2004 to 2020 Mazda 3 Forum and Mazdaspeed 3 Forums banner
1 - 13 of 13 Posts

·
Registered
Joined
·
323 Posts
Discussion Starter · #1 ·
Does anyone notice the power band in first gear to be kind of wonky? There's two issues I notice:

1) when it's cold and the idling is around 1200-1500 RPMs and I ease off the clutch the car likes to launch itself into motion pretty darn quickly so I always have to shove the clutch back in before I ram something... It's weird cause as soon as I let it out fully, it'll then roll along quite slowly if I don't touch the gas, so not sure why it's launching off the line.

2) When starting off in first there seems to be two power sets: first is when I launch the car from 800-2000 RPMs it has a nice peppy start, but once I hit 2000RPMs there's a noticeable lag in power, then at 2500RPMs the car has loads of power again. It's very very strange and not sure if this is something other people notice or if there's an issue with my drive system somewhere? Bad clutch, no idea as I usually don't work on the engine components of a car - I still to electrical and mechanical as in brakes, tires, suspension etc.

Maybe I'm just overly paranoid about my new car, who knows.
 

·
More free time than money
Joined
·
364 Posts
Does anyone notice the power band in first gear to be kind of wonky? There's two issues I notice:

1) when it's cold and the idling is around 1200-1500 RPMs and I ease off the clutch the car likes to launch itself into motion pretty darn quickly so I always have to shove the clutch back in before I ram something... It's weird cause as soon as I let it out fully, it'll then roll along quite slowly if I don't touch the gas, so not sure why it's launching off the line.

2) When starting off in first there seems to be two power sets: first is when I launch the car from 800-2000 RPMs it has a nice peppy start, but once I hit 2000RPMs there's a noticeable lag in power, then at 2500RPMs the car has loads of power again. It's very very strange and not sure if this is something other people notice or if there's an issue with my drive system somewhere? Bad clutch, no idea as I usually don't work on the engine components of a car - I still to electrical and mechanical as in brakes, tires, suspension etc.

Maybe I'm just overly paranoid about my new car, who knows.
Disclaimer: My 3i is the first stick car I've owned.
1) Ive noticed the same things as you. The car wants to keep at 1500rpm even after the 15seconds and i feel like the choice is whiplash or a smoked clutch for the 1st and 2nd gear every morning for the first mile or so.
2) Same on mine i think this is normal. Someone who knows more about engines than me can probably tell you its something to do with engine maps / timing / etc.
 

·
Registered
Joined
·
606 Posts
I'm experience the same thing on my gen 2 skyactiv 2.0 MTX, and its nice to see that I'm not the only one. Either you launch it below ~2000 rpm, or above ~2500 in 1st gear on a warm engine. In between, I also get jerky launches that promote stalling & clutch wear. Thought the situation might be different with Gen 3s, but I guess not. Considering this, I launch between 1500-2000 most of the time which produces relatively slow initial launches. After the the clutch is fully out, I go harder on the gas to gain on automatic cars around me that do faster launches. Anyone else find this?
 
  • Like
Reactions: barqers

·
Registered
Joined
·
323 Posts
Discussion Starter · #4 ·
Disclaimer: My 3i is the first stick car I've owned.
1) Ive noticed the same things as you. The car wants to keep at 1500rpm even after the 15seconds and i feel like the choice is whiplash or a smoked clutch for the 1st and 2nd gear every morning for the first mile or so.
2) Same on mine i think this is normal. Someone who knows more about engines than me can probably tell you its something to do with engine maps / timing / etc.
Glad to see it's not just me. It'd be nice if the car would ease off the throttle when you put it in gear instead of trying to hold that 1,500 RPMs because like you said, I either ram the guy in front of me and whiplash myself, or I burn the dang clutch out from feathering it so much for the first little bit. Hence why in the mornings I give super long distances between me and the next car until the revs drop.

Okay that's good to know. I thought it might've been a worn out clutch and it slips in the middle of the powerband until it kicks back in at higher RPMs. I had never experienced it on another car so my mind just shot to 'something must be wrong'
 

·
Registered
Joined
·
323 Posts
Discussion Starter · #5 ·
I'm experience the same thing on my gen 2 skyactiv 2.0 MTX, and its nice to see that I'm not the only one. Either you launch it below ~2000 rpm, or above ~2500 in 1st gear on a warm engine. In between, I also get jerky launches that promote stalling & clutch wear. Thought the situation might be different with Gen 3s, but I guess not. Considering this, I launch between 1500-2000 most of the time which produces relatively slow initial launches. After the the clutch is fully out, I go harder on the gas to gain on automatic cars around me that do faster launches. Anyone else find this?
Same mostly, but if I launch at 1,500 RPMs I find it to be quite quick for my tastes. My reaction goes like this through the power bands: launch @ 1500 RPMs which I find is much quicker than most cars in front of me so I always have to wait until they're much farther ahead before going, 2000RPMs power kind of drops, and so I either shift to 2nd or let it catch up @ 2500RPMs - 3000RPMs then shift. I'd rather get most of the power uniformly over 1500-3000rpms but it seems to come in inconvenient bursts.
 

