Lowered on KW Variant 3

[badfish]

Originally Posted by e46e92love

+ 1 million.

Not saying it doesn't look good, but I just believe BMW's //M division did know what they were doing.

KW knows what they are doing, too. Take a look at the cars they cater to. The Viper ACR that lapped Nurburgring in 7:22 comes OEM equipped with KW as does the CLK63 Black Edition. They make kits for the Enzo, GT3 and other 911s, Carrera GT, GTR, etc...

[Gary@RENN-Spec]

Badfish- Great write-up and review on the KW program for your E92 M3!!! We are always happy to see such positive feedback, not surprising considering the R&D that is involved during the development of their suspension. You're definitely right, the guys over at KW Automotive know what they're doing and we love selling a product we can believe in!!!

[AutoTalent]

The best product we have sold & installed

Not a single complaint. Most everyone has EDC & were happy to get rid of it.

[KonigsTiger]

Originally Posted by AutoTalent

The best product we have sold & installed

Not a single complaint. Most everyone has EDC & were happy to get rid of it.

Hmmm! Is there a performance gain when compared to lowering springs assuming that the coilover would be adjusted to the same hight? I´ve heard lots of back and forth on this!! Would appreciate your opinion.

[Green-Eggs]

Originally Posted by BMW-M-Mexico

Hmmm! Is there a performance gain when compared to lowering springs assuming that the coilover would be adjusted to the same hight? I´ve heard lots of back and forth on this!! Would appreciate your opinion.

There is performance obtained as the ride height range of the springs match that of the dampers optimizing suspension travel. The ride quality is smoother than stock while providing better handling. Rebound & Compression are independently adjustable allowing for fine tuning.

There are many examples like the ACR Viper running around the Ring in 7:22, E46 M3 Cup Car that went from Bilstein to KW doing 7:25, Manthey Racing, Flying Lizard, edo competition, Novitec Rosso & there is a long list of racers using the product. The technology rolls over to the street performance products for us spirited drivers

[KonigsTiger]

Originally Posted by Sam@AutoTalent

There is performance obtained as the ride height range of the springs match that of the dampers optimizing suspension travel. The ride quality is smoother than stock while providing better handling. Rebound & Compression are independently adjustable allowing for fine tuning.

There are many examples like the ACR Viper running around the Ring in 7:22, E46 M3 Cup Car that went from Bilstein to KW doing 7:25, Manthey Racing, Flying Lizard, edo competition, Novitec Rosso & there is a long list of racers using the product. The technology rolls over to the street performance products for us spirited drivers

How much is the set? You will have my car soon enough so that it would be easy to install etc...

[Green-Eggs]

Originally Posted by BMW-M-Mexico

How much is the set? You will have my car soon enough so that it would be easy to install etc...

PM Sent

[JMD0977]

I've been thinking very hard about these for a while.......

[Orb]

Some may want to look at some hard numbers beforing jumping on a train wreck.

The M3 comes with 160 lb/in front and 550 lb/in rear springs. The KW kit comes with KW 2017 rear spring which happens to come off e90 street comfort shocks and it rated at 630 lb/in. The front spring is about 285 lb/in. Now take that in that the rear wheel rate is 0.58^2 x (coils spring rate) and the front is (0.96 x coil spring rate) and you are going to need to increase the rear spring rate 2.85 times the front just to keep the car balanced. Increasing spring rate in the front 50 lb/in means you has to increase the rear spring about 140 lb/in to keep the same balance. This system will take a perfectly balanced car and introduce under steer and we haven't even cosider pitch, which BTW, can be far worse.

If you’re just into slamming a bit and not tracking these will be for you. Any serious tracking and most of these after market system are out of their minds unless they supply a complete solution to rebalance the car will roll bars. I’m don’t mean to pick on KW but these lower end solution are beyond under achieving.

Don’t under estimate how well balanced the stock car is. I spent months just to get my car close to what you already have.

