An RPM question



I have a 97 ford taurus which has a gauge for the RPM’s. My questinos are:

1. Why do I need to know my RPM’s?

2. How do I know my RPM’s are where they should be for x mph?


Assuming you have an automatic transmission, I’ll claim there is next to no use for a tach. Unless you’re experiencing some unusual driving problem (engine racing compared to the speed you’re going), there’s little important information to be gained. If you have a manual transmission, the tach can provide guidance on when to shift, when to worry about redline, that kind of thing. It’s become almost mandatory for cars to have them, even though (aside from sporty cars) they never get used.

Let the comments begin!


Most tachometers are just there for decoration. Most people who have been driving for a while can tell that the engine is running at a proper speed for the vehicle speed and gear and that it isn’t slipping out of gear just based on the engine tone and vibration. There might be few high-end cars that are so quiet that the tachometer would be the only indication that something’s amiss, but I don’t think a '97 Taurus fits that description.


This is what I figured, but I would have thought that they could have found something better to put there. Also is there a guide to know if your RPM’s are what they should be say for X speed? I mean if the car is warmed up and you are doing say 45 mph in the city should your RPM’s be around 1500?


I agree that a tachometer, or “gauge for RPMs” is pretty much of no value on a car with an automatic transmission. However, since it has become the norm for manufacturers to include a tachometer on all of their vehicles, no matter which transmission is installed, it has become part of the scenery, so to speak.

The tach can be useful if the owner/driver believes that the automatic transmission is beginning to slip. Otherwise, it is really just not very important.

As proof of it non-importance for most drivers, it seems that a large number of people who post questions on this board will tell us that the tachometer is registering “2 RPMs”, or “3 RPMs”, or… Somehow they manage to not see the message on the face of the tach that says “X 1,000”.
For someone like this, a tachometer is essentially useless.

As to knowing how many thousands of RPMs an engine should be turning at a given speed, that information might be contained in the Owner’s Manual. Or maybe not.


It’s more that if they CHANGE from what you see now is an issue. Not so much what they should be, but if a delta ever occurs…


Agree with tex; we have a Nissan without a tach and a Toyota with one; both are automatic. I seldom look at the tach, except in mountain driving when the slowing RPMs going uphill tell me when to gear down.

My wife never looks at the tach. The outside temperature gauge is far more intereasting, especially heading for the ski hills.


I am manual void as my car didn’t have one when I bought it at auction.


I’ll have to agree with those that say a tach on a car with an automatic is really only a decoration, and a tach on most manuals is really only decorative also. Engines on most cars will start to “run out of steam” (the power curve begins to drop) and you’ll shift (manual) before they approach unsafe RPM levels, and the engine management systems won’t allow you to push the engine beyond redline.

It’s also a good age reducer. Mine makes me feel like a young kid again.


I think that you can go to Ford’s website, register as an owner, and then download the owner’s manual for free. However, I don’t know if they go back as far as 97.


The rpm at a given speed depend on differential gearing, transmission gearing and tire diameter.As these all vary by car no one can tell you what yours should read.Just get familiar with what yours reads so you can tell if it changes.


I’ve driven several manual Accords with tachs and two manual civics without, and I must say, both vehicles were just as easy to drive, no problem.

Regardless of the transmission, you can use the tach to monitor your power settings and fuel consumption particularly on the freeway.

I like to cruise along at 75MPH because it keeps the RPM <3,000. At speeds > 80MPH the tach registers somewhere around 3100 RPM, thus this isn’t as efficient.

In unsophisticated light aircraft the pilot uses the tach to precisely set the most efficient power setting, but more advanced aircraft have manifold pressure gauges and the tach gauge serves only a contra function.

Practically speaking though I think that the taurus’ gauge cluster, or in any car really, looks more exciting with a tach : )


Perhaps I’m the oddball, but I actually use the Tach when driving on the interstates over long distances to maintain best fuel economy. In my case, I have found that keeping below 2500 rpm, regardless of speed, is the sweet spot that yields the best fuel economy. Under some conditions, 2500 will give me 60 mph, and at other times, 75. I use the onboard mpg gage to cross check. Using this system gives me a constant 30 mpg highway in my 2004 Chrysler Concord with a 2.7 engine.


Nope not the oddball, read my last post. Fear not, you’re not alone.


You can use the tach to help you shift lower. Then again, hearing the sound of the engine works just as well.


Agree 100%…I think a tach is a useless instrument. I’ve NEVER shifted based on what the tach says…strictly feel and sound. And IMHO if you can’t shift by sound or feel then you shouldn’t be driving a manual…I’m sure there are special situations where the tach is very usefull (NASCAR)…but NOT the daily driver.


Try or


Higher rpms=more power. You wind it up more in every gear if you are in a hurry, but you use more gas. If you are not in a hurry, you keep the rpms low and save gas.

A tach is necessary to correlate the sounds to the red line. After you know what red line sounds like, you can listen and shift accordingly.


My son bought a pick-up truck that was cobbled together by his wife’s brother-in-law. Apparently with the transmission they used, there was no way to connect the speedometer. My son marked the tachometer as to the speed for different gears. I also remember riding in an intercity bus made in the 1940’s or early 1950’s. The tachometer was marked to give the speed in each of the gears and there was no speedometer. You might want to think of the tachometer as a back-up speedometer. Otherwise, it is about as useless as a screen door on a submarine.


My '75 Civic manual-4 had no tach and marks on the speedometer for redline in each gear.
Same as many of Honda’s scooters and motorcycles.