Origin B2

[northy]

just out of intrest - what speed does your origin say when you doing 70mph.

Mine is 3mph out to the speedo !

 

[Daz]

Depends.. it changes around.

Probably about same tho.. 70 on speedo, 67/68 on RA.

 

[CocoPops]

75ish on Speedo is 70mph on B2, thats in a 182 (and same in my old 172)

 

[Pete]

2-3 mph less on sat nav than what the speedo is saying, almost spot on with the cruise control tho.

 

[northy]

So is the GPS speed accurate ?

I thought it might be out due to the slightly smaller profile tyres im running !

 

[Tom]

Quote: Originally posted by northy on 19 July 2004


So is the GPS speed accurate ?

I thought it might be out due to the slightly smaller profile tyres im running !

Yeah its bang on.

 

[dangermouse_se]

Speedos are not made accurate. The law states that a speedo must be accurate to +10% ie that it must be accurate read upto 10% faster than your going. This is because things wear over time. Speedos are made so that as wear occurs they get more accurate. Speedo these days use less moving parts but the convention remains.

The GPS will be accurate.

 

[Tom]

Quote: Originally posted by northy on 19 July 2004


So is the GPS speed accurate ?

I thought it might be out due to the slightly smaller profile tyres im running !

Yeah its bang on. the speedo will never be bang on

 

[CocoPops]

yes GPS is accurate.

Same as my cruise control on the 182 reads lower than the speedo.

70mph on Cruise Control is about 75 again on the speedo.

 

[Daz]

Quote: Originally posted by CocoPops on 19 July 2004


yes GPS is accurate.

Same as my cruise control on the 182 reads lower than the speedo.

70mph on Cruise Control is about 75 again on the speedo.

Hows that work then? Surely the cruise control gets the same info as the speedo?

 

[CocoPops]

no idea, but its the same on other peoples 172/182 etc.

Very odd.

 

[Tom]

Quote: Originally posted by Daz on 19 July 2004

Hows that work then? Surely the cruise control gets the same info as the speedo?

Well no it gets a signal from the ecu, if you read a cars obd-II port when driving the ecu/pcm gives out a much more "real" figure than the speedo is getting. The cruise uses this signal to get a speed reading.
The same reading is used by the speedo but its been "tweaked" to over read.