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E46 M3 (2001-2006) Engine: S54 - Max Hp: 333 hp at 7,900 rpm / 262 lb/ft at 4,900 rpm
Total Produced: 45,000+ - Years Produced: 2001 to 2006.


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Old Sun, Oct-14-2018, 05:45:42 AM   #81
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Default Re: FCM E46 M3 Ride Harmonizer suspension spreadsheet (bounce freqs, FRC, roll stiffn

I got under my car today to measure the sway bars so I could consider the idea of going to a factory rear sway bar and what effects it would have. They were on the car when I bought it so I'm not even sure what brand they are, I believe UCC just based on the color of the bars and bushings. I measured 32mm front and 26mm rear (I didn't know they even made either that large wow) and much to my surprise that gives me an FRC of 75% which isn't as bad as I thought it would be so perhaps I don't want to go to a stock bar (which would bring me to 82% FRC) and maybe something more in the middle. At the same time I noticed the spreadsheet has the stock rear bar set at 18mm but it's actually 21.5mm I believe?
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2001 E46 M3 - Slicktop Manual Coupe - Alpine White on Imola Red

Engine: Karbonius CSL airbox, Lang Racing stage 2.5 head, Schrick 288/280 cams & followers, Lang Racing rod journal widening kit w/ CP 12:1 87.5mm pistons & Carrillo rods, Kassel CSL DME & MAP conversion, 36lb injectors, Hassan tuned, APE Flex fuel kit, TMS Power Pulleys, SS V1 stepped headers & catless section 1, SS 2.5” twin-piped resonated section 2, SGT scza section 3.
Drivetrain: DKM Stage 2 Clutch, E60 Shifter, RE trans mounts, Motorsport 4.10 R&P, Revshift 80A diff bushings.
Suspension/Brakes: Ohlins 3DM “track day” kit, RE strut bar, AKG RSM's, UUC front sway bar, BW camber arms, TMS monoball RTABs, ZCP rotors, BW solid caliper guide bushings, PFC 08's, Motorsport Hardware stud kit.
Interior: Cobra Nogaro seats, alcantara headliner, BMW Performance pedals, OE alcantara boots, mason clutch pedal, Xtrons 9" headunit w/ carplay

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Old Sun, Oct-14-2018, 08:56:32 PM   #82
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Default Re: FCM E46 M3 Ride Harmonizer suspension spreadsheet (bounce freqs, FRC, roll stiffn

I removed my GC medium front bar to get accurate measurements.

Took measurements of the GC, H&R 30mm, and OEM rear.

GC front sway
32mm diameter
4mm wall thickness
width - need to remeasure
230mm arm length (end link clamp positioned against aft side of nub)

H&R front sway
30mm diameter
width - need to remeasure
260mm arm length full stiff
305mm arm length full soft

OEM rear sway
21.5mm diameter
width - need to remeasure
230mm arm length
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Old Sun, Oct-14-2018, 10:26:46 PM   #83
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Default Re: FCM E46 M3 Ride Harmonizer suspension spreadsheet (bounce freqs, FRC, roll stiffn

So if the stock rear sway is actually 21.5mm in diameter does that mean that the spreadsheet calculations are off? Maybe I should go with a 30mm front bar instead of the 27mm then...
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Old Mon, Oct-15-2018, 05:55:05 AM   #84
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Default Re: FCM E46 M3 Ride Harmonizer suspension spreadsheet (bounce freqs, FRC, roll stiffn

Thanks for the info gents! However, to make sure we are getting consistent measurements please post photos of the bar and tape measure/scale so we can cross-check our data! 10speed, the bar length you indicated is longer than the 30mm H&R bar I have here, which is supposed to be for an E46 M3 and also fits the non-M. I believe you made an accurate measurement but I'd like to see a picture to be sure. The arm length and bar length variations from model to model all matter in the calculations. I'll make a short video on measuring sway bar dimensions.



