Question DCT downhill engine braking

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670cc

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Late model DCT owners, I have a question regarding downhill engine braking. A long time ago I was riding a DCT, and I think at the time it as a CTX700. It would have had what I believe was called the second generation DCT. (D or S, no S1,2,3). On the test ride there was a steep downhill section. In either D or S mode, I could not use engine braking to slow my decent. When the engine couldn’t hold the speed, the speed would increase and then the DCT would upshift, which is exactly the opposite of what I wanted for engine braking. So the only way to engine brake successfully on a steep hill was to go to manual mode.

My question is, has the third generation DCT addressed this shortcoming? I seem to remember talk about the bike having an angle sensor so it would know if it was on a hill. Maybe it was only on the Africa Twin, or maybe I’m imagining it. Does anyone know if late model 700/750 DCTs have an automatic downhill mode by way of a sensor? My Ford car has a DCT and it has a button on the shifter you press for downhill mode, and it provides good engine braking. It would be nice if Honda motorcycles had that, too.
 
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dduelin

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There was no mechanical angle sensor. It would be easily fooled by G forces. Instead of a angle sensor the PCM of the Africa Twin transmission compared wheel speed to rpm or in later models throttle position to determine if the bike was gathering speed or losing speed in a way that could only be explained by riding up or down a grade.

PS I never thought of the situation as a shortcoming. You have brakes, you have mode choice. Sure, it's different from a manual transmission but the brain can cope with available options.
 

670cc

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There was no mechanical angle sensor. It would be easily fooled by G forces. Instead of a angle sensor the PCM of the Africa Twin transmission compared wheel speed to rpm or in later models throttle position to determine if the bike was gathering speed or losing speed in a way that could only be explained by riding up or down a grade.

PS I never thought of the situation as a shortcoming. You have brakes, you have mode choice. Sure, it's different from a manual transmission but the brain can cope with available options.
Thanks for the info. It apparently was the Africa Twin I was thinking of. I thought maybe the latest NC had such a feature. Like I said, my DCT car has a downhill mode. When engaged, each time you tap the brake it will downshift one more gear if conditions allow. My Ford E-450 does the same in tow/haul mode to minimize the need for brakes, particularly on hills. I found it to be a very handy feature. It would be cool if Honda could implement a type of engine brake mode on the NC, but apparently, as you suggest, the AT got the attention in that area.
 
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dduelin

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Thanks for the info. It apparently was the Africa Twin I was thinking of. I thought maybe the latest NC had such a feature. Like I said, my DCT car has a downhill mode. When engaged, each time you tap the brake it will downshift one more gear if conditions allow. My Ford E-450 does the same in tow/haul mode to minimize the need for brakes, particularly on hills. I found it to be a very handy feature. It would be cool if Honda could implement a type of engine brake mode on the NC, but apparently the AT got the attention in that area.
Maybe the newer or newest NCs have it. I didn’t address that question. However I’ve never read or heard about it except in the AT.
 

CapeMan

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2018 DCT here - I don't know if my experience is universal, but there goes ...

I most always ride in S1 (Sport 1, the lowest of three sport modes but not as "dull/boring" as the default "D" or Drive setting) When I'm in S1 on a long descent, I can use the paddle shifter to drop a gear (or two) and the bike will generally stay in that lower gear as long as the engine is really providing a substantial amount of engine braking. After I've slowed enough, either because the initial engine braking really overcomes the hill steepness and I'm actually slowing down or perhaps because the hill is actually flattening out over the course of the downhill run, the DCT will upshift. If the descent isn't steep enough to really justify engine braking from the start, it upshifts sooner.

In essence, if ya really need engine braking, i.e. it's really keeping you from accelerating 'cause of gravity, you can have it when ya ask for it. If ya don't really need engine braking, the DCT will kick it up a gear (saves some revs , I guess) It actually works pretty well - color me impressed.

Of course, this is auto mode. In manual mode, it's your choice - just pick a gear!

That help??
 

Doc True

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If you downshift, the engine will hold that gear until it receives throttle input. I think if you don't downshift, it will upshift automatically based on speed.

