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7 votes
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How fast is one RPM on average?

This is a math-only question, and no one has explained the formulas. Also I like the idea of this simple question having multiple answers so... RPM is Revolutions Per Minute, but we want a time in ...
JPhi1618's user avatar
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6 votes
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Why can a motorcycle rev higher than a car, in spite of both reaching the same speed?

One important factor is the mass of the components. Smaller, lighter components and shorter strokes allow higher RPMs. Given equal RPMs, an engine with a bigger stroke will put higher stresses on the ...
barbecue's user avatar
  • 1,597
5 votes

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

Paulster2 is right, varying the injection timing with respect to the engine crank angle timing is the main way to control the combustion process in a diesel engine. In a conventional gasoline engine (...
Renlin's user avatar
  • 51
5 votes
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Will a manual vehicle stall at low RPM without being on the accelerator?

In my experience, most manual cars can move along in 1st gear at idle – on a flat(ish) surface. I've only tried this in the process of teaching people to drive a manual. My hunch is that in 2nd and ...
dlu's user avatar
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5 votes
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Volvo XC90 8V AWD car speed to piston revolution speed ratio changed after repair

Yes, I'd take it back to the shop to see if there is something they missed. While 300 rpm at 60mph is not a huge difference, to me this is about the difference of when a lock up torque converter isn't ...
Pᴀᴜʟsᴛᴇʀ2's user avatar
5 votes

2001 Ford Explorer High Idle

The P1506 code is an idle air control overspeed error. From autocodes.com: The P1506 code means that the engine idle is out of factory specification. Sometimes the Idle Air Control (IAC) may have ...
anonymous2's user avatar
  • 5,235
5 votes
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Does the flywheel really complete 33 revolutions per second when the engine is set to 2,000 RPM?

yes, that's correct. Now, rotating a flywheel at 2000 rpm is not a big deal: it's well within the capabilities of the material, as long as the flywheel is well-balanced. Other elements in the engine ...
Hobbes's user avatar
  • 4,412
5 votes

Jeep Patriot RPM Gauge bounces / not right

I don't know for sure, but would bet the gauge itself is bad. One way you could check this is by putting an OBDII reader onto the port and check live data from the ECU to see if it matches what's ...
Pᴀᴜʟsᴛᴇʀ2's user avatar
4 votes

Will a manual vehicle stall at low RPM without being on the accelerator?

Obviously in a manual car with the clutch engaged there is a direct connection between the wheels and the engine. Also while switched on most engines have an idle setting designed to keep them running ...
Chris Johns's user avatar
  • 1,586
3 votes
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Performance Issue - 2009 Infinity FX50

first why is it revving at 4k to do 120kmph? This is concerning and could mean the car is in some sort of limp mode or you are in the wrong gear. most likely its wrong gear since there is no check ...
Cc Dd's user avatar
  • 2,879
3 votes

fuel consumption - gear - rpm relation

It depends on how far you need the throttle open in each of your described situations to maintain the 6000 RPM. If the throttle is in the same position in both situations, then the same amount of ...
HandyHowie's user avatar
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3 votes

High RPM's at highway speeds

Based on your replies to comments, here's the diagnosis: Most likely, you tripped the overdrive. Most modern cars have this, and most people don't know about it. Look at 2 things: look at your ...
tlhIngan's user avatar
  • 12.2k
3 votes

2001 Ford Explorer High Idle

This condition can be caused by a vacuum leak. Use an automotive safe spray such as carb cleaner to try to find the leak, both visually, and by noting changes in the idle speed depending where you ...
kmarsh's user avatar
  • 2,159
3 votes

dirt bike low rpm lugging

Your oil pressure is lower I think the big issue with lugging is a considerably lower oil pressure along with high load. You don't want your connecting rod breaking the hydrodynamic lubrication ...
DucatiKiller's user avatar
  • 32.9k
3 votes

Torque reduces gradually after certain RPM

Torque is a rotational force. It is a measurement of how hard it is applying force that causes the crankshaft to rotate. Torque is not a very good unit of measurement for an engine because it does not ...
doug65536's user avatar
  • 261
3 votes

How fast is one RPM on average?

