e46 M3 suspension setup, or how to not downgrade your car with suspension mods

[Bry5on]

Any chance you know what these stock numbers are for the front?

Sadly I do not, it’s a little harder to measure this directly. I’m interested if someone does have them!

[dukeofchen]

Stock e46 M3 rear has 4.5” droop, 5” bump, 1.4” until contacting the bump sto

Any chance you know what these stock numbers are for the front?

[Bry5on]

Z4M shocks have 5in of travel. I compared the stock v h and r and travel wise they were the same. So lowering the car just ate travel. I think e46 have also 5in of total strut travel.

Stock e46 M3 rear has 4.5” droop, 5” bump, 1.4” until contacting the bump stop

[maupineda]

Z4M shocks have 5in of travel. I compared the stock v h and r and travel wise they were the same. So lowering the car just ate travel. I think e46 have also 5in of total strut travel.

[01SG]

Interesting. I figured the harsher ride simply came from the stiffer chassis and sitting over the rear wheels.

[tlow98]

Are you sure about this? I do not see why the Z would not have the same exact travel as the M3. It is basically the e36 m3 front suspension mated to the e46 m3 rear suspension. Any of these cars are not exactly soft stock. Putting 19s on a Z would be bad for the ride on its own, lowering it on top of that would certainly explain any ride degradation.

As for the cat asking about B4/Dinan and whatever...I say keep stock springs no matter what shock. I have now gone from stock to lowering springs and back to stock on both my Ms and could not be happier.

I'm quoting Jason Cammissa when I say that. My understanding is the springs are shorter (and the bump stops are certainly shorter). Shocks are shorter and have different bodies, as well. I love the cars, but straying from stock and shortening the already shortened suspension is a tough pill to swallow. They are generally a bit lighter which helps, I think. FWIW, I have not compared each component in my hand with the Z4 gen, tho, I have with the E36/7 gen. They are most certainly lacking travel compared to the E36.

[01SG]

They Z cars are interesting. They lacks the travel of the sedans and coupes from which they’re mostly built on. So, lowering them puts you in situation where you go from very little travel to almost nothing.

Are you sure about this? I do not see why the Z would not have the same exact travel as the M3. It is basically the e36 m3 front suspension mated to the e46 m3 rear suspension. Any of these cars are not exactly soft stock. Putting 19s on a Z would be bad for the ride on its own, lowering it on top of that would certainly explain any ride degradation.

As for the cat asking about B4/Dinan and whatever...I say keep stock springs no matter what shock. I have now gone from stock to lowering springs and back to stock on both my Ms and could not be happier.

[tlow98]

I have the B12 Pro kit on my Z4M with 19" tires and the drop is lovely but hitting the smallest pothole makes it sound like you slammed into a brick wall. Even the oem suspension with 18" tires sounded like that. Just a very stiff chassis. Everytime I hit a pothole I feel like I bent a wheel. On smooth roads its a comfortable ride otherwise and the thing handles amazin !

They Z cars are interesting. They lacks the travel of the sedans and coupes from which they’re mostly built on. So, lowering them puts you in situation where you go from very little travel to almost nothing.

[Bry5on]

Maybe I missed it but how low can you go in the rear before you start compromising suspension geometry?

I’m 13.5 left and 13.75 right fender to center of wheel in the front but 12.75 left and 13 right in the rear measured with no driver. I’m right at 50/50 crossweights with the driver. My seating position is far enough back so my fat arse distributes more weight to the rear. So I’m sure the rear heights with me in it are lower.

Im really happy with the car’s performance as is. I’ve lucked out and been able to balance the car out with aero. I’m wondering if I can get a little more mechanical grip in the rear so I can take off the gurney flap which adds a ton of drag with my Amazon.com wing that I bought with Hilton points 🤣

Very little change from lowering the rear, camber and track changes are basically linear, and the roll center barely moves. You’re just fine

edit: you lose anti-squat performance from lowering the rear, still probably not a huge deal but you’ll be giving up a little rear grip on acceleration as you’ll increase negative camber just when you want positive (near zero) camber for traction.

[bigjae46]

Maybe I missed it but how low can you go in the rear before you start compromising suspension geometry?

I’m 13.5 left and 13.75 right fender to center of wheel in the front but 12.75 left and 13 right in the rear measured with no driver. I’m right at 50/50 crossweights with the driver. My seating position is far enough back so my fat arse distributes more weight to the rear. So I’m sure the rear heights with me in it are lower.

