Reving up the engine. Just how damaging could it be?

[Sharky]

I've just come back from my mother's hometown where I spent my easter holidays. It is located some 400km north of where I live trough mountain, two-way roads, sometimes considerably steep, with considerable traffic, particularly a lot of lorries. This means that a lot of overtaking is mandatory which is further aggravated by the short straights and uphill direction.

When I take this road I keep the engine always above 4000rpm but during overtaking it can go up to 5500-6000rpm (saw 6200 one time though). I arrived safely so I didn't blow up the engine . However, I do wonder if it's wise to push the engine so hard during such long trips (7-8 hours). Could I be inflicting permament damage on the engine?

BTW, the car that I drive for this kind of trip is a 2003 Mazda 323 1.6L (or protege as it is called in some places).

[Mackmot]

Cars that have been driven around by people that have driven in the peak hp range at around 5250-7000 depending on the car tend to be much better than ones that are all gunked up with carbon after not burning all their fuel properly at 2000-4000

[thebear]

Originally Posted by Sharky

When I take this road I keep the engine always above 4000rpm but during overtaking it can go up to 5500-6000rpm (saw 6200 one time though). I arrived safely so I didn't blow up the engine . However, I do wonder if it's wise to push the engine so hard during such long trips (7-8 hours). Could I be inflicting permament damage on the engine?

BTW, the car that I drive for this kind of trip is a 2003 Mazda 323 1.6L (or protege as it is called in some places).

What! You disposed of the car WE so carefully repaired a few months ago?

4k rpm cruising shouldn't be a problem.

Are you watching the temperature gage?

[Mark Smith]

I shouldn't worry about overrevving the engine, it'll clean the carbon out of it. I've got a fiat cinquecento sporting and it thrives on high revs.It'll rev to 7,100 before the rev limiter comes in.As long as the engine is warmed up and the oil is clean and of good quality it won't do any harm to push the engine hard as long as you don't constantly keep it on the rev limiter.

[Sharky]

Originally Posted by thebear

What! You disposed of the car WE so carefully repaired a few months ago?

Ha ha ha! Don't worry. It's still with me. It's just that with the 1.1L engine the car is hardly suitable for the mountainous road that it would have to face (in fact, as you should recall, my overheating problems came while driving uphill with full load). Hence, for such trips it is best to use my dad's mazda. No overheating problems with it

I've heard so much conflicting information on the subject. Some say that high revs shorten the life of the engine while others say that low revs are the sure way to kill the engine. I've always believed the former....but this time there was a lot of traffic therefore a lot of overtaking so I was a bit worried that perhaps I was being too harsh on the engine. In fact, an uncle has the exact same car and when I told him about my driving style he looked at me as if I was torturing the poor car.

[thebear]

Originally Posted by Sharky

I've heard so much conflicting information on the subject. Some say that high revs shorten the life of the engine while others say that low revs are the sure way to kill the engine.

High revs with little or no load will do that.
Low revs with high load will also do that. The condition is called "lugging" the engine.

Originally Posted by Sharky

I've always believed the former....but this time there was a lot of traffic therefore a lot of overtaking so I was a bit worried that perhaps I was being too harsh on the engine. In fact, an uncle has the exact same car and when I told him about my driving style he looked at me as if I was torturing the poor car.

If you can maintain your uphill momentum, don't shift to a lower gear unless you are about to pass someone. Look in the engine specifications for Horespower & Torque peak RPM. No sense driving for an extended period BEYOND the specified RPM.

[Sharky]

Originally Posted by thebear

If you can maintain your uphill momentum, don't shift to a lower gear unless you are about to pass someone. Look in the engine specifications for Horespower & Torque peak RPM. No sense driving for an extended period BEYOND the specified RPM.

The Mazda's maximum power comes at 5500Rpm while the maximum torque comes at 4200rpm if I'm not mistaken.

[thebear]

Originally Posted by Sharky

The Mazda's maximum power comes at 5500Rpm while the maximum torque comes at 4200rpm if I'm not mistaken.

No sense driving for an extended period BEYOND the specified RPM if you can maintain your uphill speed in a higher gear.

[Sharky]

When going uphill with full load (3-4people + luggage + Air conditioning) I always stay between 4000 and 4300rpm. That means I do 70-75 Kmph in second gear. If I go to third at this speed the revs drop to 3000-3200 and at this point the engine has very little "push". In fact, at high altitudes (above 5000ft) switching to 3rd gear in this situation actually results in a drop of speed which forces me to change to second gear again. Only while overtaking does the engine visit the 5000rpm zone. Of course, sometimes overtaking means getting rid of a 22 wheel truck in a straight that could be less than 100 meters (300 feet or so) long.

[thebear]

Originally Posted by Sharky

When going uphill with full load (3-4people + luggage + Air conditioning) I always stay between 4000 and 4300rpm. That means I do 70-75 Kmph in second gear. If I go to third at this speed the revs drop to 3000-3200 and at this point the engine has very little "push". In fact, at high altitudes (above 5000ft) switching to 3rd gear in this situation actually results in a drop of speed which forces me to change to second gear again. Only while overtaking does the engine visit the 5000rpm zone. Of course, sometimes overtaking means getting rid of a 22 wheel truck in a straight that could be less than 100 meters (300 feet or so) long.

Looks like you have the situation under control. That's why there is a gearbox with five speeds.