RPM = number of Revolutions Per Minute. Most commonly an acronym for engine crankshaft speed.

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Is it harmful to drive at high rpms

Does driving at high RPMs (3000-3500) in a manual transmission car cause any extra wear and tear to any mechanical parts? It obviously hurts gas mileage, but does it hurt anything else?
12
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4answers
31k views

Engine power specification at different rpm?

Car companies advertise power of an engine at different rpms. Car 1: 80 PS at 6000 rpm Car 2: 85 PS at 6500 rpm What does the power at different rpm mean? Does it mean Car 1 has better power than ...
12
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1answer
204 views

How does the tachometer on my dashboard actually work?

Recently, I asked a question about the speedometer, how it works and how accurate it is. But that got me thinking... how does the rest of the dash actually work? I understand that the RPM measurement ...
11
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3answers
6k views

Why does diesel engine have redline much lower than petrol engine redline?

why do diesel cars redline at around 4500 rpm whereas petrol ones around 6500 -8000 rpm? Does this have something to do with the compression ratio?
11
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1answer
234 views

What mechanical revolution is measured in “RPM”?

I do realize that it stands for revolutions per minute, but what are the revolving pieces that are measured? Assuming it is the crankshaft, is RPM calculated by the crank shaft sensor, or by some ...
9
votes
3answers
2k views

Why does my RPM drop when sitting idle at traffic lights?

While I'm sitting idle at traffic lights I put the car into neutral. The engine stays idling at about 1000 RPM. However every now and then it drops down to about 500 RPM and then quickly back up to ...
7
votes
4answers
727 views

2015 Honda Fit iVTEC - Shifted into 2nd Gear at Highway Speeds

I was just driving on the highway and went to pass someone uphill, so I went to put it into 4th gear (from 5th or 6th). I somehow made the mistake of putting it into 2nd and the engine screamed and ...
7
votes
1answer
2k views

Why doesn't my rev limiter bounce?

I have a BMW 630i Steptronic from 2007. If I floor the pedal in neutral the RPM is of course limited, but it doesn't "bounce" like regular rev limiters. Instead it keeps a constant and "clean" RPM. ...
7
votes
2answers
338 views

Optimal RPM range for manual transmission

Are there optimal RPM ranges for different vehicles? I've been told it's better for the engine to drive at slightly higher RPMs (e.g. 2500-3000 for my Tacoma) than low (1000-1500). I understand a ...
7
votes
1answer
5k views

Engine revs up when braking

Background: 2012 Honda Civic EX, 5-speed automatic, with no mods except a non-stock tire (ran over a large bolt). I keep it maintained per the manufacturer's manual and always see the Honda dealership ...
7
votes
1answer
127 views

Short shifting after full throttle

Other than normal wear and tear, are there any detrimental effects or added harm done to the engine by going full throttle in 1st and/or 2nd gear, then shifting up well before redline (say 4k rpm on a ...
6
votes
2answers
639 views

Checking the motor's RPM without an in-dash tach

I'm going to be doing a carb rebuild this weekend on an 84 Ranger. The truck doesn't have a tach, but I'll be needing to read the RPMs to properly adjust the carb once its rebuilt. Is there a way of ...
6
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3answers
7k views

Is it bad to drive slow at low rpms in 4th or 5th gear? Do you get better gas mileage?

Obviously running your engine at too high an RPM for too long isn't good. But what about running it too low? not so low that it stalls or lugs, but within around 1,000 RPM? Would you get better ...
6
votes
3answers
4k views

Minimum RPM at idle speed

Looking at wikipedia, For a passenger-car engine, idle speed is customarily between 600 rpm and 1,000 rpm. For buses and trucks it is approximately 540 rpm. In case of many single-cylinder ...
6
votes
3answers
3k views

What determines when an automatic transmission shifts?

I'm working on developing an automatic bicycle (mostly microcontroller based) and I'd presume I'd be shifting in a similar way to a car. So my question is, what factors does the transmission take into ...
6
votes
1answer
229 views

Can diesel engine be harmed as easily as gasoline engine by over-revving?

There is an excellent Q&A about why diesel engines have lower redline RPMs (about 4500 RPM) than gasoline engines (about 6500 RPM). The reason is related to the combustion of diesel fuel. However,...
6
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4answers
2k views

Why does the power output peak and then drop as engine speed increases?

