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E46 M3 (2001-2006) Engine: S54 - Max Hp: 333 hp at 7,900 rpm / 262 lb/ft at 4,900 rpm
Total Produced: 45,000+ - Years Produced: 2001 to 2006.


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Old Wed, Aug-07-2013, 05:02:41 AM   #21
paffy
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Default Re: End to all speculation: The CSL Kingpin

IMHO, the only thing this changes is the height of the hole where the tie rod attaches to the kingpin.

It brings it UP a little bit, increasing bump steer ?? wtf ?
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Old Wed, Aug-07-2013, 05:10:23 AM   #22
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Default Re: End to all speculation: The CSL Kingpin

Quote:
Originally Posted by ML///M3 View Post
Based on what you're seeing, are you suggesting that the CSL Kingpin is providing positive caster?

My understanding is that it provides straight-line stability but it really doesn't matter since most cars are not sensitive to caster (mainly those that can adjust caster can gain the benefit - RX-7 FD comes to mind). The downside (my understanding) to increased caster is more steering effort is required, but then again the CSL has a tight steering rack, so again it might not have a big effect on steering. Curious to know more though...
Most cars are pretty sensitive to caster, especially when on firm suspension/tires. Any change in alignment settings should be noticeable if all else is sorted. The BMWs have more caster than most cars from the factory, so increasing it more isn't as noticeable as it is on something like a Subaru, but more caster should be a big difference on most cars.

The steering effort shouldn't be increased substantially (wider tires would have a greater impact on this than caster - within reason of course), but small changes would make a bigger difference on the CSL than a standard M3 due to the CSL's lower ratio steering rack provided both cars use the same pump and pressure in the system.
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Old Wed, Feb-17-2016, 07:51:26 PM   #23
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Default Re: End to all speculation: The CSL Kingpin

Any info if the front track was widened... maybe to adjust the scrub radius ???
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Old Tue, Oct-02-2018, 10:00:50 PM   #24
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Default Re: End to all speculation: The CSL Kingpin

Abad46, did you ever install the kingpins?
Did it widen the track?
Increase negative camber?
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Old Wed, Oct-03-2018, 12:58:03 AM   #25
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Default Re: End to all speculation: The CSL Kingpin

They do not increase track at all. I have a set waiting to go on my car. I measured all the relevant dimensions that would impact track and compared to the regular M3. There was no difference.

What I did find is that they add ~1 degree more negative camber without changing the SAI(steering axis inclination).

I didn't understand why they would do this instead of using camber plates at first, so I spoke to someone much more knowledgeable about suspension geometry. Here's what I found out...

Camber plates add negative camber by moving the top strut mount toward the center of the car. Unfortunately, on a MacPherson strut front like the E46, moving the top mount inward also increases SAI. Larger SAI results in more caster loss as the wheels are turned left or right, and in turn, less effective caster throughout the range of motion results in more positive camber gain.

Note this doesn't contradict the opening post. Caster is measured with the wheels turned to a certain angle, so you would see more caster with the CSL knuckles installed.

A car with CSL knuckles will maintain more caster and gain less positive camber throughout the full range of motion of the wheels. It should also have "better" steering feel, but that's subjective and hard to quantify. Theoretically, a track car with CSL knuckles can achieve the same side to side tire wear and temperature distribution with less static negative camber than a car with the regular M3 knuckles. This is especially nice for dual purpose cars because running a lot of static negative camber will cause the inner edge of the tire to wear faster than the outside when cruising on the highway or driving around town.

For a dual purpose or primarily street driven car like the stock CSL, it makes a lot of sense why they would go through the trouble of creating a new knuckle part number instead of just messing around with the strut top mount. I'm not sure if the CSL knuckles are worth it on an all-out racecar though unless you're having trouble getting enough negative camber since straight line tire wear is not that big of a concern, and the only other benefit is "better" steering feel.
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Old Wed, Oct-03-2018, 01:12:31 AM   #26
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Default Re: End to all speculation: The CSL Kingpin

So the 5mm wider track is busted?
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Old Wed, Oct-03-2018, 01:14:59 AM   #27
ZHP
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Default Re: End to all speculation: The CSL Kingpin

Thank you Volke,
After posting this I did find the other thread with your findings.
I did not understand how it could add much caster because it does not move the lower pivot (ball joint) forward in relationship to the upper. Camber made sense to me. I hoped the distance between the wheel bearing (axle) and ball joint taper were greater to raise the roll center.
Do you know how the M3 and none-M kingpins differ?
I race a ZHP with modified Bilstein MDS coilovers and Vorshlag caster/camber plates maxed out and still cord my Hoosiers on the outside edge long before wearing them out. Unfortunately I do not know if it was the front or rear. Current alignment is -3 front camber, 7.8 caster, -2.2 rear camber.
Thank you again for sharing your findings.
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Old Wed, Oct-03-2018, 01:17:52 AM   #28
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Default Re: End to all speculation: The CSL Kingpin

