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10-17-2008, 12:48 PM | #45 | |
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10-20-2008, 08:36 PM | #46 |
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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!!!
Last edited by Gary@RENN-Spec; 10-21-2008 at 02:04 PM.. |
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11-18-2008, 11:22 AM | #48 |
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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.
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11-18-2008, 02:43 PM | #49 | |
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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 |
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11-18-2008, 02:47 PM | #50 | |
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11-18-2008, 03:52 PM | #51 |
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11-19-2008, 08:33 PM | #53 |
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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 Last edited by Orb; 11-20-2008 at 02:55 PM.. |
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11-20-2008, 10:35 AM | #54 | |
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You may be right? What you say does make some sense.
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11-28-2008, 09:52 AM | #55 |
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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.
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12-12-2008, 11:29 AM | #56 | |
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Does anybody have a response to this? I think Orb brings up a good point. PencilGeek?
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12-12-2008, 05:53 PM | #57 | |
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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. |
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12-12-2008, 07:31 PM | #58 | |
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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 Last edited by Orb; 12-21-2008 at 09:36 AM.. |
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12-12-2008, 07:44 PM | #59 | |
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12-12-2008, 09:27 PM | #60 | |
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Orb Last edited by Orb; 11-25-2011 at 12:09 PM.. |
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12-14-2008, 05:40 PM | #61 | |
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12-14-2008, 06:33 PM | #62 |
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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!! |
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12-14-2008, 07:12 PM | #63 |
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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. Last edited by Radiation Joe; 12-15-2008 at 01:21 PM.. |
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12-14-2008, 07:24 PM | #64 | |
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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 Last edited by Orb; 12-15-2008 at 01:13 AM.. |
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12-15-2008, 12:36 AM | #65 |
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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. |
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12-15-2008, 09:23 AM | #66 |
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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? |
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