Tip: The H&R rear bar for 335i is a perfect fit and you can use the OEM bushings. The effective size of the OEM hollow bar as a soild bar is 18.5 mm and the H&R is a 20 mm solid bar.

Orb

[KonigsTiger]

You may be right? What you say does make some sense.

Originally Posted by Orb

Some may want to look at some hard number beforing junping on train wreck.

The M3 comes with 160 lb/in front and 550 lb/in rear springs. The KW kit comes with KW 2017 rear spring which happens to come off e90 street comfort shocks and it rated at 630 lb/in. The front spring is about 285 lb/in. Now take that in that the rear wheel rate is 0.58^2 x (coils spring rate) and the front is (0.96 x coil spring rate) and you are going to need to increase the rear spring rate 2.85 times the front just to keep the car balanced. Increasing spring rate in the front 50 lb/in means you has to increase the rear spring about 140 lb/in to keep the same balance. This system will take a perfectly balanced car and introduce under steer and i we haven't even cosider pitch which BTW can be far worse.

If you’re just into slamming a bit and not tracking these will be for you. Any serious tracking and most of these after market system are out of their minds unless they supply a complete solution to rebalance the car will roll bars. I’m don’t mean to pick on KW but these lower end solution are beyond under achieving.

Don’t under estimate how well balanced the stock car is. I spent months just to get mine car close to what you already have.

Tip: The H&R rear bar for 335i is a perfect fit and you can the OEM bushings. The effective size of the OEM hollow bar as a soild bar is 18.5 mm and the H&R is a 20 mm solid bar.

Orb

[Pylon]

Wow... good point on the balance issue. I have a KW coilover system on my 330ci and will be getting "something" for my 09 M3 once it arrives. It would be nice to see someone track the KW Variant 3 and see how it performs in the real world compared to stock.

[Blip Bavarian]

Does anybody have a response to this? I think Orb brings up a good point. PencilGeek?

Originally Posted by Orb

Some may want to look at some hard numbers beforing jumping on a train wreck.

The M3 comes with 160 lb/in front and 550 lb/in rear springs. The KW kit comes with KW 2017 rear spring which happens to come off e90 street comfort shocks and it rated at 630 lb/in. The front spring is about 285 lb/in. Now take that in that the rear wheel rate is 0.58^2 x (coils spring rate) and the front is (0.96 x coil spring rate) and you are going to need to increase the rear spring rate 2.85 times the front just to keep the car balanced. Increasing spring rate in the front 50 lb/in means you has to increase the rear spring about 140 lb/in to keep the same balance. This system will take a perfectly balanced car and introduce under steer and we haven't even cosider pitch, which BTW, can be far worse.

If you’re just into slamming a bit and not tracking these will be for you. Any serious tracking and most of these after market system are out of their minds unless they supply a complete solution to rebalance the car will roll bars. I’m don’t mean to pick on KW but these lower end solution are beyond under achieving.

Don’t under estimate how well balanced the stock car is. I spent months just to get my car close to what you already have.

Tip: The H&R rear bar for 335i is a perfect fit and you can use the OEM bushings. The effective size of the OEM hollow bar as a soild bar is 18.5 mm and the H&R is a 20 mm solid bar.

Orb

[Ron@Modbargains]

Originally Posted by Blip Bavarian

Does anybody have a response to this? I think Orb brings up a good point. PencilGeek?

Sure I'll attempt to. For what Orb is looking for - for the track he would be a customer for a Clubsport KW coilovers. Which will be custom setup for his needs.

As to why they would generate a little bit of understeer, its basically because just like what the Manufacturers do when they are making their vehicles - you want to have an inherent bit of understeer (all manufactures build that into a oversteering RWD car) - for the average driver it lets them know the bounds of their vehicle. The car will still oversteer - so keep in mind the solution is setup for the majority of vehicles to help in controlling the car. If you watch Top Gear for example, they'll describe that mild understeer as a point for which they'll break and go into their power slide or whatever it may be they want to do with the vehicle in the turn.

