AMG3.2

Hi all,

Just ordered a set of Muller Coilovers and am wondering if I made the right choice with spring rates.

They recommend 7k front, 11k rear for all W204's (Non-amg's included).

Is that too soft?

They recommend 8k, 12k for the E9X M3.

Does anyone with spring rate experience have any thoughts or advice?

Should I bump the spring rates up a tad? I'm afraid of upping the spring rates only to find that I've diminished the ride quality...

Thanks in advance for your help.

Phil Chow

Did you get them with Swift Springs?

Every car handles springs rates differently. 8K on an M3 won't feel like 8K on a C63. Their chassis stiffening is different for each car.

I'd leave them.

AMG3.2

Yup - the Mullers come standard with Swifts. They're an option on the FA 500/510, though.

I'm so torn between keeping the rears as is, or bumping up to 12k or 13k in the rear. I HATE rear pogo sticking on freeway dips.

Phil Chow

What are the OEM Spring Rates? You can base it off that then.

Find out the OEM P30 Springs Rates if you can.

AMG3.2

I wish I could find them somewhere. I've searched high and low for them.

All I know is that my H&R springs are softer than my P30 springs were.

m a x i m u s

Contact MBUSA and ask them, them might tell you.

AMG3.2

They're most likely progressive rates so I'm not sure they'd even be able to give me much detail, unfortunately.

604 C63

I have a set of P30 springs from an 09.

I like you. I'll prove it in the PM I am about to send you.

notAMG91

I hope I'm not too late to place my input before you place your order.

I'm in a similar predicament since I too have ordered a set of coilovers from fortune auto. My issue is that I'm afraid that the ride height won't be as low as I want it to be so I called fortune auto to ask if they could custom make my struts to make the car more height adjustable. Their response was that they were able to do this for the front coilovers struts only because the rear struts are independent to the spring (meaning that the spring and the strut aren't uniform, instead they are side by side). I then asked what was the next step/route to go if I wanted a lower ride height in the rear and their response was that I would need shorter springs in the back. I then asked, well can't you guys order custom springs if I order th SWIFT spring upgrade. Their answer was no because since the springs in the back were independent, that they ONLY added SWIFT springs to the front struts. The springs they send for the rear portion of the car are generic coilovers springs that they order from a different supplier.

So in essence, no matter what coils/spring combo you get from them, you will most likely receive the same spring rate from the back. Even worse, when you order the SWIFT upgrade, you're being ripped off because you're only being given 2 additional springs not 4.

To solve my issue, I'm currently speaking with Swift directly so they can make custom springs for my rears.

I must say, this was truly disappointing.

AMG3.2

Hmm. Interesting stuff. I knew that the rear springs wouldn't be Swift/Hyperco due to the design of our multi-link suspension. That being said, I did not know ride height adjustments would be limited. Personally, I don't mind since I don't want to go low, just want an HR drop, or even a tad lower, but want the valving to match it a bit better.

Are you already on your FA Kit? And if so, which one?

Since these springs are linear and not progressive, you could always cut them down to your liking.

Let me know what you and Swift come up with, however.

Edit: Here are some pics of a member with the Muller Kit. It looks like to go plenty low, no?

https://mbworld.org/forums/c63-amg-w...c63-build.html

notAMG91

I decided to go with the 500 series since they really couldn't tell me what the difference was between that and muller. It seems to be more of marketing than anything. Of course the mullets already come with swift springs.

I have been doing research on that actually. I'm just nervous about cutting since I have never done it and I don't know how much I should cut to keep the spring rate relatively the same and still get an inch drop lower.

I know the spring rate increases as you cut down the spring but I'm not sure how much.



This would save me a big sum since swift says they would charge me 300 for a pair of custom springs. If you have any insight that would be awesome!!!

AMG3.2

So the Muller is valved to be much more compliant and less "rough around the edges" which I'm assuming has to do with the way blow off occurs in the shock internally.

I was very adamant on the fact that I did NOT want some stiff coilover that was going to break my back and make my dash rattle when hitting cracks in the road. Things like that drive me absolutely insane. They mentioned that the 500 was going to ride well, but for those that very much want to preserve the comfort aspect of their benz (like we have any, especially those of us that had P30), Mullers are the way to go. More so, once you add Swift Springs to the price of a 500 kit along with the bearings, your a couple hundred short of the Muller kit anyways. The Muller kit also has a 5 year warranty, while the 500's/510's have a 1 year warranty. Apparently, the build quality/materials on Mullers are better..

Regarding cutting the springs, I haven't done much research around the subject, but what you are describing is a progressive spring, meaning as it compresses, the spring rate becomes harder. This is a non-issue for us since our springs are NOT progressive and thus linear. Meaning, whether the spring is 3 feet tall or 3 inches tall, the spring rate itself is the same.

I echo your statements re: cutting progressive springs. In my book, a no no. Linear however -- I can't see why there'd be an issue.

EDIT: Wait -- your maxed out on FA 500's and you want to drop it an inch lol You trynna lay frame?

notAMG91

Thank you so much man!!!! I might as well cancel my order and place my order for Miller's if that's the case.

Lol lay frame I will haha. No i just want to tuck a little tire that's all.

AMG3.2

Since Muller/FA is built to order, I'm not sure you can cancel but you may be able to just bump up your order to Mullers and pay the difference?

Who did you go through to order them? Directly through FA or through a vendor like Vivid Racing, etc.?

EDIT: Wait, just thought of something. You could run into issues with spring seating in the boot... See the below in red? Thats the part that sits in the actual rubber perch. If memory serves me correctly, the rubber perch has an angled fitting meaning the spring does not sit flat in there. It's hard to tell how the cut spring would sit, but from the looks of it, it looks like the Muller kit would sit at an angle as well and could fit into the rubber perch if cut. I can't tell anything else without seeing both parts in had.



That being said, which rubber spring perches are you using. They make a range from 17mm to 5mm? I think? That may give you some more drop...

notAMG91

I was literally about to post the same picture which I found in a for sale thread. Yeah the bottom seems to be an open end and not squared. If that's the case, I should be able to cut with no problem right?

notAMG91

I might just end up keeping my order, see how they ride and if i don't like it, I'll try to send them back and see if they will bump me up or sell the FA 500 and upgrade to müllers.

Hopefully I can cut the backs myself and hopefully an inch off the body off the front coilover strut body will be enough to get the drop I want.

christyan78

If it helps,the diffuser piece looks like this when is out.

AMG3.2

Definitely wrong thread.

sytfu_colan

Anyone else own Muller or Fortune auto coils?

How do you like them and did they come with adjustable end links?

AMG3.2

I like them a lot. Yes, they do.

sytfu_colan

What spring rate did you end up going with?
I think I saw somewhere that you upgraded the rear to swifts too right?

AMG3.2

Yes, 9k front, 14k rears. Do note, that you can only run adjustable rear springs with custom fabb'ed control arms. Check my build journal for more detail.