what waste

[nicholaswgmay]

Could anyone explain in simple terms the difference between single and dual port waste gates and the advantages of one over the other????

 

[TTM]

The dual port is supposed to close faster when you release the throttle.
As a result it seems the boost pressure loads more quickly when you re floor the throttle after an upshift but as far as I have observed that might be a placebo effect

 

[barks944]

The second port acts in the opposite way to the first AFAIK. It puts pressure to close the wastegate, i think it gives finer control over boost control especially at higher boosts pressures.

 

[Diver944]

Nick I've edited (badly) an old diagram which will hopefully explain the difference:

The standard single port wastegate is held closed by the spring. Boost pressure builds in the pipe after the intercooler and flows through the banjo bolt (and cycling valve) pushing down on the blue diaphragm, hence opening the valve downwards.

A Dual Port wastegate has a second port down the side. The valve is held closed by the spring and also by pressure through the second port pushing the blue diaphragm upwards and holding the valve closed. Using an Electronic Boost Controller (EBC) you can vary the pressure very precisely at which the valve will open. It also stops the valve opening through sheer exhaust pressure alone, which is why an old factory wastegate can open prematurely and be very laggy.

 

[Frenchy]

What Paul said, the wastegate valve is controlled from both sides whereas the single port only see's pressure to open, the spring gets weaker overtime and less pressure (hence less boost) allows the valve to open the valve prematurely [&:]

 

[nicholaswgmay]

Thankyou all, especially Paul for the pictures!
N