How does a blow off valve work?

Question

Do u need to have a turbo in order to install a blow off valve?How much is a turbo?

Answer 1

You can do a turbo relative cheap by buying used, but remember, you need low compression pistons to run any real boost. So you are better off buying a turbo engine to start with.

and no, there is no benefit to put a blow-off valve on a normal engine, they are used mostly in blower applications :)

Answer 2

A blow off valve without a turbo system installed would be completely and utterly useless.

The way a turbo works, is the exahust flows through a turbine which spins a compressor, compressing the air in the intake so the ignition of the gas and air will expand faster creating more torque and horsepower.

The blow off valve is a system that releases the pressure in the turbo/compressor system when the revs in the engine slow down. For example, if you are driving your car on the highway, and the turbo system is running, and you go to an off ramp, you need to slow down. However, if the compression ratio in the engine is to high, the engine won't slow down very well, and you are creating unnecessary wear on the engine and wasting gas.

The pressure decrease allows the engine to take in less air and fuel, and run at lower revs. The blow off valve also activates during a shift, since the engine will be at lower revs than it was previously.

Short answer: You don't need a blow off valve unless you are running a medium to large turbo.

Answer 3

The valve blows off excess pressure that the turbo doesn't need. How much a turbo will cost depends on the motor. For a car, you're looking somewhere around 1,000 to 2,000 dollars, plus other special parts to make the whole thing go. Plus the labor to fit it all and retune the car, either with a new chip setup or by manual retuning on older cars. Big job but usually doable if the motor and drive train are in good shape. Turbos put more stress through the motor and drive train so if anything's a bit tired it'll probably get blown to bits.

For more detailed advice it's best to contact a place that specializes in turbocharging.

PS Edselman's dead right about the pistons. If you use the original ones your motor will not last very long at all.

Answer 4

The blow off valve releases the excess air pressure from the turbo. If you do not have a turbo, you do not need the valve!