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Discussion Starter #1
I'm ploughing through the manual for my new 2.0 petrol manual six speed Mazda 3 prior to delivery. I don't see any mention of recommended gear shift speeds for normal driving (no boy racer recommendations thank you). I know you can tell from the car's response when to change and from the gear change indicator, but I thought Mazda would publish the recommended change speeds. Any advice?
 

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Is this your first manual transmission car? Its no different than any other. Shift when you want to shift. You don't want to use the speedometer to shift anyway, you use the tach. I try to keep it over 3k for best driveability but you can certainly go lower. You'll start to get out of the powerband once you get down around 2500 rpm, on the upper end you can go to 6200 or so before the power starts to drop off, and there is a fuel cutoff at 6800. The shift indicator light is complete BS. If you go by that you'll be trying to accelerate away from a stoplight in 4th gear at 20mph.:bash: I'm eventually going to have it exorcised I think. Just learn not to look at it.
 

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Discussion Starter #3 (Edited)
Is this your first manual transmission car? Its no different than any other. Shift when you want to shift. You don't want to use the speedometer to shift anyway, you use the tach. I try to keep it over 3k for best driveability but you can certainly go lower. You'll start to get out of the powerband once you get down around 2500 rpm, on the upper end you can go to 6200 or so before the power starts to drop off, and there is a fuel cutoff at 6800. The shift indicator light is complete BS. If you go by that you'll be trying to accelerate away from a stoplight in 4th gear at 20mph.:bash: I'm eventually going to have it exorcised I think. Just learn not to look at it.
I don't need any gadgets to tell me when to shift. I've been driving manual cars since 1975 so that gives my age away. I have a very leisurely driving style changing up c 2000rpm on the level. I might accelerate up to say 3000rpm for joining a motorway. My current 2 litre Honda Accord and previous 2 litre cars worked fine in this driving style. The Mazda 2 litre petrol torque curve looks quite good by 2000 rpm - see http://www.automobile-catalog.com/curve/2017/2506865/mazda_3_sedan_2_0_skyactiv-g_120.html
 

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I don't need any gadgets to tell me when to shift. I've been driving manual cars since 1975 so that gives my age away. I have a very leisurely driving style changing up c 2000rpm on the level. I might accelerate up to say 3000rpm for joining a motorway. My current 2 litre Honda Accord and previous 2 litre cars worked fine in this driving style. I might look up the Mazda 2 litre petrol torque curve to check the response at lower rpm (by your standards).
Shifting at 2k rpm you will have very slow acceleration at best. The engine is intended to be revved a lot higher in regular operation and the car is geared as such. Running to 4500 or 5000 won't hurt it at all and is well within the normal operating range. The engine needs higher RPM operation to keep the intake valves clean. This is not a Honda by any means. :smile2:
You cannot learn how to drive a car by reading stuff the internet. Once you get the car you will see what I mean.

I learned on a 1967 Type II VW fasback:smile2:
 

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I don't need any gadgets to tell me when to shift. I've been driving manual cars since 1975 so that gives my age away. I have a very leisurely driving style changing up c 2000rpm on the level. I might accelerate up to say 3000rpm for joining a motorway.
Same here, since 1964. It's not like these are sports cars, is it, although it is nice that if you need to speed up for some reason the motors are reasonably able and willing to do so.

I generally shift up slightly before the gear change indicator would suggest that I do so. The 2.5-liter motor has the torque to manage this, and it appears to result in better gas mileage. This generally results in shifting at ~1700-2000 RPM, and on a level surface I shift into 6th gear at around 34 MPH.

The engine needs higher RPM operation to keep the intake valves clean.

I learned on a 1967 Type II VW fasback:smile2:
I will test that theory by having the shop take snapshots of the intake and exhaust valves at 40,000 miles. We're now at 37,000.

I learned on a 1959 Fiat 600, a car whose clutch engagement took place in what felt like 1/64 of an inch. That was on San Francisco's hills, which made for some really exciting getaways from stop signs and stop lights. Somehow, I managed not to roll back into any other car's front bumpers.
 

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Discussion Starter #6
Shifting at 2k rpm you will have very slow acceleration at best. The engine is intended to be revved a lot higher in regular operation and the car is geared as such. Running to 4500 or 5000 won't hurt it at all and is well within the normal operating range. The engine needs higher RPM operation to keep the intake valves clean. This is not a Honda by any means. :smile2:
You cannot learn how to drive a car by reading stuff the internet. Once you get the car you will see what I mean.

I learned on a 1967 Type II VW fasback:smile2:
The car pulls quite well at 2000rpm which is about 75% peak torque so it seems a good speed to change for economy. What's the point of revving beyond 4000rpm when the torque curve drops off so rapidly. I admit it might sound good if you like driving a noisy car.
 

