Wastegate question?

[eclipsefan98]

i'm looking at gettin a big 16g turbo and wanted to know if there is any performance gain or spool up difference between the internal and external wastegates. thanks guys!!!

[turbo2nr]

my frined was telling be that an external wastegate is better and it makes the car more responsive but thats what i herad i not sure if its true or not..

[landyacht]

I believe the external wastegate is better...best to ask Redneck or flywsi...they'd know!

[drag1320neon]

external wasgates, i think they get better adjustment

[turbo2nr]

[quote]What's the difference between internal and external wastegates?
Internal wastegates are comprised of a flapper door which is built in the turbine housing, usually operated pneumatically by a mechanical actuator. These flapper doors are limited in size, but work well in certain applications. Usually found in smaller turbos, internal wastegates are relatively inexpensive, simple in design, and very durable. Larger turbo can be fitted with internal wastegates, but boost control can be tricky. If you are looking to run high boost (20+ psi) all the time, then an internal gate may be fine. If you are looking to run lower boost levels, you will need an external wastegate.

External wastegates are generally mounted to the exhaust manifold or to the O2 housing, and are self contained units. External wastegates have the ability to bypass large amounts of air, and can provide steady boost control at any pressure level. A common myth is that in order to run higher boost pressures, you need a larger wastegate. This is incorrect. Larger wastegates are necessary to run low boost levels on large turbos

thats from http://www.forcedperformance.net/faq.aspx

1

[JekylandHyde]

turbo2nr, good post.

The benefit of the external WG is control ... specifically at lower boost levels.
If you have a big turbo, but want to run low boost on the street ... you need the external gate.

[Polygon]

We do have a forced induction forum. Even though there have already been some great responses I think you'll get even more there.

[Sluttypatton]

It isn't necessarily the boost level that necessitates an external wastegate, but the volume of exhaust. If the exhaust gas volume is larger than the internal wastegate can properly vent, you will overboost. The problem lies in the fact that since an internal wastegate must be placed in the turbine housing, space is an issue so internal wastegates tend to be small, and can in some cases be inadequate. Other benifits of external wastegates are a separate passage for wasted exhaust eliminating disruption to the main exhaust, and generally better placement of the wastegate. However, if you can get by with an internal wastegate, I would recommend it since an external one would just be an added hassle and expense. Don't buy an external wastegate just because they are better unless you have money to blow, don't get me wrong they are better but unless you NEED one I wouldn't bother.

[JekylandHyde]

Originally Posted by Sluttypatton

It isn't necessarily the boost level that necessitates an external wastegate, but the volume of exhaust.

Exactly, and with less boost you need to evacuate a larger volumn of exhuast through the WG.

[SaabJohan]

The biggest drawback from the internal wastegate is probably it's placement and that the outflow disturb the utflow from the turbine.

Larger turbochargers are usually made for diesels and their internal wastegates are usually not large enough to do the job on a gasoline engine if low boost pressures are wanted. Smaller turbochargers should have no problem with their internal wastegates if they are used properly.