Look on the bright side, at least you can peg your speedo, I've seen 115. There ain't no way on gods green earth I'll ever see 160 cause at 115 thats all there is and there ain't no more.

You don't have a speedometer application on your iPhone??

To see how fast you are going as you hit the tree?

There is a video recorder application you can get that will record until just after it detects a high-G shock, assuming it was a collision of some kind.

Otherwise, that's one way to eliminate one iPhone from circulation.

Back on track with the subject at hand...

The speedometer is certainly reading the correct speed, but a circuit in the cluster isn't allowing the display to show it.

It's been set up to display anything over 85 to be 85...

85 mph=85 mph

85+x=85

85+(x+1,2,3,...)=85

Find yourself an true electronics repair shop-one where they do the work on site, not shipped out for replacement.

Download the schematics for the cluster, and take everything to the shop. They should be able to isolate the redundancy circuit and disable/remove it.

Why??????

Stephan, I don't know why the original poster would need to do this either (unless there are track days in the car's future), but I wanted to at least try to answer the question with something not related to using a cell phone...

About 7 years ago i made hi speed run thru DETROIT when i first got my 83zx 2+2.

And thought 85 I was probably doing 110 at least.

Without seeing an analog gauge it was hard to figure out what was going on.

I was just enjoying a half hour run down the highway in my 83 today. I was working at a ford dealer and

had many looks and comments.

And got a roush performance banner big one.

The widely reported story at the time was that Joan Claybrook, who was the head of the NHTSA, believed that if the speedometer only went to 85 people would be more likely to obey the dreaded 55 mph national speed limit. You know, 55 is more than half of 85, so it looks similar to 70 on a 100mph speedometer... or some claptrap like that.

Personally that was the era of my misspent youth, and I got even by keeping my 85 mph speedometer pegged as much as possible. (As my DMV history from the era shows...)

Keeping up with traffic on most of the local interstates today, an 85mph speedometer would be nearly pegged most of the time.

Stephan, I don't know why the original poster would need to do this either (unless there are track days in the car's future), but I wanted to at least try to answer the question with something not related to using a cell phone...

As far as that cell phone claptrap goes, all you have to do is consider who started it. Especially when he continued along that path even after the question was answered. I was just wondering why this went so far beyond the scope of what the OP asked.