Engine braking

revtime said:

I was always told deceleration is the worst thing you can do to an engine. Engine is made to accelerate, brakes are made to slow down.

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Do you have the option to cease communication with this person? :lol:

Engine braking uses air compression to slow the vehicle down. One step further would be a Jacobs Brake; opening the exhaust valve at full compression to maximize braking effort through the drive train.

Not so practical on RWD cars as when the weight transfers forward, your maximum possible braking effort is reduced.

If you use your brakes incorrectly, you may break something!

matteos said:

Engine braking doesn't wear anything out that is important. It uses the other side of the teeth in the transmission, so you are not going to damage anything or wear anything out faster than things are already being worn out.

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Should probably say "proper engine braking".

The reason some people are afraid to do it is because of what can happen if you don't do it correctly. Combine that with the people that had bad experiences because of doing it wrong that have issues with their vehicle. Who spread misconceptions that it is bad for the car.

If you're going 80 mph and put it into 1st and let off the clutch, you're going to have issues.

Well of course with in reasons. There is no reason to down shift to a redline rpm. for maximum engine braking without actually braking.
It a tool to use however in stop and go traffic, you just stick in 1st gear, bring the rpm up when moving forward and just let off the gas allow the engine to slow the car down without touching the brake pedal.

nastang87xx said:

How can I take you seriously when you spell brakes brakes and breaks.:lol:

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Sorry my american friend, I only speak 4 languages and english is not my native so I sometimes make mistakes when I type from the phone on the go.

wildcatgoal said:

It's against the law to not pass in the left lane, but... ya know.

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Actually I just looking this up and GA and found this good news.

O.C.G.A. 40-6-43 (2010)
40-6-43. When overtaking and passing on the right permitted

(a) The driver of a vehicle may overtake and pass upon the right of another vehicle only under the following conditions:

(1) When the vehicle overtaken is making or about to make a left turn; or

(2) Upon a street or highway with unobstructed pavement of sufficient width for two or more lanes of moving vehicles in the direction being traveled by the overtaking vehicle.

So on the highway (2 or more lanes on your side) you can pass on the right. That's cool because I do it all the time.

Clutch in?

ForTheHordeKT said:

Heh... I always clutch in and brake. I only seem to engine brake if I know I'm going, say, 60 in a 50 zone or 85 in a 70-75mph hwy and I see a cop on the side of the road so they don't see my brakes lighting up like a xmas tree as I pass them LOL.

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Not to be offensive, but long term deperssing/holding of the clutch in puts undue wear/stress on the trust bearing. I only point this out for folks that go down long hills etc., holding in clutch the whole time at the traffic light etc. I have seen wiped out thrust bearings over the years.

Varekai said:

I always use engine breaking, I love the pops and gurgles of the exhaust when doing so

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Me too, I love that burble out of the tailpipes as the car slows . One of the many joys of the V8 and a manual transmission
Worth extra $$$'s and smiles if I've got a bmw behind me

Love the experience!!

airfuel said:

The fun of rev matching and downshifting for the cool sounds is different than downshifting and braking simultaneously on a road course to be in the correct gear for maximum drive out of the corner.

I think many people who drive today's big hp cars would greatly benefit from a high performance driving school.

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I would love to do one of these schools. I am also an engine brake guy when ever possible. Engine brake down to 1k clutch in and go to neutral.

One of the main reasons I bought a manual. Oh, and installed a louder exhaust. :cheers:

When I was first learning to drive I was doing this in my old '65 Fairlane with a C4. Blew out the planetary gears. Trans mechanic knew me and told me he had seen me all over town driving it this way and it was only going to be a matter of time before I came to visit him. :doh: I was then taught to never, ever down shift an auto trans unless I was accelerating. $500 is a tough lesson for a 18 yo back in 1980.

R3v said:

Sorry my american friend, I only speak 4 languages and english is not my native so I sometimes make mistakes when I type from the phone on the go.

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Don't worry, he was just mad he doesn't know how to use comma's. ;)

Interesting thread. Im guessing that anyone who says engine braking is bad likely heard it from an old timer. And back in the day that was really true, but not anymore.

When you are in over-run (engine braking), you have a lot of vacuum and potentially rpm. The carb is sucking in a lot of fuel to make sure it has the right ratio for air, since carburetors are stupid. With your foot off the pedal and high vacuum, you have no ignition advance, so that air/fuel mix isnt being burned efficently, and a lot of the raw gas winds up in your crank case, past your rings. (same reason youve heard warming up your car by idling is bad...not so true anymore).

a lot of that unburned air/fuel gets passed through into your exhaust or cat, and can get to high temps and start a fire. Those were the old days.

Now, with fuel injection, things are a lot smarter. In MANY cars, if you are above 2500 rpm and your foot is off the throttle, your duty cycle of your fuel injectors go to zero. Meaning they arent firing at all. Ive never put a scope on the Mustang so not sure if its true or not here... but either way its putting in very little if any fuel. So now your engine is acting as a cold air pump, which very much helps cool the engine down.

If you have weak valve seals, you may see a puff of smoke out the tail pipe when you touch the gas again, but no big deal. The gear lash is reverse on it so it isnt bad for the gears, plus there is very little torque on them at that point. Essentially, you really arent hurting anything in modern cars by engine braking.

That being said... its a mechanical connection from your rear wheels to your pistons in a standard shift car. So its easy to over rev if you put it in the wrong gear. Plus your valves can float etc. So when engine braking keep it no higher than 70% of your tach.

As a side note, it is recommended to engine brake when going down long hills, because brakes will overheat and fade. Then you're screwed. On top of it all... thats pretty much what automatic transmissions do!

my .02cents

Might be a dumb question but during quarter mile runs and dyno pulls what is the correct method of release without harm? Engine braking or clutch in and neutral. It sounds like on many dyno pulls its clutch in and neutral. I have never tracked or dynoed a car. Like I said prob dumb no flaming.

R3v said:

Sorry my american friend, I only speak 4 languages and english is not my native so I sometimes make mistakes when I type from the phone on the go.

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Nice response and it didn't need 4 languages either