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How to Finally Get Performance Out of Your KW Coilovers

35K views 61 replies 26 participants last post by  PrittyM3 
#1 ·
It's no secret that KW isn't much of a performance coilover. It is a mass produced product that sells due to such a low buy in price and an immense amount of marketing. Just look at the threads when someone asks what the best coilover system is, it is almost always KW and the reason being, "that's what I have on my car".

When you have never tried other systems it is easy to think that the KW system is great. BUT, take a ride a in a true linear rate car that has been set up properly with appropriate spring rates (or even the same spring rates) and you will see just how far off the best system you are. The reason for this being that KW uses progressive springs. This means that it takes an average over the springs compression. For example, say at 1 in of compression it is 200lbs, 2in compression = 250lbs and 3in compression= 300lbs. The spring rate would be 250lbs ((200+250+300)/3) This kind of springs set up is very unpredictable when it comes to handling and makes you car handle poorly because you don't have the quick reaction of the spring.

THE ONLY KW SYSTEM that is NOT progressive are the CLUBSPORTS.

Fortunately for those of you who already have KW coilover systems, you don't have to scrap you entire system to get a linear set up. We offer a KW conversion kit that allows you to use Swift linear coilover springs. We have offered this to the E9X community and they have been floored by how much they notice the difference and how :censor: they were for being suckered in on the KW product.

A fellow e46fanatics member explained it very well and this comparison is between two linear springs. KW springs would have been obliterated in this test.

Now as for the testing I happen to have a spare volkland spring lying around because I had a friend that wanted me to test it out. I also have a set of lightly used Swift springs in almost the same dimensions. The Volkland spring that i have is a
2.5" ID 9" length 180lb/inch spring.
The swift on the other hand is
2.5" ID 9" length 4kg/mm spring which equals to 223lb/inch spring.

Now just a little background information on this little test that I did. The lower the spring rate the spring rate changes and spikes throughout its compression is much less affected than a heavy spring rate. The spring rate spikes are obviously much more noticeable but the percentage increased are about the same. The reason I tested out such low rates though is because these springs are the only springs comparable that I have lying around.



Now there is a lot more to a spring than the spring rate but that is by far the easiest to see the quality and accuracy of the spring itself. So that is exactly what I tested first.



There is nothing bad I can really say about this spring, it is really hard to tell the accuracy of the spring rate because it is not too hard to be off on a spring rate so low. But as a 180lb/inch spring it is pretty dead on its spring rate all the way through its compression.
1st inch- 181
2nd inch- 183
3rd inch- 186 (already starting to hike up)
4th inch-250 (it was nearing coilbind so its natural to increase this much so you can judge this spring at this amount of compression)


Now with the swift spring.

again this spring is also a low spring rate, it's a little stiffer than the Volkland but it is nowhere near high enough to accurately tell how precise this spring is. But this is the spring rate that was recorded throughout its stroke

1st inch- 220
2nd inch- 223
3rd inch- 222
4th inch- 224

Now I took a picture of every inch of compression, I tested it several times through the different strokes of the springs and the numbers for both really consistent throughout their compressions. The pictures and the recorded numbers I decided to post up are numbers starting with zero preload.
These pictures posted below is where the Swift started to outshine the Volkland. This is at 3 inch of compression.




You can clearly see that the swift spring has a much larger sweet spot than the Volkland spring. You can also see that the Swift spring is much closer to the desired spring rate.

But this is not the only advantage to the spring.
Right after being put on the spring checker I remeasured the springs to see if there were any difference in length.



The Volkland spring was brand spanking new. With just a few compressions on the spring checker it had already sagged 1/16 of an inch.

the used Swift on the other hand was dead on at its height.

This was just a few minutes of compression on the spring checker. Now you can imagine what the spring would do after a few months of use with the weight of the car and the vibrations exposed to the spring.

Well Volkland springs are known to sag after a few race events in the real time racing. This is why I decided to measure it before and after the checking of the rates. I already knew the results before going into the test.
Also to show the craftmanship of these springs

^This picture was also taken before the dyno testing. Now all springs do slant a slight amount. They usually are within whatever the manufacturer specs are. This spring though is almost like an S shape which is something I only thought came with Megan springs. This was kind of disappointing to me.
Now I have tested time and time again, all sorts of different springs from all kinds of manufacturers. I am always pretty confident with the swift product. Now if I find a better product then I will back that, but so far to this day I have not found one.

Now Zerosum brought up a good point. What you claimed is the exact thing that splits the Swift springs apart from all the other spring manufacturer. Now lets say I were to get the most precise spring from Hiperco or Eibach and compared it with a Swift spring. On a spring dyno it will be very similar. The graph would probably look identical, but then if you were to physically use those springs and swap them out, to use back to back, It would be a night and day difference. You would immediately be able to tell which is Swift. The Swift will feel much more compliant, in fact its exactly what Zerosum said "the impacts are much better damped". I know it is hard to understand but I will explain.

