First impressions - one month on

[Arctra]

Sorry if this is a dumb question, but why would they deliberately make the speedo inaccurate? Slow us down? Is this common practice?

If you take a look at Wikipedia there's a decent write-up of speedo errors: http://en.wikipedia.org/wiki/Speedometer#Error

"...the legislated error in speedometer readings is ultimately governed by the United Nations Economic Commission for Europe (UNECE) Regulation 39...
The indicated speed must never be less than the actual speed...
The indicated speed must not be more than 110 percent of the true speed plus 4 km/h at specified test speeds
Australia... All vehicles manufactured on or after 1 July 2007, and all models of vehicle introduced on or after 1 July 2006, must conform to UNECE Regulation 39"

So I'm guessing manufacturer's build in the error to err of the side of caution to ensure drivers don't speed... even when pushing their luck.

[Paragon]

I imagine that would also mean that the odometer would be off by the same amount. If the engine thinks the car has done 100km when it really has only done 92km then we are really having the car services 8% earlier and the cars actually have 8% less kms on them.

[STV4SYT]

The Odometer is still accurate, the "Margin" is built into the Speedo Drive, whereas the ODO is electronic.

The ECU of the car knows exactly what speed it is really travelling at (Proven by using the Climate Control Speedo) and therefore how far it has travelled.

[Transporter]

It will never be 100% accurate and it can't be. As new tyre wears out it changes diameter. The difference in the tyre diameter have effect on the speedo accuracy doesn't matter if it is from engine's ECM or odometer.

[STV4SYT]

It will never be 100% accurate and it can't be. As new tyre wears out it changes diameter. The difference in the tyre diameter have effect on the speedo accuracy doesn't matter if it is from engine's ECM or odometer.

it will be within a reasonable amount of accuracy. what i am saying is that digitally, the car is calibrated initially to be as accurate as possible, whereas the analog speedo is calibrated to be inaccurate by a pre-designed amount.

[NZTiguan]

it will be within a reasonable amount of accuracy. what i am saying is that digitally, the car is calibrated initially to be as accurate as possible, whereas the analog speedo is calibrated to be inaccurate by a pre-designed amount.

I wonder if different countries have different requirements ? cos my NZ new Kia Sorento was only just under 2% out and my Tiguan is actually less than 1% out at 100kph checked against my GPS (given my wonky old eyes and an allowance for the thickness of the speedo needle !!!). The Tiguan is actually slightly MORE inaccurate at 50kph but I can't remember the actual figure, from memory it's about 2kph out which would be 4%. I'd be getting the dealer to re-calibrate mine if it was 10% out, that's ridiculous !!

Cheers

[Sharkie]

There has been a number of threads about speedo on the other sections of this forum.

On average the consensus is that Australian VWs overread by 8%. I personally had my GTI do 100km/h at an indicated 108km/h. Tested by GPS.

Onboard computer (average speed) was always correct though if reset and driven for more than 100m at a constant speed.

[Sharkie]

After 1 day (well 1 night & 200km anyway) of ownership and considering I did not test-drive a 125TSI manual at all before ordering I have the following initial impressions .....

1. It is more punchy than expected .....
2. it is less punchy than what I ultimately want (so an ECU upgrade is the way to go)
3. It handles better than expected.
4. It is too quiet .... really need to give it a go to hear anything. (I will need to fix this)
5. It is smooth and refined.
6. The 6speed manual is very good and smooth (IMO better than a Camry ... clip)
7. The boot is still shockingly small .....
8. I don't like the RCD310 radio .....

And

My wife commented on the lack of power compared to the explosion of power from the GTI which she really liked. I assured her the ECU upgrade would go towards fixing that .....

[clip]

1. It is more punchy than expected .....

Yeh, I had to laugh at myself the other day. I was taking it in for 2nd dealer service (I got first 3 services thrown in) so set back to 125 mapping in the afternoon. Drove it the next morning and thought, damn I mustn't have set it properly, this is still on the 190 mapping. Wasn't until I got further down the road and it had warmed up properly that I soon realised it wasn't. But that stock map is very punchy down low.

[Pullstarter]

x3 for stock punchiness, I was very pleasantly surprised also. Not to mention the look of sheer terror on the missus face when she first drove it and put the foot to the floor in 1st gear LOL.

