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7
votes
3answers
1k views

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?
6
votes
1answer
767 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 ...
4
votes
3answers
827 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 ...
4
votes
1answer
152 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 ...
4
votes
1answer
198 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 ...
3
votes
3answers
297 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 ...
3
votes
1answer
116 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
137 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 ...
2
votes
4answers
568 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), ...
2
votes
2answers
474 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
114 views

Tachometer doesnt show correct RPM sometimes

On my Honda CBF 150cc , the Tachometer shows RPM correctly when i'm at a constant speed. But some times when i slow down and accelerate the RPM Needle moves unexpectedly. (say to 0 even i'm at a ...
1
vote
4answers
137 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 ...
1
vote
1answer
304 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 ...
0
votes
1answer
822 views

Typically in what RPM range should one manually downshift an automanual transmission?

Related to this question and TMN's answer: What's a good RPM range to safely downshift an automanual transmission manually? My car does it for me when the RPMs get really low, but that throws me off ...