What is the purpose of a wastegate on turbo'd cars

 

to prevent too much boost, or over-boosting your motor. without upgraded internals, stock motors can't handle too much boost and tend to break down. once you build your motor, you can adjust the wastegate to increase the boost.

 

very true, well put bb6. the wastegate is basically the boost regulator. Without it, the turbo would spin until either IT or the ENGINE couldnt take it. They have a set base pressure, for example 10psi. That means it will never open until it sees 10psi of pressure going to it. A boost controller "hides" pressure from the wastegate, thus increasing boost pressure. Note, a boost controller CANNOT LOWER BOOST past the set spring pressure. So, if you have a 10psi spring in your wastegate, 10psi will always be your minimum boost level. You can use your boost controller to raise boost past the 10psi if you want to.

neil

 

im going to take another step back in my explination.

say you had a basic turbo, you put all the exhaust gas through it, and it spins really fast, faster and faster as you are at higher and higher RPM.

so its spin is only regulated by the amount of air going through it, which is only dependant on RPM (so far)

. well lets say you want to run 9psi, your engine might push enough air to spin your turbo fast enough to run 9psi at about 3000 RPM, well what if you don't shift until 8000 RPM, you'd be making like 30-40lbs of boost at that point OH NO!!

so you install a wastegate, which is a turbo bypass valve that is regulated by a pressure sensor, when the pressure sensor sees, say 9psi, the bypass valve opens, and some of the exhaust gas goes through a different pipe, and not through your turbo, so you get less boost, if the boost drops below 9psi, the wastegate will close again, and your turbo will see all of the exhaust gas and make as much boost as possible.

so you're racing, and you watch the boost gauge, it quickly moves up to 9psi, and the wastegate opens, and the boost stays at 9psi.

its like a thermostat in your coolant system, the thermostst is a valve that opens once the water is at oprtating temp, then closes if it is below, so the engine can warm that water up, so the valve automatically opens and closes when it needs to to keep the temperature constant.

same thing with the wastegate.

 

couldnt have said it better myself!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by onefastrx7turbo &raquo;</TD></TR><TR><TD CLASS="quote">couldnt have said it better myself!</TD></TR></TABLE>

w3rd.. that pretty much explains it

 

best explanation I've ever read...

 

wow, thanks a lot man, thats very detailed

 

Good post

 

&lt;------ I guess ol' Suichiro was with me on that one!

 

yep. I actually didnt know what the purpose of a wastegate was either, so thanks for letting me know.