[Orb]

Originally Posted by Ron************

Sure I'll attempt to. For what Orb is looking for - for the track he would be a customer for a Clubsport KW coilovers. Which will be custom setup for his needs.

As to why they would generate a little bit of understeer, its basically because just like what the Manufacturers do when they are making their vehicles - you want to have an inherent bit of understeer (all manufactures build that into a oversteering RWD car) - for the average driver it lets them know the bounds of their vehicle. The car will still oversteer - so keep in mind the solution is setup for the majority of vehicles to help in controlling the car. If you watch Top Gear for example, they'll describe that mild understeer as a point for which they'll break and go into their power slide or whatever it may be they want to do with the vehicle in the turn.

FWIW, the club sports at 500 lb/in front 800 lb/in rear is far worse for inducing under steer. The Clubsport spring specification for 335i is a joke with 400 lb/in front and 570 lb/in rear. The rear motion ratio is about 0.58^2 which mean the rear suspension is very soft and is a major change from the OEM setup for balance. A track car (no aero dynamics) and road car will have the suspension frequency in the front equal or lower than the rear and in a very few cases you might see a 0.1 higher frequency in the front. BMW cars seem to have front suspension frequency 12% lower than the rear for a flat ride. The KW suspension frequencies are way outside the norm with a 0.2 to 0.45 higher front suspension frequency than the rear. Furthermore, the rear suspension frequency is so low for the Clubsport that optimizing traction for R compound tire is not possible as we need a frequency of 2.2-2.3 HZ+ in the rear. The rear KW Clubsport is about 1.7 Hz

Let’s do the math for wheel spring rates as this is what matters:

OEM M3

• 160 lb/in x 0.96^2 = 148 lb/in
• 550 lb/in x 0.58^2 = 185 lb/in

KW v3 M3

• 285 lb/in x 0.96^2 = 262 lb/in
• 630 lb/in x 0.58^2 = 212 lb/in

KW Clubsport M3

• 500 lb/in x 0.96^2 = 460 lb/in
• 800 lb/in x 0.58^2 = 269 lb/in


Look like we will get under steer given nothing else has changed other than springs. This is not a guess but a fact as the load transfer will be biased towards the front considerably (at least 5%). It can’t be corrected without a roll bar change not to mention that the cars pitch is a mess now and over compensated by heavy front rebound damping. The only thing that the KW setup will do possible is make the car feels softer but this is far from what a performance setup should be. One thing is for sure BMW engineering is a lot better than KW’s.

Orb

[KonigsTiger]

Originally Posted by Orb

FWIW, the club sports at 500 lb/in front 800 lb/in rear is far worse for inducing under steer. The Clubsport spring specification for 335i is a joke with 400 lb/in front and 570 lb/in rear. The rear motion ratio is about 0.58^2 which mean the rear suspension is very soft and is a major change from the OEM setup for balance. A track car (no aero dynamics) and road car will have the suspension frequency in the front equal or lower than the rear and in a very few cases you might see a 0.1 higher frequency in the front. BMW cars seem to have front suspension frequency 12% lower than the rear for a flat ride. The KW suspension frequencies are way outside the norm with a 0.2 to 0.45 higher front suspension frequency than the rear. Furthermore, the rear suspension frequency is so low for the Clubsport that optimizing traction for R compound tire is not possible as we need a frequency of 2.2-2.3 HZ+ in the rear. The rear KW Clubsport is about 1.7 Hz

Let’s do the math for wheel spring rates as this is what matters:

OEM M3

• 160 lb/in x 0.96^2 = 148 lb/in
• 550 lb/in x 0.58^2 = 185 lb/in

KW v3 M3

• 285 lb/in x 0.96^2 = 262 lb/in
• 630 lb/in x 0.58^2 = 212 lb/in

KW Clubsport M3

• 500 lb/in x 0.96^2 = 460 lb/in
• 800 lb/in x 0.58^2 = 269 lb/in


Look like we will get under steer given nothing else has changed other than springs. This is not a guess but a fact as the load transfer will be biased towards the front considerably (at least 9%). It can’t be corrected without a roll bar change not to mention that the cars pitch is a mess now and over compensated by heavy front rebound damping. The only thing that the KW setup will do possible is make the car feels softer but this is far from what a performance setup should be. One thing is for sure BMW engineering is a lot better than KW’s.

