M Drivers Package

mmm-five said:
I know the Z4MC already has a little rubber spoiler (p/n 51113442832 / #23 on picture below) to reduce some front-end lift - and I've had to replace mine multiple times due to kerbs/speed bumps/debris.

BMWFans.info/Realoem says this little rubber strip is not on the Z4MR, so maybe the coupe is twitchier than the Roadster and needs a non-hairdresser to drive it?

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Hmm could be an interesting mod for MR owners then! Are they still available? How much? 8)
 
RedUn said:
mmm-five said:
I know the Z4MC already has a little rubber spoiler (p/n 51113442832 / #23 on picture below) to reduce some front-end lift - and I've had to replace mine multiple times due to kerbs/speed bumps/debris.

BMWFans.info/Realoem says this little rubber strip is not on the Z4MR, so maybe the coupe is twitchier than the Roadster and needs a non-hairdresser to drive it?

2020-01-10_10-55-53.png

2020-01-10_10-57-37.png
Hmm could be an interesting mod for MR owners then! Are they still available? How much? 8)
Was about £60 last time I bought one (about 2 years ago IIRC), and there didn’t seem to be any problem getting it.
 
Argenta said:
It would do next to nothing aerowise tho, compared to the carbon splitter for instance.

It’s hard to say. It could be a small air dam to stop the creation of high pressure, “dirty” air by the front suspension gubbins. This could have more effect (taken in isolation) than a small splitter, as a splitter is only as effective as the pressure differential it can generate.
 
Argenta said:
How you fix the front lift forces is upon taste of course.
DIY or the famed carbon splitter.

The upside with the rubber spoiler solution (apart from different look) is of course in everyday driving - it does not crack against speedbumps. :)

Which splitter is this one?
 
The problem with the OE one is it’s under the car, when any air that gets to it would be forced under the car, whereas the rubber splitter from Argenta’s post would also push the air around the front of the car.

I’d love to have a proper aero kit on the car, including a smooth floor and diffuser for the rear...but for my use and the amount of speed bumps around here, I’ll stick with just the change in rake and the Skyer rear ducktail spoiler.
 
mmm-five said:
The problem with the OE one is it’s under the car, when any air that gets to it would be forced under the car, whereas the rubber splitter from Argenta’s post would also push the air around the front of the car.

I think that’s the point of it though - it’s already working with underbody air so it’s like an upside down gurney flap or “aero screen” that creates an arc of flow over the outer parts of the front axle. The rest of the underside is relatively flat in comparison. Being made of rubber and having a central cut-out it seems like a good compromise between aero and usability.
 
MrPT said:
mmm-five said:
The problem with the OE one is it’s under the car, when any air that gets to it would be forced under the car, whereas the rubber splitter from Argenta’s post would also push the air around the front of the car.

I think that’s the point of it though - it’s already working with underbody air so it’s like an upside down gurney flap or “aero screen” that creates an arc of flow over the outer parts of the front axle. The rest of the underside is relatively flat in comparison. Being made of rubber and having a central cut-out it seems like a good compromise between aero and usability.
Sadly it does’nt really work that way, a functional spoiler always has to sit as low as possible, as forward as possible. (Hence why I don’t think the OEM rubber was for downforce per-se)

In any case it’s proven beyond doubt that it works - since what I did between the tests was removing the OEM rubber (it became redundant) and install the true spoiler.
Before = unstable
After = stable

(As I wrote above lowering the car also adds effect to the spoiler, so both mods had to count. Alignment settings were identical)
 
Argenta said:
MrPT said:
mmm-five said:
The problem with the OE one is it’s under the car, when any air that gets to it would be forced under the car, whereas the rubber splitter from Argenta’s post would also push the air around the front of the car.

I think that’s the point of it though - it’s already working with underbody air so it’s like an upside down gurney flap or “aero screen” that creates an arc of flow over the outer parts of the front axle. The rest of the underside is relatively flat in comparison. Being made of rubber and having a central cut-out it seems like a good compromise between aero and usability.
Sadly it does’nt really work that way, a functional spoiler always has to sit as low as possible, as forward as possible. (Hence why I don’t think the OEM rubber was for downforce per-se)

In any case it’s proven beyond doubt that it works - since what I did between the tests was removing the OEM rubber (it became redundant) and install the true spoiler.
Before = unstable
After = stable

(As I wrote above lowering the car also adds effect to the spoiler, so both mods had to count. Alignment settings were identical)

Strange how it wasn't on the roadster though. Same bumpers so not like it would have fit any differently...

