Aerodynamics of the Z1

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exdos
Joined: Fri 19 Dec, 2003 18:30
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Aerodynamics of the Z1

Post by exdos »

I'm presently considering a few aerodynamic mods for underneath my M Coupe, and whilst I was doing a Google search, I came across some info on the Z1 where it describes that rear end of the underside of the Z1 has aerodynamic bits and pieces, including the exhaust silencer. Does anyone have any photos of these various bits and pieces that you could post? I'd like to get a few ideas of what has already been tried and tested.
Pat Slade
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Aerodynamics of the Z1

Post by Pat Slade »

Hi Exdos, I suggest you start at Paul Drawmer's site at bmwz1.co.uk. You will find a section there on aerodynamics and in the modification section you will find some photos of the BTB exhaust which is a reasonable copy of the shape of the original.
Not sure whether anyone has any idea if it works. I tried a car without the aerodynamic silencer, it had Lorenz replacements. Couldn't tell any difference but then it really isn't a car with exactly stonking performance!
Good luck.
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spokey
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Post by spokey »

Actually, I'm pretty disappointed with the shape of the BTB -- it doesn't have the same inverted wing shape that the original did. So, although it's still a spoiler, I can't see it being quite as good as the original. :(
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Paul Drawmer
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Post by Paul Drawmer »

spokey wrote:Actually, I'm pretty disappointed with the shape of the BTB -- it doesn't have the same inverted wing shape that the original did. So, although it's still a spoiler, I can't see it being quite as good as the original. :(
Eh??? :? :?

Did the one you saw look like these pics?
http://www.bmwz1.co.uk/z1silencer.htm

If not it wasn't a BTB one.


edited to remove poor grammar.
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spokey
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Post by spokey »

Hi Paul,

I bought it direct from BTB, so I can only assume it actually was a genuine BTB exhaust! :lol:

However, if you look at the BTB exhaust (certainly the one I have!), it's basically an oval shape in profile, whereas the original steel exhaust I had on before was an actual inverted wing. So while this will act as a spoiler to a certain extent, it will not be nearly as good as a proper inverted wing.
Ciao,
Spokey
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Paul Drawmer
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Post by Paul Drawmer »

In the pic of my old silencer, it is the top that has been cut open. Whilst it isn't very clear, the top of it was convex - like the replacement BTB one.

If the one you took off was flat, or even concave on the top surface, it was a different shape from the one we modelled the BTB box on!

All depends on whether any aero lift (-ve) was being caused by Newton or Bernoulli effect!





still like the Z1 8-)
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Jet
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Post by Jet »

Speaking of Exhausts, there is a Lorenz Exhaust kit on ebay for sale.....(and an original box sold for just £42.00).
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dreamchaser
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Post by dreamchaser »

Pic of the exhaust I obtained from Germany 2 years ago
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lerock13
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Post by lerock13 »

Looks like a Agentur Hoffmann silencer. I have one under my car. :D
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dreamchaser
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Post by dreamchaser »

Well spotted, yes you are correct it did come from Hoffman
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exdos
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Post by exdos »

Thanks for the pictures Lads :!:

If BMW had tried and tested those ideas before making the Z1 then I think my ideas for the M Coupe and MR should also work too (Unfortunately, I don't own a wind tunnel :roll:)
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Racing Tortoise
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Post by Racing Tortoise »

I have a Lorenz quad-exit system on my Z1 which lacks the aerofoil design. I was concerned about this and what it might do to aerodynamics when I bought the car, but I have driven the car at upwards of 120mph and also tracked it without any noticeable problems so I guess it's not a massive issue!
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Post by Paul Drawmer »

I think the aerodynamics of the Z1 were 'overkill' in some respects, since the old girl is just plain slow. However, in other respects the aero is fantastic; e.g. side winds, cockpit buffeting, noise. In these areas, the Z1 has super performance. Mind you the sides, including the door glass, get really mucky sometimes. Proof that keeping it clean was not a consideration when designing the airflow!
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