Hot answers tagged rpm
7
It all depends on your definition of high.
In my car, the red line is at 7500 rpm, and that indicates that driving with the revs over this line for anything other than brief periods is expected to cause damage, either through overheating, increased wear, increased loading on bearings, lack of sufficient oil/fluid flow etc.
When driving I have to keep my ...
6
There are 3 key factors to work on when uprating for higher revs:
Moving parts
Spinning a rod, cam or flywheel faster than it is rated for will result in it destroying itself, often spectacularly, as the stresses become too much. Moving linkages and pistons back and forth also takes a lot of energy - Kinetic energy = 1/2 m v squared, and it is that ...
4
Although automated manuals are becoming more popular, the 2012 Civic (from my 2 seconds of searching) appears to be a normal automatic.
Even still, I'm guessing your vehicle may have the sensors and programming necessary to determine that it's descending an incline and is employing engine braking to help you slow down. What it sounds like it's doing is ...
4
Alternators aren't built for one engine so the manufacturer can't possibly know the gearing / ratio between the alternator and the engine. Therefore the RPM listed in the spec will be the RPM for the alternator.
To calculate the alternators RPM you will need to find the diameter of the alternator pully [a] and the one connected to (presumably) the ...
3
The rev limiter would have to be removed. This would be involved in a custom DME. With the limiter removed then you'd be able to blow it up if you wanted to.
To support the higher revs, the vehicle would need the engine internals worked on. Stronger camshaft(s), valves, valve springs. (Head work). Depending on the strength of the rotating assembly at the ...
2
You don't mention the type of engine you've got or the age.
Older engines that are fitted with distributors and mechanical ignition systems typically drive their tachometers off the coil trigger wire, as this pulses each time a spark plug is fired. If that is the case, you simply need to connect a suitable tacho to the -ve terminal of the coil (i.e. the ...
2
As you said the crux of the issue has to do with getting every last amount of energy out of a unit of fuel. You can consider this your total fuel efficiency.
Accelerating your vehicle from rest to 60mph or 100km/h will require a fixed amount of energy based on the weight of the vehicle. (excluding wind, friction and rolling resistance).
So you need to ...
2
Does accelerating faster worsen fuel efficiency?
Yes.
Now obviously when you accelerate harder, more fuel is being pumped
into your engine, but you'll sooner get to that cruising sweet spot
where fuel consumption is a lot less. So is the payoff worth it or
not?
No.
This is easily measured via the OBD II port. For example, my Accessport ...
2
Within a certain range, of course more RPMs mean more wear. Especially if your maintenance is based on time or miles.
Consider a bearing that has a lifetime of 1,000,000 revolutions. If you drive at 5,000 RPM, that bearing is going to use up its lifetime twice as fast as if you were driving at 2,500 RPM.
On the other hand, "lugging" an engine at too low an ...
1
If your RPM shoots up when you downshift it should cause your engine brake to or slow down. (Unless you still have your foot on the gas). I would say TMN was probably thinking about over revving the engine when downshifting If you are at 4000RPM in 4th then you downshift to 3rd and your RPM goes up to 6000+ or anywhere close to the redline you could ...
1
I did some research and on automatic-transmission models, the most common cause of this problem seems to be a broken or dirty IAC (idle air control) valve. So the first thing I tried was removing the hose from the air intake into the IAC, and spraying Seafoam into it with the engine running. In order to get the engine to run with the hose off, I had to ...
1
Probably the most critical part for higher RPM's is the valvetrain. So you want better valve springs and retainers and a custom ground cam that is designed for the RPM you are trying to acheive. This is all to ensure that you don't encounter a situation where the valves cannot close fast enough and the piston head crashes into the valve. The higher the RPM ...
1
It takes a specific amount of energy to accelerate a specific amount of mass to a specific speed. So just looking at those factors, you'd be right to assume that it matters little how quickly you accelerate said mass.
But that's not how the real world works. The problem here is that combustion engines and the many things we connect them to are astoundingly ...
1
Very much engine specific. One of my cars has a replacement engine block that came from a car that only had a cam angle sensor (and mine requires cam AND crank angle sensors). Even though it's technically the same block other than the one sensor hole missing it was still a bit of an ordeal. A hole had to be drilled and tapped (very carefully), seals ...
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