What's the carbon splitter (or rubber) your running? Looks decent, want!
 
Argenta said:
It would do next to nothing aerowise tho, compared to the carbon splitter for instance.
I know but it will do something as I've got nothing at the moment :thumbsup:
 
I suspect the reason that the ///M's brake ducts are deliberately blocked is because air being forced into the wheel arches was lifting the front at speed too. :( Not read anything to confirm that. It just seems entirely possible to me. :)
 
BMW describe the part as a "spoiler". It will act like an "airdam", which both reduces the volume of air passing under the car and speeds up the flow, thus creating low pressure beneath the car whilst the air above the car is at higher pressure. It will not create downforce but it will reduce aerodynamic lift at higher speeds.
 
Argenta said:
MrPT said:
mmm-five said:
The problem with the OE one is it’s under the car, when any air that gets to it would be forced under the car, whereas the rubber splitter from Argenta’s post would also push the air around the front of the car.

I think that’s the point of it though - it’s already working with underbody air so it’s like an upside down gurney flap or “aero screen” that creates an arc of flow over the outer parts of the front axle. The rest of the underside is relatively flat in comparison. Being made of rubber and having a central cut-out it seems like a good compromise between aero and usability.

Sadly it does’nt really work that way, a functional spoiler always has to sit as low as possible, as forward as possible. (Hence why I don’t think the OEM rubber was for downforce per-se)

No need to be sad. Sounds like an effective mod. :)

It’s just that you said earlier that “it would do next to nothing aerowise” in regard to the rubber IE part. It’s clearly there for a reason; whether it’s to block stones, improve underbody airflow or just dam air in a very compromised way in order to preserve the aesthetics of the bumper and a usable amount of ground clearance. I get that a bumper infill will spoil more air and help high speed stability (plus it looks great).

By “improve” aero, I mean that it could be for managing the air that flows around the wheels - by reducing wheel well pressure and/or wheel wake coming off all the skeletal, moving bits. So not downforce-generating in its own right, but something that allows other features to function better (e.g the floor).

Now, if you look at our cars you will probably think “what features?!”, but I recall someone running CFD sims recently who ended up with a design that featured a raised centre section (for convenience) and several elements to clean up airflow under and around the front wheels. This would definitely make your £££s go further if you then invested in floor or rear deck aero.
 
Only real world aero-related issue I’ve had on my car was this front lift around & above 250km/h. Granted only an issue on euro-trips but to me it was worth fixing (also I think it looks better :) ).
 
exdos said:
BMW describe the part as a "spoiler". It will act like an "airdam", which both reduces the volume of air passing under the car and speeds up the flow, thus creating low pressure beneath the car whilst the air above the car is at higher pressure. It will not create downforce but it will reduce aerodynamic lift at higher speeds.
This is more along my thinking, appreciate a splitter might do more but I don't like the look of them and I'd rip it off as I've not much ground clearance :lol:
 
Argenta said:
Only real world aero-related issue I’ve had on my car was this front lift around & above 250km/h. Granted only an issue on euro-trips but to me it was worth fixing (also I think it looks better :) ).

As AndyBeech said above, what’s the part you’re running? My car is very low and it might save the front bumper from further injury.

I found that front end lift at extremely high speeds (130mph+) with the OEM suspension made the car wander unpredictably. This improved significantly with Eibach springs and OEM dampers, and it was abolished completely with KW Clubsports set up with a little more rake than OEM.

As for v-max, I’ve seen a gps recorded 175mph in mine at which point I ran out of bravery rather than revs, although I doubt there would be much more in it anyway.
 
mmm-five said:
I know the Z4MC already has a little rubber spoiler (p/n 51113442832 / #23 on picture below) to reduce some front-end lift - and I've had to replace mine multiple times due to kerbs/speed bumps/debris.

BMWFans.info/Realoem says this little rubber strip is not on the Z4MR, so maybe the coupe is twitchier than the Roadster and needs a non-hairdresser to drive it?

2020-01-10_10-55-53.png

2020-01-10_10-57-37.png
Hi, any idea of whether this BMW part would fit on an E85, 2003 roadster standard bumper? Cheers
 
BMWZ4MC said:
As AndyBeech said above, what’s the part you’re running? My car is very low and it might save the front bumper from further injury.

I posted a pic of my spoiler in an earlier post.
It's rubber (like the OEM Porsche one) so scraping is no problem even 20mm lowered.

(visibly I also have the fang protectors, matt foil centre piece and removed plate holder)
 

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