revving engine before shutting off

I have seen this happen alot, especially on old F1 cars driven at historics racing.

Why do drivers do this? is there some magic that happens when they do this?

 

I always thought you should allow the engine to idle to clear excess gasoline before shutting down. Revving the engine right before shut down leaves excess gas in the cylinders which wash away lubricant that is needed for the next start up. It also contaminated the oil in the sump as it runs by the rings. But I'll bow to the seasoned techs on this one. Maybe in racing situations excess gas in the fine tuned racing engine would aid in starting later and they don't worry about oil contamination since they change it more freguently.

 

Other than sounding cool??

Seriously, on one of my old corvettes (66) if I rev/blip the throttle before shutdown it's easier to restart.... my thought is that when I do that I blow out a little extra (unburned) fuel that may have accumulated during the drive and thus when I go to start it again it's not too rich (with fuel). Just an passive theory.

 

One of my pet hates....

In the "old days", super rich badly tuned cars would need a "plug clean" blip after idling or manoevuring for a while. It just helped re-start later.

Also, if a car has a tendency to run on for some reason (pre-ignition, combustion chamber hot spot etc), a blip will cool it with a gush off fuel and reduce that.

Otherwise, there is no need on ANY car.

It was especially scary with a certain driver in the PHR race team... who did it with the 360C in pit lane... with me standing in front of the car.....

Most people use it as an "I'M HERE!!!" call......

 

Evidentaly I need to give my 66 corvette a tune up.... LOL... =) No real big surprise there.

 

I agree totally!

And revving the engine while coasting with the clutch disengaged; or at a stop.

Just a 'Look at me maneuver!'

 

I was taught that you can blow your engine by doing that. Yet I see people doing it all the time. It's really the worst thing you can do to an engine.

 

The old "italian tune up"!

I train my customers with european cars to allow a proper warm up before driving off, and a few seconds of idling to allow some normalising of temps before switching off. Easy to get Turbo guys to understand that one.

Just my thoughts.

Brian

 

Good explanation ferrarifixer.....