DCT or Manual

[yticolev]

That picture explains something I had always wondered about multiplate clutches. I had always pictured several discs coming together in full contact with each other and I had wondered how that could be an advantage. The picture appears to make it clear that the full surface area of each plate is working against the a pressure plate.

Thanks for the explanation of primary gear ratio. It is a step down from the crankshaft, reducing the rpm presumably.

If the effective final drive is the same, that can only leave frictional losses from the additional clutch to account for the lower mpg right? The additional weight is trivial at around 25 pounds. A commonly found estimate is that every 100 pounds reduces fuel economy by 2% - so about 0.5% in this case. That is a full order of magnitude lower than the 5% that Honda states. Clearly it is not the extra weight.

 

[Phil X]

Did anyone test mpg when riding a DCT 100% manually switched same style she/he would ride a manual clutch version? This would bring valuable result for the mpg discussion. As long as the computer does all gear switching, there is no use in accurate comparing DCT vs. non-DCT mpg.
Reason: so many times when riding along in 6th gear and speeding up, one would not consider gearing down just to gain some speed. Well, DCT does so. For nearly any speedup in 6th gear it will gear down 1 or 2 shifts. This is somewhat convenient since it gives better acceleration, but in terms of mpg is will definitely increase fuel consumption, especially due to the fact it may take its time until it goes back to 6th gear after accelerating. Since this happens very often, I guess this is the main reason for mpg gap.

 

[L.B.S.]

Is there an automatic transmission versus a manual, on *any* vehicle that has ever done better for "best" mpg?

I'm thinking it's not the nitty gritty of .0001% final drive ratio differences, added weight, frictional losses etc., etc., so much as just a human being able to decide when and where to shift or accelerate/decelerate, coast, and so on.

 

[yticolev]

Automatic transmissions as the term is commonly used refers to indirect hydraulic transmissions. That is very different from a direct drive clutch mechanism, even if you can automate the shifts. The efficiency should be the same as a manual clutch - and that is what we are trying to figure out why it is not.

I think if Honda can specify a difference in mpg between the manual and DCT, there is some mechanical difference, not human nature. Obviously, different riding techniques will result in individual results.

 

[L.B.S.]

Automatic transmissions as the term is commonly used refers to indirect hydraulic transmissions. That is very different from a direct drive clutch mechanism, even if you can automate the shifts. The efficiency should be the same as a manual clutch - and that is what we are trying to figure out why it is not.

I think if Honda can specify a difference in mpg between the manual and DCT, there is some mechanical difference, not human nature. Obviously, different riding techniques will result in individual results.

Dood I know what an auto tranny versus the dual clutch is. In this context yes of course, the NCX has a dual clutch and not a TH400 lol.

My point was, all things being equal, I still think a human shifting would win out for mpg numbers, versus an auto, no matter how that "auto" actually does the shifting.

...and 942 Angels can dance on the head of a pin!

 

[yticolev]

Well, a CVT beats most other manually or automatically shifted transmissions. And it does it even though it is less mechanically efficient than a direct drive clutched transmission. The efficiency gains to be had in keeping the engine in an efficient range beats the CVT transmission losses.

Excluding CVTs, I think automatic shifting algorithms will beat manual ones most every time. Whether optimizing power like on the drag strip, or economy cycles. That is why the DCT mileage is so puzzling.

 

[L.B.S.]

Well, a CVT beats most other manually or automatically shifted transmissions. And it does it even though it is less mechanically efficient than a direct drive clutched transmission. The efficiency gains to be had in keeping the engine in an efficient range beats the CVT transmission losses.

Excluding CVTs, I think automatic shifting algorithms will beat manual ones most every time. Whether optimizing power like on the drag strip, or economy cycles. That is why the DCT mileage is so puzzling.

Arguable intricacies aside, I have no horse in this race anyway, because I get sucky mileage compared to most everyone else with an NC700X lol

 

[Mycool]

Well, a CVT beats most other manually or automatically shifted transmissions. And it does it even though it is less mechanically efficient than a direct drive clutched transmission. The efficiency gains to be had in keeping the engine in an efficient range beats the CVT transmission losses.

Excluding CVTs, I think automatic shifting algorithms will beat manual ones most every time. Whether optimizing power like on the drag strip, or economy cycles. That is why the DCT mileage is so puzzling.

I'm puzzled by where this thread is going...

 

[670cc]

Been down this road before: http://nc700-forum.com/forum/nc700-general-discussion/744-fuel-efficiency-manual-dct.html

Didn't solve the "problem" back then either.

 

[turbodieseli4i6]

I'm puzzled by where this thread is going...

My bet says the OP will get a DCT.

 

[yticolev]

Been down this road before: http://nc700-forum.com/forum/nc700-general-discussion/744-fuel-efficiency-manual-dct.html

Didn't solve the "problem" back then either.

Meaning another dead end? That thread didn't come to any conclusions either.

 

[L.B.S.]

I'm puzzled by where this thread is going...

Did you ever have the chance to see a show on tv years ago, called "Connections"?

James Burke: Connections | Watch Free Documentary Online

It was an awesome show, that traced the (for the most part) inventions of many cool things, and explained how, despite the sheer absurdity and random seeming events, direct connections could be made through the supposed "flukes" and general chaos of life, to lead up to a spectacular invention, an important answer, conclusion, or breakthrough.

I often wonder when threads seem to veer off and go in peculiar directions, if one day, we might collectively stumble upon "awesome" by the strangest of happenstance.


...especially if I've had one too many beers.

 

[turbodieseli4i6]

Did you ever have the chance to see a show on tv years ago, called "Connections"?

James Burke: Connections | Watch Free Documentary Online

It was an awesome show, that traced the (for the most part) inventions of many cool things, and explained how, despite the sheer absurdity and random seeming events, direct connections could be made through the supposed "flukes" and general chaos of life, to lead up to a spectacular invention, an important answer, conclusion, or breakthrough.

I often wonder when threads seem to veer off and go in peculiar directions, if one day, we might collectively stumble upon "awesome" by the strangest of happenstance.


...especially if I've had one too many beers.

Impossible I say! Having too many beers that is.

 

[Mike Cash]

Did you ever have the chance to see a show on tv years ago, called "Connections"?

James Burke: Connections | Watch Free Documentary Online

It was an awesome show, that traced the (for the most part) inventions of many cool things, and explained how, despite the sheer absurdity and random seeming events, direct connections could be made through the supposed "flukes" and general chaos of life, to lead up to a spectacular invention, an important answer, conclusion, or breakthrough.

This is very true. Consider for instance the fact that if Gutenberg hadn't first invented the printing press almost four hundred years earlier, Alexander Graham Bell never could have invented the telephone.

 

[Pabaldeagle]

My brain hurts.

 

[johnakay]

View attachment 3689
My brain hurts.

glad I don't ..theres bugger all in mine1 if I shake my head it'll sound like one of these

no wonder I canna sleep at nights