Quote:
Originally Posted by m3vancity View Post
So the 5mm wider track is busted?
10000%

Quote:
Originally Posted by ZHP View Post
Thank you Volke,
After posting this I did find the other thread with your findings.
I did not understand how it could add much caster because it does not move the lower pivot (ball joint) forward in relationship to the upper. Camber made sense to me. I hoped the distance between the wheel bearing (axle) and ball joint taper were greater to raise the roll center.
Do you know how the M3 and none-M kingpins differ?
I race a ZHP with modified Bilstein MDS coilovers and Vorshlag caster/camber plates maxed out and still cord my Hoosiers on the outside edge long before wearing them out. Unfortunately I do not know if it was the front or rear. Current alignment is -3 front camber, 7.8 caster, -2.2 rear camber.
Thank you again for sharing your findings.
I don't have a non-M knuckle to measure, so I can't say how it would impact camber and caster, but I do know that the steering tie rod pick up point is a few millimeters closer to the steering axis. This is why the 330 has a faster steering ratio than the CSL despite the fact that the 330 and CSL/ZCP steering racks are both linear and 50mm/rev.

The 330 control arms are 10mm shorter than the M3, so I imagine the knuckle would be a little different to compensate. I'd be willing to take some measurements and try to figure out the difference if I can get my hands on a 330 knuckle.
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Old Wed, Oct-03-2018, 03:36:29 AM   #29
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Default Re: End to all speculation: The CSL Kingpin

Quote:
Originally Posted by Volke View Post
... I'd be willing to take some measurements and try to figure out the difference if I can get my hands on a 330 knuckle.
I'll ask around to try and rustle a knuckle up, but not real optimistic.
I assume there is no balljoint fore/aft different between the M and none-M control arms, or that would have come up in that other thread.

Thank you again for the insight.
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Old Wed, Oct-03-2018, 03:06:00 PM   #30
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Default Re: End to all speculation: The CSL Kingpin

Quote:
Originally Posted by Volke View Post
They do not increase track at all. I have a set waiting to go on my car. I measured all the relevant dimensions that would impact track and compared to the regular M3. There was no difference.

What I did find is that they add ~1 degree more negative camber without changing the SAI(steering axis inclination).

I didn't understand why they would do this instead of using camber plates at first, so I spoke to someone much more knowledgeable about suspension geometry. Here's what I found out...

Camber plates add negative camber by moving the top strut mount toward the center of the car. Unfortunately, on a MacPherson strut front like the E46, moving the top mount inward also increases SAI. Larger SAI results in more caster loss as the wheels are turned left or right, and in turn, less effective caster throughout the range of motion results in more positive camber gain.

Note this doesn't contradict the opening post. Caster is measured with the wheels turned to a certain angle, so you would see more caster with the CSL knuckles installed.

A car with CSL knuckles will maintain more caster and gain less positive camber throughout the full range of motion of the wheels. It should also have "better" steering feel, but that's subjective and hard to quantify. Theoretically, a track car with CSL knuckles can achieve the same side to side tire wear and temperature distribution with less static negative camber than a car with the regular M3 knuckles. This is especially nice for dual purpose cars because running a lot of static negative camber will cause the inner edge of the tire to wear faster than the outside when cruising on the highway or driving around town.

For a dual purpose or primarily street driven car like the stock CSL, it makes a lot of sense why they would go through the trouble of creating a new knuckle part number instead of just messing around with the strut top mount. I'm not sure if the CSL knuckles are worth it on an all-out racecar though unless you're having trouble getting enough negative camber since straight line tire wear is not that big of a concern, and the only other benefit is "better" steering feel.
Interesting. I do notice that the official CSL camber specs are not dramatically different from the standard M3. Would this change have been BMW's attempt at compensating for the height change?

Might consider these the next time I do a front end refresh.
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Discussing End to all speculation: The CSL Kingpin in the E46 M3 (2001-2006) Forum - Engine: S54 - Max Hp: 333 hp at 7,900 rpm / 262 lb/ft at 4,900 rpm
Total Produced: 45,000+ - Years Produced: 2001 to 2006. at BMW M3 Forum.com (E30 M3 | E36 M3 | E46 M3 | E92 M3 | F80/X)