Random thoughts about braking

[LtNoogie]

For the past 10 years or so, I've been shifting my AT into neutral on all my cars as I approach a stop, especially when stopping from a high speed like at a freeway offramp. I find that the braking is much more linear, e.g. the amount of slowing down is proportional to the amount of pressure on the brake pedal. I am guessing that when in neutral, I do not have to fight the rotational inertia of the engine in addition to the linear inertia of the car.

When I owned a motorcycle, downshifting was a normal way to slow down the bike. However, I was never comfortable with using this method with my MT cars. I would always shift my MT to neutral as I do with my AT cars. If the light changed, it was never a problem to pick a gear, blip the throttle and engage the clutch. And before you lecture me, I understand the concept that staying in gear allows for an emergency maneuver.

I've never thought to ask this but how do you all come to a stop with your MTs? Do you downshift 4-3-2-1-N? Do you immediately drop into neutral and just use your brakes?

[ddongbap]

Neutral then brakes.

Leave all the wear on the brakes, since they're easy to change out.

I could be mistaken, but I'm pretty sure constant N to D movement on a AT tranny puts wear on it.

[eTiMaGo]

keeping it in gear as you slow down (engine braking) is particularly useful in our cars as the ECU shuts off the injectors, and thus you use no fuel (Deceleration Fuel Cut-Off, aka DFCO)

So yeah, in the interest of fuel saving and quick response, I do usually keep shifting down until 2nd gear (1st is just a bit too rough and requires some clutch slipping to avoid a rough shift, for me anyway). Not to mention, using the engine to brake means your brake pads have to do less work, hence they won't wear out as fast.

I believe it's not actually recommended to shift an AT to neutral while in motion, something to do about the transmission fluid not being pumped around in that case.

[ddongbap]

In the end, I don't think it really matters.

Sure you waste fuel popping into neutral, but you save wear and tare. But then again, you'd use up fuel.

Either way, its gonna cost you.

[cleong]

I'd keep the car in whatever gear it happened to be in, and only disengage the clutch just before the car starts to judder from low RPMs.

[eTiMaGo]

Sure you waste fuel popping into neutral

Unless you turn OFF the engine while coasting with the clutch down :biggrin:

A common hypermiling technique, feels really weird at first but I use it several times every day now.

[SIPNGAS]

I waffle between going into neutral and braking or downshifting. I use downshifting more when the weather is bad and the roads are snow covered and I have time to think about it. I do the neutral/brake thing when I'm buzzing around town and wait longer to stop....

[Tamago]

heel toe downshifts all the way, every day.. it's a good habit to get into as it becomes second nature when you're at the track

[Loren]

I never downshift with the intention of slowing the car. I do downshift to keep the revs up so that DFCO stays engaged and uses no fuel. But, if you're talking about a hard stop, it's clutch in and hard on the brakes.

With an automatic, you might feel the car downshifting as you brake, but with such a wimpy engine (at idle) behind it, it's not likely to be a problem. I think you'd be at more risk by trying to rapidly shift to neutral because you could accidentally find reverse, which would not be pretty. (did that once when I was 16 and driving a car that wouldn't idle in gear... fortunately, I wasn't going very fast)

Best bet: If you're making a quick stop, forget about the gear lever and just concentrate on BRAKING. If you have a manual transmission, clutch in. Simple.

(where things get interesting is on a race track where not only do you want to slow down rapidly, but you also want to downshift to a lower gear at the same time to accelerate out of the turn that you're slowing for... but that's another story)

[ddongbap]

I never downshift with the intention of slowing the car. I do downshift to keep the revs up so that DFCO stays engaged and uses no fuel. But, if you're talking about a hard stop, it's clutch in and hard on the brakes.

With an automatic, you might feel the car downshifting as you brake, but with such a wimpy engine (at idle) behind it, it's not likely to be a problem. I think you'd be at more risk by trying to rapidly shift to neutral because you could accidentally find reverse, which would not be pretty. (did that once when I was 16 and driving a car that wouldn't idle in gear... fortunately, I wasn't going very fast)

Best bet: If you're making a quick stop, forget about the gear lever and just concentrate on BRAKING. If you have a manual transmission, clutch in. Simple.

(where things get interesting is on a race track where not only do you want to slow down rapidly, but you also want to downshift to a lower gear at the same time to accelerate out of the turn that you're slowing for... but that's another story)

HEEEEEEEEEEEL TOEEEEEEEEEEEE!!!!!!!!!!!!!!!!!!!!!

If you guys want to rock the techncials, turning on anything that draws electrical power on your car, can worsen your gas mileage.


Btw, I remember popping my moms van, with the column shifter, into reverse at 60 mph. It just stalled out, and took itself out of gear. I put it back into D, and all was normal again.