325i manual vs. automatic RPM

[bmwdriver]

Hi there,

A strange question. I have a '01 Bimmer 325i with stick trans. One of my buddies just bought a '04 325i with auto trans. The interesting finding is, his bimmer hits 80 mph with 3K RPM. Mine hits 80 mph with 3.5K RPM. Is this normal? Is there something to do with the difference in trans.? Thanks.

[Ohrid]

Its got to do with the gear ratios and differential. His gearbox has either a taller top gear, or taller final drive ratio.

[bmwdriver]

Thanks... but isn't all bimmers (at least E46s) suppose to have the same ratio?

[GRD-4-3L]

No sir, they do not.

Manual and automatic gears definitely have different gear ratios.

Even in manual gear models, 6 gear models have overdrive (less than 1.0 gear output ratio) so it will rev lower at 80 mph.

If you want to know the gear ratios in detail, just look at the specifications given out on bmwusa.com or other BMW corporate sites.

[bmwdriver]

Ooommm, very educational. Thanks very much.