An important question about RPM.

[markuszoom5]

I know that my 2010 Mazda5 is underpowered, but sometimes on the highway when I have to merge or switch lanes, I have to push on the gas pedal a little harder, not all the way though. When I do that, the MZ5 sometimes revs up to 5000 rpm or more. Is it just mine? Is that bad for the car. I always thought it would be, but then I need to be safe, and I am also not sure about the new engines these days.

 

[rkhanso]

That shouldn't be an issue. In my opinion, the car is underpowered and the higher RPMs are needed to get the thing accelerating quickly at those speeds. It's not bad for the car, and may even be good for it once in a while. The car won't do anything to damage itself....you know, that whole prime directive thing. (2cents) - really....don't worry about it.

Mine is a 2006 5-speed, and it runs at a constant 3000 rpm when driving between 60-65.

 

[flcruising]

Sounds like you are concerned about over-revving the engine. This isn't something you can do with a modern vehicle unless you do a PCM upgrade/reprogramming. The worst you could do is put your transmission into manual mode and maintain a low gear near redline for an extended period. Then the automatic transmission (or engine) would probably become overheated and issue a warning light. Absolutely nothing for you to worry about with normal driving as the PCM controls the shift points and will not over-rev the engine.

I'm in agreement with rkhanso, an I-4 likes to rev and should be done every once in a while. To me underpowered is subjective as I'm used to I-4's and this one hasn't left us for wanting yet, even when fully loaded. If you came from a V-6 or 8, then you'll have some getting used to.

 

[markuszoom5]

I guess I get it...

Sounds like you are concerned about over-revving the engine. This isn't something you can do with a modern vehicle unless you do a PCM upgrade/reprogramming. The worst you could do is put your transmission into manual mode and maintain a low gear near redline for an extended period. Then the automatic transmission (or engine) would probably become overheated and issue a warning light. Absolutely nothing for you to worry about with normal driving as the PCM controls the shift points and will not over-rev the engine.

I'm in agreement with rkhanso, an I-4 likes to rev and should be done every once in a while. To me underpowered is subjective as I'm used to I-4's and this one hasn't left us for wanting yet, even when fully loaded. If you came from a V-6 or 8, then you'll have some getting used to.

Before the MZ5, I have driven a 2006 Jetta 2.5L I-5 (that's right, 5 cylinder) manual 5 speed for 5 years and traded it in for the MZ5. Overrevving was never an issues because the car was so powerful even in lower RPM, plus it was naturally aspirated and a low-stressed engine. Only 150 hp. I also drove a 60 hp Fiat Punto in Europe which was definitely underpowered and it had no RPM gauge, but you would listen to the engine and shift accordingly. However, I have no control over the MZ5 automatic on the highway when it goes into 5000 rpm before it shifts, so it makes me feel uneasy, and I don't like the manual mode, it lags a bit. Not like a manual. I should have probably bought a 5-speed-manual MZ5 but they did not have any in October 2010, and my wife doesn''t know how to drive manual.

 

[thaxman]

Remember the 2.3 is a VVT engine, so the valve timing and duration change around 3500 rpm. That is where the peak hp becomes accessible. If the engine never changed profiles, it would probably reach a peak hp closer to 130 hp, not the 157 advertised. Would be nice if the 2.5 had 20 more hp to match the increase of 20 lbs more torque tho. (toetap)

 

[Silentnoise713]

I know that my 2010 Mazda5 is underpowered, but sometimes on the highway when I have to merge or switch lanes, I have to push on the gas pedal a little harder, not all the way though. When I do that, the MZ5 sometimes revs up to 5000 rpm or more. Is it just mine? Is that bad for the car. I always thought it would be, but then I need to be safe, and I am also not sure about the new engines these days.

Unlike Toyota who tend to have taller gearing for lower NVH and maximum MPG (no sportiness), Mazda on the other hand, is the exact opposite with their zoom zoom motto. The transmission logic is probably programmed to determine your speed and throttle input to determine you want to hustle along so it down shifts to maximize what little power the MZR is capable of producing. Add short gearing to the mix, you get high RPM. BTW, the Mazda's MZR is not new, in fact, is prob as old as any modern engine can get. Internals are a little weak but very reliable. Nonetheless, way past its prime and the newer 2012 is just bored out for more power (weaker block). 'Sky' engines is the way for Mazda.

