# Do we need tachometers in our autos? **URL:** \ **Category:** In My Humble Opinion\ **Created:** [July 6, 2000, 10:44pm UTC](https://boards.straightdope.com/t/do-we-need-tachometers-in-our-autos/24794 "2000-07-06T22:44:02Z")\ **Posts on this page:** 10\ **Page:** 2
**Author:** ![occ](https://avatars.discourse-cdn.com/v4/letter/o/8c91f0/32.png) [@occ](https://boards.straightdope.com/u/occ)\ **Post date:** [July 9, 2000, 11:49pm UTC](https://boards.straightdope.com/t/do-we-need-tachometers-in-our-autos/24794/21 "2000-07-09T23:49:22Z")
> [@](#): > > \*Originally posted by single files \* > \*\*I had an automatic Taurus … no tach. The transmission quit getting fifth gear, which I might have picked up on with a tach. Instead, I kept running 85 mph with the radio blasting till it burned up. I don’t have that car anymore. Now I drive my old Jeep. Gauges for everything. I don’t need the tach to shift, and I always know what gear I’ve put myself in, but I like it anyway. \*\* Your automatic Taurus had five speeds? ---
**Author:** ![aha](https://avatars.discourse-cdn.com/v4/letter/a/eada6e/32.png) [@aha](https://boards.straightdope.com/u/aha)\ **Post date:** [July 9, 2000, 11:53pm UTC](https://boards.straightdope.com/t/do-we-need-tachometers-in-our-autos/24794/22 "2000-07-09T23:53:19Z")
E.) engine temperature ? Just a guess ---
**Author:** ![Coldfire](https://avatars.discourse-cdn.com/v4/letter/c/a587f6/32.png) [@Coldfire](https://boards.straightdope.com/u/Coldfire)\ **Post date:** [July 10, 2000, 12:02am UTC](https://boards.straightdope.com/t/do-we-need-tachometers-in-our-autos/24794/23 "2000-07-10T00:02:09Z")
My guess is engine temp as well. When you rev too much, there’s usually a limiter anyway. ---
**Author:** ![aha](https://avatars.discourse-cdn.com/v4/letter/a/eada6e/32.png) [@aha](https://boards.straightdope.com/u/aha)\ **Post date:** [July 10, 2000, 2:25am UTC](https://boards.straightdope.com/t/do-we-need-tachometers-in-our-autos/24794/24 "2000-07-10T02:25:06Z")
> [@](#): > > \*Originally posted by Coldfire \* > \*\* When you rev too much, there’s usually a limiter anyway. \*\* Coldy here in the states we call that a “governor.” Keeps the engine from over reving. ---
**Author:** ![Gunslinger](https://avatars.discourse-cdn.com/v4/letter/g/4491bb/32.png) [@Gunslinger](https://boards.straightdope.com/u/Gunslinger)\ **Post date:** [July 10, 2000, 2:53am UTC](https://boards.straightdope.com/t/do-we-need-tachometers-in-our-autos/24794/25 "2000-07-10T02:53:09Z")
> [@](#): > > \*Originally posted by Coldfire \* > \*\*My guess is engine temp as well. When you rev too much, there’s usually a limiter anyway. \*\* Nope. “C”-- Overheating, speed, and electrical power quickly become irrelevent with no oil. ---
**Author:** ![Coldfire](https://avatars.discourse-cdn.com/v4/letter/c/a587f6/32.png) [@Coldfire](https://boards.straightdope.com/u/Coldfire)\ **Post date:** [July 10, 2000, 8:47am UTC](https://boards.straightdope.com/t/do-we-need-tachometers-in-our-autos/24794/26 "2000-07-10T08:47:18Z")
I beg to differ! I once drove my then 8 year old Peugeot 205 (1.4 liter 4 cylinder, reliable as hell itself) for over 100 kilometers with no oil whatsoever. I didn’t know that at the time, I only thought it was losing cooling fluid, but when I arrived at the garage, they told me it was completely out of oil as well. I kept it under 110 km/h on the motorway, so the revs must have been some 3000 rpm’s in fifth. It heated up a bit more then normal, but it did not overheat. After a checkup, the engine showed no damage whatsoever and I drove it for many more happy km’s. So I guess it can be done, although it is quite logical that a 300 horse power Jeep is more likely to overheat without oil than a 75 horse power li’l Peugeot. ---
