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Discussion Starter · #1 · (Edited)
I've come to the conclusion I really do hate this dual mass flywheel. I don't think I've ever had a car with a dual mass flywheel before. But I definitely don't like the one on this car.


#1 it's so soft on takup and the springs adds another level of complexity in managing the release of the clutch. It's like a box of chocolates, you never know what kind of take up you are going to get, which makes letting out the clutch a bit of a crapshoot even after a year of driving.

#2 The springs between the dual masses are soft and the rotational stop at the end of relative travel is metallic hard. So when I shift hard (yes even before I got the tune) the dual mass flywheel bottoms out with a "BANG'

It doesn't rock the car but it's very sharp and violent to the drivetrain, way more so than a hard shift with a single mass flywheel where the clutch is fully responsible for arbitraging the load. It makes me reluctant to perform hard shifts on any regular basis, again I'm left trying to shift as fast as I can without bottoming out the flywheel, which is almost impossible to do with any consistency.

#3 The flywheel is too heavy. Granted I came from a miata with an 8.5 lb flywheel that the car loved, but I think the Mazda 6 would really benefit from a 12-14lb lightened steel flywheel. The main reason is 1st gear is so short that the engine is accelerating so fast that the flywheel is sucking major energy from the engine that could be going to the wheels. 2nd gear is much taller but would still have a noticeable acceleration benefit. i've always loved the smoother shifting and quicker throttle response and acceleration in gear of a light flywheel at every amount of throttle not just full throttle. it would sure be nice to have that on this car.


So I sure hope between the Mazda 3s MTX and the Mazda 6 MTX that there is enough interest for Exedy or somebody to develop a single mass flywheel replacement to resolve my dissatisfaction.
 

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I am in full agreement with everything you've said here. I love the shifter in this car, but the flywheel/clutch feel so laggy that it's a constant struggle to drive smoothly. I always feel like I'm slow with letting the clutch out on the 1-2 shift because I'm trying to find the right engagement point.

Given that Mazda didn't offer the MTX on the GT and the 2.5L Skyactiv isn't much for performance, I'm not holding my breath on there being a market strong enough for someone to put $$$ into the development of a flywheel kit. The 3 having the same engine/transmission would help significantly, though. Did they offer the MTX on the 3GT?
 

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My suspicion is that the DMF + clutch is basically the diesel's.

DMFs are usually used in diesel applications as a means to smooth out the idle. SMFs on diesels often rattle unacceptably for most people and this not only translates into vibration you can feel you also wind up hearing it.

What we don't know (and won't learn unless Mazda opens up with the data) is whether the DMF dampening is part of the engine's dynamic balance and thus not so much a parts-convenience thing for Mazda, but was actually engineered into the SkyActiv engine design. If so then swapping it out runs the risk of long-term and quite-severe trouble with engine internals (e.g. crank end bearings, etc.)

A SMF would probably require a different clutch too due to how the pressure plate and clutch itself is designed to interface with the DMF. I don't know if there's enough of a market for anyone to come up with the engineering on this -- and it's a fairly expensive job to swap them due to the requirement to drop the gearbox to get to it. Getting the gearbox out is frequently a serious pain in the ass on front-drive cars leading to nasty labor bills if you pay someone and a lot of hassle if you do it yourself.
 

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^^^ This.

Don't disagree that a SMF would have some serious perfomance benefits, but I would imagine the NVH impact would be pretty noticable... all that undampened energy has to go somewhere, and it's not just going to end up at the wheels.
 

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There's no way to know what the NVH impact would be without either trying it (expensive and a pain in the butt, especially if you don't like the result and have to rip the car apart a second time to put it back!) or Mazda's engineers coming out and talking about it in some context.

Mazda does have a performance division, and it MIGHT be possible for someone who has a relationship with them to tease out some information on this subject. There's nothing really proprietary there since the DMF is a known thing in the car and not a secret, but the reason it was used is something I'd want to know before I spent the 8+ hours ripping the car apart to change it out.

It's not the money for the clutch and flywheel kit that's the problem, it's the labor.
 

