Im getting ready to build my vtec b20 turbo and im going to use ether a gt28 or gt30 and should i buy with a internal wast gate or not ? what are the pros and cons of going with a internal wast gate and a external?

 

It really is a matter of use, and how large the wastegate opening is, the size of the flapper door, and what the spring is rated. The only real cons is that if either of these are being pushed to their limits of use, you could experience boost creep, which could lead to a damaged engine. An external one can still cause that as well, but not as likely because the manifold should have it strategically placed where that shouldn't be an issue.

I guess it seems that your underlying question is "is it bad to use a GT28R or GT30R that has an internal gate?". The answer is no, if the amount of power and purpose are used correctly. I've had many GT30R internal gate setups that work just fine, but made sure that the wastegate was using a heavy duty spring, (about 14psi or so) and that the opening and flapper door were large enough. The ATP units can supply that.

Don't forget, that you will limit your choice of exhaust manifolds for the honda if you use an internal wastegate. There is really no cost savings in using an internal gate over an external one.

 

thanks buddy