Your uncle practices a dumb and dangerous habit.
No driving instructor would ever even suggest something like that!
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When I rode motorcycles the only time I put it in neutral was at long traffic lights. If this uncle does this on a motorcycle that sounds like a good way to guarantee a crash .
Can you shift a motorcycle to neutral at 45mph?
Your uncle must have learned to drive in a car with a carburetor. It would save gas in one of those. Not a good practice but it worked.
It is counter-productive in a fuel injected vehicle. In a fuel injected and computer controlled engine, the fuel is shut off under high vacuum conditions which you would encounter when decelerating in gear. If you push in the clutch or put it in neutral, then the fuel injectors have to supply gas to keep the engine alive.
In a carburetor, the high vacuum condition would actually suck gas into the engine that was not needed and contributed to a lot of unburned hydrocarbons. Respect your uncle but follow your driving instructors advice.
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@q.irontail_164778:
Keith raises a good point. That technique may have saved gas in carburetor-ed or the early fuel injected cars. But now it will consume more gas.
There are numerous ways people operate manual shift cars. I donāt consider your uncleās style wrong. Itās just different and itās not a style I would use, for the many reasons previously given.
As others have noted, this is a case to listen to your instructor.
After watching the video, Iām wondering what causes the Jake Brake to make the exhaust louder.
I had always assumed the thing worked by somehow restricting exhaust flow, essentially compressing it and creating the cackle Iād hear from big-rigs when they were decelerating.
The exhaust valve opens near the top of the compression stroke, releasing the pressure that would normally ignite the fuel and force the piston down. Thatās why the exhaust is louder.
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Thanks for the information, when I asked on of the mechanics at work, I was given the closed valve answer. Obviously I never investigated further.
Yes you can.
On those that can be shifted into neutral at 45 mph a miss step through neutral to 1st might be costly.
If anyone is interested, it appears jake brake / exhaust brake is more complicated than most of us might have thought.
At least now I think I understand that exhaust racket from decelerating big-rigs.