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Another RPM question

I just bought a 2003 MazdaSpeed Protege. This car is bad, it’s got a 2.0 liter, 4 cylinder with a turbo charger. My husband and I are having a disagreement about shifting. He says that I rev it up too much, I say he lugs it out too much. He likes to keep the car under 2000 rpms most of the time; he actually will shift at a mere 2000-2200. I like to keep it at just above 2000 and I usually shift at 2800-3000 rpms. This car redlines at 6500. He says that the reason my last Protege blew up at 140,000 miles is because of my shifting at too high rpms all the time and that if I continue to drive this car like that it will blow up too. That seems wrong to me because I always heard that these smaller engines didn’t mind the high rpms, and that it is actually better to rev them up than lug them out. So what’s the truth of the matter?

to keep it simple he’s right.

I support your methods. However, what does the owner’s manual say?

Drive an automatic transmissioned car, with a tachometer gage, and the same size motor, and see at what rpm’s IT shifts. Judge how smoothly IT makes the shifts. Let That be your model.

The owner’s manual gives speeds for shifting when cruising. They are 15, 25, 35, 45. Pretty easy to remember, and that’s usually what I do. My hubby will actually shift into 5th gear at 40 though. I just want to know what is the better of two evils, lugging it out or revving it up. Thanks so much for your reply.

That’s a good idea; think I’ll do that.

Neither of you is revving the engine too much. You’re shifting at 3K or less, which is less than half the safe speed for the engine.

I’d rather rev a small engine than lug it. I say rev it all you want and enjoy it.

Based on your information in the owner’s manual it is clear this is much ado about nothing. You are both shifting in a sensible range. The engine is neither being lugged nor revved. So now you both have to clean the bathroom.

Shifting a rev happy/turbo at under 3K RPM’s??

How boring.

My 87 Ranger 2.9 liter has a red line at 5500 & I routinely shift at 4500 RPM’s.

Example when merging into freeway traffic i’m in 3rd gear at 4500 RPM’s & 70 MPH. I skip 4th & shift to 5th.

Been driving it this way since it was new (after a break in period) i’ve had zero engine problems & it’s still running very strong with 235,000 miles on it.

Likewise the 4 banger in my wifes 02 Sonata loves to rev & my wife -with her lead foot- loves to rev it.

Hasn’nt hurt it a bit in it’s 1st 103,000 miles.

Like MCP sez, rev it up & enjoy it.

You are doing fine. Running an engine with a 6,500 rpm red line to 3,000 rpm WON’T hurt it – not immediately and not in the long run. If your previous car died at 140k miles, it was for an entirely different reason.

The next time you are out on a rural interstate at the speed limit, check the engine rpm. It will be somewhere around 3,000 rpm. During a long trip, you will spend hours like this. If your husband never exceeds 2,000 rpm, he must not go faster than 45 mph.

Since your car has a turbo, it needs better care than a non-turbo engine.

  • During the last few minutes before you turn it off, don’t run it hard. This will give the turbo time to cool off while oil is still running through it.
  • Don’t skimp on oil changes. Turbos are harder on oil than are non-turbo engines.
  • Keep full-throttle runs to red line to a minimum. Regularly running any car this hard accelerates wear. Since it is more powerful than most, this is even more applicable to turbos.

This is not really a useful suggestion. The torque converted influences the torque to the wheels, the final drive ratios will be different and the number of gears will likely be different. Automatic transmissions shift at different points under different conditions.

Setting a mandatory shift point at a particular RPM makes no sense anyway, as others have already pointed out. Merging onto an urban interstate, or accelerating out of an uphill turn sometimes requires more HP than pulling away from a stop sign in a school zone, or from a downhill turn so let it breathe under the former conditions. It sounds like the two of you bought the wrong car. I think that neither of you is shifting correctly and you should have bought the one with an automatic transmission. With those, when you push on the accel pedal lightly they shift at a low RPM saving wear and tear on the engine and fuel. Step on the accel hard and they wind up the engine yielding more power. This is all done automatically with no knowledge of physics or mechanical details like gear ratios!

It depends greatly on your individual driving style. The aggressive driver should shift a little higher than the conservative driver and will use a little more fuel. To me et sounds that you are both close enough not to worry about it.

Thank you for your reply, but I am unclear about what you mean when you say we shouldn’t have bought a stick shift because we are both shifting incorrectly. In your opinion what would be correct? To be honest this kind of offended me because I consider myself and my husband very good drivers who have been driving stick shifts for years. I just posted this question because we have been disagreeing about it for years and I wanted to get some outside feedback.

Wow, 3rd gear at 70mph??? My husband would kill me if I did that!! But the fact that you have had no issues with your engine for 235,000 miles says it all. Thanks for posting…

The question is really how does the car respond? The most economical way to drive a manual transmission car is to take it easy, not rev up too much before you change gears. The engine and transmission will let you know if you are at too low RPM by lurching until you ease in the clutch and give the engine some gas, or the gears will not synchronize, and you will have difficulty getting the shifter into the higher gear. If you wind out the engine too much, the car will slow down when the gear is engaged, indicating that the engine was rotating too fast for the gear you are shifting to. Sounds like both of you still drive like my grandmother, so I wouldn’t get into an argument over 200 RPM.

It is really quite simple. Neither 2000-2200, nor 2800-3000 rpm is the correct range to shift. Sometimes 2000 rpm might be correct and sometimes 6500 is correct. It depends on the circumstances. That is why automatic transmissions vary the shift points with hydraulic and mechanical (historically) or electronic (contemporary) controls. Neither one of you is shifting correctly if you want to set a narrow rpm range that is correct.

With modern vehicles with electronically-controlled automatic transmissions you will get much better gas mileage with an automatic than with a poorly-shifted manual. Now, you have told us little about what kind of driving you do. If it is virtually all in high gear on the interstate, it won’t make a significant difference what kind of transmission you use, poorly-shifted manual or automatic. If you have to use the transmission significantly, you would be better off with an auto.

Some good drivers are not great passengers. I always say that I’ll take it under advisement. I don’t really say that. I change my driving habits a little bit. I only have one goal. Don’t crash the thing. It costs more than broken engines. A man used to preach to his wife that he wanted her to park the car perfectly straight in the garage. She was a few inches off the mark so she turned the wheel all the way and straightened the car. He gets in te next day and tears the car up when backing out. I never bother my wife about her driving anymore.

Pleasedodgevan wrote:

I never bother my wife about her driving anymore.

This is so true! I’ve long since learned that everyone in our family has different driving habits, and that the cost of bugging them in order to save marginal wear-n-tear on a vehicle definitely isn’t worth it.


So right. I spoke with my husband about this and we both had a good laugh at ourselves. We both drive just fine and we shouldn’t nitpic each other. Yes, we are terrible passengers; neither of us can stand riding in the passenger seat; doesn’t really matter who is driving. Thanks everyone for your input.

Well derr!!! Of course we know you can’t set a definite, all-the-time number on this. I was just referring to regular, around town driving. Neither of us has had any problems shifting (our car is not poorly operated by a couple of idiots like you seem to infer). Thanks again for your reply, but maybe you could try not to be so snotty about it.