Digits skip under hard acceleration
 

Just noticed today, was coming on a on ramp at full tilt and looked down briefly noticed the digits skip pretty bad in 1st and 2nd gear. Like 10-16-21-28-31-26-32-38-44-50-54-58-62 etc... not exactly like this but you get the picture.

Got back in town and did a few brisk acceleration from the lights and noticed it again. Makes me wonder, how did the car mags get a accurate time from 0-60? I think i may seen the actual number "60" once or twice during my test. Usally around the ,57, 58, 59 mph it would skip to 62, 63 mph.

So could are cars be a hair quicker or slower than the estimated 5.9 ticks?

Thats not how they do it...if you have ever been to a track...you can see that they use other methods to trap speeds, not the speedometer.

^^^
Like he said.
There's no way some guy with a stopwatch in the passenger seat watching the speedo is accurate enough for split second differences in 0-60 times. They use radar, lasers and a nuch of other complicated stuff at the track. Of course, none of these can overcome the fact that black is the fastest color :eyetwitch

BRILLIANT point!! :rofl:

your car is accelerating too fast for the speedo to keep up that why its skipping numbers. All digital speedo do that.

Digital speedometer has a certain refresh interval. Let's say it refreshes every 1/2 second. If your speed changes from 50 mph to 53 mph within that 1/2 second, then you will see the speedo jumping from 50 directly to 53.

Besides, speedos on cars just provides estimates. Accurate measurements are taken by using radar, laser and other external sensors.

They use a device called an "optical 5th wheel" and they back that up with a pro-level g-tech like performance meter that measures with GPS and accelerometers. The optical 5th wheel "watches" the ground go by and measures the rate at which it is going by.

I have an amateur, first generation gTech and works like an absolute charm for 0-60 measurements -

So how accurate is it, anyway?
 

Anyone know? I think I heard that on the Miata, at least, it reads a bit faster than you're going.

I love looking down at my speedo and seeing it skip numbers. It feels good to know that the speedo can't keep up with the car.

I think legally it has to be

well my rx8 read about 3 mph faster than my true speed... prolly something like 1.5-2% off. It's probably set to the absolute largest diameter possible for the "stock" tire for tire pressure and tread.

You should have seen how bad the first generation digital speedo's (like GM's) were in the 80's... their sample rate was horrible- they would skip worse than that under light acceleration. I was actually very against the RX8 having one until I saw how well it kept up.

Except for Velocity Red :lol:

^In your dreams :p:

I never paid attention to it on my test drive, every time I looked down, I was at a constant speed, so I figured it was pretty accurate. Typically there is a margin or error built into any speedometer, whether it is digital or not. The 1.5-2% number sounds about right, makes more of a difference the faster you go.

Since I have had the car for a while now, I have noticed the skipping, but I think it does do a good job catching up. I have done some experiments to see how fast I can get it to skip and the best I have done is 6mph with a WOT 2nd gear run on flat surface starting at 5500rpm. I did also notice that sometimes when you are moving at a constant speed and then get on it to merge in traffic or onto a hi-way that it will sometimes lag a little before it starts catching up. I have grown to like the digital speedometer however and the fact that the passenger can not read it :naughty:

when accelerating I focus not much on the speed clicks as much,but my tach revvs and leave the rest to history.

the speedometer on my RX-8 is pretty accurate, usually within 0.5mph to the calculated speed my GPS gets when I'm driving.

Not mine with my aftermarket tires!

Nothing is faster than LIGHTNING.

Lightning Yellow that is ...

Need I remind you all again? Shinka black cherry is the fastest, the best handling, and its exhaust smells like lilacs.

That is not mantastic!

Ti is the fastest, best looking, gets 30 MPG, and has exhaust that smells like sausages & beer!

Yeah. My wife can't complain about me driving too fast if she can't read it!

We all know titanium is very light so its the fastest, plus now its the fastest in the galaxy

Well, at least we can all agree that the slowest is the new copper.

(after all, there's nobody here to dispute. :) )

I'd go as far that whether lightning or brilliant or velocity or titanium, in the end WINNING blue would take the cake.