[D989]

I 'm currently running the B12 set, but it is a little too rough imo for these roads. Considering going back to the sport springs with the b8's. I know the eibach's are Fronts = 148 lbs/in, Rears = 457 lbs/in.
Also looking for slightly more clearance for bigger tires.
As far as I'm aware the b8's should still be compatible with the slightly taller sport springs as far as length is concerned.
Does anyone know the oem sport spring rates?
Will this change the ride comfort much?
Also my car which is a diesel is at least 200lbs lighter than stock.

[whyzee125]

OEM m sport springs are almost identical in rate to the Eibachs.

Front: ~145
Rear: ~460

The progression may be a bit different but the stiffness is likely more due to the dampers and/or being closer to the bump stops.

[D989]

Originally Posted by whyzee125

OEM m sport springs are almost identical in rate to the Eibachs.

Front: ~145
Rear: ~460

The progression may be a bit different but the stiffness is likely more due to the dampers and/or being closer to the bump stops.

Thank you. Bump stops shouldn't be an issue unless they are actually bottoming out right? I feel it in normal dips, bumps and expansion joints so I don't think it's bottoming out. Plus these are from Strut Monkey so they are probably the correct bump stops. Starting to think I should have spent the extra on Ohlins.

[D989]

Also thinking that if I go one size up in tire profile It might mitigate the damping stiffness enough. Going back to oem springs would help give me the clearance to do that.

[Tambohamilton]

Bump stops are called "auxiliary springs" by BMW, because they're engaged at ride height (or very close to it) with stock/m-sport springs. So they're very important to get right. I wouldn't be certain strutmonkey would have the correct part, but also the eibach springs are garbage and will not give comfort/control. They're barely any stiffer than m-sport, but significantly shorter so you're always crashing into the bump stops on any sort of bump/compression.

M-sport and b8 should be a decent combination.

Have you considered BMW performance springs? They're about the same height as eibach, but the fronts are around 190; significantly stiffer. The rears are stiffer too, but I can't remember the numbers. It was possible to get complete OE sets (struts, shocks, bump stops, etc) with BMW P, so may be an option if you can find the parts. You'll need the stiffest set - ones made for a 335i ("T4"?).

...or just fix the problem with money, and go ohlins.

Going up one step in tyre profile won't do a huge amount for comfort - a step down in wheel diameter would help though...and save some weight

[whyzee125]

Originally Posted by D989

Thank you. Bump stops shouldn't be an issue unless they are actually bottoming out right? I feel it in normal dips, bumps and expansion joints so I don't think it's bottoming out. Plus these are from Strut Monkey so they are probably the correct bump stops. Starting to think I should have spent the extra on Ohlins.

Tambohamilton got it right; there's not quite a "bottoming out" on these cars as the bump stops are super progressive and are designed to be utilized on most everything you hit except small chatter.

But yes, almost no aftermarket lowering springs get it right with bump stops, and especially not Eibach unfortunately.

If you are any lower than stock, you're sitting on the bump stops at ride height. Trimming them helps but tends to feel very abrupt when they engage. The e36 ones commonly recommended up front ramp up too fast (designed for a lighter car) so they result in a bit of a crashing sensation. The z4 ones for the rear, I will say, work great and are a P&P, set it and forget it solution so I highly recommend those.

Up front, the e36 ones are decent but I'm currently playing with the 55mm Koni bump rubbers like those used in the TC Kline kit to try to get it just right. Already, however, I'm finding in their stock 55mm form, they're too long even for my much milder drop at twice the spring rate.

[D989]

Originally Posted by Tambohamilton

Bump stops are called "auxiliary springs" by BMW, because they're engaged at ride height (or very close to it) with stock/m-sport springs. So they're very important to get right. I wouldn't be certain strutmonkey would have the correct part, but also the eibach springs are garbage and will not give comfort/control. They're barely any stiffer than m-sport, but significantly shorter so you're always crashing into the bump stops on any sort of bump/compression.

