Rpm v speed

[Matt Argent]

I'm currently driving a 1.3 1999 inspiration that I originally bought for the engine to go in my classic mini, but ending up keeping it and sourcing another engine.

Can I just asked at what rpm are you guys doing at 70mph. I ask, as my car shows 72 mph (GPs speed)at 3500rpm, but according to a few gear calculators it should be running more like 80mph.

It's fitted with 165-60-14 tyres. The reasons is I was working out was due to running 10" wheels on my mini. Which works out at 70mph at 3600rpm.

Difference in wheel curcumfrance is about 14%, was should be about 10mph difference.

I now beginning to think I've got a 998 4.4 FD?

The speedo is wrong by about 8%, but does anybody know if the Rev counter is accurate?

Cheeky photo of the mini clubman

 

[r-reg-sr]

this is a pre facelift rev/speed check on 13 inch rims but it depends all on the actual tyre height on the rim
https://www.micra.org.uk/threads/r-reg-slx.43129/#post-456749

 

[Fujiwara-Ben]

Can i ask @Matt Argent what setup are you using for the ignition? Thanks

 

[Matt Argent]

It's a dta S40 with Vauxhall wasted spark

 

[fuzzy-hair-man]

I wouldn't be surprised if the tacho is a bit off, I have a spreadsheet of micra gear ratios (I wanted to know revs with 10" wheels for my conversion) so plugging in the tyre size you gave gives

with a 1.0 gearbox 3800rpm @115km/hr or 72mph in 5th with the 4.05 diff

If it was the 1.3 gearbox; 3240rpm @ 115km/hr in 5th with the 3.89 diff.

All with 165-60-14 tyres with a calculated circumference of 1.740m

Gear ratios from here: http://www.micra.com.au/technical-articles/nissan-micra-specifications.php