Revs for Speed?

[Morat]

Folks, I've just had my speedo fixed but the mechanic reckons it might be reading a bit low. For a standard 325i Touring (manual) what speeds/revs would you expect?
At the moment I'm getting 70mph at 3000revs in 5th and about 90 at 4000 revs in 5th (on private motorways only, of course).

Is this about right?
Thanks
Morat

[MikeeMiracle]

90mph @ 4000rpm is what my mates 325i does, as does my 318iS, I believe they use the same gearbox, 70mph = 3200rpm, 80mph = 3600rpm.

FAO regulars forum users: Whats the attitude towards speed on this forum? Are we allowed to talk openly about driving antics/speed or do we have to keep up a stupid pretence about never breaking the speed limit on public roads?

[bmwe30mtech]

90mph @ 4000rpm is what my mates 325i does, as does my 318iS, I believe they use the same gearbox, 70mph = 3200rpm, 80mph = 3600rpm.

FAO regulars forum users: Whats the attitude towards speed on this forum? Are we allowed to talk openly about driving antics/speed or do we have to keep up a stupid pretence about never breaking the speed limit on public roads?

I once mentioned doing 90mph in a sweeping statement i wish i hadent. Everybody seems to cruise at 90 in areas of the M25, and yet on here a lot of people behave like that never go over 70, doenst add up .

[320Touring]

FAO regulars forum users: Whats the attitude towards speed on this forum? Are we allowed to talk openly about driving antics/speed or do we have to keep up a stupid pretence about never breaking the speed limit on public roads?

Its entirely up to you! do you want folks to know what you've been doing?

We as a whole dont really condone "dangerous driving" like past a school at 60mph at 3pm....

however, a wee blast or two down a backroad at 2am doesnt do any harm

[MikeeMiracle]

Its entirely up to you! do you want folks to know what you've been doing?

Well, it's just a matter of personal opinion. On the other forum I use we regularly have meets with speeds well in excess of 100mph. We have quite a few coppers as members also that do sometimes attend. Always a good laugh when they bring out the flashing blue lights, it's the one garuntee of being able to clear the fast lane in front of us.

Just want to find out if this forum if full of posers or people who actually enjoy driving their cars so I can arrange some appropriate meets without getting flamed. To be honest I don't think the E30's are quite grunty enough to make the high speed runs worthwhile so the meets would be more of twisty country roads


PS: I apologise for the thread hijack.

[Morat]

Thanks for the info, and the amusing replies
So, my speedo is about right, cracking.

As for high speed runs - well once I've got this thing healthy, and my bank balance back up I'll be looking at altering the lack of power

[Brianmoooore]

Speed versus revs depends entirely on the diff ratio, and tourings have a higher ratio than saloons.
All E30 speedos should work correctly in any E30, but you've said its been repaired. There is a preset adjustment on the speedo PCB, which will make the speedo, which will make the speedo either less or more accurate than it was.
Note, that under German law, all speedos under read by a considerable amount. The OBC tends to be much more accurate.

[Morat]

I can never remember whether higher diff ratio means lower top speed and more acceleration or the other way round but thanks for the tip. I'll try comparing it to a GPS since I don't have the OBC, just a check/control panel.
Cheers!

[nickso]

Speed versus revs depends entirely on the diff ratio, and tourings have a higher ratio than saloons.
All E30 speedos should work correctly in any E30, but you've said its been repaired. There is a preset adjustment on the speedo PCB, which will make the speedo, which will make the speedo either less or more accurate than it was.
Note, that under German law, all speedos under read by a considerable amount. The OBC tends to be much more accurate.

thats interesting cos everytime i get a new car now i check the speedo against gps to see what the difference is and how much i can drive over the "speed limit" by.

my touring is exactly 10% under gps speed across the range from 30-110mph

can the preset be adjusted accurately or is it best to steer well clear of messing with it?

[Project_E30]

Speed versus revs depends entirely on the diff ratio, and tourings have a higher ratio than saloons.
All E30 speedos should work correctly in any E30, but you've said its been repaired. There is a preset adjustment on the speedo PCB, which will make the speedo, which will make the speedo either less or more accurate than it was.
Note, that under German law, all speedos under read by a considerable amount. The OBC tends to be much more accurate.

How do wer get an accurate speed from the OBC as mine give me an average speed?

Magic button combination?

Oh and mines a 13 button.

[Brianmoooore]

[

How do wer get an accurate speed from the OBC as mine give me an average speed?

Only by the limit function. Mine is spot on when compared with GPS

[handpaper]

Press 'SPEED', then press the 'SET-RES' button to reset it. Immediately afterward, it will show your current speed, as this will be the average since it was last reset.

OBC can be deadly accurate because it's not trying to indicate using a poorly-damped needle rotated by a magnetic coupling.
Analogue speedometers can never be reliably accurate without incorporating some form of feedback into the driver electronics.

Query: Do the 'police speedometers' work like this?

Note, that under German law, all speedos under read by a considerable amount

ITYM 'over read"

[Brianmoooore]

ITYM 'over read"

Could be right, there! Well done for spotting the deliberate mistake!