Hi guys im looking at turbos and are after one with an external wastegate but only come in gt3071 and up,would that be a good choice for my 300hp and up ca18det?

To give an idea my 13b has a gt40/94 strapped to it which should easily make 450-500.id say a 30/71 would be fairly close for you

A GT3071 would be capable of closer to 300kw at the wheels depending on supporting mods.

Hi guys I have a ????,with the internal wastegate is it the actuator that does the release off pressure so I don't need a bov or do u still run a bov with a internal wastegate?

I'm pretty a motor making decent power should be running an external gate

If you are going to use a external gate, you can use a internally gated turbo. Just remove the actuator and tack weld the waste gate valve closed on the outside of the turbo where the actuator rod would normally go on. A BOV releases pressure between the throttle body and compressor wheel when the throttle is closed which puts less stress on the turbo. The waste gate opens when the required boost pressure is meet so it won't over boost. This is done by controlling the amount of exhaust gas which goes through the turbine. So to answer the question, you need both a BOV and a waste gate