(all dimensions in mm)

A = arm length
B = distance between arm holes (for adjustable bars)
C = bar length (to approx. center of arm bend)
D = bar thickness
F = thickness at end of bar. Also note if it's solid or tubular (and include wall thickness if known).

EDIT: Can anyone else measure their OE front and rear bars (if available) to confirm sizes / dimensions? From '.' who has an '01 he got 21.5mm on rear bar diameter, and 10speed with an '05 also got the same. So this seems to be the correct value on the M3. I likely forgotten to update the rear bar value in the final M3 spreadsheet as my 330i w/ Sport package was definitely 18mm. I'm actually using a 15mm now. But M and non-M rear bars aren't compatible so that doesn't matter for you M guys.

When I update the spreadsheet in the next couple days I'll include the new data points.

In terms of ultimate FRC (i.e. handling balance) what matters most is whether your new FRC is higher or lower to either address an understeer or oversteer condition. The new stock FRC with 21.5mm is about 5% lower, or 70.1% vs. the 75.3% I had with 18mm rear bar.

The updated sway bar diameter will make the spreadsheet more accurate, but it's the *relative* changes that matter most. You want to change one or two variables and predict the new ride frequencies, FRC, and roll stiffness. Regardless of the rear bar's size, you're not changing the rear bar at this time so that's a constant in this upgrade. Your car currently has a certain handling balance and we're looking to maintain it or slightly increase the FRC (slight front bias). The 27mm front bar you'll be installing plus the 448/840 springs will make the FRC 67.4%, which is 2.3% higher than if you kept the OE front bar (assuming I have the front bar measured accurately-enough). That's also assuming the new bar's arm lengths work out to be close-enough to OE (or shorter meaning stiffer) which we won't know until we have measurements on the Eibach bar. If necessary, you could go to the stiffer front hole position (and also provide measurements of both holes which I can include as reference in the next version of the online spreadsheet). We can have a follow-up phone chat once you have the bar and can get some measurements and/or photos posted for reference.

I feel you made the right choice with the 27mm front bar. If you wanted, you could install the new springs and see how that feels / works in terms of handling behavior before sending your dampers in to me for FCM Elite Stage 2 upgrade. Keep in mind I can change the front bump stop to either soft or medium which will influence the handling and FRC as well (though ideally as a small contribution). My goal is to create a neutral balance and throttle-friendly handling at the limit.

The bump stop interactions are also an unknown (and we'll largely have to guess at the front (internal to the strut housing), while you may be able to observe / zip-tie the rear shock to see where the bump stop ends up in mild and hard cornering.

We're breaking new ground here with getting this analytical on the E46 M3 so the more data people gather, the more accurate this spreadsheet will be. The sway bar arm lengths in particular are VERY helpful as I've seen quite a lot of variation between brands as I mentioned previously.
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FCM Elite Ride Harmony suspension spreadsheet for: E46 M3, Shock dyno testing / driving feedback: E46 M3 (with Eric_SMG)

Take our short Ride Harmony survey and earn a credit on FCM Elite Bilstein damper services


Last edited by ShaikhA; Mon, Oct-15-2018 at 06:39:58 AM.
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Old Mon, Oct-15-2018, 02:28:31 PM   #85
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Default Re: FCM E46 M3 Ride Harmonizer suspension spreadsheet (bounce freqs, FRC, roll stiffn

Quote:
Originally Posted by RT-66 View Post
Does anyone know if the ZCP Competition Package sway bars are the same dimension as the CSL's? Looking for what to enter if those OEM bars are used.
ZCP has 100% identical suspension to all 2004+ M3s, including sway bars.
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Old Mon, Oct-15-2018, 03:39:41 PM   #86
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Default Re: FCM E46 M3 Ride Harmonizer suspension spreadsheet (bounce freqs, FRC, roll stiffn

Shaikh, what are you thoughts on the Ohlins dampers found in their Road & track kit? I had previously been pretty set on MCS or JRZ's but after your comments on how over pressurized they are, it's possibly making me reconsider. Ohlins had been my backup plan and Ohlins states they can take up to a 30% increase in spring rates without needing to be revalved. I could then easily swap the rear springs for something along the lines of 775lbs and pair this with a csl rear sway bar giving my 4% flat ride and 76.6% FRC which sounds like a killer setup.
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2001 E46 M3 - Slicktop Manual Coupe - Alpine White on Imola Red