[jimbomort]

speedo accuracy

All VAG cars under read by the same amount, 93 @ 100. Its tricky to change using VAG COM but if you have climatronic then you should be able to force it into diagnostics mode by pressing ^ and AC at the same time, then go to 19-0 and the right hand temp display is the accurate speed form the ECU. Its annoying but now i just drive to the variance. 110 is exactly 103 which in vic is keeping the license safe.

Not sure where this info came from, but Tig owners be careful with assuming your speedo is over reading (ie indicating more than you are actuallu doing).

I recently tested our speedo accuracy against the speedo check distance markers (ie 0, 1,2,3,4 and 5 km) you sometimes see on freeways and found that our speedo was actually slightly under. According to our speedo we covered only 4.9klm rather 5. In all other cars I have tested (at least 4-5 different makes and models (not VW) they were always over and I have always assumed that 110 is probably more like 105, so a buffer there. This is the first time I have got under for any car I have owned. This means for our 125 TSI, 110 is actually 112klm/hr.

So if you have a Tig with standard wheels and tyres, be careful assuming it is over reading, IN OUR CASE ITS UNDER READING BY about 2%.

The only comment I can make is that our Tig has had the APR stage 1 upgrade, so not sure if that varies ours from the normal. In any event, be careful assuming.

[suparockin]

Not sure where this info came from, but Tig owners be careful with assuming your speedo is over reading (ie indicating more than you are actuallu doing).

I recently tested our speedo accuracy against the speedo check distance markers (ie 0, 1,2,3,4 and 5 km) you sometimes see on freeways and found that our speedo was actually slightly under. According to our speedo we covered only 4.9klm rather 5. In all other cars I have tested (at least 4-5 different makes and models (not VW) they were always over and I have always assumed that 110 is probably more like 105, so a buffer there. This is the first time I have got under for any car I have owned. This means for our 125 TSI, 110 is actually 112klm/hr.

So if you have a Tig with standard wheels and tyres, be careful assuming it is over reading, IN OUR CASE ITS UNDER READING BY about 2%.

The only comment I can make is that our Tig has had the APR stage 1 upgrade, so not sure if that varies ours from the normal. In any event, be careful assuming.

Seems like a big possibility there, if you've got a stock Tiguan then I wouldn't worry but if you start remaping chips etc then that would seem to be the logical reason for the problem.

[Kyeema]

18. Tow bar is too expensive, waiting on Hayman Reece cheaper solution.

It is however, a well designed tow bar. You can easily take it off when you don't use it so you don't have to bruise your shins on the ball.
You can't even see you have a towbar when it's off.

[Maverick]

Not sure where this info came from, but Tig owners be careful with assuming your speedo is over reading (ie indicating more than you are actuallu doing).

I recently tested our speedo accuracy against the speedo check distance markers (ie 0, 1,2,3,4 and 5 km) you sometimes see on freeways and found that our speedo was actually slightly under. According to our speedo we covered only 4.9klm rather 5. In all other cars I have tested (at least 4-5 different makes and models (not VW) they were always over and I have always assumed that 110 is probably more like 105, so a buffer there. This is the first time I have got under for any car I have owned. This means for our 125 TSI, 110 is actually 112klm/hr.

So if you have a Tig with standard wheels and tyres, be careful assuming it is over reading, IN OUR CASE ITS UNDER READING BY about 2%.

The only comment I can make is that our Tig has had the APR stage 1 upgrade, so not sure if that varies ours from the normal. In any event, be careful assuming.

Yes be careful making assumptions.

You measured the odometer's performance over that 5km and not the speedo's which is seperate and is the part that has the error introduced as per UNECE 39/00 rev 1 adopted by ADR 18/03.

The odometer as you found is accurate. The speedo much less so.

Volkswagen Speedometer Error Correction

[jimbomort]

Yes be careful making assumptions.

You measured the odometer's performance over that 5km and not the speedo's which is seperate and is the part that has the error introduced as per UNECE 39/00 rev 1 adopted by ADR 18/03.

The odometer as you found is accurate. The speedo much less so.

thanks, you learn something new everyday

yes even seemingly reasonable assumptions like the Government placing distance markers on major freeways marked with large signs saying "Speedo check" that provide a check of the ODO only, not the speed at all, as odo accuracy doesn't equal speedo. The odometer of other cars (3+) I've checked against those distance markers were overeading like Speedometers, but I'm living in the past there - most if not all of those were before the introduction of ADR 18/03.