Tachs


#1

Why has tachometers become such a large part of the dash board lately? In two of my newer fords, they are the same size as the speedometer. I bet that 95% of the drivers out there don’t have a clue what a tach is for. And 95% of the cars are automatics.


#2

It’s true that a tach has limited use on a car with an automatic transmission, but it still serves a purpose.

If you downshift for a hill, and then forget to upshift after cresting the hill, the tach will display the high revs–if the driver did not hear the roaring of his engine. And, if you are familiar with the “normal” revs at highway speeds, it is relatively easy to see if the transmission is slipping by looking at the tach. Of course, for those drivers who rarely look at their instruments, these commnets may not make much sense!

However, as to why it is as large as it is…I have no answer.


#3

Even on a manual transmission, they are of limited use for regular driving. My truck does not even have one.

I think it is more a sex appeal thing rather than for any real purpose. Think of that Cadillac commercial with the girl in heels pushing down on the gas and the tach quickly but steadily rising to near the red line.


#4

“Lately?”

When did you notice this trend?

Tachometers have had a prominent place in many dashboards, in many cars, from many manufacturers, for a long time. Have you just noticed this?

Tachometers are usually the same size as the speedometer, although there are a few cars on which they are smaller or larger.

Larger?

Yes, larger. Imagine a dashboard with a big tachometer and a smaller speedometer.

Scary, isn’t it?

It means someone might be more concerned with the rotational speed of the engine as opposed to the speed of the vehicle, and maybe they have a manual transmission (radicals, no doubt). We’re going into really dangerous territory here, so let’s just stop.

You’re correct in that most people neither pay attention to the tach, nor care what it’s for, but the tachometer is there, regardless.

Have a nice day.


#5

I used to worship tachs, adding them to vehicles that didn’t have them but nowdays, I pretty much ingnore them. I even removed one on a motorcycle I owned to clean up the look of the bike.
A vacuum guage is actually a more useful instrument if you want an instrument to tell you when to shift gears with a manual transmission.


#6

What ever happened to the speedometer of the 70s, where the speedometer needle swept the entire length of the instrument cluster?


#7

Dead and buried, I hope (was this a joke on your part?). Very poor human factors there – difficult to read compared to a round gauge.


#8

Take away the tach and people will scream,studies have shown.


#9

I concur…the tach is probably the most USELESS of all the instruments. I’d rather see oil pressure gauge, or oil temp.


#10

They put one on almost all cars for standardization. In the sixties, General Motors had a possible 9,000 interior combinations and the dealers sold the options heavily. It became almost impossible to manufacture a line of cars, and there were some combinations that wouldn’t fit if ordered together. Now there are even limitations on interior color. Only scam artists try to make you believe that it is possible to please everybody. Everybody gets a tach and we save money while we slowly go crazy in a one size fits all planet. Gotta love that sentence structure!


#11

While I understand the reasoning listed here, I do not think Tachs are a waste. Yes I am in the minority. While towing I like to look at the Tach. It helps me keep the RPM’s in the “sweet” range of the motor regardless of mph. I use the Tach for reference on the race track (which I realize is outside normal driving). Maybe cars should come with shift lights instead :wink:

Yes, Tachs are used as much as styling as function. I vote for keeping them and getting rid of at least 2 of my trucks cup holders…talk about a waste!

What I dislike is all the idiot-gauges. Oil pressure and temps gauges in today’s cars are damped…oil pressure varies with temp and engine rpms…not the steady state way its displayed on the gauge. I put a mechanical oil pressure gauge on the track car. Its nice to know what the pressure is actually doing.

I had an 82 Rx-7 that had a Tach centered in the instrument pod with a smaller speedo next to it. If you ever drove a rotary hard, you would understand the design. Maybe I am just sentimental, my first job was assembling aircraft tachometers.


#12

Things are simpler on a race track. The engine is usually run at full throttle and so a shift point can be put on the tach.
On the street, the engine is mostly run at part throttle and the optimum part throttle shift point is lower than the optimum full throttle shift point. If you want to use a tach to indicate optimum shift points, a computer or something like that will have to move the shift point line up and down the rpm scale with throttle opening.
This is why I shift by feel instead of being a slave to the tach.

If you have to shift by instrument readings, a manifold vacuum gauge is actually more useful. Maybe someone will invent a tach with a moving shift point indicator that moves with engine manifold vacuum. This will have you shifting like an automatic transmission is programmed to shift.


#13

While I understand the reasoning listed here, I do not think Tachs are a waste. Yes I am in the minority. While towing I like to look at the Tach. It helps me keep the RPM’s in the “sweet” range of the motor regardless of mph. I use the Tach for reference on the race track (which I realize is outside normal driving). Maybe cars should come with shift lights instead :wink:

Most people I know who drive a lot can tell what the engine is doing by listening. I can easily tell what the sweet spot is just by listening to the engine. Take you eyes off the tach and listen to the engine and you’ll be amazed how easy it is.


#14

Most people I know who drive a lot can tell what the engine is doing by listening. I can easily tell what the sweet spot is just by listening to the engine. Take you eyes off the tach and listen to the engine and you’ll be amazed how easy it is.

Except for some cars where the engine is so darn quiet you don’t hear it. My Accord V6 is like that. I can easily be in 4th instead of 6th and not realize it until I glance at the tach. By the time I can hear the engine it’s revving pretty fast. Well, the acceleration characteristics give it away, also.


#15

I can hear what the motor is doing and shift by feel and ear. On the track glance at the track to see if I have gained any engine rpms at a reference point (corner exit) to guage if I am taking a better line. On the truck I GLANCE at the tach to stay away from the shift point on the automatic.