Tachometers on Auto Transmission Cars - Why?

[jsinger]

My Infiniti has a nifty looking tachometer to measure engine RPM. Yeah, there's an ominous looking red line area at the top of the scale, but I've never been close to that level.

So what's the point of a tachometer on a car without a stick shift? Just to look cool?

By the way, the car's manual devotes one sentence to the gage.

[Webwork]

It's there so guys can thrill at the power of instantly getting their needle up - again and again.

[edited by: Webwork at 6:27 am (utc) on Aug. 24, 2006]

[mcavic]

I like to keep an eye on the tach to get a feel for how the engine is performing. It may also help evaluate transmission problems like slippage and rough shifting. I'm not sure it's all that necessary, but since I'm used to it, I like having the visual cue to go along with the sound of the engine revving.

And I like getting my needle up, too.

[ganderla]

I like to make sure their power curve is where they say it is.

[percentages]

>So what's the point of a tachometer on a car without a stick shift? Just to look cool?

Yeah, it is pointless. Even in a manual you aren't likely to drive it that hard. I've only had my Porsche in the red line area twice in 2 years.......it is actually a hard thing to naturally do when driving.

My "Sweet Spot" is at about 5600 RPM, why not change gears a fraction of a second later?

[trillianjedi]

Does it not have a sports mode where you can manually change gear?

[jsinger]

No sport mode on my 2002 Infiniti I-35 (nice car, btw).

Another thing: I don't recall having any car recently, including the Infiniti, where the manual discusses the low gears...when to use them (going up/down hill? Into a strong wind? Or only pulling a trailer?) My teen kids ask about that and I just don't know much.

getting their needle up - again and again

Nicely put.

[katana_one]

So what's the point of a tachometer on a car without a stick shift?

So they can use the same dashboard parts for standards and automatics.

[LifeinAsia]

Basic troubleshooting. If your car normally idles at 1000 RPM and one day it's idling at 2000 RPM, then you know right away something's up. If you have the radio blasting, you might not ever notice it until the engine blows up. (Then, hopefully, you's notice! :) )

[Automan Empire]

You are somewhat right that it is pointless. Try flooring the car in neutral, you'll find the engine management will not allow redline to be exceeded. Even without manual shifting, some cars have shifting "modes" like sport and economy. Also, when you use those mysterious positions other than drive, the engine may be winding out without really being able to hear it, as these high-end cars are sooooo well refined as far as sound insulation. Manual trans or not, there are a certain percentage of us who are happy to have a tach, but most drivers get confused when you try to explain that or the gears, and they seldom bother to read the manual anyway.

Use the position next to D (3 or 2 usually) if you are pulling up a long grade and don't want to lug the engine or have it keep upshifting as you move the gas slightly. Also use it when going down a long grade so you don't ride the brakes. Position 1 is only useful in low-speed, steep grade situations, unless you are such a gearhead that you manually downshift your auto trans when stopping. Also if you are in moderate traffic that is speeding up and slowing down (30-45mph range, not stop-and-go), holding it in a lower gear helps you control the speed without having to keep tapping the brake.
HIH
-Automan

[digitalghost]

Why is there a permanent press setting on irons? Why do two-way switches need to have both on and off embossed on them?

[monkeythumpa]

When I am driving an automatic and I am revving high in its operating range I can give it a pulse to get it to upshift and save gas. Also if you are towing you can make sure it operating normally. Cars suck ride a motorcycle.

[Bewenched]

Many of todays newer automatics have an option to shift the car although most dont allow you to seriously red-line it.

I have custom programming in my automatic for drag racing and having the tachometer helps me quite a bit.

[engine]

Yep, the tacho helps indicate when downshifting may not be a good idea. It also helps to know where the engine's power band operates. Although, probably, a lot of people hardly look at the rev counter.

I can slip my car into sports mode and use a sequential shift. That's when the rev counter is useful. Although, as soon as you hit the 7k rpm redline the limiter helps stop the expense of an engine blow-up.

[lawman]

Nowadays even cars with manual trannys have rev limiters.