[Kankles]

Update: have installed KW linear front 80-180 main and 20-80 helper and linear rear 160-200. Very close to the spring set up from the KW clubsport.

[swagon]

Originally Posted by Kankles

Need some forum "math in public" assistance.

With more track days planned in the future I'm looking to upgrade (at least the front progressive springs) to a linear spring for more aggressive set-up. I'm also running millway street CPs FWIW.

From what I've read the V3 struts are same as the club-sport but with different valving. So I need to be careful not to go too stiff and exceed the strut capabilities.

As I'm in EU "KW Racing" springs are likely the best option as they have 61mm ID linear springs, etc. If I were in the US I'd probably do a swift upgrade from Harold at HP as they've been doing these upgrades at least since E46 days.

My biggest question that I hope to get answered here is what spring length would you guys recommend in order to keep same height adjustment? Also, taking into consideration the helper spring and "helper spring separator" into the overall spring length.

Front progressive spring is 220mm uncompressed, 175 while compressed (max ride height).

This makes me think I need at least a 170mm front spring combined with 60mm helper (18mm stack height) and needle bearing plate (5mm), but I'm not 100% sure.

The club sport uses an 80-220 front spring, so even stiffer. I'm also open to spring rates but I'm considering 60 Nmm for the front (342 lbs/in).

Any insight greatly appreciated

I don't know where in the EU you are located, but I'd give one of the shops around the Nordschleife a call. Schirmer, Raeder or Laptime Performance all do custom suspension work, for example. Or even KW themselves since they also are able to make custom builds.

[Kankles]

Originally Posted by swagon

I don't know where in the EU you are located, but I'd give one of the shops around the Nordschleife a call. Schirmer, Raeder or Laptime Performance all do custom suspension work, for example. Or even KW themselves since they also are able to make custom builds.

Ok, thanks for the tip, appreciate it! I'm in Holland.

Email is currently out with KW. I'll keep going down the list if they can't help. I imagine they can as I shouldn't be the first to switch the V3 to linear springs.

After doing a bit more research I've found the clubsport uses front 170 length with 80 Nmm springs. So that will get me a bit closer to where I want to be considering helper spring, spring divider, top roller bearing, etc

[swagon]

Originally Posted by Kankles

Ok, thanks for the tip, appreciate it! I'm in Holland.

Email is currently out with KW. I'll keep going down the list if they can't help. I imagine they can as I shouldn't be the first to switch the V3 to linear springs.

After doing a bit more research I've found the clubsport uses front 170 length with 80 Nmm springs. So that will get me a bit closer to where I want to be considering helper spring, spring divider, top roller bearing, etc

I'm sure you've already found the certificates with all the specifications that the manufacturer has to provide TUV. If I recall, the KW V4 kit for F80/82 uses linear springs unlike the V3 that has progressive springs. OEM springs are also progressive.

I think getting your coilovers dialed in by a professional to your liking and according to your usage is worthwhile... It is the point of adjustable coilovers after all.

[Kankles]

Originally Posted by swagon

I'm sure you've already found the certificates with all the specifications that the manufacturer has to provide TUV. If I recall, the KW V4 kit for F80/82 uses linear springs unlike the V3 that has progressive springs. OEM springs are also progressive.

I think getting your coilovers dialed in by a professional to your liking and according to your usage is worthwhile... It is the point of adjustable coilovers after all.

Yup, exactly, I.e. the same struts being used on multiple variants. But even though they use the same strut I've read that the valving is different. Why I want to go stiffer but not quite as stiff as the CS. Luckily the race springs are a relatively inexpensive upgrade.

Also with the CS you lose 10mm of ride height. I desperately need every mm of ride height I can get with my current tire set up Just another thing that goes into the equation.

I've been playing around with the V3 settings and have it dialed in now to my liking. I'll likely take your advice before track season next year and have it aligned/set up by a reputable race shop. There's a couple near me.

Ultimately I'm not chasing lap times, just chasing fun times and also enjoy working on the car/tweaking things.