Just tap the downshift, and you're engine braking down the hill. There's no separate mode for it
 

670cc

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If you downshift, the engine will hold that gear until it receives throttle input. I think if you don't downshift, it will upshift automatically based on speed.

Just tap the downshift, and you're engine braking down the hill. There's no separate mode for it
OK. Maybe I touched the throttle or something. When I was riding, the hill was steep enough that the engine braking could not keep the speed from increasing. When the speed increased enough, with closed throttle, the DCT upshifted, when what it really needed to do in that situation was downshift. But maybe I touched the throttle and that triggered the upshift. Next time I have the chance I will try it again.
 

DirtFlier

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On my 2013 DCT, I never considered that it lacked compression braking. As DDuelin stated, "...it has brakes." If I feel my bike is going too fast down a hill, I apply the brakes and also manually downshift.
 

670cc

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On my 2013 DCT, I never considered that it lacked compression braking. As DDuelin stated, "...it has brakes." If I feel my bike is going too fast down a hill, I apply the brakes and also manually downshift.
I understand, but I wasn’t looking for options or workarounds. My question was about how the DCT brain can or does make use of engine braking on steep downhill situations in automatic mode. If you say you need to downshift manually, then apparently the DCT is unaware that it is on a hill. I was thinking that at I had read that a program or sensor was added for that situation, but the answers so far suggest that is not the case at all or not the case for the NC DCT. I guess it like my car’s DCT, which requires manual intervention in that downhill situation.
 
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the Ferret

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I understand, but I wasn’t looking for options or workarounds. My question was about how the DCT brain can or does make use of engine braking on steep downhill situations in automatic mode. If you say you need to downshift manually, then apparently the DCT is unaware that it is on a hill. I was thinking that at I had read that a program or sensor was added for that situation, but the answers so far suggest that is not the case at all or not the case for the NC DCT.
I was thinking about your thread yesterday when riding my other manual clutch bike and was going down a slow curvy hill after just coming off a long straight at a higher speed, just coasting and using engine braking, and thinking since I was going slower than on the long straight, the DCT would probably downshift (which is what I did with the manual shift) but if coasting and picking up speed the DCT would probably upshift ? ..... but I don't know ... I have no experience with a DCT yet.
 

670cc

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I was thinking about your thread yesterday when riding my other manual clutch bike and was going down a slow curvy hill after just coming off a long straight at a higher speed, just coasting and using engine braking, and thinking since I was going slower than on the long straight, the DCT would probably downshift (which is what I did with the manual shift) but if coasting and picking up speed the DCT would probably upshift ? ..... but I don't know ... I have no experience with a DCT yet.
Let me know what you experience when you get your new DCT. I would think anytime the DCT brain sees speed increasing with a closed throttle, it would not upshift (except to prevent engine damage if it was about to hit redline), but in my memory of the second generation DCT, that was not the case.
 

Havok

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On my 2020 the automatic downshift is related to speed. As I use my brake the bike will automatically downshift.
If I am going down hill as I brake the bike will automatically downshift and hold the lower gear. If I manually downshift the bike also holds that gear. I have not experienced the bike upshifting while going downhill with throttle closed.
 

670cc

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On my 2020 the automatic downshift is related to speed. As I use my brake the bike will automatically downshift.
If I am going down hill as I brake the bike will automatically downshift and hold the lower gear. If I manually downshift the bike also holds that gear. I have not experienced the bike upshifting while going downhill with throttle closed.
Thanks. Then either I had unintentionally touched the throttle going downhill during my test of the second generation DCT, or Honda has improved the programming on the third generation DCT (which answers my original question).
 

CapeMan

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On my 2020 the automatic downshift is related to speed. As I use my brake the bike will automatically downshift.
If I am going down hill as I brake the bike will automatically downshift and hold the lower gear. If I manually downshift the bike also holds that gear. I have not experienced the bike upshifting while going downhill with throttle closed.

Unless, I think, you are actually, really slowing down and the engine revs are dropping. It seems to me that as long as the revs are high and the engine braking is doing some good, the DCT will hold the gear I'm in but when the revs start dropping, I'll get an upshift at some point. When that happens, I can use the downshift switch to force a lower gear but unless the hill has gotten steeper, the DCT will upshift again fairly soon. Consistent with your experience?
 

