Hi,

I have a MT base FIT. I want to know the best technique for braking to achieve maximum efficiency. I have seen several pieced of conflicting advice. Should I:

- Keep the car whatever gear I'm in, NOT push in the clutch, allow the car to glide to a stop and then, when the car is about to stall, push in the clutch and brake.

- Push in the clutch, brake as normal.

- Downshift a gear or two to "engine brake".

 

I just shift to N and use the brakes.

Holding the clutch in puts unnecessary wear on the clutch. Engine braking puts some unnnecessary wear on the engine, too. Downshifting to engine brake faster seems like it would also put more unnecessary wear on the engine and transmission. I mean, that is if you're doing that every time you come to a stop, it would.

Just remember it's easier and much more inexpensive to replace the brake pads than parts of your engine and/or transmission.

 

Took the words right out of my mouth.

 

i keep it in gear and coast/brake unless i need to come to a fast stop all of a sudden, then i down shift and brake(tends to happen a lot here with crappy drivers all around...)

 

Agree on not holding the clutch in - it can cause premature wear on the throwout bearing.

Also agree on downshifting, at least on a regular basis. If you do proper revmatching, I don't think you'd wear things out too quickly, but there would be a little more clutch wear due to the extra downshifts. If you don't revmatch, there'd be more clutch wear for sure (perhaps quite a bit) .

I don't see how engine braking puts unnecessary wear on the engine though - at least not any more than the engine turning during normal driving does.

I usually just coast (in gear) to a stop, using brakes as needed (still in gear), and shift into neutral just before I stop, or when the rpms get to ~1500 or so, whichever comes first.

I do downshift w/revmatch in certain situations, such as cloverleaves on freeways where I want to stay in the poweband the whole way round...

 

street...clutch in -> N -> clutch out and depending on teh situation I'm braking as I'm doing that if I have to or once I go N.
track...down shift with a rev match while breaking. lol, I don't see how anyone can rev match in a fit though my feet are to big, only way I've been able to get my foot on break and gas is slide my foot over and use the umm the right side of the front sole

 

this is simple..
Brakes are cheaper than transmissions.
use em

 

I still don't understand why someone should avoid using their brakes "at all cost". The reasoning behind that is beyond me.

Agreed. +1

 

+1

lol, what is so anti-eco about that ?

what is eco ? it's maximize the car efficiency & minimize the TOTAL cost

 

Agreed.

Fit MT tranny - $2,000
Replacement brake pads - $50, if that much

So, after 100,000 miles, who will have the least total cost? Is the guy who puts unnecessary strain on his engine and transmission, in the end, going to have saved considerably more than the guy who shifts to N and uses the brakes? Will his car even last another 100,000 miles? Even if he does save more, he'll pay it to repair his worn engine and tranny.

And I'm getting an average of 33MPG, 90-100% city, thank you very much.

Fuel economy is only a part of a vehicle's total cost efficiency. If you want to work some driving practices than will probably have some high dollar repercussions down the line, then be my guest. Personally, I'd like to replace the parts that are meant to be replaced and maintain the parts and systems that are meant to be maintained.

Besides, maximum fuel efficiency is determined more by how fast you accelerate, when you shift, and how fast you drive and much less by how you brake.

 

Someone said that'd make the engine/tranny fail? Well, that wasn't me.

Unnecessary/excess wear ≠ failure.
Unnecessary/excess wear = $$$ repair bills, which negate the purpose of trying to be efficient, and possible failure or shortened engine/tranny life.

 

"When slowing down, you can get extra braking from the engine by shifting to a lower gear [downshifting]. This extra braking can help you maintain a safe speed and prevent your brakes from overheating while going down a steep hill." (p. 149)

If I'm coming to a stop, I shift to N and use the brakes. Honda says that if I want "extra braking" "while going down a steep hill", I can downshift and engine brake. Says nothing about doing that every time I come to a stop.

