Does revving the engine speed up the process of jumping another car?

[blurredvision]

I'm in the process of jumping my fiance's car, as the cold finally got to it last night. I started thinking on how in the past I've always seen people sit in the car that is initiating the jump and start revving the engine. Does that actually speed up the whole process, or is that some kind of urban legend?

 

[JMWarren]

It allows the alternator of the running car to turn faster thus producing more power and lowering the load placed on the running cars battery.

 

[TuxDave]

Originally posted by: JMWarren
It allows the alternator of the running car to turn faster thus producing more power and lowering the load placed on the running cars battery.

Wouldn't the car engine rev up naturally if it the voltage droops too much due to the added load?

 

[spidey07]

Originally posted by: TuxDave

Originally posted by: JMWarren
It allows the alternator of the running car to turn faster thus producing more power and lowering the load placed on the running cars battery.

Wouldn't the car engine rev up naturally if it the voltage droops too much due to the added load?

nope, it would just drain the battery.

 

[blurredvision]

Thanks for the info. At the time I posted this, my car had been running for 10 minutes, with no sign of life from my fiance's car yet (not even trying to turn over). After you answered, I went out, revved up the engine to 2k for about 45 seconds to a minute, and the fiance's car finally started up with no problems.

Thanks again.

 

[spidey07]

Originally posted by: blurredvision
Thanks for the info. At the time I posted this, my car had been running for 10 minutes, with no sign of life from my fiance's car yet (not even trying to turn over). After you answered, I went out, revved up the engine to 2k for about 45 seconds to a minute, and the fiance's car finally started up with no problems.

Thanks again.

if your eletrical system is weak (like when its really cold, your battery or alternator are old) you'll have to rev the motor to provide enough juice to start the other motor.

 

[TallBill]

You couldn't just try that before coming here to post?

 

[compuwiz1]

The alternator of the car giving the jump would have no bearing, if the battery in the jumper car is topped off. The running car is pretty much running off it's charging system anyway.

 

[blurredvision]

Originally posted by: TallBill
You couldn't just try that before coming here to post?

Well, I was perusing ATOT while the cars were hooked up, and figured I'd post it. The first reply was pretty damned quick, so I went on outside.

Do you want a fvcking timeline?

 

[Mark R]

On modern cars you should be careful about jumping with the engine running - best to do it with the 'booster' car shut off. Although, sometimes you just have to do it with the engine running (if its an emergency, and there's no alternative)

If your booster car won't give sufficient power to start the discharged one then you really ought to find a better booster car.

When the discharged car cranks the engine, there is a huge power draw (starter motor running + battery charging). If the booster car engine is running, the alternator will try to supply that surge - it's not uncommon to blow the diodes on the alternator if you aren't careful. This is particularly the case, if your booster car is 'small' e.g. a 4 cylinder and your discarged car is big e.g. v8

 

[DrPizza]

Originally posted by: TallBill
You couldn't just try that before coming here to post?

lmao, I was thinking the exact same thing.

I can imagine the conversation went like this:

fiance: "Hurry up, I'm cold."
OP: "well, your car just isn't turning over."
fiance: "why don't you rev the engine like everyone else does?"
OP: "Hang on a minute, I'm going inside so I can ask the people on ATOT if that works or not."

 

[cavemanmoron]

Originally posted by: blurredvision
I'm in the process of jumping my fiance's car, as the cold finally got to it last night. I started thinking on how in the past I've always seen people sit in the car that is initiating the jump and start revving the engine. Does that actually speed up the whole process, or is that some kind of urban legend?

Dukes of Hazzard jump the car?

Or Jump start the car,
yes rev the charged vehicle to about 1200-1800 rpm,that allows the altenator to work
better.

At idle the system is not fast enough to produce near max amperage.

 

[Rubycon]

Speed would push a button on the steering wheel and the mach 5 would jump like a frog.

 

[PHiuR]

for most regular jumps you usually don't need to rev the engine.

edit: for example if you are useing a 6/8 cylinder to jump a 4 cyl.