are truly awful. Think budget cuts meets warzone. At the Ohlins stock rates (400/630), my car was constantly in motion and absorbed nothing. Felt like I was on horseback.

Current rates are 342lb front (Ohlins stock spring off the E9x RT kit); 504lb rear (Swift, 6”). Stock sway bars.

And as mentioned above, on my new setup, I’m able to happily run the damper rebound setting where I like them—fairly firm. FWIW, soft springs and firm dampers are how GT3s come from the factory.

[cobra]

Finally got back to the M3 this week.

Ohlins E9X front springs installed. The front upper rubber spring mounts was trimmed slightly and they went on without issue.

In short, the slightly softer e9X springs make a world of a difference. It was a game changer.

Disclaimer: I am (hyper) specific about suspension setup. I want things firm but compliant. I want to feel the road, but don’t want to be disturbed by it. I also like to run higher rebound than others, data be damned. At 10f / 11r clicks off from full stiff with 500lb rear springs, the ride is sublime.

So what rates are you running now?

I am currently on 400/630 Ohlins rates and while incredible on a smooth road, it's too damn stiff for bumpy roads.

[LSB4Me]

Any update on the e9x front springs as a better option?

Finally got back to the M3 this week.

Ohlins E9X front springs installed. The front upper rubber spring mounts was trimmed slightly and they went on without issue.

In short, the slightly softer e9X springs make a world of a difference. It was a game changer.

Disclaimer: I am (hyper) specific about suspension setup. I want things firm but compliant. I want to feel the road, but don’t want to be disturbed by it. I also like to run higher rebound than others, data be damned. At 10f / 11r clicks off from full stiff with 500lb rear springs, the ride is sublime.

[LSB4Me]

Any update on the e9x front springs as a better option?

I have been preoccupied with other projects, but this is on my todo list.

My present intent is to make three changes at one time (probably in October at this point): (1) E9x front springs; (2) 3DM Ohlins front spacers (shop declined to install them the first time; I won’t take no for an answer this go-round); and (3) Hotchkis front sway bar.

There is an outside chance that I will install the springs alone for science, but I would like to put this behind me once and for all. If the brain trust here would like to hear how things go with just the springs, I could be persuaded.

[Obioban]

66% is pretty… exciting.

IMO

I’m much happier with the car ~75%.

[Bry5on]

I may have asked this before - but how does tire width play into the handling balance?

I’m not modeling width on mine as I run square, but generally you’ll get more cornering traction out of a wider tire. For road feel, you want to manage your scrub radius and also width (not too wide) and tire blocks. The tire stuff is mostly above my pay grade, but actually the most important thing to optimize. Changing your width and offset can also change your track width, and therefore your handling balance and target FRC. That’s down in the details!

[Bry5on]

How much more FRC% would you recommend targeting if I lower the car? Probably going to stick to 13.5" front 13" rear. If 66% is neutral at OEM height and the spreadsheet puts me at 69% with these spring rates and sway bar, should I be targeting somewhere around 72% FRC if I lower the car? Also does it matter if I'm switching over to a square setup?

Your best bet is other M guys with experience here or to run the math. I haven’t run the numbers on that setup exactly but a half inch is probably a 2% change, from memory. Based on some of the math I wrote up in my build thread, you can self calculate if you’re so motivated.

When I said 66% is balanced, I’d assumed square. Good call out

edit: I’ve had good luck around 69-69.5 at stock height, that’s what I run.

[gaiakai]

This is a good target if you run OEM ride height. If you’re lowering the car (really, the front) then you’ll want to bring the FRC up because of how much the roll center drops in front when you lower the car. Geometrically, a ~66% FRC is neutral at OEM ride height. Neutral is hard for us humans, so a few percent higher will keep traction on corner exits. These numbers come from my own measurements and CAD models of the suspension geometry, everyone should feel free to recreate and verify! The math never lies

As much compliance as you can get away with will be fastest and most grip. Also, the net least disruption to the driver is likely to also be fastest, that’s the nature of pitch balanced ride frequencies. Flat ride is just a term coined by one dude to make this easier for people to understand, which is why it looks like its origin comes from fat cat motorsports.

How much more FRC% would you recommend targeting if I lower the car? Probably going to stick to 13.5" front 13" rear. If 66% is neutral at OEM height and the spreadsheet puts me at 69% with these spring rates and sway bar, should I be targeting somewhere around 72% FRC if I lower the car? Also does it matter if I'm switching over to a square setup?

[K-Dawg]

Sorry what I meant was your rear spring rate hz, not overall spring rate. IE 1.8 front, 2.0 rear

Everything I can find posted on the web traces back to this guy Shaikh, who owns Fat Cat Motorsports. Everything, on every single forum. BMW, Porsche, Miata. Every single one.

I'm not saying he doesn't know what he's talking about, because I've watched his videos, and he seems pretty knowledgeable.

But there's a ton of factors that go into your suspension besides spring rate, I'm not sold on generic "flat ride" spring rates for every E46 M3.

Try searches related to "pitch" instead of "flat ride."

[freshprince2421]

Update on the Strohlins Kit. Barry confirmed that the E9x Ohlins front springs are a very close fit to the E46M3 Ohlins front damper. It seems like the rubber upper spring mount on the E46M3 stock strut mount will require a little trimming to get the spring seated properly. I have agreed to be the guinea pig. Bet my shop is going to love me for this.

Attached are two photos: (i) one depicting the slight interference of the rubber mount; and (ii) one without the rubber mount confirming the spring will fit once the rubber is trimmed away slightly/properly.

I will try to make time to run this to ground in the coming weeks and will revert. In the meantime, any thoughts, suggestions or ideas regarding the rubber mount are welcome and appreciated.

Any update on the e9x front springs as a better option?

[cobra]

This is a good target if you run OEM ride height. If you’re lowering the car (really, the front) then you’ll want to bring the FRC up because of how much the roll center drops in front when you lower the car. Geometrically, a ~66% FRC is neutral at OEM ride height. Neutral is hard for us humans, so a few percent higher will keep traction on corner exits. These numbers come from my own measurements and CAD models of the suspension geometry, everyone should feel free to recreate and verify! The math never lies

As much compliance as you can get away with will be fastest and most grip. Also, the net least disruption to the driver is likely to also be fastest, that’s the nature of pitch balanced ride frequencies. Flat ride is just a term coined by one dude to make this easier for people to understand, which is why it looks like its origin comes from fat cat motorsports.

I may have asked this before - but how does tire width play into the handling balance?