Do you guys use engine braking?

[clos561]

pretty much, and if learn to downshift correctly the extra wear should be minimal

yea i know how to rev match and stuff so if i ever started doing it, it shouldnt be a problem

 

[Rotus8]

how tho? the rpms are higher... it would take mroe fuel to turn the motor at high rpms compared to neutral roll and using my brakes...i dont get it(braindead

The fuel isn't turning the motor, the inertia of the car's motion is turning it. No fuel needed, that's why it's slowing down.

 

[knowledge007]

never..i like my gas

I use it when it is needed during rolling stops mostly. Other than that when I need to stop and have some room I will throw it in neutral and let it coast.

With that said, I agree with clos, I like to use my gas to its full potential.

 

[knowledge007]

The fuel isn't turning the motor, the inertia of the car's motion is turning it. No fuel needed, that's why it's slowing down.

Wrong, engine is till making its turns at high rpms. Need fuel in order to turn...

 

[jred321]

Need fuel in order to turn...

why? and why does it need a lot of fuel because it is at a high rpm?

 

[xelderx]

Wrong, engine is till making its turns at high rpms. Need fuel in order to turn...

If the throttle plate is closed the car isn't using any more fuel than it needs to maintain idle. Have you ever seen a wideband O2 when you close the throttle plate? Car goes super lean...Actually much leaner than when you are just idling. Engine braking could save fuel if it wasn't for the initial throttle input to rev match.

To add....most car's fuel control is based off of RPM & Load....if there is no load on the motor there is no need for significantly more fuel.

 

[Kosh]

Correct me if I'm wrong...

Neutral = throtle open used to keep engine at rmp so it doesn't stall

In gear with foot off gas = drivetrain turning the engine and throtle plate closed

Either way the amount of fuel used is so nominal it is not even going to net you 1/8 mile on a tank of gas.

 

[shane02pro5]

I wouldn't say rev match and dump the clutch! That would be hard on everything! I begin to brake slightly and just blip the gas to about 2500rpms and gently let the clutch out. You know your doing it right when you barely feel the engagement and it doesn't buck.

 

[Kosh]

If the throttle plate is closed the car isn't using any more fuel than it needs to maintain idle. Have you ever seen a wideband O2 when you close the throttle plate? Car goes super lean...Actually much leaner than when you are just idling. Engine braking could save fuel if it wasn't for the initial throttle input to rev match.

If you rev match there isn't any resistance from the drivetrain so it really isn't burning that much more fuel than putting it into neutral.

 

[We Are Ninja]

yea i know how to rev match and stuff so if i ever started doing it, it shouldnt be a problem

By the time I got good at it, it was habitual...

 

[xelderx]

If you rev match there isn't any resistance from the drivetrain so it really isn't burning that much more fuel than putting it into neutral.

Yea thats what I was implying. From a fuel saving standpoint there is probably no real world driving measurable difference.

 

[bbychvz]

an easier way to ask this question
"do u down shift to brake"
(butt)
only if i need 2, other than that no

 

[crashkelly]

Wrong, engine is till making its turns at high rpms. Need fuel in order to turn...

ummm no....its turning on its own inertia. Think of it this way...you put your foot on the gas to go (and your injectors add gas) and the engine rpms go up, but when you take your foot off the gas (the injectors stop adding gas to the cylinders) the pistons dont stop dead where they stand...they keep moving but more slowly....like when you ride a bike you peddle really fast then when you stop peddling the wheels keep turning, they just dont stop.

 

[clos561]

Correct me if I'm wrong...

Neutral = throtle open used to keep engine at rmp so it doesn't stall

In gear with foot off gas = drivetrain turning the engine and throtle plate closed

Either way the amount of fuel used is so nominal it is not even going to net you 1/8 mile on a tank of gas.

so ur saying that the only time the no fuel thing aplplies is when the car is at high rpm and the "tranny" is turning the motor and NOT when the engine is IDLE and at its lowest rpm possible? throttle is open when idle of course the engine needs to breathe but i dont get y the throttle would be closed when the rpms are high and no throttle......(uhm)

 

[clos561]

ummm no....its turning on its own inertia. Think of it this way...you put your foot on the gas to go (and your injectors add gas) and the engine rpms go up, but when you take your foot off the gas (the injectors stop adding gas to the cylinders) the pistons dont stop dead where they stand...they keep moving but more slowly....like when you ride a bike you peddle really fast then when you stop peddling the wheels keep turning, they just dont stop.

the wheels keep turning on the car....and the pistons are still moving because it stil ignites..if the rpms go high the engine has to compensate with fuel/air

 

[jersey_emt]

The momentum of the car rolling makes the pistons go up and down without the need for little explosions in the cylinder.

 

[xelderx]

Another real world example. You are at the drag strip and run the 1/4 mile, then let your car engine brake all the way down. Now pull a spark plug. It will be very white showing that the motor is running lean. That's why if you want to check your plugs at the end of a drag run for mixture you have to shut the engine completely off when you cross the finish line or you get false readings.

 

[Kosh]

The momentum of the car rolling makes the pistons go up and down without the need for little explosions in the cylinder.

Right. When in neutral you are removing the connection between the transmission and the differential through the collar. The engine is fighting friction all the time and in neutral ignition occurs to keep the engine from stalling.

 

[jred321]

if the rpms go high the engine has to compensate with fuel/air

why can't the pistons just spin quickly on their own? why do they need to have combustion to move up and down quickly?

when you're accellerating it's your engine powering your wheels. when your foot is off the gas it's your wheels powering your engine. (though i'm sure that's a super simplified version, but it's the basics)

 

[FlyinMSP]

You don't use gas while engine braking as many have already said, just look at the vacuum!! (if you have a gauge)
If you do a nice heel+toe downshift, you save the clutch as well as having a smooth transition. And yes, you do save on the brakes as well (plus they will be cooler when needed)