In a car rpm are very often shown. From experience you might know that for a normal car it varies between 1000 and 3000 rpm for normal use cases. 3000 rpm = 50 rotations per second = 1 rotation per 0....
Chris Maes's user avatar
3 votes

RPM Flucating when ac is on

I suspect you are referring to the apparent dip in idle speed when switching the A/C on and subsequent correction. What actually happens is that the A/C compressor clutch kicks in so that the ...
Steve Matthews's user avatar
3 votes

Why my car RPM goes up while Parked

This does not mean there is a problem. When you take it out of gear (R or D) and put it into park you change the demand on the engine from the gearbox and the fluid flywheel, this allows the engine ...
Solar Mike's user avatar
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3 votes
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Increasing engine rpm when AC on

When the A/C is switched on the engine ecu increases the idle speed by a few hundred rpm to make sure the engine does not stall and keep a "smooth" idle. This is normal. Also, the A/C system can ...
Solar Mike's user avatar
  • 34.6k
3 votes

Does the flywheel really complete 33 revolutions per second when the engine is set to 2,000 RPM?

RPM stands for ROTATIONS PER MINUTE. Converting to RPS (rotations per second) means you divide RPM by 60 (because there are 60 seconds in a minute) and you get RPS. So your question on 2000 RPM ...
jwh20's user avatar
  • 12.1k
3 votes

Is it normal that the RPM jumps to 800 from 600 when I switch on the AC in my Toyota yaris automatic 2015

Yes, it is normal. The ac requires some 10 to 12 bhp from the engine and the ecu is allowing for that energy demand by increasing the idle speed so it will not stall.
Solar Mike's user avatar
  • 34.6k
3 votes

Possible misfire or another problem, car looses power

You're not describing a misfire. The weird driving, power and RPM symptoms that you mentioned can all be explained by a fault in the accelerator pedal position sensor or the wiring and connectors ...
MTA's user avatar
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3 votes
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RPMs at 0 while driving. Can't re-start car without 45 min cooldown but then runs normal for 30 min

It is most likely a faulty crankshaft position sensor. This sensor tracks your engine r.p.m. That's why your tach goes to 0. On many cars when they fail while running the computer remembers where the ...
Jupiter's user avatar
  • 3,330
2 votes

Minimum RPM at idle speed

A NASA-Crawler-Transporter engine seems to idle at 400 rpm although it may not fit your garage. https://en.wikipedia.org/wiki/Crawler-transporter http://www.cnrphotos.com/gallery2/main.php?g2_itemId=...
KennyG's user avatar
  • 21
2 votes

Truck problem need some help

It sounds to me from your description, the transmission is going out of your truck. Either it lost line pressure or the clutches just weren't holding. The constant pressure of running the truck via ...
Pᴀᴜʟsᴛᴇʀ2's user avatar
2 votes

Why Tachometer shows idle RPM range instantly when closing the throttle and clutching

From what I can understand, assuming the OP is curious as to why instantly pulling on the clutch the RPM goes down in a swift moment and not gradually? Simple: Inertia The reason for this is that ...
Shobin P's user avatar
  • 8,936
2 votes

Why Tachometer shows idle RPM range instantly when closing the throttle and clutching

It's a bit hard to understand your question, but I'm assuming you're asking about the RPM jumping between idle and back toward 5,000 when you disengage/engage the clutch. When you start the throttle ...
raydowe's user avatar
  • 3,012
2 votes
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Does free revving diesel engine near redline for 2-3 seconds harm it

You are being overly paranoid. While this action isn't good for the engine, it won't harm it. There's a redline for a reason, that being an engine speed you should not exceed. You weren't exceeding ...
Pᴀᴜʟsᴛᴇʀ2's user avatar
2 votes

How can I rev a "drive by wire" car from under the hood?

Have a friend / relative help you. Only suggested as "use a brick etc" is not safe and you have to make sure you get the electronics correct otherwise you can permanently damage the ecu.
Solar Mike's user avatar
  • 34.6k
2 votes

Do rev limiters like the Bee-R Rev Limiter cause any wear on engine components?

I'll admit that I don't have experience with these rev limiters, and I'm drawing conclusions from other experience. That said... On cars with catalytic converters in the exhaust, when the engine ...
JPhi1618's user avatar
  • 13.2k

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