some say it's good for the car? what effect does it have if any?

thnx

 

i heard its good for your gears to down shift. I guess it lubricates it or something. Thats what i heard so i dont know. But its easy on the breaks.

 

of course it uses more gas.


greater rpm= more gas usage

 

i think if you are shifting to a lower gear, if you rev match, it is good for your synchros/gears as there is less work to be done by them.

and if your rpm's shoot up, but you are slowing down, then no, it does not waste gas. because you are not stepping on the gas means the momentum of the engine is what is keeping it going, not the gas. in fact, you would waste gas cruising in neutral to slow down vs. slowing down in gear.

the only gas u waste is what is used to rev match which is minimal, if you decided to do so. if i am wrong, someone correct me.

 

You rev match when you downshift so that your clutch doesn't slip. If you don't rev match, that sudden "slowing down" you feel, is your engine speeding up to match the speed of the wheels. Your clutch takes the brunt of this. If you do not rev match when you downshift, your clutch will suffer more wear.

When you rev match to downshift, yes, you use more gas. You're revving the engine with no forward progress, so essentially that gas is being wasted. It might be a minimal amount, but technically the gas isn't being used to move the car, so I suppose you could say it's not necessary usage, and therefore it's wasted.

If you really want to save gas, just put the car in neutral (or put the clutch in) and use the brakes to slow down. Then put the car back in gear when you want to go again. No damage to your clutch, no wasted gas. But then again, how much fun would that be?

 

Engine braking is a little tougher on your clutch, engine mounts, tranny mounts and tranny. Rev matching is a related issue as it helps to prevent that initial jerk to your car, but then engine braking afterwards still puts extra stress on your car.

Use your brakes to slow you down. Its cheaper to change brake pads than it is to change transmission/engine parts.

 

downshifting to slow down is no good.

our cars have great brakes, there is no need to shorten the life of the clutch.

would you rather pay 100 bucks for brake pads, or 1000 for a new clutch?

 

Exactly!

More drivers need to understand this.

 

I don't see how engine braking puts any more wear on your engine than just decelerating with the car in gear- that's pretty much all that you're doing.

If you match revs, there is little extra wear on your clutch, as you are avoiding the "slippage" which is what damages the clutch.

 

not to say that this is my habit of daily driving, i usually just slow down in the current gear that i am in then put the car into neutral then use the brakes to slow the car down.

but to answer the original question. gas is used in neutral, but not used in gear when slowing down so it would be the opposite of this statement. that is why if you are in gear and let your car slow to a stop, the engine will die because it is not getting gas. of coarse this isn't how the normal person drives.

here is a useful example. it is useful if there are lots of long hills in your area. i used to cruise down the 405 in neutral applying brakes to maintain speed thinking i was saving gas, but now i just get up to speed, stay in gear and let the hill build momentum for me in gear.

i agree, brakes are cheaper than clutches.