·
Registered
Joined
·
606 Posts
Same mostly, but if I launch at 1,500 RPMs I find it to be quite quick for my tastes. My reaction goes like this through the power bands: launch @ 1500 RPMs which I find is much quicker than most cars in front of me so I always have to wait until they're much farther ahead before going, 2000RPMs power kind of drops, and so I either shift to 2nd or let it catch up @ 2500RPMs - 3000RPMs then shift. I'd rather get most of the power uniformly over 1500-3000rpms but it seems to come in inconvenient bursts.
Yeah, slowly increasing the gas such that the rpm is held at around 1500 while smoothly releasing the clutch seems to produce the smoothest launches and decent acceleration. This will probably make the clutch last longer, a likely reason why Mazda calibrated the power delivery this way.

On the Gen 3, you are right that power (torque) falls off a bit between 2000-2500 rpm, then increases lots after 2500. This can observed on dynos:

Gen 2 skyactiv vs. Gen 3 (CX-5). Note the CX-5 2.0 is comparable to a Mazda 3 Gen 3 2.0
CX-5 vs. mazda 3 dyno.jpg

CX-5 2.0 Corksport stock vs. SRI:
CX-5 SRI dyno.png

For the Gen 2 models tuned without the 4-2-1 header, the fall off is after 2500, and much larger. I was able to make the power delivery much smoother with my tune. I no longer see much power drop-off at 2500.
 
  • Like
Reactions: barqers

·
Registered
Joined
·
606 Posts
It's less apparent on the stock run here (maybe because of my other mods), but I removed the torque dip after 2500:
Stock vs. Tuned VDyno (both short ram intake & exhaust).jpg
 

·
Registered
Joined
·
323 Posts
Discussion Starter · #8 · (Edited)
It's less apparent on the stock run here (maybe because of my other mods), but I removed the torque dip after 2500:
View attachment 99074
Nice graphs btw, how'd you get those? Is it using a dyno where you hookup your car and strap it down then rev it, or do you use an app through an OBD2 scanner? I might've gotten the exact RPMs that I feel the power surge/drops at wrong a little bit, your graphs show the exact positions (I never have a chance to look at my RPMs since the tach is so tiny so I was guessing :p)

Your first graph shows it very nicely now, a steady start at 1500 RPMs, huge power surge from 2000-2500 rpms, then a huge huge drop off until 3000, that's the annoying dip I was talking about, I guess the idea is to probably start around 1500, rev til 2500 then switch. Doesn't give me long in first before needing to shift but I guess it is kind of a huge gear ratio drop from 3.36 to 1.68?
 

·
Registered
Joined
·
606 Posts
Nice graphs btw, how'd you get those? Is it using a dyno where you hookup your car and strap it down then rev it, or do you use an app through an OBD2 scanner? I might've gotten the exact RPMs that I feel the power surge/drops at wrong a little bit, your graphs show the exact positions (I never have a chance to look at my RPMs since the tach is so tiny so I was guessing :p)

Your first graph shows it very nicely now, a steady start at 1500 RPMs, huge power surge from 2000-2500 rpms, then a huge huge drop off until 3000, that's the annoying dip I was talking about, I guess the idea is to probably start around 1500, rev til 2500 then switch. Doesn't give me long in first before needing to shift but I guess it is kind of a huge gear ratio drop from 3.36 to 1.68?
The first graph was from Mazda Inc. It was extrapolated results from their real dyno testing (cars were strapped to rollers & engine rev). I should clarify that in the first graph, the Mazda 3 model was actually my Gen 2 Mazda 3, whereas the the CX-5 is comparable to your Gen 3. Here is a better graph from a Mazda skyactiv presentation comparing the actual Mazda 3 skyactiv 2.0 models Gen 2 (2012-13) vs. Gen 3 (2014+):
2012-13 vs. 2014 mazda 3 skyactiv 2.0 dyno.jpg

The second graph I posted was from an actual dyno performed by Corksport on a 3rd gen skyactiv (CX-5). I think K&N did a similar test on a 2014 Mazda 3 skyactiv 2.0 while testing their new SRI, and the dyno is on their website. These real dyno graphs confirm what Mazda was showing.

So for your car, the dip in torque actually happens between 2000-2500 rpm, whereas on mine from 2500-3000 and becomes way more pronounced. The huge dip on mine is why I really wanted to tune it out... Based on your smaller torque dip, it would be smart to shift right after hitting 2000 rpm as you said or rev past the dip to >2500. Your feeling of the low-end power band is spot on. For my car (or at least on the stock tune), I need to shift anywhere <2500, or rev it past 3000 to avoid the larger dip. And for the 3rd tuning graph, its a Vdyno from calculated results recorded through the OBDII port. I just posted it to give you an idea of the shape of the curve rather than numbers.
 