It is not the spring rate that distinguishes the differences in the impact of uneven pavement. Spring rate has more to do with the reaction of the amount of force put onto the spring. In other words to put it in simple terms, it will affect body roll. I am not saying that initial impact of uneven pavement can be softened by softening spring rate, but that is not the correct way to make a car more compliant. The correct way is the shock absorber the main reason for this is because there is a form of mechanical lag with the spring. This is why some suspension companies do not even believe in adjusting spring rate (talk to the techs at KW).

Now for some reason the reaction rate or the time to respond from impact with the Swift spring is much much quicker than ANY other spring company. This is something that can not be seen on a spring dyno. But can be tested. In fact through the testing that I have done we have seen that even with the exact spring rates being used the tire temperatures with the Swift springs is always cooler. This is the reaction rate of the spring, or frequency of the spring is what some suspension scientists explained it to me as. (LOL)
But of course track testing is nowhere near accurate for testing because there are so many different variables that come into play with simply measuring tiretemps.

Anyways the reason why we came to the conclusion that the reaction speed is different is because we ended up taking the car to a shaker rig. Which is an extemely expensive process, which I obviously did not pay for but was there to help figure out why the Swift springs were so different.

Anyways what I am trying to say is that the Swift springs even with the same rates will durastically make a difference with the performance of the vehicle.
 
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#4 ·
We have not personally done any testing between Swift and Hyperco but it is almost impossible to be any better than Swift as the tests show. They are very light springs and compared to other linear rate options on the market, seem to far surpass them.
 
#8 · (Edited)
Why not just get a quality set like GC or TCK?

I don't know why progressive spring coils are pushed so hard on the M cars. IMO, the KW2 and Kw3 ride like crap compared to linear spring coil packages from the high end manufacturers (GC, TCk, AST etc.) . My old E46M I ran TCklines but had problems with the Vorshlag plates. The new M I bought, came with Kw2's and it rode like a boat. But then again, I was used to the old TCkline setup.

I must say, good work on your modification! I like to see folks think out of the box. You may find a market for these springs, as a whole lot of poor souls were convinced to buy Kw2's from group buy discounts at m3forum.

Nice work sir!
Mike
 
#6 ·
I've actually talked to a few buddies of mine and they said the same thing about the Hyperco's. They said they are the best springs they have ever used, and it would be almost impossible to be any better, lol.

Guessing they're both on the same page quality wise, although I would love a real comparison!
 
#7 ·
#9 ·
Today i got a KW V2 setup and im thinking about changing to clubsport. But if the price is right for a setup of swift springs i might try change that just to feel the difference. Could you recommend me a package of springs for a car that only runs on track & autoX events.
 
#12 ·
Why would anyone go thru all this when they can just get GC/TCKs and call it a day? .
That's what I was thinking! I love my GC setup at 450/500 for the street. And even though I have a set of stiff springs for the track, the 450/500 handle the twisties just fine.

I probably would have appreciated the Kw2's more if I never rode in a TCK equipped car before.
 
#13 ·
So, my question is, if you are suggesting using the KWV2 shocks and struts paired with a different spring set-up, how about some distributor and pricing info? Also, if someone isn't tracking their car, i.e. me, then is this switch worth it?
 
#14 ·
S Also, if someone isn't tracking their car, i.e. me, then is this switch worth it?
If you like the car to handle like it should, yes. Just a reminder though... Ignorance is indeed bliss. If you don't know what the M3 should handle like with a quality set of coilovers, you'd never know the difference.

My advice, if you don't want to spend more money on suspension parts....do not ride in a car with a quality set of linear spring coilovers. That way, you'd never know what you're missing. :craig:
 
#15 ·
Although I kind of agree Mister, I also dont. Reason being, most guys just tool around in the M on the streets. There is no desire for pushing the handling limits and simply weaving in and out of traffic is enough. I'm not at all trying to make it sound like I'm talking down to that group of owners, but they certainly dont need anything special. A progressive spring on a coilover to let them set the height they want should be enough. Well, a set of lowering springs should be enough, but that doesnt sound cool enough :p So imo, if someone is just daily driving their M, I dont see any reason for them to switch springs.

And props to HP, I'm sure they'll definitely have a market for these!
 
#16 · (Edited)
Reason being, most guys just tool around in the M on the streets. There is no desire for pushing the handling limits and simply weaving in and out of traffic is enough. I'm not at all trying to make it sound like I'm talking down to that group of owners, but they certainly dont need anything special. A progressive spring on a coilover to let them set the height they want should be enough. Well, a set of lowering springs should be enough, but that doesnt sound cool enough :p So imo, if someone is just daily driving their M, I dont see any reason for them to switch springs.
Good points Chris. If I never had the pleasure of driving the E46M on a quality set of coils, I would most likely feel the same way. IMO, the handling is the high note of this vehicle, and I would never spend my money on parts that negatively affect the handling. I felt the car handled better in 100% stock form, than the KW2 coilovers that came with my 2nd E46M. And I tweaked the settings many times. Adjusted ride height, corner balanced twice.... etc. It handled like a boat. :( Whether my main use was weaving in and out of traffic, or a dedicated track car, I want to maintain or increase the stock handling performance.

