Perhaps since cars are so quiet these days the “tach” can serve the purpose of telling you your engine is running (or not running).
You’re not the center of the universe, you know.
There are A LOT of other people who own the same van you do, and they do drive on the freeway, and they do tow trailers, and they do check their rpms, so for them, the gauge makes perfect sense.
Just because you don’t have a use for a tool, doesn’t mean that the tool shouldn’t exist.
BC.
indy–When you post a message in a few months, along the lines of…“My tachometer is registering high RPMs, but the vehicle is barely moving”, that information will help us to diagnose your transmission problem.
;-))
i second that, i had a 1998 saturn and you couldn’t tell it was on without looking at that gauge.
It’s not all that useful on a car without a manual transmission, but it’s a ‘toy’, one of the features that people have come to expect on a well-equipped vehicle. In my opinion, the more info the better, but some would rather just have idiot lights and no actual info unless something is broken. Two different schools of thought I guess–people who like transportation and don’t care about much else, and people who are more ‘gearheads’ at heart and actually enjoy driving a decent automobile.
I haven’t owned a car in a long time that didn’t have a tachometer and none of them were stick shifts. A friend had a base model Kia that didn’t have a tach or even a shift light, but had a manual. Silly I thought. But it’s not like people watch the tach to tell when to shift—at least most don’t. If you can’t tell what your engine is doing by the feel and sound, a tach is likely going to be meaningless to you anyway. But they are handy to tell if the engine is surging, overdrive isn’t working right, or to learn the right shift points for your car.
Even on cars with manual transmissions, in order to know wnen to shift, the driver would have to memorize the engine’s torque/horspower verses rpm curves for every concievable throttle opening.
The horsepower/torque graphs most people are familiar with were measured at full throtttle and are only relevent for full throttle operation, as in a racing situation.
Here’s an actual dyno chart where an engine was measured at different throttle openings. It beautifully illustrates what I’m talking about.
![](http://pic.photobucket.com/bwe.png)
A manifold vacuum gauge is actually a more useful instrument for telling you when your engine wants to be shifted.
Well then google RPM gauge and most of the results mention that it is a tachometer, And heaven forbid the OP just read the owners manual it is in there to.
it tells you what it is, but really doesn’t tell you the reason. I mean ITS A MINI VAN, I find it hard to believe that people who chose mini vans’ are doing so because of that. I just was wondering why people thought it was there and was wondering what could have been put in it’s place that actually might have been of more help.
When my car was at the body shop and I drove an automatic rental for a few days, I was annoyed with the automatic because I was hopping constantly between gas and brake. On the 2nd day, I was so fed up with the lack of engine braking in D I decided to drive in the lowest gear possible when traffic slows. I know slamming the transmission into L on the freeway was not healthy for it, but it wasn’t my car and I hated what it was doing. Driving in L was when I used the tachometer to determine when to upshift before I was bouncing off of the limiter.
Mine makes me feel young again.
Seriously, while it’s actually there to add a bit of “pizzazz” to the car with little cost, it does serve a function. Some years back my mom called saying that after my sister had borrowed her car it began making a strange noise on teh highway. I took it for a drive, and the tach told me where the noise was coming from…my sister had (probably inadvertantly) released the OD (overdrive) button on the shifter, leaving the car running in 3rd on the highway rather than the overdrive gear. I pushed the button back in and the car sounded normal again. It also allowed me to show her that the engine had been running in a “safe” zone and the car was fine. My mom was thrilled.
In short, the manufacturers put them in for sales reasons, but they can be useful in knowing what the car is doing and in troubleshooting problems.
To be honest, BLE, I don’t think either is truely helpful to the average driver in the average street-legal car in determing when to shift. The power curve on stock vehicles levels out before redline is achieved. The ability of the mechanicals to go fast exceeds the ability of the engine to breath and continue to increase fuel flow at those RPMs. That, really, is when people shift.
Performance vehicles are excepted. High performance engines will sometimes not level off like an average sedan until past redline, and that’s where one can get into trouble, although modern engines are protected by the ECU from over-reving.
Do people actually drive at quarter throttle?
