Engine Braking

[SubieNate]

I engine brake all the time. I always rev match, and frequently heel toe. If you're rev matching clutch wear should be relatively minimal as you can get it from fully depressed to no slippage very quickly since you're not at all worried about stalling the car and everything is spinning at approximately the same speed.

My Impreza had over 200k on it when I sold it and I drove it the same way.

The only thing engine braking has the potential to do that is negative that I've heard about is slightly increased oil consumption because of the way the pressure differential is on the rings while running in pump mode. Not an issue with an engine that's been taken care of.

I bought this car to have fun. I find rev matching and good smooth heel toe shifts very satisfying. The car will easily do them for lots and lots and lots of miles, so I'm going to do them.

Nathan

[whtchocla7e]

Brake pads are easier and cheaper to replace than engines and clutches. But wear and tear is the natural course of the life of a car so a little here and there doesn't do anything in the grand scheme of things.

[dem00n]

I can't help but have my BS meter go off when someone uses the term "Save your brake pads". The fuck? Should i not open my door and crawl through the window so i don't wear out the hinges?

The shit people say...

[ahausheer]

It should be stated that some automatics are designed to utilize engine braking and will do so automatically. For example my moms Yaris and my companies Honda Element will downshift when you are driving downhill while braking (conditions such as speed and gradient must be just so). For the Yaris at least, this is noted in the owners manual and described as being normal and a way to lengthen brake life. Often, in the Element, it is actually a bit of a jerky experience and is a little unsettling on snow. So from an anecdotal view I would say some engine braking is just fine.

Not to thread jack but does anyone know what happens to the PCV/oil flow during hard engine braking?

[EBMCS03]

Negligible wear and tear if you're not slipping the clutch.

Did you read this?
http://auto.howstuffworks.com/auto-p...ine-brakes.htm

[Ingen]

Originally Posted by Wattage

As the engine works as a positive displacement piston compressor during this type of operation, that makes sense to me. I have some mechanical inclination (I work as a nuclear power plant operator - but I am still in training and thus a noob). Since it is naturally aspirated, the engine will draw whatever volume the piston displacement will demand, correct?

Exactly right.

So as far as engine braking goes - clutch wear is entirely from changing gears and not from the act of engine braking itself. This is what I was thinking, it makes the most sense. I'm also not worried at all about slightly increased wear from changing gears a couple more times than normal.

As far as transmission wear - i.e. "transmission operated under load" - is this significantly different than wear + load experienced during normal driving? Because if it is pretty much the same, again I don't think I would be that worried. There will ALWAYS be wear, it is EXCESSIVE wear that I want to avoid. These transmissions were designed for a certain amount of regular loading, if engine braking doesn't exceed this loading then I don't see why I should be worried about it.

It will wear less than it would under powered acceleration, but more than it would in neutral. While the load is not very high, it is higher than neutral. Le gasp, your transmission might only last 400000 miles instead of 500. Really, don't worry, this won't break the car.

Originally Posted by jmaryt

however it is NOT a requirement to be an "engineer" to understand this,
just many years of driving stick.

love you too I posted it that way because I spend too much time on reddit where you need credentials for knowing how to breathe.

[fatoni]

there could be some other things going on but i think its worth noting that your car is engine braking all the time. if the wearing of the engine that you are concerned with is purely mechanical, the drag of the engine is always happening. i dont see how it can be bad for the trans, clutch or engine considering that the car probably has 40 hp worth of braking but nobody is worried about the damage caused by the 160 hp for acceleration

[FirestormFRS]

I think it depends on how you are defining "engine braking". Sliding into a lower gear on a steep grade? Not an issue. Charging a corner at 9/10 and dropping two gears and using the driveline to slow the car? Probably gonna wheel hop and that's never good.

Ingen....eer. WVU fan are ya?

[zooki]

Actually with the throttle closed you will not pull in the same amount of air as when the throttle is open. You are throttling the inlet with a closed throttle body. The motor goes into a high vacuum situation, and the effective compression is way less than if the motor were accelerating. Actually, even under acceleration the cylinder won't pull in the maximum amount of air it could because very few naturally aspirated engines achieve 100% volumetric efficiency due to intake manifold design, throttle body restrictions, etc.

interesting tidbit: in NASCAR, on the restrictor plate motors they were forced to run at the super speedways, teams were building the motors with 17+ to 1 compression ratios in order to maximize the cylinder filling while doing the equivalent of trying to suck through a straw.

[Grishbok]

Man, i havent thought about this in ages, I always rev match, heel toe, left foot brake, and ALWAYS engine brake as well as downshift and use hard brakes. I do this because im accustomed to maximizing brake force and minimizing brake distance.

[Bristecom]

It drives me crazy when I'm riding with someone who always coasts in neutral instead of letting it engine brake. There is nothing wrong with engine braking as every pro driver I've seen for years has done so. In fact, in some states you aren't even allowed to coast in neutral. So don't even worry about it. You're not gonna blow your engine or clutch out much sooner simply for engine braking. On the contrary, having to bring the engine back up to speed every time you want to accelerate means you'll be slipping the clutch more and sending more vibrations thru the engine and transmission/driveline.

[gmookher]

Y'all first time mt drivers?

Learning how to use engine braking is part of drivin manual.
No harm
No foul

[Wattage]

I am, yes.

[Grishbok]

I have found a lot of FRS owners are first time manual drivers.

Ive recomended to most I meet to take an advanced driving course at their nearest circuit, go to auto-x, drift events, and track days. Most of the people their can help you learn to master the manual, but the most invaluable lessons will come from the advanced driving course. Ive helped teach a few select candidates, but its a rare to be inspired enough to do so.