Im really happy with the car’s performance as is. I’ve lucked out and been able to balance the car out with aero. I’m wondering if I can get a little more mechanical grip in the rear so I can take off the gurney flap which adds a ton of drag with my Amazon.com wing that I bought with Hilton points 🤣

[maupineda]

I have the B12 Pro kit on my Z4M with 19" tires and the drop is lovely but hitting the smallest pothole makes it sound like you slammed into a brick wall. Even the oem suspension with 18" tires sounded like that. Just a very stiff chassis. Everytime I hit a pothole I feel like I bent a wheel. On smooth roads its a comfortable ride otherwise and the thing handles amazin !

I feel you! With the changes I made I was able to “round off “ the edges lets say. But before it was actually pretty bad.

[Maxima SE]

I have H&R coils on my Z4M, and though a different chassis, i think the consensus is clear. Bilsteins are harsh. The H&R coils use Bilstein shocks, and to make them livable i had to Swiss cheese the setup

- linear front springs - Swift 225#
- linear rear springs - TCK 600#
- rear B8 from non M Z4, supposedly less aggressive and shorter (less droop)
- shortened bump stops - cut to give 1.5in of free travel before stop compression.

what I found, though not backed up with solid data, is that between H&R version vs Bilstein branded shocks, is the latter set have digressive valving. I did feel the back of the car a bit more compliant after the B8 install v H&R variant.

I kept OE height to avoid geometry changes, the springs are about 10-15% stiffer than stock, and I added a CSL front sway. Did I gain anything over stock? More likely “nada” other that learning 😂.

i am a firm believer that the high pressure gas is what makes Bilsteins jarring.

when roads are smooth and not sharp bumps the ride and body control is beautiful. The key to improve ride was to ensure there was free suspension travel before engaging the stops just as the OE setup. Lowering these cars screw up the ride if not done properly.

I have the B12 Pro kit on my Z4M with 19" tires and the drop is lovely but hitting the smallest pothole makes it sound like you slammed into a brick wall. Even the oem suspension with 18" tires sounded like that. Just a very stiff chassis. Everytime I hit a pothole I feel like I bent a wheel. On smooth roads its a comfortable ride otherwise and the thing handles amazin !

[Drewrivera]

Koni yellow and H and R Springs was my set up before and before that was Status Gruppe coils and i have to say, Status Gruppe was smoother to me. I had harsh road feels with the Koni, but I can't exactly point out what went wrong because i installed the set up, didn't refresh the entire set of rubber bushings or pads for the suspension and i bought the dampers from a website that had them for cheaper. And to date , without realizing that Dinan and H and R are the same spring, i ended up putting on b4 with Dinan, which i have absolutely no travel at this point, 😜😜, so i now have to get back to restoring this suspension for better feel. I still have the dampers and springs from previous set ups but not sure what to do with them. I thought i could rebuild but that may be the same amount as new purchasing of dampers. What did the alpina have in there set up by the way, was it just springs with Sachs?

[maupineda]

I have H&R coils on my Z4M, and though a different chassis, i think the consensus is clear. Bilsteins are harsh. The H&R coils use Bilstein shocks, and to make them livable i had to Swiss cheese the setup

- linear front springs - Swift 225#
- linear rear springs - TCK 600#
- rear B8 from non M Z4, supposedly less aggressive and shorter (less droop)
- shortened bump stops - cut to give 1.5in of free travel before stop compression.

what I found, though not backed up with solid data, is that between H&R version vs Bilstein branded shocks, is the latter set have digressive valving. I did feel the back of the car a bit more compliant after the B8 install v H&R variant.

I kept OE height to avoid geometry changes, the springs are about 10-15% stiffer than stock, and I added a CSL front sway. Did I gain anything over stock? More likely “nada” other that learning 😂.

i am a firm believer that the high pressure gas is what makes Bilsteins jarring.

when roads are smooth and not sharp bumps the ride and body control is beautiful. The key to improve ride was to ensure there was free suspension travel before engaging the stops just as the OE setup. Lowering these cars screw up the ride if not done properly.

[JokerElite]

+1 on B6 being a harsh. I was running the B12 pro-kit for years which is B6 + Eibach lowering springs and it would crash on the slightest bumps. I changed to new Sachs with OE springs and I love it. Imo, the look of the slight drop wasn't worth the harshness as I do not track the car.