What is the RPM at highway driving?

[jelliotlevy]

Originally Posted by Moltisanti2009

That's wrong too. Any time your engine is running, wear is happening. Oil just minimizes wear.

The 3 to 4 shift is an easy shift if proper shifting techniques are used. Turn your hand over and cup the shifter so your palm is facing away. This ensures a proper shift.

Too many people grab the shifter normally and thus, pull it towards them and end up in second.

There's no reason anyone should shift from 3rd to second if proper shifting techniques are used.

.........

Yes, you're right. However, when many thousands of shifts are performed, and many of them are performed rapidly and aggressively, some poor fool will eventually make the fatal error. 99.9% effectiveness is not good enough for an event performed 1000 times. I will support the palm position concept. When aiming for first or second gear, the palm should be facing you. When aiming for third or fourth, the palm should be facing directly downward. When aiming for fifth or sixth, the palm should be facing away from you.

[ThomP]

Originally Posted by Daemione

Sorry to sound nitpicky - but that's a logical fallacy . . . 20% higher rpms doesn't equate to 20% more wear on the engine. When your engine oil is doing it's job, engine wear is ZERO, no matter how many times the piston is going up and down a minute.

Zero wear would be nice - I want that oil

I think an "all else being equal" assumption is missing in the original statement - if all else is equal, 20% higher rpms will cause more tear. But of course, all things aren't equal - if the AT delivers the same work at lower rpms, it must be "pushing harder", causing more tear per rev?

[jelliotlevy]

Originally Posted by ThomP

Zero wear would be nice - I want that oil

I think an "all else being equal" assumption is missing in the original statement - if all else is equal, 20% higher rpms will cause more tear. But of course, all things aren't equal - if the AT delivers the same work at lower rpms, it must be "pushing harder", causing more tear per rev?

.....

And that is the reason that the torque converter 'flexes' as soon as there is any serious pressure on the pedal. Instantly, the 2100 rpm at 60 mph becomes 2500+, and that prevents lugging the engine, which is, in the real world, a source of extra wear.

[Daemione]

Originally Posted by Moltisanti2009

That's wrong too. Any time your engine is running, wear is happening. Oil just minimizes wear.

Originally Posted by ThomP

Zero wear would be nice - I want that oil

Like I said - when the oil is doing it's job, there's zero wear. i.e. no metal parts contacting any other metal parts . . . unfortunately it can't do that 100% of the time (cold starts, severe duty, etc.), so wear obviously occurs.

[john21031]

[quote=ThomP;646047].....
Originally Posted by ThomP
Zero wear would be nice - I want that oil

I think an "all else being equal" assumption is missing in the original statement - if all else is equal, 20% higher rpms will cause more tear. But of course, all things aren't equal - if the AT delivers the same work at lower rpms, it must be "pushing harder", causing more tear per rev?
quote]


Good point. That's why I mentioned "based on piston travel alone". Of course other factors play a role in wear, one of which is load.


It would be nearly improssible to hypothize on the rate of wear speculating with variables such as piston travel, load difference on AT vs AT and specific oil.. You are talking about an expensive research project...

In the ideal world, the oil is suppose to create a thin layer which would prevent metal parts from directly rubbing against each other. But we are not living in an ideal world. Furthermore, compression rings are rubbing the cylinder wall without any direct oil lubrication.

That's why diesel engines last much longer on average. Diesel fuel is a natural lubricant, while gasoline, when burnt, leaves dry and clean cylinder wall.

[hoss10]

If it makes people feel a liitle better about wear, I have a 1994 Accord with a 4 speed automatic. It spins about 2800 -3000 at 100 kph (about 62 mph) depending on the torque converter and load. It has about 320,000 km on it and it runs great, and does not burn a drop of oild between changes.

However I feel my Fit would be a little closer to a perfect car with a 6 speed MT (and an outside temp. gauge). I think I know why Honda did it (short gearing), they worried people wouldn't shift on hills, passsing etc. and would lug the engine. I really can't believe how flexable a car the Fit is on the highway despite having such a small engine, but I would like another gear, and I promise to shift down.

[ThomP]

Originally Posted by john21031

It would be nearly improssible to hypothize on the rate of wear speculating with variables such as piston travel, load difference on AT vs AT and specific oil.. You are talking about an expensive research project...

I'm not talking research projects at all - I'm just trying to say the same as you - it is impossible to make a meaningfull comparison because a lot of things aren't equal, and some of those are in favour of the MT.

In my opinion we just have to believe that Honda did their homework and made sure both the AT and the MT versions are built to last and be used - and I'm sure they did

[mahout]

Originally Posted by john21031

What is the rpm for 2009 5MT at 55 mph, 60, 65 and 70?

I heard some people feel the car is geared too low for highway cruising.

My altima runs at 2500 at 65 mph.

My brother's 95 mazda 626 used to be much higher - around 3500 rpm for the same speed.

A fit with AT runs about 2400 rpm at 65 in 5th; a manual runs around 3100 rpm ditto. It's the difference in gear ratios. The At engine turns 2.508 times per wheel rev; the manual 3.24 times.