Orb

Wow!!! Nice way of making your point Orb. Thanks for the info!!!

[Orb]

Originally Posted by BMW-M-Mexico

Wow!!! Nice way of making your point Orb. Thanks for the info!!!

No problem. Just to let you know I put theory (load transfer calculation) into practice as well over the last few months. I am having a slightly used spring sale soon. Avoid doing your suspension twice and get something good the first time that has some solid engineering behind it...Moton or JRZ with Hypercoil springs comes to mind.

Orb

[KonigsTiger]

Originally Posted by Orb

No problem. Just to let you know I put theory (load transfer calculation) into practice as well over the last few months. I am having a slightly used spring sale soon. Avoid doing your suspension twice and get something good the first time that has some solid engineering behind it...Moton or JRZ with Hypercoil springs comes to mind.

Orb

Hahahaha!!! Sound wonderful!

[roverrich]

Hey Orb, I have a question:

Does the lowering effect on the car with say KW's come into play in anyway with your calculations? I mean, it seems that if the car is lowered, the center of gravity will also be lowered and therefore the effects of a changed center of gravity will need to be factored in in the weight transfer and car balance considerations. Am I totally off track here? Thanks in advance!!

[Radiation Joe]

I don't know about our cars, but in the past, lowering an e30, e36 or e46 changed the roll center of the front suspension enough to negate any advantage of lowering the car's center of gravity. This means if you didn't stiffen the springs and anti-sway bars enough, your car cornered worse after lowering. The solution is to offset the ball joint from the strut by some amount. Then you mess up the bump steer characteristics of the suspension and have to offset the steering arms a similar amount. Suspension tuning is not as simple as some folks would have you think.

This is an e36 with Moton DA race shocks and some nice components from Ground-Control. Note the offset mounting points for the hub carrier and steering link.

[Orb]

Originally Posted by roverrich

Hey Orb, I have a question:

Does the lowering effect on the car with say KW's come into play in anyway with your calculations? I mean, it seems that if the car is lowered, the center of gravity will also be lowered and therefore the effects of a changed center of gravity will need to be factored in in the weight transfer and car balance considerations. Am I totally off track here? Thanks in advance!!

What you said is correct but there are other things we have to consider like suspension geometry and roll center heights. Performance cars are generally lowered since the spring rates increase significantly which means that for a given load the suspensions compresses less so we can still maintain good suspension geometry. If you go outside these limits then you start to lose as you have to deal with poor suspension geometry and less than optimal camber/toe curves. The big loss is that your CG does not change proportionally to your roll center height so if you go to far you will have a car that has more roll although you have less jacking effects. It is always a game of endless tradeoffs and there a bit more to this as well.

In general, you can say ½” drop for this car is reasonable with modestly stiffer spring. To know how far you can go we have to map the roll center vs ride height which BTW I am doing over the holidays. It is amazing how far a bathroom scale and tape measurer can take you to figure this stuff out with very good accuracy.

Orb

[doba_s]

good info Orb ... thanks for your input

what would you say about Dinan and H&R springs for e92 m3 ? would it be in the same category as KW or closer to the stock specs ?

thanks.

[Blip Bavarian]

Orb, Thanks for all the great info. I think i speak for all of us when i say that we greatly appreciate your explanations.

What setup would you use on an M3? Or would you leave it stock?