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Is engine braking bad?

10K views 19 replies 7 participants last post by  XCNuse 
#1 ·
Hey so me and my friend have diff opinions on this subject and I am wondering what you guys do. When slowing down do you downshift to help slow you down or do you think that's bad.

My opinion is that you are reducing the load on the engine if anything because it is just ridding along instead of having to use the power stroke to turn over .. Other than affecting the mpg a little I see it as a good idea and should be done by all people.
 
#3 ·
I'm going to assume we're talking about a manual transmission? Depends what exactly we're talking about. Agressive downshifting that involves revmatching, or switching gears when you're in range?

In general, engine braking involves fuel cutoff meaning you're not using any fuel while you're coasting. This is good. If you're waiting until you can switch gears without needing to revmatch you're also being as fuel efficient as possible, and there is nearly 0 "wear and tear".

If you're aggressively downshifting, you're using a bit more gas and a negligible amount of extra wear and tear on the engine due to higher RPMs. If you're anticipating needing to get back on the gas quickly (i.e. to quickly zip in front of someone so you can pass them, or need extra power to get up a hill), this is the way to go. If you are NOT revmatching, this will wear your clutch significantly.

If you're coasting in neutral (no engine braking) you're using gas (engine at idle), and you're not prepared to quickly get back in gear should you need to. This is lazy driving and isn't a good habit. Wears the brakes heavily, as opposed to negligible clutch wear from the other two.
 
#4 ·
I'm honestly curious if a revmatch or two will burn more fuel than coasting in neutral over a 30 second period though. That's what I'm more curious, at which point does sitting in neutral become more economic than otherwise.

I wouldn't call going into neutral lazy, I do it majority of the time when driving around on the street; at least when headed into a red light or stop sign.

I can't stand people that don't rev match, it crushes me inside lol
 
#11 ·
Heel toe Is hard, rev matching is easy. Like Nuse said, just blip the gas. The more aggressively you're downshifting, the more you push.

Nuse- you don't need to rev match if you're just coasting... Just leave it in gear until you're just about to bog down, then downshift
 
#10 ·
Knowing how hard to blip the throttle is the only "hard" part about it.
You don't literally hold the throttle pedal and try to get it to an RPM lol

Just tap it to let the revs go up to where you think they should be, release clutch: boom, congratulations, you rev matched lol

it's seriously not that hard.
 
#14 ·
I've been downshifting over 100k miles in my 3 and I've had 0 issues because of it. Transmission is still smooth and I'm on my 2nd (first aftermarket) set of rotors and pads in the front. Still have the original pads and rotors on the rear and they have plenty of material left.
 
#15 ·
Ahh great comments that all supported my side if the argument haha that's for your opinions guys.

My friend however says you guys are all idiots and the extra wear and tear is what he was talking about. Haha but never mind him.. He thinks putting the car into gear and sitting at the stop light with your foot on the clutch is bad too.. I know wtf haha . I did forget to tell you guys that he drives a 2014 ford focus st. Maybe that is why he does all that crazy stuff. He is scared his crappy ford is going to break I dunno
 
#16 ·
He thinks putting the car into gear and sitting at the stop light with your foot on the clutch is bad too..
Technically it is.

But then again; turning on a car is bad for it too. It's all relative.
I only engine brake whenever I'm driving a bit more hard. Otherwise it's technically a bit more hard on the internals as the engine will run more hot since it isn't being cooled by fuel.

Like I said; it's all relative. Anything you do to something the reality is you're technically damaging / wearing it, and there's no way around it.
 
#18 ·
Well it's more or less heat soak; the fuel reduces that as it's sprayed in.

Since it isn't getting active cooling, just from the coolant running through the block.
It's still compressing air = heat.

But we aren't talking like OMG YOUR ENGINE IS GONNA OVERHEAT AND BLOW THE INTAKE MANIFOLD AND DROP THE FLOOR PAN!

But I wouldn't be surprised just from thinking that engine braking increases cylinder temperatures more than when there is spark and fuel.
 
#20 ·
It's possible, but depending on engines it looks as though some DI engines I'd assume due to functionality require a lot from the injectors; particularly the tips, which under extreme cases of engine braking don't get proper cooling as they would during operation.

At either rate it's an interesting conversation that doesn't seem to go anywhere across all platforms.

One thing I have not really come across however is increased oil consumption. I haven't done enough research see what the cause is, likely due to increased vacuum.

I wonder if that explains my oil consumption during trackdays vs actual burning oil as my engine has never "burned" oil, but I do consume some during trackdays and doubtfully during load, but I can believe from massive amounts of engine braking throughout the day.
 
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