  • Like
Reactions: barqers

·
Registered
Joined
·
323 Posts
Discussion Starter · #10 ·
The first graph was from Mazda Inc. It was extrapolated results from their real dyno testing (cars were strapped to rollers & engine rev). I should clarify that in the first graph, the Mazda 3 model was actually my Gen 2 Mazda 3, whereas the the CX-5 is comparable to your Gen 3. Here is a better graph from a Mazda skyactiv presentation comparing the actual Mazda 3 skyactiv 2.0 models Gen 2 (2012-13) vs. Gen 3 (2014+):
View attachment 99090

The second graph I posted was from an actual dyno performed by Corksport on a 3rd gen skyactiv (CX-5). I think K&N did a similar test on a 2014 Mazda 3 skyactiv 2.0 while testing their new SRI, and the dyno is on their website. These real dyno graphs confirm what Mazda was showing.

So for your car, the dip in torque actually happens between 2000-2500 rpm, whereas on mine from 2500-3000 and becomes way more pronounced. The huge dip on mine is why I really wanted to tune it out... Based on your smaller torque dip, it would be smart to shift right after hitting 2000 rpm as you said or rev past the dip to >2500. Your feeling of the low-end power band is spot on. For my car (or at least on the stock tune), I need to shift anywhere <2500, or rev it past 3000 to avoid the larger dip. And for the 3rd tuning graph, its a Vdyno from calculated results recorded through the OBDII port. I just posted it to give you an idea of the shape of the curve rather than numbers.
Wow I totally see the difference now. If I noticed that slight decrease in power from 2000-2500 I couldn't imagine how noticeable the 2500-3000 drop in gen2s would feel. No idea where you found all the graphs but they're very helpful in understanding where the power is felt in the rev range. Compared to my old E46 I noticed more of a smooth consistent power range and a drop off around 4500-5000 RPMs which was why I thought a drop in the middle of the range and a pickup 500RPMs later wasn't possible.

I guess shifting before 2000 RPMs is possible, just seems low to me, definitely won't be drag racing this car, even though apparently the 2.5L has a 7.3s 0-60 time, I wonder what the 2.0L is, probably around 10-11s considering how low we have to shift first to maximize the power
 

·
Registered
Joined
·
606 Posts
Wow I totally see the difference now. If I noticed that slight decrease in power from 2000-2500 I couldn't imagine how noticeable the 2500-3000 drop in gen2s would feel. No idea where you found all the graphs but they're very helpful in understanding where the power is felt in the rev range. Compared to my old E46 I noticed more of a smooth consistent power range and a drop off around 4500-5000 RPMs which was why I thought a drop in the middle of the range and a pickup 500RPMs later wasn't possible.

I guess shifting before 2000 RPMs is possible, just seems low to me, definitely won't be drag racing this car, even though apparently the 2.5L has a 7.3s 0-60 time, I wonder what the 2.0L is, probably around 10-11s considering how low we have to shift first to maximize the power
That big dip in torque was very noticeable when I first got the car coming from a prior V6. Felt like I had so little torque before the tune. The effect is probably less pronounced on Gen 2s though, considering the 2014+ 2.0 uses taller gears 1-3. That may be why Gen 2 and 3 skyactiv's achieve about the same 0-60 (7.8-7.9s) even though the Gen 3 is a bit lighter and has more low end torque. Gen 3s do get better city fuel economy because of the gears.

2012 Mazda 3 i Touring Skyactiv Test - Review - Car and Driver
2014 Mazda 3i Hatchback 2.0L Test ? Review ? Car and Driver

True, shifting @ 2000 can be fairly low and promote engine bogging. Your car makes a fairly steady increase in torque throughout the low end range. That tiny decrease after 2000 is probably not enough to make that much difference overall, but it can be useful knowing that its there.

The 0-60 between 2.0 and 2.5s are actually not too far apart for the manual trans versions. The big advantage in the 2.5 is the low end torque. It's also proven to be very tunable (post #138 ):

2.5G power potential - Page 14 - Mazda 6 Forums : Mazda 6 Forum / Mazda Atenza Forum
 
  • Like
Reactions: barqers

·
Registered
Joined
·
39 Posts
Wow I totally see the difference now. If I noticed that slight decrease in power from 2000-2500 I couldn't imagine how noticeable the 2500-3000 drop in gen2s would feel. No idea where you found all the graphs but they're very helpful in understanding where the power is felt in the rev range. Compared to my old E46 I noticed more of a smooth consistent power range and a drop off around 4500-5000 RPMs which was why I thought a drop in the middle of the range and a pickup 500RPMs later wasn't possible.

I guess shifting before 2000 RPMs is possible, just seems low to me, definitely won't be drag racing this car, even though apparently the 2.5L has a 7.3s 0-60 time, I wonder what the 2.0L is, probably around 10-11s considering how low we have to shift first to maximize the power
Here's my stock 2.0 manual https://youtu.be/7b0xy8cUgVM
 
1 - 13 of 13 Posts
Top