I have been looking at the power bands for my car (2000 Opel Agila 1.2) recently, as I want to work out when it is best to change gear and stuff, as I have no life! This is the approximate graph I ...
6
votes
1answer
899 views

Engine revs to 4000 RPM without pressing gas pedal

I tried to start my car today but something strange keeps on happening. It turns on just fine, but once the engine is operating it starts revving to 4000 RPM even though I am not pressing the gas ...
5
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4answers
299 views

Can 100% calculated load be reached in neutral?

While searching for information about how is engine load calculated I came across this question which contains an equation for the ECU load calculations. As I understand it under fixed atmospheric ...
5
votes
4answers
2k views

RPM bouncing when in idle, especially when AC in switched on

I have a diesel common-rail 1.5l engined car. Lately I am facing an issue where the RPM needle is bouncing in the tachometer when the car is idling. The normal idling RPM is around 820. When idling, I ...
5
votes
3answers
5k views

Does accelerating faster worsen fuel efficiency?

I've often heard that accelerating harder makes for bad fuel efficiency, but have yet to be given a sound explanation of why. Naturally this makes me question this advice. Now obviously when you ...
5
votes
1answer
3k views

RPM fluctuation when maintaining speed in high gear

I recently got an oil change on my 2008 Audi A4 Quattro. Now I notice that when I am cruising in 3rd, 4th, or 5th gear (but not 6th), and I am at about 1200 RPM, the tachometer is not stable. The ...
5
votes
1answer
1k views

Suzuki GSR600 low idle revs and unstable

Just a week ago I noticed in my motorbike unstable rpm, +-300rpm. But today I found that the idle rpm are below 1000rpm, at some points around 500rpm (Normally is 1500rpm). I'm due for the annual ...
5
votes
1answer
2k views

Automatic: revs dropping then stalling when stopped at lights

Kia Sedona 2012 automatic. Drove 180 miles on a full tank of fuel without any problems. Started the car the next day and it didn't start cleanly but did eventually. Was waiting on the drive with the ...
5
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0answers
123 views

2012 KTM Duke 200 - Low acceleration in low rpm [closed]

Recently my bike (KTM Duke 200) is suffocating to deliver enough power between 2000-3000 RPM. I took the bike to a service station and they told me that its an engine problem, low compression and ...
4
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1answer
1k views

Does using the entire rev range of a car damage it?

On my standard 2000 1.2 Opel Agila, I often have to get to about 5000RPM to join a fast road on a steep (1 in 10) hill, as it is gutless on hills. I have to do this almost every day, and I have ...
4
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4answers
3k views

RPM jumps up & back down at 40mph

My question is for a 2006 Dodge Magnum, 2.7 liter engine. Just over the past month or so, I noticed when I'm cruisung, just coming from a dead stop, when I'm at 40 mph my car kinda feels like it ...
4
votes
1answer
36 views

2004 Honda Civic ex rpm spike and lose acceleration.

I have a 2004 Honda Civic. Sometimes when pushing on the gas at a slow pace around town the rpm jump up and it's difficult to accelerate. Once doing 60 it doesn't appear to do it. Does the ...
3
votes
5answers
16k views

What modifications need to be made to an engine to enable higher safe RPMs?

I first had this question while playing a racing game - it was a touring race with BMW 320i's, and I noticed that I could rev up to 8,500 RPM before shifting gears. Now my car (an older 320i), ...
3
votes
1answer
49 views

No Damage/ top fuel economy rpm shift point

I am driving my Brother's 2002 4.0L gas ford ranger truck 5 speed manual transmission. What RPM should I shift at for best fuel economy. Also what RPM should I not let the truck go below while driving ...
3
votes
3answers
349 views

Should fuel pump noise be changing according to electrical load and RPM?

One thing that bugs me about my car is that the fuel pump noise is fairly inconsistent. Turning on the lights, aircon, defroster, etc. lowers the fuel pump speed and gives a lower pitched noise. It ...
3
votes
1answer
234 views

1980 Suzuki GS 850 trouble at high rpms

I have a 1980 Suzuki GS 850 and I am having a problem where the rpms spike when I really get on the throttle. If I slowly accelerate there is no problem, everything runs smoothly. When I'm on the ...
3
votes
2answers
328 views

Do all engines typically support the installation of a crankshaft position sensor

I have recently purchased an 800cc dune buggy but unfortunately it doesn't come with a RPM sensor so I have been looking at my options in terms of installing one. In the process I have found that the ...
3
votes
1answer
2k views

Clearing a P0507 on a Dodge Stratus

My 06 Dodge Stratus (4 cylender) is showing a P0507 off of the Torque app. My idle is sitting at near 1100 rpm versus the standard 800. I read up on the code and started looking for a vaccum leak ...
3
votes
0answers
37 views

High acceleration and dieing when brake is pressed

I have a 2003 Ford Taurus its been good only needed a new starter and new brakes besides the standard changes in the 6-7 yrs since i got it. Then 7 Jan 2016 hit. Since then it has been in the shop 5 ...
3
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0answers
45 views

Is there a rev matching device?

