I was wondering something tonight as I drove home. I know it's supposed to save gas if you shift at slightly lower rpm's, like 3000 or so, right? But I'm wondering if shifting at too low an rpm can have a negative effect on your car, aside from the obvious possible stall.

This is just out of curiousity, since my Versa is going to be a CVT.

If you drop out of the power band, the car will accelerate really slowly, which might adversely affect fuel economy.

the best way to do it is, let your foot up the gas pedal for a brief moment. Then use as little as possible to maintain speed, then from there on, any small increase will increase speed without affecting fuel economy too much. I do this in the highest gear to get really good FE ratings (as good from 60 to 90 mpg depending on how light i'm playing with the throttle) I'm always changing my foot position depending on how the road is.

As for shifting, I can get away with accelerating from 1000 rpms, but you have to increase your revs slowly, I've accelerated in this matter before and I've pissed a lot of people off so I only use it when no one is behind me. When people are behind me I shift at 2000 rpm, and it usually gives me enough power to satisfy traffic demands and most road conditions. So 2500 rpms and up is hardcore for me.

Your car is still fresh isn't it? Should rev it once in awhile to ensure total break in. More on this topic can be found at http://www.cleanmpg.com/forums...=2232 on a technique we call Driving With Load (DWL) which means when driving up a hill, we use only just enough gas to maintain speed, those who satisfy more fuel economy savings can slowly bleed their speed off by slowly raising the gas pedal, (ex: 40 mph, 39 mph, 38 mph... ect) until they reached the peak of the hill. From there one can choose to pick up speed slowly again, or resume driving at the speed they are at if they picked up speed from the begging before climbing the hill

once again I like to remind people be careful who you piss off, be curteous and use reason! I do what I can to get my upcoming 50 mpg tank.
Modified by philmcneal at 3:05 AM 9/29/2006

From what I've been told, there's nothing wrong with shifting too early. I've always heard that excessive "lugging" could cause excess wear on the engine. Lugging is when you're on the gas in too low of a gear, but the car doesn't accelerate or fails to maintain speed. Accelerating like philmcneal says, wouldn't be considered lugging.

proxim2020 wrote:From what I've been told, there's nothing wrong with shifting too early. I've always heard that excessive "lugging" could cause excess wear on the engine. Lugging is when you're on the gas in too low of a gear, but the car doesn't accelerate or fails to maintain speed. Accelerating like philmcneal says, wouldn't be considered lugging.

When you shift too low, it puts excessive wear on the tie rods, lugging the engine. Not only does it strain the enigne, but it also results in worse fuel economy as you need to use a bit more throttle to get to speed.

My point: shift at 3000 on a regular basis...your engine will thank you and you will see better fuel economy...

LA02MAX wrote:

When you shift too low, it puts excessive wear on the tie rods, lugging the engine. Not only does it strain the enigne, but it also results in worse fuel economy as you need to use a bit more throttle to get to speed.

My point: shift at 3000 on a regular basis...your engine will thank you and you will see better fuel economy...

I use to think 3000 would be where the engine is most efficent to achieve the most of the powerband, however, to achieve that good efficency one has to burn a lot of gas just to get that kind of power. And in my opinion that kind of power is useless for a guy like me since I got traffic lights everytime I hit 40 mph!

If you demand very little accel, I don't see how I'm lugging the engine. Even the scangauge says engine load is under 20 percent, on the highway, my engine loads are always 40 to 60 to maintain more than 55 mph highways so in theory the engine has to work harder at highway speeds even though the engine is more in the powerband area (2500 + rpms)

If you had a scangauge and you used the gallons per hour tool (I use liters) you can totally see that the rate of fuel eaten always goes up when revolutions rise. An engine always need to fight over its own weight and I can imagine to maintain that would be much higher at high revs rather than low simply because engine demands are at an absolute low. Like Lao2Max says, if you press the throttle just a little too much then yes you will here that "chug a lug dug" and the engine will strain to produce power at such low revs. But if the power request is low at the low revs, then your fuel economy will spike up! Not down!

If you need the power, that's what downshifting is for, since the revs are so low already a downshift from 5 to 4 doesn't require much effort.

I agree with you, to some extent.

Think about it this way: As you're getting on the highway (say a 60mph speed limit) it will take less time for you to reach your designated speed when shifting around 3k, and it won't take as much effort. Yes the engine does consume more fuel at higher RPMs, but the ECU also sends more fuel when the Accelerator pedal position is further down (ie: throttle is open more) and when you're accelerating at lower RPMs, it takes a bit more throttle to get to speed, and you're accelerating for a longer period of time, burning more gas in the process.

I can totally understand shifting at 2k when lightly acclerating in traffic, or on a 30mph speed limit road, but when it comes to getting to speeds like 60 or 70, shifting at 3k, IMO, seems like a better option.