Engine: Karbonius CSL airbox, Lang Racing stage 2.5 head, Schrick 288/280 cams & followers, Lang Racing rod journal widening kit w/ CP 12:1 87.5mm pistons & Carrillo rods, Kassel CSL DME & MAP conversion, 36lb injectors, Hassan tuned, APE Flex fuel kit, TMS Power Pulleys, SS V1 stepped headers & catless section 1, SS 2.5” twin-piped resonated section 2, SGT scza section 3.
Drivetrain: DKM Stage 2 Clutch, E60 Shifter, RE trans mounts, Motorsport 4.10 R&P, Revshift 80A diff bushings.
Suspension/Brakes: Ohlins 3DM “track day” kit, RE strut bar, AKG RSM's, UUC front sway bar, BW camber arms, TMS monoball RTABs, ZCP rotors, BW solid caliper guide bushings, PFC 08's, Motorsport Hardware stud kit.
Interior: Cobra Nogaro seats, alcantara headliner, BMW Performance pedals, OE alcantara boots, mason clutch pedal, Xtrons 9" headunit w/ carplay

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Old Mon, Oct-15-2018, 07:49:57 PM   #87
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Default Re: FCM E46 M3 Ride Harmonizer suspension spreadsheet (bounce freqs, FRC, roll stiffn

Hey Zach, I'll take your question at face value since if you've read through this thread (and my comments in the Ohlins thread) I posted my feelings there. Yes, Flat Ride tuning always helps your suspension be more fluid and settle more quickly. You can turn the damping down which will help reduce the impact of the high-speed rebound which is almost certainly too high and will cause jacking down.

But I'm curious - why are you considering Ohlins, which typically have a short service life, linear damping (non-ideal for street/track applications), and often excessive gas pressure? Is it a name/brand thing, or wanting a knob?

Don't you have Bilstein PSS9 on your car right now, according to your sig? I could rebuild and optimize those so you wouldn't need to buy anything. an Elite Stage 2 tune for whatever spring rates you're looking for would work far better than Ohlins/MCS/KW/etc. for all the reasons I've indicated on all these pages, based on what I've read/seen/heard/tested up to this point. I don't brag because I want to, but because the evidence supports what I'm saying. I'd be optimizing everything from compression/rebound forces to gas pressure (which I think by now people are getting how important it is).


Generally, knobs are placebo and having a damper with an external valve leads to more rapid nitrogen leakage (hence the short and $$$ service interval).

In case you wanted to go with a new setup and not service what you have there (you could always sell it to someone who did want to get them optimized) I would recommend going with H&R Street Performance coilover, which uses Bilstein monotube design front and rear. It's my new favorite starting point for Elite tuning when an owner wants stiffer springs and ride height adjustment plus ability to corner weight. For stock or lowering springs, the Bilstein HD or Sport are the right choice. The H&R's have no damping adjuster - and NO external valve to leak! - so there's less that can go wrong or cost you more money in a short period of time. As you know, I optimize the damping here at the shop, with feedback from you about your driving needs/environment.

E46 M3 H&R Coilovers at ECS Tuning

This would be an optimized, tailored setup. Throwing different springs on Ohlins would improve the ride but you're still left with drawbacks. Oh, and while I was more active on the Miata forum a few years ago, one owner posted this comment. I don't know why he'd lie, so it bears reading. Essentially Ohlins giving me credit for what I'm doing:

===



===

Anyhow, you asked so now you know my thoughts...!