I didn't say that, exactly. I said that coasting or engine braking to a stop every time you stop will cause unnecessary wear on the engine and transmission. You may end up needing a new tranny, or a few gears, or whatever. It'll still be costly and could have been avoided.

At what year and miles? I can't predict the future. All I can say is that the engine and/or tranny won't last as long as it could have.

 

Honda does not recommend to engine brake all the time. You must've missed the "while going down a steep hill" part =P The function of the brakes, not the engine and tranny, is to slow and stop the car.

I only post what makes sense, especially to my Mechanical Engineering set of mind.

 

Brake without downshifting with throttle released; drop the clutch at any time you want long as the engine is well above stalling.
The old 'saw' about downshifting to brake is a holdover from the old days when brakes were so marginal that if you didn't use engine braking you'd soon have no brakes - well back in the last century.

 

Saving fuel at all cost without consider other factors & the reliability of the engine/transmission is not eco. There's more than fuel that affect the total cost of owning. Also, saving fuel at all cost is not equal to maximize the effective of the working condition of the engine/transmission. That's all common sense.

Why should I use my own car to "experiment" common sense (which are already proven for a long time). That's dumb. Also, the real experiment requires meeting very strickly condition (to filter distracting inputs, which may strongly effect the output result) & specific number of testing. Do you think you meet all the requirement ? Not likely

Also, reliability requires a long term data. The effect of constantly doing engine braking on the transmission is not likely to show immediately. That's why track cars engine wear faster than normal cars because their engine setup and driving style focus on minimize laptime (engine braking is used at the beginning of every tight conner), not maximize reliability.

Lolz, Those 2 parts can't be put in the same sentence at the first place. They're incompatible right from the cores.

 

My shop manual says anytime the throttle is closed the injectors shut off and will not re-engage until the throttle is pressed or the rpm falls below 1500 rpm in neutral. That makes slowing down with engine compression a waste of ring wear. And that makes sense given the need for higher mpg.

What data do you have?

 

I'm curious whether or not the fuel consumption is negligible at idle. I guess it depends how long you idle. What's the GPH when in neutral?

It seems we can't have an intellectual debate without someone low-balling and bashing others. Sad, really.

 

OK I removed all my recommendations based on 55 years of driving and averaging 44mpg in my 2008 Fit.

Have fun

 

Its not braking with the engine that counts, its the time fuel flow is interrupted. The real trick is to delay dropping the clutch til the engine in gear gets below 1500 rpm.

IN SHORT DOWNSHIFTING IS A WASTE OF TIME AND DOES ADD MECHANICAL WEAR ON THE CLUTCH SYSTEM.
Just brake while in whatever gear you are in and drop the clutch when you get close to the stopping point. The point is to interrupt fuel flow, not use engine to brake.

I'm going to comment on that. I rarely go very far with the engine in gear and coasting but if you do then not dropping the clutch is advantageous. As long as the engine is in gear and slowing you are better off mpg wise with the engine in gear than in neutral as others have said. No flow is better than very little flow. I just don't have that much time in my stopping or slowing to a stop.
For P&G driving the coating time is tripled or quadrupuled going from in gear to neutral so the advantage falls back to coasting in neutral as the difference betwen no flow and idle flow doesn't get max mpg..

But for normal stopping don't wear the clutch out with unnecessary shfting, just let it come down in gear and drop the clutch when you get below 1500 rpm.

 

Unless I'm mistaken, the injectors shut off w/no throttle only if the engine is in gear and moving, i.e. engine breaking. The wheels are what keeps the engine turning. If the injectors shut off and the card was in neutral, the engine would stop because it's not getting any fuel, and nothing else is keeping it turning.

How is slowing down with engine compression a waste of ring gear wear? I don't see how engine braking wears the engine down 'unnecessarily' any more than driving the car at 30 mph wears out the engine more than sitting with it idleing. When a car runs the pistions happily go up and down all day.

Why is braking with the engine hard on it, especially if you just let up on the thottle and let the engne help you decelerate? Isn't it just the reverse of getting up to speed?

Not trying to be a jerk, I just really don't get this.....