But I wouldn't recommend anyone buying lowering springs alone for this car. It truly does ruin the steering geometry of the M3. A set of cheap progressive rate spring coilovers is a much better idea than lowering springs with stock height struts and RSM's etc.


And props to HP, I'm sure they'll definitely have a market for these!
Much agreed. I like when distributors get creative.
 
#18 · (Edited)
We carry KW but it wouldn't be the first thing I would offer you.

By KW competition do you mean KW clubsport?
 
#20 ·
I'm not sure what you are asking?

Would you like to purchase a set of competitions? We can get them for you if you'd like.

I suggest some TC Kline D/A or AST 5200's first.
 
#22 ·
I chose the V2's because they retain stock-like comfort (if you can really call a stock M3 "comfortable") which is important to me for a daily driven car. MisterM, I can say without a doubt that the car handles significantly better and more predictably with the KW's compared to when she was stock.

For a linear spring setup that has OEM like comfort, I'd assume that there would be a trade-off in handling capabilities too.
 
#23 ·
If you bought the same spring rates that you have now but linear it would handle more predictably and ride smoother. Your springs now are progressive (spike) as you travel through the range of motion. Swifts do not spike at all.
 
#33 ·
LOL it sounded like KW v2 handle like crap. No kidding that a Ferrari is faster then Corolla. The v2 handles, ride and corner way better than stock. Progressive spring give a comfortable ride on the street. At the same time it gives a very good handling on the road. If we want to track then we wouldn't think of v2 would we? It's also how you handle the car.
 
#34 · (Edited)
It's no secret that KW isn't much of a performance coilover. It is a mass produced product that sells due to such a low buy in price and an immense amount of marketing.
KW Coilovers aren't much of a 'performance' coilover? Is that right? They're the best coilovers I've ever ridden on which is why i own a set. Without a doubt, performs MUCH better than OEM & handles/rides just amazing on the street which i think is what they were designed to do. I would hardly call +/-$2000 a 'low buy-in price' Just my $.02

LOL it sounded like KW v2 handle like crap. No kidding that a Ferrari is faster then Corolla. The v2 handles, ride and corner way better than stock. Progressive spring give a comfortable ride on the street. At the same time it gives a very good handling on the road. If we want to track then we wouldn't think of v2 would we? It's also how you handle the car.
:werd:
 
#35 ·
They're the best coilovers I've ever ridden on which is why i own a set.
Is that because they are the only set you've ever ridden on?

And no they are not a performance coilover. Yes they are better than stock but until you are using linear springs they are just coilovers. TC Kline, AST, Moton, GC, etc are performance coilovers with a likeness in that they use linear springs.

My price reference was within reference to non-m e46's which are about $1300, it is $1700 for V1 for the M3. For that much money why not buy a proper set up from TC or AST for a couple hundred more?
 
#37 ·
Retail:
Clubsport: $3,595
TC Kline: $2,998
AST 4200: $3,299

At this level it really depends on what you are looking for. All three utilize progressive springs but unlike the others KW does not allow you to pick custom spring rates. With AST and TC you can have them revalved higher, choose custom spring rates and they are easily rebuildable.
 
#41 ·
HP, Thanks for the data. Over the past few days I have been trying to figure out what direction I want to go for the suspension of my car. I first thought of just doing springs and shocks, then a budget coilover, now I'm leaning toward the TCK SA truematch. I'm trying to figure out what I need versus what I want, lol. I definately want a linear spring coilover set. By my understanding the linear spring will give me a bit harsher of a ride but it will be more predictable. I don't track the car but I have opprotunities too and I would like to start. What else would you say is necessary? I was thinking a front sway bar then replacing some bushing and calling it good. What are your thoughts?
 
#42 ·
We sell TC Kline products as well (we actually share an office with TC himself).

The two main advantages of linear springs are that they are more predictable and they decrease body roll in comparison to same rate progressive springs.

I would also add to the list, camber plates (we suggest Vorshlag), check the front control arms, and rear trailing arm bushings. A front sway bar helps as well on this car and Hotchkis is who I would recommend. I personally use their products and the quality vs H&R, Eibach, etc is great plus Hotchkis bars are hollow, therefore lighter.
 
#46 ·
I personally had KW V2's on my old Audi B6 S4 and they blew in 2 months. I didnt want to go through that hassle again so I went with TCK's on my E46 M3 and they are way better built hands down.

Can I get a quote on Hotchkis sways for my car? Also some adjustable front sway bar links. thanks!
 
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