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Discussion Starter · #6 ·
I've always heard people complain about NVH with lightweight flywheels, but didn't experience any of that on the miata. If anything it was better because shifts were smoother as a result of the reduction in energy transfer during shifts. Could have just been that engine though. I know the 2.5 is big enough it has balancing shafts and still you can tell the idle is a little lumpy. I'm not sure how much of that would translate into NVH in the cabin.

I cringe at the thought the flywheel could be a harmonic balancer for the engine. That would be bad to change it in that case. I thought he crankshaft pulley off the front was typcally the harmonic balancer.

I likely wont try to replace the flywheel until I need a new clutch which is way out there in time. For now I'mm just complaining.

I've heard something like $1500 quated to have fidanza design a new lightweight flywheel condition, but that may be a different story going frmo DMF to SMF, and they still need to borrow somebody's car for a bit.

I like the idea of an Exedy lightweight flywheel because their clutch disks for stage 1 are pure bliss. So they would likely develop a flywheel and stage 1 clutch as a combo that would be made for each other literally.
 

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I wouldn't EXPECT that the DMF is part of the harmonic balancing scheme for the engine (yes, it's usually in the front pulley) but a DMF is unusual on a gas engine, so.....
 

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Discussion Starter · #8 ·
I wouldn't EXPECT that the DMF is part of the harmonic balancing scheme for the engine (yes, it's usually in the front pulley) but a DMF is unusual on a gas engine, so.....
Also for the DMF to be the harmonic balancer means the funky ATX dual clutch/torque converter would have to have matching mass properties as the DMF which makes it even more unlikely. Although from my back to back test drives I would say engine acceleration out of gear was very similar between the two trannies.
 

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I am so glad this is not just me somehow sucking at driving stick. I've been driving stick smoothly for years and this car frustrates the hell out of me with the electronic throttle lag, weird clutch and I now realize it has a dmf. My opinion is that the vibrations would be horrible without a dmf. Since they are expensive and complex, Mazda would not put them on the car unless they really needed to. Although you could argue they were willing to spend a little money to reach for an upscale smooth feeling. 2.5 liters is pretty big for a 4 cylinder, after all.

My friend let me drive his 91 miata and it felt like home again. The best thing I can contribute is, this car seems to like to start with a bit more slip than other cars, but when shifting from gear to gear you either have to wait for the revs to fall to the right spot to the next gear, or use more gas and slip the clutch very minimally, aka let it out to a point closer to fully engaged, an "aggressive" change if you will.

I've also noticed that the shifter itself requires you to be a little more forceful, otherwise it snags especially when cold. I think this is a result of all those close tolerances.
 

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I agree! I thought it was just me! I have been driving manuals for years. I have a 2015 sport and some days are better then others. I have about 5000 miles. My only issue is the 1-2 shifts. The clutch is very ticklish. The pedal has a low engagement point. When shifting from 1-2 if you let of the clutch to fast it will jerk. Like your popping the clutch to fast. You almost feel like you have to ride the clutch. I'm still getting use to it. It's like I have to over think it when I shift from 1-2(Gas and clutch seems like i have to use special science) the other gears feel pretty good. I agree you have to use a bit of force when shifting to be more precise. Overall I enjoy the car. I'm about to get my first service. Should I ask the dealer to check anything specific in regards to this?
 

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I can't comment on the technical aspects of this thread, but I agree totally with the gripes about the clutch. In test driving I assumed that I just needed practice to learn how to make it work smoothly, but after 4500 miles I still can't get 1st and 2nd gear to engage without a lurch, and I've been driving manuals for 45 years. There are a lot of things I like about the car, but this is a real problem. I drive manuals for the driving enjoyment, and this problem puts a mild damper on that every time I get in the car. :-(
 

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Thanks tickerguy. Someone also said I should have the dealership check the tranny fluids.
I highly doubt that there's an oil level problem in the gearbox, although it's easy to check. Odds of it being low at this mileage (unless there's an obvious leak on the gearbox or around the half-shaft boots at the gearbox) is near zero.

