Calculating Speed vs RPM in a stock 260z 5 speed

[stevo_gj]

Hey guys,

 

Just wondering if anyone knows the ratios of the 260z 5 speed manual box. Assuming I have stock rolling diameter and stock diff what other numbers will I need to crunch out a speed vs RPM list?

 

I need to do this because I have still not got around to correcting my speedo.

 

Cheers,

 

Steve

[620Z]

We will need your diff ratio?

Either that or jump in the car and drive next to a buddy or better still some Sat Nav's have the land speed klms whilst driving along.

[ZED660]

Steve,

 

Here are a couple of sites that may assist.  With the first one, if you have a standard 260 gearbox the ratio will be the one specified as Factory competition-close ratio with the 2.9 first gear.

 

The second site will let you know the closest gearbox speedo drive cog you need taking into account your diff ratio and tyre size.

 

 

http://www.geocities.com/z_design_studio/

 

http://www.graytechsoftware.com/garage/cogcalc.asp

 

Hope this helps,

 

Geoff

[Zedman240®]

Save yourself heaps of grey matter and just borrow a GPS Sat nav and that should tell your Kph pretty accurately.

[stevo_gj]

Haha I'll do both and check my calculated speed versus GPS speed 

[Jospef]

2800rpm at 100km/h, if memory serves me correctly.

[stevo_gj]

Cheers man, I'll still try and do the calcs anyway.

[stevo_gj]

http://www.geocities.com/z_design_studio/transmission.html

 

This link was very useful! Stock R180 Auto Diff and 77- 79 Factory 260z 5 speed gearbox give me about 2584 RPM for 100 km/h. This sounds about right to me.