This is very interesting about the bump stops. I had no idea that any manufacturer used bump stops in this way (always engaged). Do you think I could move the boot to tell which version is in there?
[/QUOTE]
M-sport and b8 should be a decent combination.
[/QUOTE]
This is what I was hoping for.

Have you considered BMW performance springs? They're about the same height as eibach, but the fronts are around 190; significantly stiffer. The rears are stiffer too, but I can't remember the numbers. It was possible to get complete OE sets (struts, shocks, bump stops, etc) with BMW P, so may be an option if you can find the parts. You'll need the stiffest set - ones made for a 335i ("T4"?).

This doesn't sound like a good solution because they are stiffer/firmer.

...or just fix the problem with money, and go ohlins. :lol:

I'm glad you laughed at this because I was half joking. I always thought coilovers
Were a horrible idea for a road car ( even if they do have "Road" in the title), but everybody swears by them. Also it's probably hard to admit they are not great when you spent over $3k.

Going up one step in tyre profile won't do a huge amount for comfort - a step down in wheel diameter would help though...and save some weight ;

This seems to be the opposite of what most people say. I notice a difference on my winter beater when I go up to a 60 from a 55. Wouldn't the reason for comfort from a step down in wheel be because you are trading for more tire? I'm on 18's and not sure that 17's would clear the front brakes.

[D989]

Originally Posted by whyzee125

Tambohamilton got it right; there's not quite a "bottoming out" on these cars as the bump stops are super progressive and are designed to be utilized on most everything you hit except small chatter.

But yes, almost no aftermarket lowering springs get it right with bump stops, and especially not Eibach unfortunately.

If you are any lower than stock, you're sitting on the bump stops at ride height. Trimming them helps but tends to feel very abrupt when they engage. The e36 ones commonly recommended up front ramp up too fast (designed for a lighter car) so they result in a bit of a crashing sensation. The z4 ones for the rear, I will say, work great and are a P&P, set it and forget it solution so I highly recommend those.

Up front, the e36 ones are decent but I'm currently playing with the 55mm Koni bump rubbers like those used in the TC Kline kit to try to get it just right. Already, however, I'm finding in their stock 55mm form, they're too long even for my much milder drop at twice the spring rate.

Very interesting. I will have to look into the z4 stops and curious to see what you come up with for the front.

[whyzee125]

Btw, with one caveat, the Tein S tech springs (old version) are the best springs I've found for these cars.

They sit too low in the front, but once you do the e30 perches and pads, they sit nicely, ride as well as stock, soak up chatter like absolute butter, while still providing flat ride and more support than OEM springs. The front bump stops are the last thing needed to make this just about a perfect setup.

[D989]

Originally Posted by whyzee125

Btw, with one caveat, the Tein S tech springs (old version) are the best springs I've found for these cars.

They sit too low in the front, but once you do the e30 perches and pads, they sit nicely, ride as well as stock, soak up chatter like absolute butter, while still providing flat ride and more support than OEM springs. The front bump stops are the last thing needed to make this just about a perfect setup.

How low do these sit compared to Eibach and Where can you get those springs? Also what dampers did you have pared with them? What is the benefit of the e30 perches?

[whyzee125]

Originally Posted by D989

How low do these sit compared to Eibach and Where can you get those springs? Also what dampers did you have pared with them? What is the benefit of the e30 perches?

They're NLA, I had them back in the day and loved them and tracked down a used set this time. Then I realized Turn14 still has a few sets I can get through my work.

I had mine paired with Koni oranges last time and Koni yellows this time. They sit low. The e30 pads and perches raise the front ride height 19mm and add that amount of travel back. After that, they sit nicely. Roughly Eibach height up front and a little lower than Eibach in the rear. No rake at all.



These ride as well if not better than stock while being more supportive. They're very progressive so you need a little more damper than Eibachs do. The oranges felt slightly underdamped.

If you aren't obsessed with figuring out every detail, just going Ohlins is a great route. But Ive tried every spring out there and these are my favorite.

The rates are:

191 front - linear
593 rear - progressive

[Tambohamilton]

Interesting - those rates are probably very similar to BMW performance