Yeah, i've got a turboback exhaust. I could hear the wastegate before i installed it though.

 

The reason why it doesn't build up to full boost is because of the throttle position. The boost solenoid is sensitive to throttle position and if you were to hit full boost all the time you gave it a little gas on the freeway gas mileage would be horrible, thus the reason for the wastegate opening trying to slow down the turbo. Also the throttle position plays an important role is the opening of the throttle body. I think the easiest way to explain it is picture a ballon that you are trying to fill up (intake manifold) but has a slow leak (combustion chamber) you can blow hard enough to fill the ballon even with the leak but you can only fit so much air through the hole (throttle body) so when the hole is small the air will leak out faster than you can fill it therefore the pressure is staying consistent (boost). The waste gate is opening to try and slow down the turbo and the bov is venting the extra pressure.

With your situation the wooshing noise is probably a combination of both the bypass and wastegate opening. If you have an intake the bypass would be much more pronounced.

-skooter

 

Aint' he smart! Noise could also be spooling noise. I got alot more noise from the wastegate, turbo and bov just by adding an intake. Dizzywrx said they have a turbo back is ther any other mods like an intake or maybe just a silencer removal?

 

Nope, only a turboback on my car.

I think that analogy makes sense. Maybe it would make more sense if i understood the whole combustion thing better. I always thought that the more air (boost) in the mixture, the better gas mileage, only it will run hot. So if that is right, then why would running high boost when cruising be bad for gas mileage? I could totally be wrong. Also, i thought the gas throttles gas, not air. So in the analogy, how does throttle position determine how big the "air leak" in the balloon is? Maybe i've confused your analogy. Somebody fix me cuz i'm totally broke!

 

The more air you send into the engine the more gas you use.

The gas pedal does not throttle gas it throttles air and with the amount of air passing through the throttle body the ecu adds fuel to make a mixture of air to fuel 14.7:1 (actually because the world isn't perfect it is more like 12:1).

Below is a picture of the throttle body off of my truck. The WRX has a different design with only one plate and one big hole. You can see the two holes with the plates in them. The plates are controlled by your foot the farther you push the pedal the more they open. The more they open the more air goes into the engine and the more gas you use to create fuel. Thus the reasoning behind more boost=less MPG...

My analogy with the ballon and the "leak" I can see could be kinda confusing. The "leak" I was talking about is you engine pulling the air and gas into the combustion chamber which makes the engine run and delivers power to the wheels. The "hole" I was talking about was the one you are using to fill the ballon (throttle body) so the more you push on the pedal the larger the hole gets...

I hope this helps a little more...

-skooter

 

I think i get it. So the wastegate and the bov work together to vary the amount of boost going to the throttlebody. Also, the amount of boost desired by the ecu depends on how much you depress the gas pedal, to optimize the gas mileage when cruisin, and then build full boost at wide open throttle. Do i got it right???