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Discussion Starter #7
Same here, since 1964. It's not like these are sports cars, is it, although it is nice that if you need to speed up for some reason the motors are reasonably able and willing to do so.

I generally shift up slightly before the gear change indicator would suggest that I do so. The 2.5-liter motor has the torque to manage this, and it appears to result in better gas mileage.


I will test that theory by having the shop take snapshots of the intake and exhaust valves at 40,000 miles. We're now at 37,000.

I learned on a Fiat 600, a car whose clutch engagement took place in what felt like 1/64 of an inch. That was on San Francisco's hills, which made for some really exciting getaways from stop signs and stop lights. Somehow, I managed not to roll back into any other car's front bumpers.
Most petrol in the UK has additives to prevent valves clogging up - you must have the same in the US? My current Accord now 11 years old at 75000 miles still runs very sweetly, despite changing up at 2000 rpm! Why are you taking the head off after only 40000 miles?
 

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Your 2.0 will probably have the gear indicator on the left. It actually tells you when to shift.

On our sGT, it's about 1750 rpm to not be any lower than 1500 rpm in the next gear. If you want to skip a gear, go to 2250 rpm. I do this to go from 3rd to 5th. 4th seems a very short gear.

These rpms are for best fuel economy and on level to slight downhill. If going uphill, you'll need to rev higher.

The 2.5 liter that we have actually is quite happy down to 1300 rpm. Think the 2.0 will need 1500 rpm minimum.

We've also a 2.0 liter MX-5. Its shift points for economy are pretty much the same.

I used to use 15, 25, 35, 45 and 55 mph as the shift points on past cars, and these still work for our Toyota Tacoma. The Mazda3 is so smooth, you almost shift it like your would an old Rolls Royce stick: pretty much any gear at any speed. Think the 2.5 is especially forgiving. It's only at speed going up hills where you need pretty good rpm to keep the engine from bogging much.

I call our 3 the Bimmer in the way it works and feels. The MX-5 is our baby Benz. Had a couple Benzes. It feels like a peppy, small version of them.

Ralph
 

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Have you actually driven the car other than a test drive? I can assure you the car won't pull very well if you shift at 2000 rpm, that is actually the bottom of the power band. If you want to enter the freeway without getting smashed you will need more than 2k rpm from the car. Once again, looking at charts and graphs is quite different than experience in the real world.
The shift indicator light is there to tell you when to shift for best fuel economy. You will get maybe 10% of actual performance potential if you go by that thing. Not what you want when accelerating up an on ramp.:surprise:
 

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Most petrol in the UK has additives to prevent valves clogging up - you must have the same in the US? My current Accord now 11 years old at 75000 miles still runs very sweetly, despite changing up at 2000 rpm! Why are you taking the head off after only 40000 miles?
A number of DI (direct injector) engines in the United States have had issues with intake tracts and the backs of intake valves becoming coated in hardened oil residue. Among others, some models of BMW (a marque with which I am much more familiar) have suffered from noticeable loss of power due to this issue. The solution is to blast the intake tract with walnut shells to remove the residue, a procedure which must be performed time and time again, at a cost of many hundreds of dollars each time it is done.

There has been some discussion as to whether the Mazda Skyactiv motors, being direct-injected, will suffer from this problem. Mazda has devised what they say is a solution for the Skyactiv motors that will prevent the problem. I intend to see if that is the case. I think only the intake plumbing needs to be removed to take photos of the backs of the intake valves. I mentioned exhaust valves previously - that was in error, the shop won't be photographing the backs of exhaust valves.
 

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Most petrol in the UK has additives to prevent valves clogging up - you must have the same in the US? My current Accord now 11 years old at 75000 miles still runs very sweetly, despite changing up at 2000 rpm! Why are you taking the head off after only 40000 miles?
I see by what you have posted here that you really do need to read up on the SkyActiv engine and it capabilities.
Additives have no bearing on the subject. These engines have direct injection, so the intake valves do not get the needed washing from fuel passing across them. Carbon buildup on the intake valves is an issue for a lot of cars with direct injection. Mazda has engineered a solution for the SkyActiv motor apparently. This involves keeping the valves hot enough to keep deposits from forming. Driving like your grandmother in a 65 Buick will only lead to early engine issues. The car needs to be revved somewhat to operate normally. Letting that silly indicator tell you how to drive is silly and it only exists because the EPA says it has to.
 

