new speedo reading 160mph at ~30mph - calibration?

[phatcat]

(On a 2012 1.6 Sigma Roadsport):

I had a speedo that was working just fine, except that the digital odometer display failed.

I ordered a new speedo from Caterham and fitted it. This new one is massively overreading - 80mph at ~10mph, and maxed at 160mph at ~30mph. Also, for a 15 mile drive it registered 61 miles on the odometer.

Do I need to do something to calibrate the speedo? All I did was take out the old one, plug the cable in the new one and go on a test drive.

 

[simon_h]

Probably need to input the calibration number. 

The details will be on here somewhere I expect. 

[phatcat]

Great, thank you - found this stuff:

You can press the speedo button in as you turn the ignition and a menu comes up and enter a code.

On electronic models, hold the central speedo button and turn the ignition to the on position, screen should change to 'Set PPU' (if it says 'DTS PPU', press it again to switch mode). Press the button again and the currently set code will display. Each number will then flash in sequence - press the button on each number until the correct code is entered. When the whole number flashes, press the button again and the display will say "DONE"

Earlier models have a removable rubber cap on the back of the speedo case which contains dip switches instead.

Most of them seem to be Caerbont speedos. They have pdfs here with fuller instructions including a "drive to set" option for electronic speedos. There are several links under the speedometer picture, depending on your model, including a pdf with all the dip switch settings.
http://www.caigauge.com/product-instructions

I also found a table for 7s:


Also, from another post it's 034187 for a 160.

It sounds like you can tweak it with in-between numbers as someone stated that 038457 worked well for him with the CR322s.

Will go and fiddle, then go for another spin with a GPS speedo on my phone.

This looks like a good candidate for a tech article if someone could gather all the info together for all the various speedos/tyres/wheels used by Caterham over the years.

[Jonathan Kay]

Will go and fiddle, then go for another spin with a GPS speedo on my phone.

Exactly.

Jonathan

[phatcat]

Used the appropriate setting from the table, and it was only 1mph above the GPS reading (with brand new tyres) 

[John Vine]

I also found a table for 7s

That looks like one of my Photobucket images.  Glad it was of use.

And yes, by fiddling with the code, it's possible to tune the speedo (and, specifically, the odometer) to amazing levels of accuracy.

JV

[aerobod - near CYYC]

On my R400D with km/h speedo and new 195/50-15 tyres, the calibration code is 025991 to be accurate to GPS speed. Looks like the calibration is tied more to the pulses-per-unit of distance rather than alignment with the painted units on the face.

[John Vine]

Here's the equivalent table for km/h:

JV

[Jonathan Kay]

Yes... but if you're going to polish it with GPS won't it work to set the diameter to 0.56ish and go straight to the final tweak?

Jonathan