V10 S8 top speed governor
 

How many owners have tested this? I'm in Germany and have been trying out the autobahns. The handbook says it is limited to 250kmh. So imagine my surprise at hitting 255, with the car still pulling hard (then had to brake as I ran out of empty road).

Anyone else found the 250 limit appears to be a bit soft?

Also, booting it from 180-190 or so is a formidable experience! It leaps forward and then continues to accelerate hard.

Depends where you are in Germany and on which autobahn.
I used tofind that silly o'clock in the morrning on the A61 was pretty good and the A7 used to be brilliant before they completed the southern end because traffic started to use it then. +++

The car is meant to be limited to 155mph so that's pretty close to your 255 kmh and given the optimistic speedos i would think you would be close to hitting the limiter

I think car being German the limit is set in km/h at 250 not at 155mph but it's pretty much the same speed anyway. Speedo reading is is way out, you will be seeing about 280 on the clock by the time 250km/h limiter kicks in. Compare the speed on the clocks to GPS and you will see the difference or even better to the speed in VCDS as that is the speed that limiter will use and it can vary from GPS speed depending on tyre size and wear.

I wondered about speedo error. But how does the car know its real speed (ie not the speed that the speedo is showing). I thought to establish speedo error you had to hook up some external measuring equipment. If the car knows the real speed it is travelling, why not tap into that?

I have a VCDS cable but not on me. Might poke around when I get back. Also have a GPS watch with me so might see what that reads compared to the speedo. Did that once on a plane. The watch was pretty close the speed reported on the moving map!

My D2 S8 didn't limit itself until it hit an indicated 177 mph on the clocks....

I didn't have GPS back then to verify, and 155 to 177 is a bit of an large percentage error if im honest, but 177 is defo when it *could* keep pulling, but electronically decided not to....

I've no reason to believe its factory 155mph was in any way compromised....

There was us, and 2 other random A6's we'd picking up doing a 155 mph convoy all clearly sat on the limiter early in one morning. It was quite surreal really. No one could go any faster lol...

Got a better run on the way home. The limiter cuts in at 260 and a little bit (topped out just on 260 the first time, but the second was still pressing I as I hit it). Nothing dramatic; you just see the rev needle dropp a couple of thousand rpms suddenly.

Got absolutely *blitzed* by a Carrera GT when I was doing around 190kmh. Appeared in my mirror like an incoming missile! Pulled over fast without holding it up too much and it rocketed off into the distance. Giving it full beans meant I could keep it in sight, but although I had thought traffic had been moving over for me, that thing might as well have been vaporising the cars in front of it!