I have asked 2 dealers what the difference is between the D and the S on the shifter... neither one could answer me... Any ideas? I don't have one yet but would like to know what it means before I get it since the dealers don't seem to know...

 

You can consider S to be somewhat like 2cd on a conventional automatic or like a sport mode. Essentially it keeps the transmission "gear" ratio lower, allowing the engine to rev higher at any given speed. That allows you acheive a "sportier" driving experience or engine braking while coasting down steep grades, reducing the amount of braking necessary to maintain speed going down that grade. In fact, your HCH has no real gears at all.

 

Brandon,

According to the '06 HCH Manual:

S = Second - Used for better acceleration, and increased engine braking. Use when you are going down a steep hill, or in stop & go traffic.

L = Low - Use low to get more power when climbing, and for maximum engine braking when going down steep hills.

I have never tried either to accelerate, BUT I have found both helpful when descending steep snow-covered hills. I also have not used in stop & go traffic.
I live in a rural setting.

Best of luck,

 

The S gear causes the engine to rev higher.

There is a steep downhill for me soon after I leave home. When I use D it's too soon for regen to kick in when going down that hill. But if I shift to S regen kicks in immediately.

 

In the HCH-I at least, full regen only seems to happen when the engine is spinning at 1500RPM or faster. I suppose that is minimum RPM at which the electric motor can take its full charge.

I will usually use "S" going downhill from my house every day. I live on a long steep hill, and even with full regen, I would still need to ride by brakes with the transmission in "D" to stay within a reasonable margin of the speed limit. I set the tranny to "S" and on warmer days actually run the A/C on max all the way down as well-- this has the added benefits of both saving my brake pads, and saving me fuel, this cools the car down a lot, then if I run the A/C on a hotter temp, it only has to come on sparingly to maintain that.

 

Given that 'S' disables Auto Stop, I thought about shifting to 'S' when I'm coming to a stop that I know will only last a very short time. For example, coming to a stop sign, or approaching a few cars stopped at a light that just turned back to green.

I figure there's no point in Auto Stopping the engine only to have it restart in a second. So my questions are:
1) Is this a good idea?
2) When would be a good time to shift back to 'D', before I accelerate or after?

Thanks!

 

I believe this is why Honda recommends you use "S" when in stop and go traffic -- to prevent excessive starting and stopping of the engine for short periods of time, which wouldn't benefit fuel economy much, but would add a lot of wear and tear to the transmission components.

Actually, I can't tell you how many times I've gone to pull into a busy street only to find the engine has stopped, costing me about a half-second, which in some cases can be a pretty scary: press gas, nothing happens, then all of a sudden a huge lurge of acceleration. Shiting into "S" in that situation would be smart.

 

To answer your questions first... 1) Yes, 2) before accelerating, but only from a FE, not a wear perspective, IMO

Your description of how you use 'S' mirrors mine. The 'break-even' between using AS and keeping the engine running, from the perspective of fuel used during that time and in the process of restarting from an AS, is about 7 seconds. So if your AS will knowingly last (substantially) less than 7 seconds, it's worth considering purposefully defeating the AS.

While I've taken to counting the seven seconds off during the AS in recent days, I generally skip the AS only when it's obvious I'll be moving again within about 2 seconds. Also, once you defeat it, the only way to invoke it if you 'guess wrong', is to turn the key. So I tend to let the AS kick in most of the time, probably during some instances where I shouldn't (stop signs, etc). But I'm not going to try constantly shifting between 'D' and 'S', yet, anyways.

 

Yes, but... If you're in stop and go traffic, it won't auto-stop if you haven't gone more than 10 mph anyway. So sometimes it won't stop at all when you're in D anyway, if traffic is really bad. But then, in D it still does give that lurching acceleration feel.

I drive stop-and-go traffic frequently, and I've started using S when we're creeping along less than 20 mph. It seems to accelerate more smoothly when going from a stop, and I feel like the surge of accceleration in D is wasting gas. But then, if we go faster I put it back in D because I feel like the higher revs in S are wasting gas.

My 2 cents...
--A