[tetsuo111]

This is correct.

I'm running M3 spindles / wheel carriers on all corners. The purpose is to gain the M3 attachment points / link geometry. A second order benefit is PnP fitment of BW rear toe arms.

Originally Posted by Biginboca

I don’t think the M3 subframe is different I think the knuckles are using a different toe arm attachment location, that’s why the M toe arms are shorter. So you would need to swap the knuckles I believe. The Bimmer world toe arms using a really great heim joint, the specs on it are way overkill for the application I would run them without a second thought

[Tambohamilton]

So you also run m3 front struts?

[Biginboca]

Originally Posted by tetsuo111

This is correct.

I'm running M3 spindles / wheel carriers on all corners. The purpose is to gain the M3 attachment points / link geometry. A second order benefit is PnP fitment of BW rear toe arms.

I have fantasized about running M3 front knuckles because I suspect the Ackerman and scrub radius are corrected for wider wheels, hence why they use a different tie rod. Also I think they are aluminum, so less unsprung weight?

The issue is big brakes for the M3 are super expensive lol

Are the rear knuckles aluminum or cast iron? And do they accept the 328 wheel bearings and axle shafts?

[Tambohamilton]

Stock non-m knuckles are aluminium too...

+1 on big, expensive brakes

[ornicar]

Originally Posted by Biginboca

I have fantasized about running M3 front knuckles because I suspect the Ackerman and scrub radius are corrected for wider wheels, hence why they use a different tie rod. Also I think they are aluminum, so less unsprung weight?

The issue is big brakes for the M3 are super expensive lol

Are the rear knuckles aluminum or cast iron? And do they accept the 328 wheel bearings and axle shafts?

Aren't the tie rods longers just because the M control arms are longers too?

[Tambohamilton]

Originally Posted by ornicar

Aren't the tie rods longers just because the M control arms are longers too?

No; non-m rods are perfectly adequate to accommodate the m 'wishbones'. The difference is mainly in the knuckle.

[Biginboca]

Originally Posted by Tambohamilton

Stock non-m knuckles are aluminium too...

+1 on big, expensive brakes

So a way around this would be to run M4 front knuckles they use the same brake mounts as the non M e9x and have the steering geometry of the e92m3

[ornicar]

Originally Posted by Biginboca

So a way around this would be to run M4 front knuckles they use the same brake mounts as the non M e9x and have the steering geometry of the e92m3

the brake caliper is fitting axial +11mm outboard and radialy +5mm on M2 M4 knuckles. Check if you have enough caliper clearance / wheel if you choose this way.

[Biginboca]

So on the subject of M4 knuckles I found this in an old forum post comparing E9XM3 knuckles to F8X M3/4 Knuckles...

“1- First difference is the mounting point for the calipers, the F8X knuckles mounting lugs sit further out to allow for accommodating the massive 380mm rotors and Brembo calipers.

2- F8X knuckles are lighter and stronger than E92 M3 knuckles. They're made of cast aluminium alloy, the engineers have went to extreme length to reduce unsprung mass at the knuckles, they shaved all additional material that's unneeded on the knuckles and hubs, and managed to get 1.13kg off per corner. Remember that this unsprung and rotational mass, people spend $5k on a lightweight set of wheels just to save 2kg per corner haha, these knuckles will save you 1.13kg already

3- F8X knuckles have a larger SAI angle (SAI = Steering Axis Inclination) to reduce understeer, without getting into too much suspension talk, as it's beyond the scope of this thread. A larger SAI angle will result in negative camber gain when the steering wheel is turned. This allows for running lower static -ve camber to save tyre life, yet by merely just turning the steering wheel, the outside wheel will gain negative camber to give the tyre a full contact patch on the asphalt, which results in more grip, as well as resulting in even tyre wear (reduces the outside tyre shoulder wear that E9X generation is famous for).

If you jump back to back between a F8X and an E9X, you'll immediately notice that the F8X has more front-end bite on corner entry, and more front-end grip.”

Now I’m taking all that in and I realized there is potentially another benefit to fitting the m4 knuckles. That would enable someone to run the M Carbon Ceramic Brakes also if one chooses to, lol

[Biginboca]

I realized I haven’t posted pics of the whole car in a while so here’s an update of where it’s at. I added some carbon mirror caps (oem style by AutoTeknic) and although you can’t tell the weave is a perfect match for the roof weave, so they look really good I think.

So here’s where she sits today. I’m waiting on some Blackline tails to ship hoping to have them in the next 10 days or so those will transform the rear a bit once I get them on...

[Tambohamilton]

Originally Posted by Biginboca

So on the subject of M4 knuckles I found this in an old forum post comparing E9XM3 knuckles to F8X M3/4 Knuckles...