Final edit: I post a lot of this information so that vendors can improve their methods and consider some of these key elements of Ride Harmony as I discuss. They may have their own tuning philosophies, standard practices, etc. There is often a certain 'feel' to a particular vendor's product. Some people may like it and find it awesome, others would want more. Some don't know what else is out there that could be better. I operate from principles and then turn that into design choices and finally products / services. If / when Ohlins / MCS / etc. announces a 'high frequency filter inspired by off-road racing', 'reduced nitrogen gas pressure for better grip on rougher roads', or 'spring rates chosen to create Flat Ride' I'll be thrilled for everyone's sake!
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FCM Elite Ride Harmony suspension spreadsheet for: E46 M3, Shock dyno testing / driving feedback: E46 M3 (with Eric_SMG)

Take our short Ride Harmony survey and earn a credit on FCM Elite Bilstein damper services


Last edited by ShaikhA; Mon, Oct-15-2018 at 08:08:18 PM.
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Old Mon, Oct-15-2018, 10:03:42 PM   #88
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Default Re: FCM E46 M3 Ride Harmonizer suspension spreadsheet (bounce freqs, FRC, roll stiffn

Shaking the etch a sketch on my spring rates!

I have the JRZ RS Pros with true coil over in the back. Its a double whammy with items you don't like. My shocks have a minimum gas pressure of 150psi-350 max according to JRZ, and my thought of the rear coil over initially was to take the stress off the subframe and move that to a reinforced strut tower.
All of my setups have always felt pitchy. I was always chasing the a good ride on the streets and performance on track. Even with my current set up of 450/250- which equates to 500 lb in the rear, I still feel the harshness. Needless to say, my wife doesn't ride in the car anymore.
Thanks to all this great info and your spread sheet, I just ordered new springs.
350F /350R = 700lb rear for the shock and spring guys.
Based on my 30mm TMS front sway in the middle position.
I should have 6% flat rate and an FRC of 74.1%

700lb just seems like a lot but I didn't want to go softer than a 350lb up front. With this setup, my bounce frequency is going to be at 2.06, I know you like to keep it below 2 for back road stuff. Do you think this will be a comfortable set up or do you feel I should have gone with a 650lb rear 1.96HZ and drop my flat rate down to 2% 75.4% FRC?

Thanks!
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Old Mon, Oct-15-2018, 10:41:22 PM   #89
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Default Re: FCM E46 M3 Ride Harmonizer suspension spreadsheet (bounce freqs, FRC, roll stiffn

^ are you still running a rear coil over? Did you change the motion ratio on the bottom of the spreadsheet?


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Old Mon, Oct-15-2018, 10:58:30 PM   #90
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Default Re: FCM E46 M3 Ride Harmonizer suspension spreadsheet (bounce freqs, FRC, roll stiffn

Quote:
Originally Posted by ShaikhA View Post
Hey Zach, I'll take your question at face value since if you've read through this thread (and my comments in the Ohlins thread) I posted my feelings there. Yes, Flat Ride tuning always helps your suspension be more fluid and settle more quickly. You can turn the damping down which will help reduce the impact of the high-speed rebound which is almost certainly too high and will cause jacking down.

But I'm curious - why are you considering Ohlins, which typically have a short service life, linear damping (non-ideal for street/track applications), and often excessive gas pressure? Is it a name/brand thing, or wanting a knob?

Don't you have Bilstein PSS9 on your car right now, according to your sig? I could rebuild and optimize those so you wouldn't need to buy anything. an Elite Stage 2 tune for whatever spring rates you're looking for would work far better than Ohlins/MCS/KW/etc. for all the reasons I've indicated on all these pages, based on what I've read/seen/heard/tested up to this point. I don't brag because I want to, but because the evidence supports what I'm saying. I'd be optimizing everything from compression/rebound forces to gas pressure (which I think by now people are getting how important it is).

Testing monotube damper gas spring frequency response at low and medium fill pressures (pt 2) - YouTube

Generally, knobs are placebo and having a damper with an external valve leads to more rapid nitrogen leakage (hence the short and $$$ service interval).

