internal VS external waste gate? why?

[2geclipse565]

ok so i know what they are and how they work im just wondering why go external over internal?? from what I understand the external helps eliminate boost creep? but is it a performance upgrade? and also is illegal, if i coul get some information on this i would apreciate it, thank you

 

[gsxeclipse97]

No there are no legal problems having an external unless its vented to atmosphere. you could run into some porblems there but not likely it you have it hidden

As far as the other questions I'm not to sure but if it has no internal waste gate there is a big reason to buy one there. If i comes with one than i see no point if you can eliminate boost creep with a larger flaper

 

[awdtalontsi1992]

In short, and interal wastegated turbo has the wastegate flapper and seat built into the turbo's exhaust housing. All stock DSM turbos come this way. External wastgates are mounted by themselves either off the manifold or the O2 housing.

There aren't any power gains to be had by switching to an external wastegate. The main reason to switch to an external gate is boost control. There is a point where an internal wastegate can no longer expell enough gases to maintain boost levels. This is one of the reasons for boost creep. If your turbo isn't having boost creep issues than the upgrade to an external gate is not needed. You can also help an internally gated turbo by porting the O2 housing and the passages in the turbo.

 

[2geclipse565]

ok good to know, thanks for the info. . .

 

[CTP_MADDOG]

also dont forget internal wastegates tend to spike alot, regardless if they are overworked or not, its inherent to the design. personally i think internal wgs are pointless and i never run them.

 

[DGajre777]

Why go external? - better boost control.

No matter how good an internal gate is or who makes them, at high RPMs when the engine's VE is higher, the internal gate will creep open if you have a big turbo. An external gate does what it is supposed to go - holds the boost right where you want it and then it opens. This is specifically important when you run a big turbo like the FP Green or a 50trim.

You will also notice on your stock car - like mine, if you have a boost gauge, you might start at 15 psi and by the time you go to 6500RPMs, the boost has dropped to 10psi. If you had an external setup, it would hold the boost at 15psi throughout the RPM band.

Yes, externals are more expensive that internals. If you get an EVO III 16G or T28, you can use an internal gate, port the turbo and o2 housing and you won't get creep.

 

[tunermt]

ok so i know what they are and how they work im just wondering why go external over internal?? from what I understand the external helps eliminate boost creep? but is it a performance upgrade? and also is illegal, if i coul get some information on this i would apreciate it, thank you

This is a VERY common question and here is the best explanation with pictures and diagrams I’ve run across to help ensure anyone can fully understand how the internal and external wastegates work.
Internal vs external wastegates