FCM E46 M3 Ride Harmonizer suspension spreadsheet - aka Flatride !!!

[Obioban]

Does running square vs. staggered tires play into that? If you're running a stock-like stagger, I'd imagine you want to be closer to 70 versus a stock setup.

If a larger tire were to increase front grip (I don't think so, but for the sake of discussion), that would give you more oversteer, so you'd want a higher FRC-- not lower. Higher FRC is more underdersteer biased, lower FRC is more oversteer biased.

I run square on track, staggered on the street. It's neutral on track and... honestly, no idea on the street. PS4Ss are grippy enough that I don't find myself exceeding them on the street.

[r4dr]

Does running square vs. staggered tires play into that? If you're running a stock-like stagger, I'd imagine you want to be closer to 70 versus a stock setup.

[Obioban]

Here's how I'm currently sitting, exactly:



She's pretty neutral at the limit. I was previously at a ~71 FRC, and it was more oversteer biased than I wanted.

[Obioban]

Those look like very reasonable spring rates for the street. How is body roll? Which GC sway are you running?

Jesse

The race front sway, and a CSL rear sway.

My numbers probably aren't directly comparable, as my car is ~300 lbs lighter than stock and a bit front biased (52:48).

But, it's a street an track setup. More than double stock spring stiffness sufficient for track, IMO :P

[D-O]

Neutral FRC is ~75. Those a look a bit oversteer biased to me.

I ended up in the middle of you’re range— ~362 up front, ~675 in the rear.

Those look like very reasonable spring rates for the street. How is body roll? Which GC sway are you running?

Jesse

[D-O]

Neutral FRC is ~75. Those a look a bit oversteer biased to me.

I ended up in the middle of you’re range— ~362 up front, ~675 in the rear.

It was my understanding that neutral was 70-75. Thanks for the heads up.

Jesse

[Obioban]

Neutral FRC is ~75. Those a look a bit oversteer biased to me.

I ended up in the middle of you’re range— ~362 up front, ~675 in the rear.

[D-O]

After getting jerked around by Eibach I am planning to move to TCK SA. After fooling with the spreadsheet for a while I am beginning to get a feel for it, and have come up with some options. This is strictly a street car.

Here are three options that include the stiff Turner sways front and rear:



How much different are these going to feel? I see the difference in bounce freq. and bar and spring ratios, but how do these translate to driving feel?

Here is an option with a Hotchkis bar on the front (set to med) and the stock bar in the rear.



Flat ride in the neutral zone of FRC, but much less roll stiffness, with the springs doing more of the work and the sways doing less. How will this feel compared to the above options?

Anyone have the wall thickness and bar and arm lengths for the Hotchkis rear bar? I would like to plug it in and see how it compares to the Turner.

The GC bars look very interesting, but the purchase options on the their website don't really coincide with the spreadsheet.

TIA.

Jesse

[Chas3n]

I had them on the wagon, but didn’t bother— the shocks just felt like junk. Replaced them with Koni yellows and was much happier.

That’s not good news to hear.. What didn’t you like about them?

I believe the the ZCP‘s I’m looking at a 350 f and a 650ish R. My question if the rear damper will comply well with that much of an increase in sprig rate.

[Obioban]

That's exactly what I've got. Love it as a DD, but it's about due for an upgrade to the M control arms + bushings.

Yeah, I did the m3 subframe bushings and it helped some.

[r4dr]

Rwd manual.

That's exactly what I've got. Love it as a DD, but it's about due for an upgrade to the M control arms + bushings.

[Obioban]

Was it AWD? Manual?

Rwd manual.

[r4dr]

I have Dinan springs with the konis on the wagon.

Our former e91 had konis with eibach springs and it was... eh, fine. I think the non M e9Xs just aren’t a great handling platform, and not because of springs or shocks.

Was it AWD? Manual?

[Obioban]

Did you pair them with Eibach Pro-Kit springs? Or Dinan?

I've got an E91 wagon on Pro-Kit springs & B4 sport shocks, wish I had gone with Koni yellows in hindsight.

I have Dinan springs with the konis on the wagon.

Our former e91 had konis with eibach springs and it was... eh, fine. I think the non M e9Xs just aren’t a great handling platform, and not because of springs or shocks.

[r4dr]

I had them on the wagon, but didn’t bother— the shocks just felt like junk. Replaced them with Koni yellows and was much happier.

Did you pair them with Eibach Pro-Kit springs? Or Dinan?

I've got an E91 wagon on Pro-Kit springs & B4 sport shocks, wish I had gone with Koni yellows in hindsight.