Mini mph/rpm

I can't remember the exact figure, but I though the later Minis on 12" wheels with teh 3.1 diff did about 20mph per 1000rpm?

Only, either the thing I have got is very quick (for a 998cc!), or the speedo's very optimistic, I'm trying to work out which!

It's an 87 Mayfair, so should have the longer diff, and seems to going by the red line in lower gears (31mph in first)...

Anyone got a reference for speed per 1000rpm in each gear kicking about?

Reply to
Stuffed
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Check the speedo with the mile markers on a suitably quiet stretch of motorway. Sit as close to 60mph as you can manage, 60 seconds should be the time between markers. Take a few stabs then average the results. You might need a suitably be-sweephandwatched assistant.

I did this recently to discover that my speedo reads 60 when I'm doing 68. That could've got me into trouble within a couple of weeks of ownership!

Reply to
DocDelete

Hmmm.. motorway... That'll be a nice 30 mile drive to find one of those around here then! :) But next time I have a reason to venture out anywhere, I'll look for the markers and give it a whirl. In the meantime, I think I've spotted I get about 20.5 or so mph per 1000rpm, so taking rev counter and speedo inaccuracies into account, I'll see how it looks from there...

Oops! Good job you spotted it...

I've just got to work out if my speedo's right or not, before I put my foot down thinking it's massively over reading, only to have som eblue lights tell me it's not. I'm used to Minis feeling faster than they are though, not slower!

Reply to
Stuffed

The message from "Stuffed" contains these words:

Borrow a GPS with a speed output. It will be a good deal more painless than trying to drive at 60 while counting 100m posts and will be sufficiently accurate at any speed you care to try it at provided you can give it a reasonable view of the sky.

Reply to
Roger

Assuming you have an odometer (mileometer) does it under-read by the same amount? Mine does. Not quite sure what that proves, though.

Geoff MacK

Reply to
Geoff Mackenzie

I have no idea yet... Not driven the car a great deal so far..

I suppose if the speedo under reads, but the odometer doesn't, then it's a fault with the twirly bit of the speedo connected to the needle, and not a problem with the number of turns of the cable or something like that!

I guess if yours under reads on both, then either the box has got the wrong sender cogs in it, or the speedo's the wrong one. Seemto remember you posting about it in the past, speedo was original wasn't it?

Reply to
Stuffed

Yes, the speedo's original, so's the back axle and the tyres are the right size. And it's always been about 15% slow. I just live with it!

Geoff MacK

Reply to
Geoff Mackenzie

Minis don't have back axles (apart from stub axles) but you probably mean the final drive. Is the speedo drive original - there are different ratios? By law your speedo should read between -0% and +10%. If your instrument is reading -15% I suggest that you get it recalibrated by someone like Speedy Cables. They'll tell you what to measure. Alternatively buy a s/h speedo for £5 (if it's the normal

95mph type) and see if it's any better.
Reply to
Richard Porter

Ah! That's what comes of trimming too much of the previous message, changing the topic and not changing the subject line! Sorry.

Reply to
Richard Porter

I don't have a Mini, and if I did I think I might have noticed it didn't have a back axle. It was a generic post about speedos, not specific to Minis.

Geoff MacK

Reply to
Geoff Mackenzie

No offence taken, or intended by my previous rather curt note. Bad day at the office!

Re worth - well, it did cost £825. In 1974. Might be a bit more now.

Geoff MacK

Reply to
Geoff Mackenzie

Why should you? The writers/directors of The (original) Italian Job didn't!

Reply to
Chris Bolus

Eh, what? Please elucidate! Sounds like a good story here....

Geoff MacK

Reply to
Geoff Mackenzie

I think he might be refering to the bit where the cars are in the garage, being "strengthened" ready for carrying the weight of the gold. Charlie looks at a pair of legs sticking out from under the _rear_ of one of the cars, and says something like "What're you doing then?", at which point the man underneath rolls out, and replies along the lines of "Just changing the diff, Charlie".

I'm impressed myself - I've played with Minis off and on for a few years, and I can't change the diff witht eh engine in the car, from the rear!

Reply to
Stuffed

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