rpm's vs mph

[ETA fro]

according to my dad, in bmw's the rpm's match the speedo in top gear. they rise and drop in unison and its on purpose.
he has owned his fair shair of e30s, e28s and e34s but i was skeptical.

but i tried in it in my auto eta, and it was right on, then we tried it in weston's 325i and it worked again.
anyone else know anything about it?

[LikeCDoos]

after Sean told me this we experimented and it was freaking me out. Maybe we'll take some pictures later

[Stuart B]

its kinda simple really.

every gear the rev counter can use full range, only ttime the speedo can use full range is in 5th....so both clock needles fall in a similar position when in top.
:D
Stu

[EtaSport]

Man, I noticed this on my car back when i used to ride in it with my dad when i was like 7 or 8. I didnt know it was "on purpose" but seems interesting. I wasnt sure if the i cars did it or not, but mine is close not 100 percent. and when I get on off-ramps and start to slow down in 5th they get off again.

[///M42 sport]

I noticed this too. I guess it becomes pretty useful if one or the other gauge goes out.
________
Sex

[LikeCDoos]

I noticed this too. I guess it becomes pretty useful if one or the other gauge goes out.

ya my tach goes out every once in awhile...how i will be able to tell roughly where my rpms are at

[Fred]

Re: rpm's vs mph

according to my dad, in bmw's the rpm's match the speedo in top gear. they rise and drop in unison and its on purpose.
he has owned his fair shair of e30s, e28s and e34s but i was skeptical.

but i tried in it in my auto eta, and it was right on, then we tried it in weston's 325i and it worked again.
anyone else know anything about it?

You guys never noticed that? Yeah, a lot of BMWs do that (like the E36 six cylinders), but many of the newer ones don't, like the E39 540i/6 because the overdrive gears are so tall.

[M-technik-3]

Not for me, till I change rear end.

[ETA fro]

yeah this might be an old school stock kinda thing

[Jarvis]

I noticed this too. I guess it becomes pretty useful if one or the other gauge goes out.

ya my tach goes out every once in awhile...how i will be able to tell roughly where my rpms are at

Open a window, turn off your music and listen. I'm sure I'm not the only one here that can fairly accurately guess what rpms they're turning based on sound (helps if you have an aftermarket exhaust).
My speedometer hasn't worked since December. I really don't need it. I know the gearing so well, while cruising I can guess within 5mph of my speed as long as I know the rpm and gear. My only incentive to fix it is so my OBC will start being useful again.
I had never actually noticed the matching of the tach and speedo in 5th gear. Good to know though.