z4m performance incredible with scans

[golfiste]

hi to every member of jabbas

today i bought and they say that the engine from the z4m is able to reach 8000 rpms which means that the speed of the pistons reach 24,3 m/s.(which is nearly the same as a formula one car)they said also that the z4m is superior in performance compared to the porsche boxster s????and it can even reach the 1000 m stand still faster than a maserati gt spyder.

Man bmw and inline 6 are legend

[saadie]

short piston arm lenght ? .. no big deal ... but the performace is :shock:
can you post scans of the magzine?

[bmagni]

damn, sounds tempting... i think is worth considering also with the M3...

[coombsie66]

Originally Posted by Saadie short piston arm lenght ? .. no big deal ... but the performace is :shock: can you post scans of the magzine?

The point of him quoting the piston velocity is to irradicate the effects of stroke reduction on increased RPM ability. Having that kind of piston velocity (i think it may be mean piston velocity actually) is very impressive! :shock:

[golfiste]

[twboy1999]

not feeling the z4 m roadster at all

but z4 m coupe is sick

[dutchmasterflex]

I was bout to flame golfiste for the lack of being able to write proper english until I opened up one of the links to the magazine scan..


How does an inline-6 that revs to 8000rpm have the same piston velocity as a V8/V10 that revs to 18000rpm?

[Wutputt]

Originally Posted by dutchmasterflex How does an inline-6 that revs to 8000rpm have the same piston velocity as a V8/V10 that revs to 18000rpm?

Cause this engine has a long stroke (91 mm) compared to the stroke of an F1 car (V10 F1 engines had a stroke of about 45 mm).

Thus the pistons can reach the same average velocity at relatively low revs compared to the pistons of an F1 engine, which don't have to travel much up and down due to the short stroke of an F1 engine.

The mean velocity of this BMW engine at the limiter is about 24,26 m/s, and for an F1 engine with a stroke of 45 mm the mean velocity would be the same at about 16200 rpm.

But of course the mean velocity doesn't tell you much about the maximum velocity. More however, piston acceleration figures are far more important to the design of the moving parts of the engine.

[DeMoN]

amazing car it is, but way to expensive compared to the previous M roadster.

[golfiste]

pistons accelerations are increased when the weight of the car is reduced but also like you said it is based on the design

[dutchmasterflex]

Thanks Wuttputt! Didn't realize you were so knowledgable about engine design. Your avatar makes sense now


Interesting that the M3 engine(S54?) can accelerate it's pistons to such a high velocity.. but it makes sense with its longer stroke. The piston acceleration in an F1 must be absolutely insane considering its traveling half the distance..