redwagon

what are the pros and cons of both? i can see that internal is alot easier for fabrication, but is there a gain from one to tne other, also does an external need any tuning or tweeking? thanks

Lucas_Gchips

Internal wastegates are a fixed size. Generally suit smaller turbo chargers.
On larger ones, they have not got the room to make the wastegate big enough to fit in a small exhaust housing, so what you may find is you will suffer from Boost Creep.

boostedQs

Good for 500hp and internally wastegated.
They've had very good results with it.
And you don't have to mess with a $400 external wastegate and additional labor to get to 500hp.
Less work, less $.....Sounds good to me

Audiboy

But as Lucas pointed out, external will always have better control or elimination of boost creep. This is because the more expensive valves pop open vertically, not hinged as in an external wastegate. The hinged gates (imagine a trashcan lid opened by a foot lever), will always have uneven opening area as they start to open. This crack is what is anticipated to minimize severe boost spikes. For example, if you want the turbo to start opening around 10 psi, you might want to start applying pressures around 6 (called crack pressure) to an internal wastegate so that by the time the gate is open enough, it's around 10. FOr a good external gate, you can almost just let it open at 10, or a smaller value closer to 10.

A400

Boost creep means you cannot get enough air to the WG to bleed boost. Once it starts there is not a cure except to have the WG bleed more. I understand that internal WG cars are notorious for this when the turbo is large. I go to ext. WWG 1st thing so I cant say I have experience with them, but only cure in a ext. WG car is a smaller turbo or a bigger WG. I would never pay for a chip where boost creep was a part of the programming, why would anyone allow it?
Rod

Audiboy

if the tuner is not careful to program the duty cycle control with respect to boost demand and the rising RPMs, then there is a danger of getting massive boost spikes and/or boost creeping upwards until the internal wastegate is open large enough such that the turbine slows down. That's my point about the boost creep and the tuning, or the need to attend to it. I won't be surprised if some kits out there had initial problems because of detonation - from boost spikes and from ignoring boost creep