I have no problem with smooth launches but the 1-2 shift issue is a matter of the ratio between 1 and 2 being quite wide. The rest of the gears are reasonably narrow (I'd argue maybe too narrow) between them; what would have been nicer is to have a somewhat narrower 1-2 ratio difference and then widen the rest. But that's not what we got, so it is what it is. I suspect what Mazda was TRYING to do is wind up with a 0-60 run with one shift; they failed due to the rev limiter starting to pull power stock before you get to 6k RPM, but given how road speed, gear and redline all align it's pretty obvious what they were attempting (60mph comes up in 2nd almost exactly at the redline.)

It took me a bit to adjust and once in a while I still get a little rough 1-2 engagement but I don't find it to be a big deal.
 

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Discussion Starter · #15 · (Edited)
No, it's the 1-2 ratio -- it's quite wide, and that's a tough combination especially with a DMF.
Yes. As much as people don't want to do it, you need to shift from 1st to 2nd at 3500-4000 rpm to overcome the ratio spread and get a consistently smooth 1-2 shift. That's your two options. A rough 1-2 shift or high revving in 1st.

It's one of the three things I always have to remember force myself to do: rev high in 1st gear, always lead the shift with the depression of the clutch, not the release of the gas pedal, and finally shifting the lever with more gusto, not more finesse. Do those things consistently and shifting stays smooth consistently.

Also, the miata has always had the large 1-2 ratio spread, although the tranny and engine seemed to deal with it more gracefully. I read one time about an automotive journalist complaining about that to a mazda engineer who shrugged his shoulders and said "1st gear is just for getting out of the pits."

One could argue 1st gear isn't short enough until you are spinning the tires all the way through the gear, but I understand this is not a race car it is a family car that often has passengers that prefer to not look like bobble-head dolls, andthe shorter 1st gear is the shorter 2nd gear should be so you don't drop out of the powerband on redline shifts.
 

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If I was going to change one thing about this car it would be the ratio factors.

I'd leave 1st alone, shorten 2nd a good bit and then pull down 3-5 to fill the gap.

But I know why Mazda didn't do it, as it's quite clear the intent was to make a 0-60 run a one-shift deal. They blew it with the stock ECU however, in that it yanks power at ~5700 RPM, leaving you short of the mark in second gear!

With the new ECU code, however, it's now an entirely-reasonable proposition.....
 

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Its a shame the zero to 60 test has become the only go-to for acceleration. Quarter mile is much better at showing a cars actual acceleration power, whereas the 0-60 takes more of drive layout and tires in the equation.

I agree about needing to wind out first more than usual and pushing in clutch before gas. Tried the clutch one on the way to work today and it works pretty good.
 
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Yes. As much as people don't want to do it, you need to shift from 1st to 2nd at 3500-4000 rpm to overcome the ratio spread and get a consistently smooth 1-2 shift. That's your two options. A rough 1-2 shift or high revving in 1st.

It's one of the three things I always have to remember force myself to do: rev high in 1st gear, always lead the shift with the depression of the clutch, not the release of the gas pedal, and finally shifting the lever with more gusto, not more finesse. Do those things consistently and shifting stays smooth consistently.
I constantly find my self jerking aroung a corner or off the line with a 1-2 shift. I agree with your technique. I shift at 4000 and lead in with the clutch and hold the clutch in until 2500 and slow to get back on gas...
 

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Have the same issues as the rest of you. I too thought it was me needing to get used the clutch even though all of my cars except for one have been a manual in the last 20 years. I get a jerky surprise every now and then from a rolling start and either have to gas it or immediately up shift. Overall I like the trans and clutch feel but the DMF much like my Golf TDI adds a wild card to the shifting experience.


Sent from AutoGuide.com Free App
 

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Hi all, I agree with a lot of others comments. I solved the issue by letting the clutch slower with a consistent travel, especially from 1-2. I also find everything shifts smoother if there is always a minimum level of throttle. i.e. lift off of the throttle so the revs drop but not all the way off. After a year and a bit, I am pretty much up to 98% smooth shifting but every once and a while "crap shoot". I also find if I think about it too much it gets worse.
 
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