my 530d (a) - 50000km - previously got top speed to 260km/h on speedo

Now pushed hard the other day AND battle to reach 240km/h

Any idea what problem could be ??

 

Wind...? Changed tyres to bigger ones, etc...
On my 530XD I do reach 260 no problem..now. Yet it has been remap. Before remap in DS mode it would reach about 250.
anyway, except few places in Germany, nowhere else such speed is of any use...

 

Doesnt sound like a problem. There are lots of factors as listed above, tire air pressure, air temp, atmospheric pressure, tire wear, even road surface. at those kind of speed everything comes into play

 

Sounds like you might have an injector going down, out of interest are you running a tuning box ? I had this problem until I removed the box after a trackday at Cadwell Park.......?

 

Really, what was wrong with the tuning box Mark i have one !!

 

No idea, worked fine and then at Cadwell the car just did not want to accelerate past 80mph properly, stuttering with what felt like fuel starvation or fuel pressure problem, day after the track day I removed the box and the car pulled fine again pulling well over 140mph with ease. As you may know the tuning boxes mainly just ramp up the fuel pressure, which leads me to suspect I may have a weak or slowly failing injector which just cant handle the extra pressure sent from the tuning box.

Oh and also with box fitted I occasionally had lumpy idle RPM, and when CC enabled a surging, constant speed but the torque converter kept on dropping the clutch in and out occasionally, neither problem since box removed.

 

Makes sense bud, seem a tad odd though as usually a worn injector would show in other operating values, (like hills and acceleration) hmm ill keep an eye out for that one, thanks for the info

 

Wow! I can't believe a 530d can actually reach over 220 kph! I also can't believe that you guys drive so fast. I have not done more than 220 kph.

 

And some

 

Even the 520d can do 220.