[StratoAlpha22]

Originally Posted by Kankles

Update: have installed KW linear front 80-180 main and 20-80 helper and linear rear 160-200. Very close to the spring set up from the KW clubsport.

Hi there you seem to be the only person I can find online which have done the same modifications I wanted to do, just wanted to ask you, did you notice a huge amount of difference from changing the progressive springs to a linear spring. Also which car did do this on? I’m looking to do the same for my F80 M3. I’m still unsure on which springs to use, after stumbling on your post you, helped me and gave me an idea on which direction to go. I hope it turned out the way you wanted.!

[papolosa]

I would also like to hear more on the results. Have the V3s and would also like to increase spring rates for improved track experience without going all the way to Ohlins RT or KW Clubsport harshness (..relative to my tolerance for street).

I had a chat with HP Auto and they said 400#s would be about the max for v3 fronts(don’t recall rears), they will sell me the swift springs, but I need to get the perches milled down to 60mm. I also need to figure out how to get 60mm on my current TCKlein camber plates. I was hoping they would have a conversion kit like I have heard they have done for E46 and E9X.

Now exploring getting KW springs and just need to resolve the camber plate situation with TC Klein.

[Kankles]

Hi, I did the upgrade to my M2c but I used v3 from F80, which are the same. For the updated springs I used the same KW springs/rates from the F80 club sport. I ordered them from KW directly but with the part numbers you could probably go through one of their suppliers, depending on your location. I also did helper springs and separators, same as the club sport set up. See bottom with the part numbers and quantities of the parts and springs.

This was one of the best upgrades I did to the car to be honest and it is much better performing. I had them 10km or so on the car and they never faltered. Did multiple track days with them and combined with the millway street plates performed so much better than standard v3, which were too soft and allowed too much roll. I sold the car this past fall and the new buyer went back to stock as he has no intention of tracking car. His call but the set up I had was much better even for spirited street driving.

Qty Pos Article No. Description

2 10 65243000 Zwischenring lila/ K28.09.02.02

2 20 60110173 Rennsportfeder 80-180* RAL 1021

2 30 60110005 Vorspannfeder 20-60-80 RAL 1021

2 50 60110322 Rennsportfeder 160-200* RAL 1021

[papolosa]

Thanks for the update!! Did you still have good range of rebound/compression settings at those spring rates or were you close to max? Thanks again, I think this is the direction I am going with.

[Kankles]

Originally Posted by papolosa

Thanks for the update!! Did you still have good range of rebound/compression settings at those spring rates or were you close to max? Thanks again, I think this is the direction I am going with.

Struts weren’t close to being maxed out for compression or rebound. I’ve heard that although the body of v3 is same as CS the valving is different and the v3 struts can’t handle the stiffer springs. This was not my experience. I really thought it was a nice balanced street/track set up.

[papolosa]

Awesome! Thanks again!

[CroGoc]

I am also very interested in this and cannot find any other thread online about this topic.

What bothers me is the occasional bottoming out of the default 2041 springs on my KW V3 and in my opinion, for M140i is way too soft. So I am thinking also about buying a clubsport springs and put it to my V3 to make it more stiffer.

But I have a big dillema here, will it really work properly, how does it effect the longlife of the struts? You said it wasnt even close to the max setting of compression and rebound, but I was emailing with KW a little bit and they told me that I should not go more than 20N/mm above default spring rate of the 2041 spring (default V3 spring). And Clubsport springs are 40N/mm above default spring rate of 2041.

Investing 500euros in the springs now, maybe is just smarter to sell my V3 and buy a clubsport?

Thank you.

[_pancho_]

This is a good upgrade .
Pm me if you are interested as I have a conversion kit to sell (Sweden)

[Sequence_]

Originally Posted by _pancho_

This is a good upgrade .
Pm me if you are interested as I have a conversion kit to sell (Sweden)

What is the specs on this setup?

[_pancho_]

Originally Posted by Sequence_

What is the specs on this setup?

HRF120140 60mm ID, 120mm, 140N/mm
HZF080020 60mm ID, 80mm, 20N/mm
10382 Adapter 90-60 for 60mm spring F2X
10202 Middle ring 60mm