What's your in gear speed at 4000rpm?

[Black Beaut]

Hi All,

I picked up my 240Z on Saturday and had to drive home with it about 150miles mainly motorway. The thing that I really noticed was that the car seemed to need to rev pretty high to get a shift on. I did some testing today and came up with these rough figures at 4000rpm:

2nd gear = ~30mph

3rd = ~45mph

4th = ~60mph

5th = ~70mph

I had a look at the transmission calculator and these figures don't seem to tally with any on there. I'm assuming I have a 3.9dif which was the one used in the UK AFAIK and the closest gearset that seems to match the speeds I'm seeing is the 32010-N3201 Factory Competition (rally transmission) gearbox. The other alternative is that I have a standard box and a ~4.9 diff which strikes me as pretty unlikely.

Of course I'm not discounting the fact that my rev counter and/or speedo could be whacked I guess I can check the speedo by timing over a known distance, rev counter is a bit trickier, all I can say is that the engine sounded like it was doing 4000.

Any thoughts? I've got loads of bills dating back years but can't see any mention of any work done to the gearbox/diff.

Cheers,

Rob

[venom42]

Dunno if it helps, but at 4k in 4th gear I am at about 85-90 mph. My car is a '75 280 with a 4-speed. It is completely stock (just got it today).

[Victor Laury]

Rob,

PM me with your Email and I'll send you my Excel based TransCalc spread sheet. I have models of each transmission, including the FS5C71A, installed in the European/JDM/Aussie markets

[Victor Laury]

By the way,

Your numbers point to a 4.38 rear or even lower!

FS5C71A (standard gearset), 4.38 rear, 195/60/14 tires

RPM 4000

1st 21.4

2nd 34.0

3rd 48.2

4th 63.2

5th 74.2

[Ed]

Here is a stupid question: Is a UK mile the same distance as a US mile?:stupid:

[venom42]

They are the same. :classic:

[Black Beaut]

Thanks for the replies guys.

It's still a bit of a mystery but I haven't had much time to investigate as I've been battling with rusted in headlamp bowls for a bit and now the car is blind I can't drive it - joy

I'll keep you posted.

Cheers,

Rob