In case you wanted to go with a new setup and not service what you have there (you could always sell it to someone who did want to get them optimized) I would recommend going with H&R Street Performance coilover, which uses Bilstein monotube design front and rear. It's my new favorite starting point for Elite tuning when an owner wants stiffer springs and ride height adjustment plus ability to corner weight. For stock or lowering springs, the Bilstein HD or Sport are the right choice. The H&R's have no damping adjuster - and NO external valve to leak! - so there's less that can go wrong or cost you more money in a short period of time. As you know, I optimize the damping here at the shop, with feedback from you about your driving needs/environment.

E46 M3 H&R Coilovers at ECS Tuning

This would be an optimized, tailored setup. Throwing different springs on Ohlins would improve the ride but you're still left with drawbacks. Oh, and while I was more active on the Miata forum a few years ago, one owner posted this comment. I don't know why he'd lie, so it bears reading. Essentially Ohlins giving me credit for what I'm doing:

===



===

Anyhow, you asked so now you know my thoughts...!

Final edit: I post a lot of this information so that vendors can improve their methods and consider some of these key elements of Ride Harmony as I discuss. They may have their own tuning philosophies, standard practices, etc. There is often a certain 'feel' to a particular vendor's product. Some people may like it and find it awesome, others would want more. Some don't know what else is out there that could be better. I operate from principles and then turn that into design choices and finally products / services. If / when Ohlins / MCS / etc. announces a 'high frequency filter inspired by off-road racing', 'reduced nitrogen gas pressure for better grip on rougher roads', or 'spring rates chosen to create Flat Ride' I'll be thrilled for everyone's sake!
I apologize if you already mentioned them in this thread and I didn't see it. I saw MCS and JRZ called out specifically but I didn't remember seeing ohlins in your list and I didn't know if that was on purpose or not but I guess I just missed it. I also didn't see the ohlins specific thread but I'll definitely look for that. I asked mostly because I love to know every single one of my available options, I've seen some positive feedback on them here on the forums before, and also I do have somewhat of a fondness for ohlins from other hobbies i.e. mountain biking (Let me know if you ever start custom valving forks and shocks for mountain bikes haha) though thats not such an important factor. I will definitely be eagerly awaiting gearhead55's feedback on your elite stage 2 and seeing if thats a viable option for me (I'll have to figure out the logistics of pulling the suspension off my daily for a while). Thanks for the provided video and education I thought I knew a decent amount about suspensions but most of this is new info to me and with that it brings up a lot of questions and scenarios.
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2001 E46 M3 - Slicktop Manual Coupe - Alpine White on Imola Red

Engine: Karbonius CSL airbox, Lang Racing stage 2.5 head, Schrick 288/280 cams & followers, Lang Racing rod journal widening kit w/ CP 12:1 87.5mm pistons & Carrillo rods, Kassel CSL DME & MAP conversion, 36lb injectors, Hassan tuned, APE Flex fuel kit, TMS Power Pulleys, SS V1 stepped headers & catless section 1, SS 2.5” twin-piped resonated section 2, SGT scza section 3.
Drivetrain: DKM Stage 2 Clutch, E60 Shifter, RE trans mounts, Motorsport 4.10 R&P, Revshift 80A diff bushings.
Suspension/Brakes: Ohlins 3DM “track day” kit, RE strut bar, AKG RSM's, UUC front sway bar, BW camber arms, TMS monoball RTABs, ZCP rotors, BW solid caliper guide bushings, PFC 08's, Motorsport Hardware stud kit.
Interior: Cobra Nogaro seats, alcantara headliner, BMW Performance pedals, OE alcantara boots, mason clutch pedal, Xtrons 9" headunit w/ carplay

IG: Zach_e46M
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Discussing FCM E46 M3 Ride Harmonizer suspension spreadsheet (bounce freqs, FRC, roll stiffness) in the E46 M3 (2001-2006) Forum - Engine: S54 - Max Hp: 333 hp at 7,900 rpm / 262 lb/ft at 4,900 rpm
Total Produced: 45,000+ - Years Produced: 2001 to 2006. at BMW M3 Forum.com (E30 M3 | E36 M3 | E46 M3 | E92 M3 | F80/X)