Tachimeter

Hi everyone, thanks again for to reply to me at my other Threat l opened and now l want asking you a "silly" question : well, there in U.S. you have your Tachimeter written in miles then here in Europe in KM. This is not a problem for me, but l would like to know this, the Cherokee's are there and here they had the same engine (I mean the 4.0 normal, not the HO) with about the same HP (close to about 174). Well, mine Cherokee (for example) on top speed is close to the KM 170 (about Miles 105), but l see in some pictures that your Tachimeter sign the top speed close to the 85 miles. It mean a top speed of 136 Km. So my question is, if my Cherokee do that top speed, your Cherokee do the same? Or do you have some speed limitator?

I know that it's a silly question but its a thing that l always wanted to know.

Then (l don't remeber who) one day someone told me that your Tachimeter was written in that way also if your car run fanster, because there was a old law there that oblige the Factory cars to write low speed so the people reading that doens't let the people run more. Is it right this? Or it is the usual bullshit?

Thank you very much!

Moreno.

it was an old federal mandate. there was never a governor that limited the actual vehicle speed to 85mph

the vehicles governor (91-01 for sure) stops it at 116mph (about 190km/h) the speedometer stops at 85 because, as four_shot said, it was a government regulation to stop there.

Just to make sure we're all on the same page...

"Tachometer" - the gage that tells you how fast the engine is going (given in rpm at the crankshaft.) Doesn't change with measuring systems used.

"Speedometer" - the gage that tells you how fast the vehicle is going - given in miles per hour (US) or kilometers per hour (everywhere else. Somtimes also called "klicks" when used in reference to motion. A "klick" is radio slang for a kilometer.)

With some maths, a tachometer can tell you how fast your vehicle is going, but it takes a minute and some figuring.

As far as top speed, I do not believe there was ever a vehicle-speed based governor installed on the XJ, but I know that later models have had an engine/I]speed based governor (called a "rev limiter," and built into the Powertrain Control Module) set somewhere around 5000rpm. The top speed, at that point, can be figured from top engine speed, transmission ratio, axle ratio, and tyre size.

Your top speed is whatever you can get the vehicle to do (I've not tried. I'm not afraid of speed - I just haven't been interested in finding out...) with your particular combination. Just remember - you're going to be more limited by the fact that the XJ is about as aerodynamic as a brick flying through the air, and that's going to be more limiting than a speed limiter in the control system.

Look at an XJ. Look at your typical racing car. Need I say more?:rof:

Meanwhile - welcome aboard, and "Hi!" from the States!

....a rusty brick.

Well, if l understood well, your Cherokee goes to the top speed like mine ( l mean with original tires and ratio),that was just an old law to "push" the people do not go other the 85 Mp/h, right?
So, there's no "speed limitator" on the vehicles that stops the vehicle on the top speed written on the tachometer. Do l right?

Gasoline said:

Well, if l understood well, your Cherokee goes to the top speed like mine ( l mean with original tires and ratio),that was just an old law to "push" the people do not go other the 85 Mp/h, right?
So, there's no "speed limitator" on the vehicles that stops the vehicle on the top speed written on the tachometer. Do l right?

Click to expand...

correct.

Thank you very much h2opete987. From tonight l can sleep well ;-) .

Glad you can sleep well with people from around the world asking all these meaningless questions about Speedometers.

In 73' we had our first oil shortage, thanks to our pals at OPEC.
Shortly after that, the National speedlimit was set to 55mph. Someone decided that a bit over 1/2 scale reading made more sense than a less than 1/2 reading on a 110mph guage. Not every car came with a 85mph guage, but that isn't too relevant either.

In the mid 90's the National speed limit came up to 65mph, and the new/old 110/120mph speedometers still read just over 1/2 at that speed.

Sure there are speed limiters on the new OBDII stuff. But the OBDI computers weren't able to do much more than rev limiting.

Still, as I said, this is all irrelevant. Who would bother to drive a Cherokee at 85mph anyway? The fuel economy would really suck...bad, and so would the handling.

Good luck with all your "Zs"

Good words Zuki ;-)

Anyway guys, l know that the price of gasoline is high, but you don't know how much we pay here in italy. You have just to know there here we pay so old taxes on the price of gasoline, so absurd. Example? We pay old taxes since the second war, and other old disaster happened her ein italy close to the 60's and 70's!!! And we continue to pay!!! Here the gasoline price is on Litre and not on Gallons as there. BUt to let you understand better, here the price is Euros 1.40 per litre (it mean $.2.04 !!) so if we had the gallons here, you could pay the gasoline $.7.71 per Gallons!!! So you still lucky to pay the gasoline in your way. Here many big car and offroad cars with gasoline engine they put on the GPL system. The GPL system is a propane fuel. it's cost is about Euros 0,65 per litre $.0.94. So many people use that. What can l say, l live in italy :-(