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I'm ploughing through the manual for my new 2.0 petrol manual six speed Mazda 3 prior to delivery. I don't see any mention of recommended gear shift speeds for normal driving (no boy racer recommendations thank you). I know you can tell from the car's response when to change and from the gear change indicator, but I thought Mazda would publish the recommended change speeds. Any advice?
I found the following information in the manual for my 2.5-liter motor - perhaps similar data can be found in your manual, too.
 

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The downside of the gear shift indicator is that it doesn't know what you want to do in the next two seconds. For example, if the car sees you maintaining speed while waiting someone to pass so you can merge then accelerate, it might tell you to upshift which is not what you want.

It's useful though if you're just cruising and wanting to get optimal fuel economy. :)
 

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I found the following information in the manual for my 2.5-liter motor - perhaps similar data can be found in your manual, too.
Yep. I think you will find those numbers quite similar to those displayed on the shift indicator. They are the operational parameters needed to hit the economy numbers required by the EPA, not based at all in reality.
 

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I enjoy lots of different kinds of driving, most of all spirited carving of curvy country roads. Obviously when I do that, I keep the revs higher, typically 3,500-5,500 but higher too. But I do not drive that way when running errands around town, probably around 2,000-3,000 RPM. But when on long distance road trips, making 600 miles a day on the interstates, will get into sixth when appropriate, set cruise control and on flat level ground, and I spend the day often in the 1,500-2,000 RPM range, more of course in the mountains.

And from just my Mazda 3 one-hour test drive, I concur with above posts, that the shift light comes on way sooner than I typically drive, being set for maximum fuel economy.
 

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Yep. I think you will find those numbers quite similar to those displayed on the shift indicator. They are the operational parameters needed to hit the economy numbers required by the EPA, not based at all in reality.
When I'm using higher revs than I normally would, and the car is on a level stretch of road, my car's shift indicator suggests shifting from 5 --> 6 at 39 MPH - so, somewhat similar to the recommended 43 MPH in Mazda's "Cruising" chart.
My reality is that I shift into 6th at ~34 MPH when on the flat. Your reality is likely quite different. :wink2:
 

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Lugging an engine is really bad for it. The best definition I have seen is being in too low a gear when you are trying to accelerate. If you are going up even a slight incline, and are trying to accelerate in a gear and are under 2,000 RPM, you are definitely lugging your motor. When going up a hill, I personally am at least 2,500 RPM, more if it is a steep hill, and again trying to accelerate when in a lower gear than we should be, is really bad for our motors. Honest drivers will tell you that they have at least a few times lugged their motors, most often when they were either distracted or too lazy to shift to a lower gear.

Conversely, if we are in a top gear, going down a hill and not trying to accelerate, we can be at a fairly low RPM and not lug our motors.

It is important for us all to avoid trying to get that last bit of fuel mileage when accelerating and/or going up an incline.
 

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The car pulls quite well at 2000rpm which is about 75% peak torque so it seems a good speed to change for economy. What's the point of revving beyond 4000rpm when the torque curve drops off so rapidly. I admit it might sound good if you like driving a noisy car.
The problem with that thinking is this- if you shift at 2000 rpm you are less than half way into the torque curve. Shift up and you will be back at the bottom of the curve with very little power available. Get the rpms up above 3k and you'll be well into the power band for the next gear. Keep the rpms low and mashing the throttle results in lugging the engine, not a good situation with a high compression motor like this.

When I'm using higher revs than I normally would, and the car is on a level stretch of road, my car's shift indicator suggests shifting from 5 --> 6 at 39 MPH - so, somewhat similar to the recommended 43 MPH in Mazda's "Cruising" chart.
My reality is that I shift into 6th at ~34 MPH when on the flat. Your reality may vary. :wink2:
34???:scared::scared: In 6th gear? Really? Does the car actually move like that?:laugh2:
Where is 6th gear anyhow? I was in traffic on the freeway today, 4th gear, between 60 and 80 indicated.
 

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I agree that 34 MPH in sixth gear, less than 1,000 RPM is not where I would want to be, nor would I be unless I was coasting to a stop down a pretty good hill, and as I slowed even a little further, would be downshifting to 4th or lower. If your foot is completely off the throttle and you are going up hill in too low a gear, and you are starting to feel your car starting to gently tug and pull you back-and-forth in your seat, you are lugging your car.

I like @arathol's earlier post, that he drives not by his car's speed, but by its tach/RPM. The only time speed is important is in traffic, avoiding a ticket and/or doing something unsafe.

Actually having the large tach right in front of me (maybe 10X bigger than the speedometer), is one of the things that initially appealed to me about the Mazda 3 GT. Early race cars, before "pit lane speed limits," did not even have a speedometer, but they had a tach right in front of the driver.
 
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