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Fuel Cut Rev Limiter - Can It Do Damage

turbo87

By turbo87,
in Engines & Forced Induction

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turbo87 Enthusiast

turbo87

Posted
Posted

Is there a problem with having boost in the chamber and no fuel? is it the same effect as leaning out or is it safe, as most aftermarket computers seem to use this function.

Just wondering, as my car can spend a bit of time bouncing on the rev limiter and my EMS only has a fuel cut function.

Busky2k Veteran

Busky2k

Posted
Posted (edited)

Apparently yes fuel cut can cause leaning out whilst banging the limiter. My theory is that as you're basically switching on and off the injectors whilst the engine is still breathing all the air in. So for example some piston intake cycles may not get the right amount of fuel it needs as the injector might only be active half way thru the intake cycle. Kinda hard to explain my theory. Ignition cut IMO is alot better.

Edited by Busky2k
Sydneykid Grand Master

Sydneykid

Posted
Posted (edited)

Turning the fuel totally off to a cylinder doesn’t not cause lean running in that cylinder. No fuel = no combustion, therefore there is no running for it to be lean. Remember we are talking maximum rpm here. In the unlikely event that there is any fuel left over from one cycle, it will be consumed in the nest cycle. One cycle of combustion of a miniscule amount of fuel will not damage anything.

:D cheers :(

Edited by Sydneykid
Sydneykid Grand Master

Sydneykid

Posted
Posted (edited)
Nah what I mean SK is if the fuel injector is switched off 3/4 the way through an intake cycle.. then... its lean for that cycle!

One cycle is not going to do anything.

Think about it, you snap off the throttle every gearchange.

The injector duty cycle goes to zero while you change gear

Until you get back on the throttle

What's the difference?

:rofl: cheers :ban:

Edited by Sydneykid

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