Bov And Wastegate

[CJF077]

What's the difference between a blow off valve and a wastegate? Which is better and why?

[Mals BA XR6T]

No expert, but simple terms is that the blow off valve vents pressured air (to the intake, or outside) when not required, the wastegate releases exhaust pressure/flow in the Turbo (into the exhaust pipe) to reduce the boost the turbo is making

[F6 RAPID]

No expert, but simply terms is that the blow off valve vents pressured air (to the intake) when not required, the wastegate releases exhaust pressure in the Turbo (into the exhaust pipe) to reduce the boost the turbo is making

Go to www.autospeed.com.au, when it loads, go to Special Features on the left hand side.

When that page loads, scroll right down to the bottom of the page and in the search box type boost. Do a search and you will have plenty of articles to keep yourself amused.

Essentially, the wastgate (under direct from the boost solenoid and wastegate actuator) bleeds off excess boost - the xr6t is limited to a max of 6psi - as you know. It is a valve-like thing that is situated right beside the exhaust turbine in the turbo.

The BOV vents excessive boost build up between gear changes (what it was meant for). For example, imagine you are motoring along at full throttle nearly full revs, the turbo will be spinning at something like 150,000-200,000 rpm. When you back off the throttle, the turbo is still spinning at these revs but can no longer push air into the motor and the boost builds up VERY quickly in the intake chamber. If this air continues to build, it actually forces back onto the compressor of the turbo and can slow it spinning quite dramatically sometimes to the point of damage. The BOV vents this excess air while leaving the turbo spinning so as to minimise the time taken for it to "spool" back up again when you plant your foot for the next gear.

Does that make sense? Read autospeed, they explain it a little better than me I'm sure.

[Ninka]

Good explanation TURBO6

[CJF077]

what is better for the car? say if i had the choice of getting a BOX or a external wastegate on the car?

[bcl]

I wouldn't go near an external wastegate unless you plan to increase your power by at least 50% over standard. Generally internal wastegates work fine and there's no need to change it. If you want to add an external wastegate you will require a custom built exhaust manifold, plus either weld your internal wastegate shut or replace the turbo exhaust housing. Plus some mechanism to control it. Not cheap... probably around $2,000. For general road use not really required.

Brian

[F6 RAPID]

Good explanation TURBO6

Thanks Ninka - appreciate the sentiments!!

bcl is correct. Unless you are pumping in excess of 25psi into it, an external wastegate is not an option. And even then you will be using a different turbo - methinks not.

Your car already has a BOV. You have no need for one and don't even think about changing it for external venting one! You will sound like all the imports on their way down the street between gear changes! There is NO more performance to be gained be an external venting valve.

[fordboy1981]

just a note: I notice you guys have been ragging on the turbo that is in the XR6 standard, saying that if you want more power you'll need to upgrade the turbo.... the garrett GT40 that ford use is rated at like 650-700 horsepower and is the biggest they offer....I think that would be WAY past the limits of the rest of the drivetrain....

Dave.

[Dagabond]

just a note: I notice you guys have been ragging on the turbo that is in the XR6 standard, saying that if you want more power you'll need to upgrade the turbo.... the garrett GT40 that ford use is rated at like 650-700 horsepower and is the biggest they offer....I think that would be WAY past the limits of the rest of the drivetrain....

Dave.

Who said what where when?

[F6 RAPID]

just a note: I notice you guys have been ragging on the turbo that is in the XR6 standard, saying that if you want more power you'll need to upgrade the turbo.... the garrett GT40 that ford use is rated at like 650-700 horsepower and is the biggest they offer....I think that would be WAY past the limits of the rest of the drivetrain....

Dave.

If you read the comments, not one person has said anything about the turbo being inferior. Why? Because we all know that it is a pretty capable device.