(Sorry, just joking. Couldn’t resist.)
Anyone who drive a manual should have the good sense to downshift when the car is not responding to the throttle as desired. There’s no need to look at the vacuum gauge for that. However, if one cares about driving smoothly and reducing clutch wear, the tachometer is extremely useful in that regard
Given enough experience with one particular vehicle, the driver can do a match rev without looking at the tach. But it is not precise.
Actually, when I’m talking about shifting when the power curve levels off, I’m talking about upshifting.
Driving a manual is 2% technical knowledge and 98% feel combined with technique. It helps to understand how the thing works, especially when learning, but “feel” is the essential ingredient.
In most of 40 years driving manuals I’ve only worn out one clutch…and that one at 295,000 miles after having taught two kids on it. And most of the vehicles didn’t have tachs. Actually, the one that did wear out didn’t begin to slip until my daughter had been driving it daily for a few years, but I’ll assume it had spent its life anyway. I’ll take the blame. At 295K, I can’t complain.
I understand vacuum gages and tachs, but I don’t know that they’re really necessary for daily driving. It’s really just preference, I guess.
I like manual transmissions and prefer to have a tach. Even after 20+ years as a professional musician and piano tuner, I do not have perfect pitch to hear the RPM accurately, and the tach helps me get to know an unfamiliar (manual) car better. After driving a car for awhile, I don’t need it much, but it still is a help.
If driving an auto, I rarely look at the tach, but sometimes it is nice to know just how far I’m pushing it.
I supposed you have to get used to an automatic if you always drive a manual, and vice versa of course. I know how to drive a stick, but I have an automatic, and I’m used to the car’s rate of deceleration such that I rarely have to do as you describe. (and I don’t drive like a grandma with 90 car-lengths between me and the car in front)
I am with those who believe a tachometer is a tool which an owner can choose to use or not to use. A tool which a person may know how to use or not know how to use.
There are plenty of people who don’t even use the tool that gives you a light which means Stop - the - car - immediately - the - engine - is - out - of - oil.
I have had two mini-vans with tachometers. I learned to observe the tach as part of my normal dash scan. I know about what rpm I should have at a given speed. On the old Dodge, which was more of a Ford (Fix Or Repair Daily) if the rpm was higher than it should be, there was always a problem which unlike some highly talented mechanics we ordinary mortals would not otherwise notice.
This Sienna needs few repairs. When I got it, rpm’s at 70 mph was high, maybe like 2850. As it broke in, it gradually dropped down. By memory (there are few places I can drive 70 here in rural Mexico) it is now down closer to 2600. When I changed to synthetic ATF, it dropped a tiny bit, not even 50 rpm, but it was visible to an old meter reader.
Also, the tach has helped with idle control actuator problems, which I had about once a year with Dodge parts, and only once in 170,000 miles with Toyota parts. Even wobbling around a tiny bit near its normal idle speed indicates problems are on the horizon.
The fact that many people don’t look at it does not reduce its value to those who do.
Back in the late 1950’s and early 1960’s I rode an intercity bus back and forth to college where the tachometer served as the speedometer. There was a scale for each gear (the transmission was a 5 speed) that gave the miles per hour. There was no separate speedometer. The bus was probably manufactured in the late 1940’s or early 1950’s. It had a Flxible (yes, the spelling is correct) body on a GMC chassis.
If your vehicle is just an “appliance” no tach is needed.I won’t own a vehicle without one.
Monitoring the engine can save gas,keep the engine in the most efficient power band range,and also monitor if the engine is running and how smooth.
I do agree with caddyman when it comes to the clueless vehicle owner. Its just another distraction like a temperature gauge, gas gauge and oil pressure gauge, that just fill a hole in the dash and is something else to worry about.
Okay but how do you 'know" how to read it. I have one and will glance at it at times, but how do I know it is where it should be at certain speeds. Is there a book on this?
Mountainbike, most automatics with overdrive that I know about, works just the opposite to what you said in your post. Push the button in to lock out the overdrive and let the button back out to let the overdrive operate. Also when you restart a car the overdrive will be opporative.