Does engine braking consume gas?

[dkmlam]

Does engine braking (slowing down by downshifting and staying in gear) consume gas or have any negative effects? From my understanding, it doesn't.

What do you guys do when slowing down?

[Twin_Cam_Turbo]

On newer cars, the imjectors should shut off when coasting, so it shouldnt be consuming fuel.

[86max]

RPM going up = fuel going down

An engine needs fuel to run, the higher the rpm it's at, the more fuel it will consume.

If you're concerned about fuel consumption when slowing down, just throw it in neutral and use your brakes.

edit: What I wrote above is false

[J NRG]

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[syritis]

unless your braking at the last possible second before corners and would like to be in the correct gear for exiting in efforts to reduce your lap times, i can't think of any reason why you would want to wear out your expensive clutch before your inexpensive brake pads.

engine braking is also good for you motor occasionally. apparently the higher vacuum can break up some carbon build ups in the intake.

[Sentry]

On fuel injected cars, when you let off the gas above a certain RPM (1500-2000) it's not injecting fuel anymore and it's just sucking in air. So no it doesn't use gas.

Any EGT or AF gauge can prove this.

[Sentry]

Originally posted by syritis
unless your braking at the last possible second before corners and would like to be in the correct gear for exiting in efforts to reduce your lap times, i can't think of any reason why you would want to wear out your expensive clutch before your inexpensive brake pads.

I don't know what kind of downshifting you do buddy, but if you do it properly it won't wear clutch components.

[89s1]

edit: keep reading the thread.

[86max]

@ sentry^^ but the engine is still running is it not? So what is combusting in the cylinders to keep it running, just air?

I'm not trying to be an ass, just looking for more clarification.

[89s1]

Originally posted by syritis
unless your braking at the last possible second before corners and would like to be in the correct gear for exiting in efforts to reduce your lap times, i can't think of any reason why you would want to wear out your expensive clutch before your inexpensive brake pads.

Its called rev matching chief, look it up.

[Sentry]

The car moving in gear is what keeps the engine running.

[89s1]

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[Sentry]

Originally posted by 89s1
then it isn't "running" either, it's just being forced through the movements mechanically.

Yeah. But when you step on the gas again or it drops below that RPM point and fuel is injected again it's ready to go.

[Sentry]

Anyways like I said:

Originally posted by Sentry
Any EGT or AF gauge can prove this.

[86max]

Are you talking about hybrids?

[89s1]

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[Ashers]

On my TDI, overrunning (Engine Braking) uses no fuel at all. I know this from the sound... downshift, let off the gas, and the knocking goes away. Give it gas, knocking comes back. AFAIK, all fuel injected cars when overrun shut off all fuel injectors... it only takes a few milliseconds to get the fuel back again. I can probably log the injection quantity using vag-com on both my Golf TDI and my sisters 1.8T to see if this is correct.

[Sentry]

Originally posted by 86max
Are you talking about hybrids?

No, I'm talking about any fuel injected vehicle since the 90s.

Originally posted by 89s1


by your logic a car uses no fuel whatsoever at idle.

No, what I said is when the engine is ABOVE a certain RPM, like say 1500 or 2000, and it's coasting it doesn't use fuel. When it drops below that it starts to inject again to keep the engine from stalling.

[Sentry]

Originally posted by Ashers
On my TDI, overrunning (Engine Braking) uses no fuel at all. I know this from the sound... downshift, let off the gas, and the knocking goes away. Give it gas, knocking comes back. AFAIK, all fuel injected cars when overrun shut off all fuel injectors... it only takes a few milliseconds to get the fuel back again. I can probably log the injection quantity using vag-com on both my Golf TDI and my sisters 1.8T to see if this is correct.

See this guy gets it.

[syritis]

Originally posted by Sentry

I don't know what kind of downshifting you do buddy, but if you do it properly it won't wear clutch components.

Depending on the brake bias i have set I do let out the clutch at a lower RPM, to slow the car faster. why not just set it with a higher rear bias and rev match perfectly? so I can down shifting through several gears (like in turn 1 at RCMP) without locking up the rears cuz not every down shift will be perfectly matched especially when you can barely shift as fast as the car slows down.

if you rev up the engine to match RPM then let out the clutch wouldn't that do the complete opposite of what the OP is trying to accomplish?