Turbo/Supercharger question

[MBTN]

Just curious about something. I know how both work, so I'm not asking that. My question is does a car with forced induction run "leaner" than a car with out? Both allow more air into the engine, so is the engine leaned out or what?

[ales]

Yes, it is a probability. NA carbs/injectors do have some reserve built into them, but if you're really pushing the boost up, they will run out of potential (BOOM!!!!). That's why you can often read/hear about bigger injectors.

[texan]

Originally posted by MBTN
Just curious about something. I know how both work, so I'm not asking that. My question is does a car with forced induction run "leaner" than a car with out? Both allow more air into the engine, so is the engine leaned out or what?

Not if it's tuned properly. In all likelyhood, if it was an NA car from the factory it's now running more rich in an optimal state of tune (for power production), since boosted motors like a slightly richer mix. All the dynamic compression begs for a little extra fuel over the optimal NA ratio.

[Polygon]

Only if you slap the Turbo/Super on and don't change the fuel to air ratio.

[SaabJohan]

No, it doesn't. They use a fuelpressure regulator wich increase the fuelpressure when the boost comes. With a standard regulator, let's say 1 bar boost pressure and 3 bar fuel pressure at no boost. When the boost rises to 1 bar the fuelpressure will rise to 4 bar. With a progressive regulator with say 1.2:1 the pressure will be risen to 4.2 bars.

But if you tune the car more than the injectors/fuelpump can handle it will be leaned out. But with the right stuff it's not a problem.