Revving could be bad if critical fluids are not warmed or maintained (cold, old, or low on engine, transmission, coolant, etc.). If the car is well maintained, not an issue at all. My belief is if you only cruise in the lower RPM, you don't really drive a car, you are just steering it. I read an article many years ago that occasional high revving is good for the car to help break up/prevent deposit build up around the valves. Drive it like you stole it and enjoy the experience. Car's are meant to be driven, not garage queens unless you have a million dollar collectable -that's the way I look at it now.

Attached is another member's (don't remember SN) stock 2007 Mz5 dyno chart, Max HP 111, TQ 113 –ouch! but keep in mind Mustang dyno and Colorado elevation. Point is, not much power on tap so Mazda uses short gearing to make it more responsive under the penalty of NVH and MPG.

 

[markuszoom5]

Unlike Toyota who tend to have taller gearing for lower NVH and maximum MPG (no sportiness), Mazda on the other hand, is the exact opposite with their zoom zoom motto. The transmission logic is probably programmed to determine your speed and throttle input to determine you want to hustle along so it down shifts to maximize what little power the MZR is capable of producing. Add short gearing to the mix, you get high RPM. BTW, the Mazda's MZR is not new, in fact, is prob as old as any modern engine can get. Internals are a little weak but very reliable. Nonetheless, way past its prime and the newer 2012 is just bored out for more power (weaker block). 'Sky' engines is the way for Mazda.

Revving could be bad if critical fluids are not warmed or maintained (cold, old, or low on engine, transmission, coolant, etc.). If the car is well maintained, not an issue at all. My belief is if you only cruise in the lower RPM, you don't really drive a car, you are just steering it. I read an article many years ago that occasional high revving is good for the car to help break up/prevent deposit build up around the valves. Drive it like you stole it and enjoy the experience. Car's are meant to be driven, not garage queens unless you have a million dollar collectable -that's the way I look at it now.

Attached is another member's (don't remember SN) stock 2007 Mz5 dyno chart, Max HP 111, TQ 113 –ouch! but keep in mind Mustang dyno and Colorado elevation. Point is, not much power on tap so Mazda uses short gearing to make it more responsive under the penalty of NVH and MPG.
View attachment 189808

The chart shows that torque is highest at 4200 rpm so even though there is more engine power the torque decreases at higher rpm I don't get why

 

[Sounbwoy]

Torque and HP don't have the same curves and both are dependent on engine design and tuning. Here's something to help:
http://www.car-videos.net/articles/horsepower_torque.asp

 

[johnnieboy]

If your 5 is equipped with an automatic transmission, keep it in "Drive" and you will never over-rev your engine. If you have a stick (or shift your auto manually), just keep the tach needle below the red-line when accelerating.

 

[Davicho]

Even if he has it on the manual shift mode the engine will never over rev. It will either up shift itself or simply hit the rev limiter. To my knowledge the only way to over rev the engine is mechanically over revving with a manual trans in which you mis-shift into a lower gear. Otherwise the rev limiter will always kick in before it gets to that dangerous point.

 

[ljmattox]

Good thoughts throughout here; as has been said, it's a 4-cyl, with it's top HP occurring pretty high in the rev range (153@6500 rpm, in this case). So 5000+ rpm won't be harmful, and is well within the design limits.

My 2010 5MT hasn't felt underpowered to me, and I have a blast driving it. It is what it is, but having owned 4-cyl cars most of my adult life, these modern ones with electronic controls, fuel injection, and so forth are pretty amazing to me: tractable, good fuel economy, and a nice rush in the upper range, even in this mild state of tune.

I've hit the rev limiter / cutoff a few times accidentally in 1st or 2nd; it really is there as a safeguard for you, so no worries, and your A/T would shift up before then anyhow.