**Author:** ![Sangria](https://avatars.discourse-cdn.com/v4/letter/s/87869e/32.png) [@Sangria](https://boards.straightdope.com/u/Sangria)\ **Post date:** [July 11, 2000, 4:46am UTC](https://boards.straightdope.com/t/do-we-need-tachometers-in-our-autos/24794/27 "2000-07-11T04:46:37Z")
I used to think all the guages were irrelevant, but now I don’t like driving a car with just a light instead of a temperature meter. I’ve been stuck overheated in the desert once too often. ---
**Author:** ![jayron\_32](https://avatars.discourse-cdn.com/v4/letter/j/41988e/32.png) [@jayron\_32](https://boards.straightdope.com/u/jayron_32)\ **Post date:** [July 11, 2000, 4:58am UTC](https://boards.straightdope.com/t/do-we-need-tachometers-in-our-autos/24794/28 "2000-07-11T04:58:18Z")
I drive stick, and no car I have ever owned has had a tach. You learn to shift by the “feel” when the car doesn’t respond the way it should to more gas, you shift. It’s that simple. I taught my wife to drive stick without a tach, and she has no problem finding the optimal shift points. It’s not that hard to do. You only really need two meters in a car: speed and gas. Anything else is just fancy-schmancy extras built for guys who believe even their penises should have pressure guages. ---
**Author:** ![voltaire](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/voltaire/32/313_2.png) [@voltaire](https://boards.straightdope.com/u/voltaire)\ **Post date:** [July 12, 2000, 3:41pm UTC](https://boards.straightdope.com/t/do-we-need-tachometers-in-our-autos/24794/29 "2000-07-12T15:41:10Z")
> [@](#): > > You only really need two meters in a car: speed and gas. Anything else is just fancy-schmancy extras built for guys who believe even their penises should have pressure > guages. Ummm, not quite. Tachs, even in automatics, are important to be able to monitor your idle speed. The idle either going up or down (after warm-up) can indicate problems. Also, if you notice the idle fluctuating (going up and down) it can also be indicative of problems. Another use for tachs, other then for shifting, is for monitoring how hard you’re dogging the engine. The speedometer tells you how fast your going when your hauling ass, but a tach will tell you exactly how much strain you’re putting on the engine. Without a tach, you could very well be hauling ass down the highway with the radio blaring on a long road trip and have the engine running at excessive RPM’s over a long period of time. Redlining the engine a little from time to time isn’t that bad, but going on a long trip on or near redline the whole time WILL kill your engine. ---
**Author:** ![Gunslinger](https://avatars.discourse-cdn.com/v4/letter/g/4491bb/32.png) [@Gunslinger](https://boards.straightdope.com/u/Gunslinger)\ **Post date:** [July 13, 2000, 5:04am UTC](https://boards.straightdope.com/t/do-we-need-tachometers-in-our-autos/24794/30 "2000-07-13T05:04:49Z")
> [@](#): > > \*\* > You only really need two meters in a car: speed and gas. Anything else is just fancy-schmancy extras built for guys who believe even their penises should have pressure > guages. > > * * * > > Ummm, not quite. Tachs, even in automatics, are important to be able to monitor your idle speed. The idle either going up or down (after warm-up) can indicate problems. Also, if you notice the idle fluctuating (going up and down) it can also be indicative of problems \*\* And you can tell you speed with a tach, too, if you know your gears. So all you really need are: tach, fuel, an oil pressure(not _absolutely_ necessary, but definately nice to have (see below) > [@](#): > > \*Originally posted by Coldfire \* > \*\*I beg to differ! I once drove my then 8 year old Peugeot 205 (1.4 liter 4 cylinder, reliable as hell itself) for over 100 kilometers with no oil whatsoever. \ > > So I guess it can be done, although it is quite logical that a 300 horse power Jeep is more likely to overheat without oil than a 75 horse power li’l Peugeot. \*\* More spalling the bearings, grinding the cam down and pulling off piston rings than overheating. [Previous page](https://boards.straightdope.com/t/do-we-need-tachometers-in-our-autos/24794.md?page=1)