internal or extrenal wastegate

[viperlp01]

I'm new to this Turbo stuff i guess you can say. I would just like to know the main differences in extrenal and internal wastegate. I'm looking to turbo my car asap and i keep finding turbos that are internally dumped. Will those still work if i wanted to extrenally wastegate. I'm guessing that the external goes on the turbo or the manifold. Just wanted to learn something new.
thanx john

 

[oldman]

I'm new to this Turbo stuff i guess you can say. I would just like to know the main differences in extrenal and internal wastegate. I'm looking to turbo my car asap and i keep finding turbos that are internally dumped. Will those still work if i wanted to extrenally wastegate. I'm guessing that the external goes on the turbo or the manifold. Just wanted to learn something new.
thanx john

An external wastegate goes on either the manifold or the O2 housing, not on the turbo itself. You can either go with a turbo without internal wastegate path (specifically setup to run external) or you can weld the internal flapper shut on an internally gated turbo.

 

[DGajre777]

Wastegates

On the exhaust side, a Wastegates provides us a means to control the boost pressure of the engine. Some commercial diesel applications do not use a Wastegates at all. This type of system is called a free-floating turbocharger.

However, the vast majority of gasoline performance applications require a Wastegates. There are two (2) configurations of Wastegates, internal or external. Both internal and external Wastegates provide a means to bypass exhaust flow from the turbine wheel. Bypassing this energy (e.g. exhaust flow) reduces the power driving the turbine wheel to match the power required for a given boost level. Similar to the BOV, the Wastegates uses boost pressure and spring force to regulate the flow bypassing the turbine.

Internal Wastegates are built into the turbine housing and consist of a "flapper" valve, crank arm, rod end, and pneumatic actuator. It is important to connect this actuator only to boost pressure; i.e. it is not designed to handle vacuum and as such should not be referenced to an intake manifold.

External Wastegates are added to the exhaust plumbing on the exhaust manifold or header. The advantage of external Wastegates is that the bypassed flow can be reintroduced into the exhaust stream further downstream of the turbine. This tends to improve the turbine's performance. On racing applications, this Wastegated exhaust flow can be vented directly to atmosphere.

http://www.turbobygarrett.com/turbobygarrett/tech_center/turbo_tech101.html

 

[DGajre777]

Some pics.

O2 housing for Internal wastegate, routed back in

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O2 housing for Internal wastegate dumped to atmosphere

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External Wastegate on o2 housing, dumping atmosphere

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External Wastegate on o2 housing, routed back in

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SBR's Manifold for exhaust manifold mounted external wastegate (you can also have a flange welded to your 2G manifold and SBR can do it for you (if not your local exhaust shop)

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DNP Tubular manifold with external wastegate

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And my favorite, DNP's manifold with external wastegate routed back to their o2 housing

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Thanks to www.122performance.com, www.slowboyracing.com, www.dnperformance.com and www.punishment-racing.com for their pics.