Speedo seems wrong after box swap?

[mikey14sr]

Changed from an F10w to an F13c/r, the speedo seems to be under-reading though. Haven't had chance to check it against my tom tom yet, anyone else had similar troubles?

[Asa-James]

my speedo kept reading wrong, then i found the snapped speedo cable.....

anyways, when you check against your tom tom, pull teh front of the clocks off, pull the needle off (carefully) and drive at 70 on the tom tom, place the needle on 70 and bobs your uncle! my speedo is accurate at almost every speed now

[Adam]

Its because theres a small number on your speedo w-***
That number relates to your final drive ratio.

So you've changed the box/fd, which will have altered your speedo reading.
Depends how far out the "w" numbers are on the speedos

[mikey14sr]

If thats the case, it's oh b88ger time, as the box is from a '92 sri, and the clocks are from an '89 1.3sr!

[Adam]

Compare the speedo readings to Stu's speed in gear program, see how far out it is.

[mikey14sr]

mmm, good idea. if it is stupidly out I think there's a place that does gearboxes to fit into the cable to correct it, either that or does anyone know what the w= number is on an sri with f13cr/3.94?

[General Baxter]

when i went from a F10 (**** knows what ratio) to a F13cr 4.18 my speedo was reading 40mph when my sat nav was reading 29 lol

it looked so quick lol

[Adam]

Cant remember what W**** is on my sri speedo.
Will check tomorrow.

[mikey14sr]

cheers ad.

[mikey14sr]

Been out in it this morning, noted revs and speed at a few points. Just checked it against Stuart's speed in gear calculator, and it's reading 1mph lower than it should, Think it was the change from w/r to c/r and the increased revs that shocked me yesterday.

[Adam]

Sounds fine then.

The W number on my sri speedo is W-1849