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

[Driver407]

ok, so divorced vs true coilover. Thanks

[duracellttu]

Doesnt really help me understand what is different between the two row types tho.
Why should I be looking at 1/2 instead of 3/4. What is the bolded label actually mean in relation to the numbers?

Use the standard setup for the stock e46 configuration where the spring is on the rear perch and separate from the damper.

Use coilover if you have a setup similar the front suspension where the spring and damper are integrated.

[Driver407]

Doesnt really help me understand what is different between the two row types tho.
Why should I be looking at 1/2 instead of 3/4. What is the bolded label actually mean in relation to the numbers?

[duracellttu]

Can anyone help me understand what the difference between "setup 1/2: standard rear spring" and the "setup 3/4: coil-over rear spring"?
The math that comes out of each option is different and one of them says I am Flat while the other says I am not. Trying to understand which row i am looking at?

From my understanding it's a difference in motion ratio which factors into how the frequencies are calculated.

[Driver407]

Can anyone help me understand what the difference between "setup 1/2: standard rear spring" and the "setup 3/4: coil-over rear spring"?
The math that comes out of each option is different and one of them says I am Flat while the other says I am not. Trying to understand which row i am looking at?

[lvm3sm46]

Heres some updated numbers and these spring rates are available.

[Obioban]

Yeah, you're limited to what exists. You can game it by using metric spring rates, and springs are cheap enough that you can buy a couple and measure them to get one close to what you're looking for. E.g. but a couple 700s and use the one that measures high.

[cobra]

I recently had my corner weights taken and started messing with the spreadsheet. What section of the spreadsheet should I start with?
Regarding the spring rates, aren't we limited to what is actually available for sale? Like 700# 750# etc.

I am trying to get 1.9 hz front, 2.1hz rear like Obioban mentioned.

attached is my corner weights and what I have input at the moment.

Just get close with the rate, I highly doubt anyone can tell the difference between a few % difference or imbalance. Besides - springs don't always measure what they're labeled at. I bought an Eibach 600lb spring that measured 580 on a calibrated tester.

[Cronenberged]

Should be able to order the weights you want
from GC thats where I'm ordering mine from.

[lvm3sm46]

I recently had my corner weights taken and started messing with the spreadsheet. What section of the spreadsheet should I start with?
Regarding the spring rates, aren't we limited to what is actually available for sale? Like 700# 750# etc.

I am trying to get 1.9 hz front, 2.1hz rear like Obioban mentioned.

attached is my corner weights and what I have input at the moment.

[Chas3n]

Anyone with the Eibach pro kit springs play around with their sway bar sizing?

I have the Hotchkis on there now, but want to shoot for an optimized freq.

[Obioban]

Do you have the DIY on 3?

For others reading:

3) lithium ion battery/battery cable delete

4 cylinder e46 coupes (not sold in the USA) had the battery installed in the drug bin. My lithium battery is 5.6 lbs, so it wasn't doing anything meaningful for weight distribution in the trunk. I bought the factory under hood wiring parts for a 4 cylinder car and made a bracket to mount it in the drug bin. I pulled all the factory battery mounting hardware out of the trunk and, since my interior was already gutted at the time, pulled the positive battery cable that runs to the trunk (which was surprisingly heavy-- 8 lbs per real OEM IIRC).

I even happen to have an up to date picture on hand, as I took a picture of the washer fluid level a month ago to see if I'm losing fluid (just replaced the pump gasket because I was).

[Obioban]

Hmm... even with the XT springs, a 6" 350lb version only has 4.1" of travel. How much bump travel do you have and what rate are you running?

Also, random question.... anyone know what the maximum wheel width and offset is allowed to fit a 2.25" spring next to the tire/wheel?

Just saw this. My shocks don't have a ton of travel-- 110mm total IIRC, but there's a bump stop in there so functional travel is even less. have it set at 60% bump travel, of which some of that is the bump stop-- so 66mm of "travel", but really more like 40-45.

I have a 375lb on the driver side and 350lb on the passenger side IIRC.

I am absolutely right at the design limit of the spring-- but there's zero evidence that coil bind has ever occurred.

[Cronenberged]

1) ~45 lbs
2) 59 lbs
3) ~50 lbs
4) ~45-50 lbs... mostly wire

Do you have the DIY on 3?

[cobra]

Yeah, 7" springs should do the trick.