“1- First difference is the mounting point for the calipers, the F8X knuckles mounting lugs sit further out to allow for accommodating the massive 380mm rotors and Brembo calipers.

2- F8X knuckles are lighter and stronger than E92 M3 knuckles. They're made of cast aluminium alloy, the engineers have went to extreme length to reduce unsprung mass at the knuckles, they shaved all additional material that's unneeded on the knuckles and hubs, and managed to get 1.13kg off per corner. Remember that this unsprung and rotational mass, people spend $5k on a lightweight set of wheels just to save 2kg per corner haha, these knuckles will save you 1.13kg already

3- F8X knuckles have a larger SAI angle (SAI = Steering Axis Inclination) to reduce understeer, without getting into too much suspension talk, as it's beyond the scope of this thread. A larger SAI angle will result in negative camber gain when the steering wheel is turned. This allows for running lower static -ve camber to save tyre life, yet by merely just turning the steering wheel, the outside wheel will gain negative camber to give the tyre a full contact patch on the asphalt, which results in more grip, as well as resulting in even tyre wear (reduces the outside tyre shoulder wear that E9X generation is famous for).

If you jump back to back between a F8X and an E9X, you'll immediately notice that the F8X has more front-end bite on corner entry, and more front-end grip.”

Now I’m taking all that in and I realized there is potentially another benefit to fitting the m4 knuckles. That would enable someone to run the M Carbon Ceramic Brakes also if one chooses to, lol

Well, I'll have to eat my words if I'm wrong, but I swear the knuckles on my car are aluminium too. I'd be stunned if the m4 ones were 1kg/corner lighter. Oh, and I bet you a cup of tea at my place that they're forged not cast, too.

So with the fitting differences between the 2 knuckles, what needs to be changed to run the m4 ones, coming from stock 18" wheels and non-m brakes, struts and track rods? Maybe wheels/spacers to clear the caliper...anything else?

[Biginboca]

Originally Posted by Tambohamilton

Well, I'll have to eat my words if I'm wrong, but I swear the knuckles on my car are aluminium too. I'd be stunned if the m4 ones were 1kg/corner lighter. Oh, and I bet you a cup of tea at my place that they're forged not cast, too.

So with the fitting differences between the 2 knuckles, what needs to be changed to run the m4 ones, coming from stock 18" wheels and non-m brakes, struts and track rods? Maybe wheels/spacers to clear the caliper...anything else?

That is a great question, and I’d really like to know the answer!

tetsuo111 probably knows I imagine it would be the same as fitting the e9X M3 spindle/knuckle. So maybe he can say what hurdles there were swapping knuckles on his car.

[Biginboca]

Tambohamilton so guess what... Shirmer just put their parts website live and they are using the Meyle uniballs for their suspension upgrade kits (at double the price too)...

https://www.teamschirmerparts.com/pr...ear-axle-strut

[Tambohamilton]

Right enough! That's good the meyles get another vote as being suitable

[Phil325i]

Originally Posted by Biginboca

Have you ever considered doing a diff swap from an automatic?

Out of interest, do you mind sharing what revs your engine is pulling at 70mph in 6th gear with the auto diff? Thanks.

[tetsuo111]

Holy smokes that site's filled with sparkly car porn....

Schirmer is a Nitron R3 suspension advocate. They also claim the E92 M3 Nurburgring record. I think we can agree that this is among the last reasons to pick a suspension brand, bordering on 13 year old boy playground boasts.

I do recommend the R3 from a performance and build quality standpoint. I also am of the opinion this is massive overkill for a dual use toy, other than for pure fun factor.

Originally Posted by Biginboca

Tambohamilton so guess what... Shirmer just put their parts website live and they are using the Meyle uniballs for their suspension upgrade kits (at double the price too)...

https://www.teamschirmerparts.com/pr...ear-axle-strut

[tetsuo111]

Some pics of various M3 suspension parts as they fit the non-M platform...

1. The front knuckles are aluminum. The rears are steel.

2. BBK. I like to run 17" rims for less unsprung weight (16.5 lbs / wheel) and 40 series tires for survival on public roads. StopTech has a nice 355 square BBK for the M3 that fits nicely / PnP in this setup. I like the 355 rotors for minimizing unsprung, rotating mass. With a relatively lightweight chassis, huge brake rotors aren't needed for the same stopping force.

3. The M3 geometry is partly / mostly a result of the M-specific knuckles, due to different attachment points. The M3 knuckles also enable use of M3 toe links.

4. After installing M3 knuckles, the front track width appears similar to my old, non-M car with a 12.5mm spacer. In other words, the front track width using M3 knuckles just fits within the non-M bodywork.

