dual wastegates, why?

[matt87]

hey guys, i'm in the process of buying a mid 10 sec t-type from a fellow board member. the car has atr headers and two delta gates. one under the tubo and one on the x-over pipe. what are the advantages/disadvantages of this setup? i've always used h/d stock style wastegates and thdp with no problems. thanks!

 

[zam70]

With an increase in exhaust gases (hi-pro engine) there needs to be enough cfm flow to dump the additional exhaust. To little flow will not allow enough to dump, hence the use of 2.

Theoretically, you could use one BIG one if they made them big enough.