Hey guys, long time away, tried search, easy to just ask.
Im again going down the route of twin wastegates this time on an EFR9180 13b. I have in the past used twin 44mm Tials, was reluctant to go down to just 38s back then as no one them had tried them.
Been a while since then, so has anyone used twin 38mm external wastegates on a big single, results? would love to see down to 12 psi or there abouts and wastegate placement will be in best place. I do see Full Race make a manifold for twin 38s, so surely they work?

 

It depends on how the turbo manifold is designed and how much wastegate priority you have. It also depends on what type of port the engine has, if engine VE is very high, that usually means you need more wastegate control( unless on the edge of turbo flow, then its less of a priority). Also if you want to run very low boost, you generally need bigger gates. Twin Tial 38 units work just fine on our cast long runner for 95% of applications( non semi pport/full pport).

 

Full race manifold has poor wastegate priority, but it does have the wg entries far from the exhaust ports which helps make up for it.

If you go FR have them put 2x 44 MVR flanges on it if you have any doubts and can ask them to use 45 bends with tear drop entries to the WG- might as well teach them how to make manifolds for rotaries.