5. In the rear, on my LCI car, the track width does NOT appear to match the front track width using M3 knuckles. The wheels appear a little bit sunken inside the fenders. I ordered 5mm spacers to remedy. I haven't had time to install yet. I've meant to measure track width front and rear but haven't had time. I wonder if this results from different length half shafts or a bigger pumpkin, or some other reason.

https://www.e90post.com/forums/showp...&postcount=145

Originally Posted by Biginboca

That is a great question, and I’d really like to know the answer!

tetsuo111 probably knows I imagine it would be the same as fitting the e9X M3 spindle/knuckle. So maybe he can say what hurdles there were swapping knuckles on his car.

[Biginboca]

Originally Posted by tetsuo111

Some pics of various M3 suspension parts as they fit the non-M platform...

1. The front knuckles are aluminum. The rears are steel.

2. BBK. I like to run 17" rims for less unsprung weight (16.5 lbs / wheel) and 40 series tires for survival on public roads. StopTech has a nice 355 square BBK for the M3 that fits nicely / PnP in this setup. I like the 355 rotors for minimizing unsprung, rotating mass. With a relatively lightweight chassis, huge brake rotors aren't needed for the same stopping force.

3. The M3 geometry is partly / mostly a result of the M-specific knuckles, due to different attachment points. The M3 knuckles also enable use of M3 toe links.

4. After installing M3 knuckles, the front track width appears similar to my old, non-M car with a 12.5mm spacer. In other words, the front track width using M3 knuckles just fits within the non-M bodywork.

5. In the rear, on my LCI car, the track width does NOT appear to match the front track width using M3 knuckles. The wheels appear a little bit sunken inside the fenders. I ordered 5mm spacers to remedy. I haven't had time to install yet. I've meant to measure track width front and rear but haven't had time. I wonder if this results from different length half shafts or a bigger pumpkin, or some other reason.

https://www.e90post.com/forums/showp...&postcount=145

So you are saying the M3 front spindles widen the track about 12.5mm? Like in other words they move the wheel bearing mounting surface out 12.5mm?

[Phil325i]

Originally Posted by ornicar

The skid plate in your photo is the old one :

the new one is 51717191160 it has x3 fixing points (instead of x2) ans seems to be thicker (to my eyes...)

According to RealOEM there are four different part numbers for the skid plate:

51717191160 which was superseded in Feb 2007
51714402651 which was superseded in June 2007
51717191215 which was superseded in April 2010
51617046337 which is the current part number.

However RealOEM is confusing, because in some places it says 51717191160 is superseded, and in other places that is it is still available. Incidentally, 51617046337 weighs 0.421 kg whereas 51717191160 only weighs 0.240kg, so it looks like the later part is made of thicker steel.

The part I've just received (51617046337) has two fixing holes not three. I'm assuming that it's 51717191160 that has three holes..?

Confused? You bet I am!

Incidentally, I notice the center subframe mount has a slot that seems to accommodate the tab on the 'Lock plate' that's mystifying us. I shall see if I can determine its function before deciding whether or not to fit it.

[ornicar]

Originally Posted by Phil325i

According to RealOEM there are four different part numbers for the skid plate:

51717191160 which was superseded in Feb 2007
51714402651 which was superseded in June 2007
51717191215 which was superseded in April 2010
51617046337 which is the current part number.

However RealOEM is confusing, because in some places it says 51717191160 is superseded, and in other places that is it is still available. Incidentally, 51617046337 weighs 0.421 kg whereas 51717191160 only weighs 0.240kg, so it looks like the later part is made of thicker steel.

The part I've just received (51617046337) has two fixing holes not three. I'm assuming that it's 51717191160 that has three holes..?

Confused? You bet I am!

Incidentally, I notice the center subframe mount has a slot that seems to accommodate the tab on the 'Lock plate' that's mystifying us. I shall see if I can determine its function before deciding whether or not to fit it.

I am agree with you, It is not really clear.
51717191160 is the one i have bought and it is really strong with x3 fittings points.

[Biginboca]

I bought this one:

51-61-7-046-337

It came in last week and has 2 fixing points. It’s probably 4mm thick and weighs 2-3lbs. I honestly think it’s more than sufficient I’m actually reluctant to mount it cause of the added weight but you guys have me second guessing not using it so I’ll install it next time I have the car lifted.

It’s nice how cheap these parts are I got mine for $12 with shipping!

[Bimmer_Engineer]

I’d just like to say how much I enjoy reading this thread. So many good ideas in here if you’re in to tinkering. I also appreciate that it’s in a less trafficked forum so you can easily see when it’s updated...