Brace yourself, Winter commute is comming

[HyperMileQC]

Hello everyone,

I will begin my winter commutes in december, with a 2007 Mazda 3. Only problem is that its an automatic.

I can say for sure that I am better at driving manual than automatic (weird. I know...) and I wanted some advices from guys who are regular automatic driver.

The car as what you call "manumatic" wich is kind of manual but with no clutch pedal. Do you think that DFCO is possible with this manumatic?

Also, I've been debating with my father, and I want to know, is it possible that turning the transmission from "Drive" to "Neutral" when coasting, can damage the tranny?

Anyway, the car has no mods, doesn't have a/c, and has an OEM block heater. Perhaps I'll do a hidden grille block. And inflate tires to 36 PSI. I cannot modifiy the car because it is not mine. So no 50 PSI, no skirts and all that... only hypermiling.

I'll keep you in touch with this, and maybe upload some pictures.

[nbleak21]

D->N coast downs are 100% fine and will not hurt your trans. Just make sure you don't push it to reverse!!!

DFCO, not that I am aware of on manumatics, you're prob best off neurtral coast downs or EOC.

[HyperMileQC]

Not to sure about EOC with auto trans, how will I do to bump start the car... I've also heard its damaging the trans.

Effectively, if D to N coasts are ok, i'll do this instead of DFCO coasts.

[PaleMelanesian]

Neutral coasting engine-on should be fine.
DFCO should work, just manu-matic downshift to keep it engaged. But in most cases, neutral will give you better results.
EOC - check your manual for towing instructions. If it's ok to tow with 4 wheels down, you're fine. If it requires a tow dolly or trailer, don't do it.

[HyperMileQC]

Thanks for your input, Pale.

I still have the bump start problem tho... I don't think you can bump start an automatic, so EOC is not a good solution, even if it's ok to tow with 4 wheels down.

Maybe EOC to a red light that you know you will have to stop for more than 20-30 secs. then i'll key start. I don't think key starting is really good when rolling...

[UltArc]

I would not engine off coast.

It MIGHT not work out well. But an alternative to N coasting, which in SOME cars is worse than in gear, I would just stick to top gear. In my 96 Escort, in gear rpm would stick to 950-1200, and in N the engine would jump to 1600-2000. Now, maybe engine temperature, or other things made it do that, but that iswhy I stopped with it. My wifes Escape also does this, where it is SLIGHTLY more efficient to coast in gear vs out of gear, regarding fuel use.

Please note, regarding fuel use. I believe in gear will create driveline drag, and slow down faster(it is not drastic in her vehicle), so it might break even, or the other might be better, I say this because every car is different, and it would be wisest to test out different methods and see what works best for you and the vehicle.

[star_deceiver]

You can't bump start an automatic.

Just put it in N and coast down with the engine running. Coasting in N with the engine off in an automatic is just asking for a blown transmission as the running engine turning the converter is what criculates the transmission fluid.

Also, your "manumatic" is nothing more then a top-gear limiter.

[Gealii]

The best is to learn what your car does yourself, I have found that on my auto when in Drive the transmission shifts itself into Neutral by itself but if in 3-2-1 there is a gear reduction. Neutral coasting engine on should not hurt one bit, i would still be weary on eoc just because that some trannys don't like it.

If you plan on doing pulse and glide it still helps with the engine on just make sure to use your torque converter as much as possible. If you don't it can actually hurt your mpgs.

[HyperMileQC]

Originally Posted by Gealii

If you plan on doing pulse and glide it still helps with the engine on just make sure to use your torque converter as much as possible. If you don't it can actually hurt your mpgs.

I don't really know how to use the torque converter. I'm an automatic tranny noob

Originally Posted by UltArc

it would be wisest to test out different methods and see what works best for you and the vehicle.

I will surely test in-gear coasting vs. neutral coasting and see what does the best.

Some precisions about the commute. It is a 33.1 Km (20.5 miles) 5% suburban with 12 stops & 4 ligths / 90% Highway (at ~70 km/h (40 mph)) / 5% rural city with 5 lights & 1 stop.

[Gealii]

Originally Posted by HyperMileQC

I don't really know how to use the torque converter. I'm an automatic tranny noob

its kind of hard to explain but what happens for me is when your on the throttle the rpms drop and then you can put around 95% engine load and your rpms will increase with your speed instead of jumping to around 2800 rpms or so. I tend to feather the throttle a little bit at around 2000rpms until it kicks in and on my car at least you can feel it kick in it is quite a different feeling compared to just driving normally.