I understand that rev matching is acquired skill by practicing and driving more. I'd like to know if there was a device you could attach to your car that would detect and notify you if engine rev is ...
3
votes
0answers
336 views

1992 Mitsubishi 3000gt sl. no power and won't go above 2k rpm

I bought an automatic 1992 Mitsubishi 3000gt sl 2 days ago. I got it cheap knowing it would have problems, and that's why I'm here. When I put it in drive and slam on the gas the car just simply ...
2
votes
3answers
599 views

How do I reduce engine idling rpm without stalling it?

Considering idling losses are present in every engine, reducing the idling rpm might be providing significant savings. But, as I noticed on my bike, the chances of engine stalling increases with ...
2
votes
2answers
1k views

Is alternator rating at pulley rpm or engine rpm?

I just got a new alternator for my jeep that says 160amps at 2k rpm. Is this rating for the pulley rpm on the alternator - or is it the rpm of the engine? Also, if the pulley is spinning slower than ...
2
votes
1answer
205 views

Installing an RPM meter

I need to install one in my car, as it doesn't have one, what modifications do I have to do? Edit: My car is: Suzuki swift 1996 But I would like the answer to be generic, as to what to look for if ...
2
votes
2answers
532 views

cause of Rough / fluctuating RPMs in low RPMs

It's not dying (hasn't yet) but when the car is idling or in low RPMs the car (Mazda Protege 5 2002) is fluctuating in RPMs. Also, the last start was rough. I've had issues with air intake before ...
2
votes
2answers
51 views

Torque reduces gradually after certain RPM

I just know the plain definition of the Torque. Torque: Definied as the force applied to the object to rotate on its axis The torque will be increased only upto a certain RPM and it will gradually ...
2
votes
1answer
147 views

How do I know if car ECU has a REV Limiter?

My car is fairly new and not that well documented online (it's a new model from late 2015) For safety, how do I know if my car has a REV-limiter without testing it and letting it go up the red line ...
2
votes
1answer
63 views

What is rev matching, and how do you do it correctly? [closed]

I understand that not doing this properly will destroy your transmission/synchros. What's the proper way to do it? I think I'm doing it right, but I've found most people's descriptions to be vague and ...
2
votes
1answer
2k views

Subaru Outback 1998 high idle rpms and CEL P0507

My wife's 1998 Subaru Outback threw a check engine light the other day, and when I read the code, P0507, it corresponded to a problem I'd noticed for a while: high idle rpms. The problem is most ...
2
votes
1answer
39 views

Honda City vTec Slow Start

I have a Honda City 2005 vTec Manual Transmission Car, which will be due for servicing in another 1000KM. I am not well used to driving manual car and I face a lot of traffic everyday going and ...
2
votes
1answer
670 views

2004 LEXUS GX470

I have a 2004 Lexus GX470. I am having this problem where as I accelerate, my RPM goes up to like 5/6 and my speed is not going up. If I back off the pedal and try again it sometimes will accelerate....
2
votes
1answer
11k views

Why does my engine rev up when I put it in park?

I've seen questions about engines revving when braking and when idling, but my engine revs way up (and stays up) whenever it's in park--whether on startup or shifting to park. It doesn't rev unusually ...
2
votes
4answers
4k views

Is starting idle RPM always lower in colder temperatures?

I've noticed that my 2008 Jetta 2.5L 5W40 generally starts up with an idle RPM of at most 1.2K RPM around the freezing temperature (say when the temp sensor reads 33°F), or even at just about 1K ...
2
votes
0answers
29 views

Increase of RPM meter after reaching my destination [closed]

I'm driving Camry 2001 4 cylinder, automatic gear. Just recently I noticed that after reaching my destination, when I put gear to P, I find the RPM meter increase to reach slightly lower than 2, ...