Is everything I read true?

[allh2k]

Hello

I was just reading some car reveiw sites so I can sit smuggly in my chair after having had my leon tdi 110 for 4 months and being very happy.

I came across top speed 120... on.

http://www.whatcar.co.uk/car-review-performance.aspx?RT=2415&ED=4604&U=1

Now I'm a very carful driver and would never go that fast on the roads but mine did go higher(10% higher..) would this be down to the speedo being out? or as I've found my air box has lots of drilled holes covered in sticky tape has it been modded?

 

[Sisson]

speedo's can be around 10% out..

 

[JKM]

We can see how far out speedo's are when we run cars on our rolling road. You would be surprised how many are infact reading high!

Keith

 

[jonjay]

The speedo's are 3-4mphs wrong. Tested with two different GPS devices at the same time.

 

[allh2k]

Woo I got scared then..

 

[woodyTDI]

Is a gps navigator more accurate than the speedo?

 

[allh2k]

I think it is m8

 

[woodyTDI]

Just seen your sig, Honest john! my girlfriends dad swears by him!

 

[allh2k]

I just read it today I must have missed it when I was buying the car god damn it! Its now full of scraches and stone chips 4 months later

 

[Georgel]

Over two set points to calculate an average, yes.

 

[muddyboots]

The speedo's are 3-4mphs wrong. Tested with two different GPS devices at the same time.

They'll be a certain *percentage* out, which means the actual error will vary with speed. It varies from car to car too.

They are allowed to over-read (up to 15% IIRC ? ) but not under-read at all, which is why manufacturers tend to err on the side of caution and make them over-read, so that with all eventualities of tyre wear, pressures etc etc the speedo will still never under-read.

Oddly, my Mk4 TDI Sport was the only car I'd had which was absolutely bang-on accurate, tested with my GPS. My previous Rover read 10% over - IE at an indicated 70mph you'd actually only be doing 63mph.

 

[basstard]

I was thinking of this the other day when the road I was on was full of those "your speed is: " electronic signs,,, my speedo is WAY OUT and it overreads by a quite a bit,,, and I am on stock rims too!!