Red Rider

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Thanks. Then either I had unintentionally touched the throttle going downhill during my test of the second generation DCT, or Honda has improved the programming on the third generation DCT (which answers my original question).

Let’s see if this helps. To leave or enter the area where we live there are two very steep and very long hills. It’s the low mountainous region around Birmingham. After reading your question, I’ve made it a point to see just what the DCT does in D mode if “left to its own device”.

Normally as I begin these descents I’ll be in D mode slowing down into third and then, just before going over the crest to start down, I’ll hit the button and take it to second gear - still in D mode. This puts it a little higher in the rev range of second but my throttle is CLOSED. Now starting the descent...

Normally, as I coast down the hill, I’ll engage the brakes a few times just to limit the RPM’s as the bike revs higher without shifting itself to third. The last couple times, I’ve stayed off the brakes.

The hills are simply too steep for the engine braking alone to maintain a speed compatible with second gear. It climbs to a little over 4000rpm and that seems to be where it holds onto as I near the bottom of the hill still with CLOSED throttle and no braking.

As the road begins to level and I’m at a point where I need to “take over” again, I’ll very gently re-engage the throttle. As I do the bike will promptly go to third gear and a moment or so later, to fourth. Throttle now full engaged and I’m back to normal.

Hope that helps - if you need further info let me know, I ride these areas very often.

this is a 2016 DCT... bought new
 

670cc

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Let’s see if this helps. To leave or enter the area where we live there are two very steep and very long hills. It’s the low mountainous region around Birmingham. After reading your question, I’ve made it a point to see just what the DCT does in D mode if “left to its own device”.

Normally as I begin these descents I’ll be in D mode slowing down into third and then, just before going over the crest to start down, I’ll hit the button and take it to second gear - still in D mode. This puts it a little higher in the rev range of second but my throttle is CLOSED. Now starting the descent...

Normally, as I coast down the hill, I’ll engage the brakes a few times just to limit the RPM’s as the bike revs higher without shifting itself to third. The last couple times, I’ve stayed off the brakes.

The hills are simply too steep for the engine braking alone to maintain a speed compatible with second gear. It climbs to a little over 4000rpm and that seems to be where it holds onto as I near the bottom of the hill still with CLOSED throttle and no braking.

As the road begins to level and I’m at a point where I need to “take over” again, I’ll very gently re-engage the throttle. As I do the bike will promptly go to third gear and a moment or so later, to fourth. Throttle now full engaged and I’m back to normal.

Hope that helps - if you need further info let me know, I ride these areas very often.

this is a 2016 DCT... bought new
Sounds good. I think your 2016 is 3rd gen DCT.
 

Havok

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On my 2020 the automatic downshift is related to speed. As I use my brake the bike will automatically downshift.
If I am going down hill as I brake the bike will automatically downshift and hold the lower gear. If I manually downshift the bike also holds that gear. I have not experienced the bike upshifting while going downhill with throttle closed.
I guess I should have clarified my statement by adding I always ride in S3 which holds gears longer. Also no mountains in Iowa so my hill’s don’t compare to some other posters.
 

670cc

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I guess I should have clarified my statement by adding I always ride in S3 which holds gears longer. Also no mountains in Iowa so my hill’s don’t compare to some other posters.
Ok. That might make a difference. I was thinking of a pretty steep hill, where engine braking could/would play a big role. I dunno, maybe something like a 11+ degree incline.

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Red Rider

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These hills are just what you’re looking for. ;-)

I’m certain that if the DCT was ever going to shift on its own while coming down a mountain it would have done so rather than screaming along at almost 4500rpm in second gear. I don’t know about “incline sensors”, I really haven’t read up on all the wizardry that goes into these transmissions, but I‘m thinking the closed throttle position mentioned previously must be a key factor.

I’ve really enjoyed adapting to the technology and learning how to use it to its full potential in any riding condition I encounter - every time I start mulling over something new and different in the garage - and deciding what must go, I decide all over again this NC STAYS!

But that doesn’t mean I know jack about what makes it work.
 
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