Rep Power: 511

im kinda new to the turbo stuff and i had a question about wastegates. i know the basic turbo info, but im kinda confused on this. what is the difference, beside location , in internal and external wastegates? which is better annd such? i know external wastegates can be a bit more expensive then the internal ones, but does it really make that much of a difference if i was to go with an internal wastegate? thanks for the help.

 
Rep Power: 0

There are a few differences... but a lot of it is personal preference.

External wastegates are easier to use if you want a dumptube that is not tied into your exhaust, and replaceable springs can be used to set the boost level.

Internal wastegates sometimes requre a boost controller to set a level of boost other than stock (but some can be adjusted w/o a boost controller as well).

Many people think that internal wastegates are not as accurate at controlling boost and are prone to "boost creep"... but I think that's more of a queston of the reliability of the parts, not the design.

For only running 10psi or so, both will do a good job as long as you buy something with some quality. For large amounts of boost (20 psi+) you'll need to go with a large external wastegate to handle the flow.

 
Rep Power: 511

well, i already plan on getting the greddy profec B II electronic boost controller and i dont think i will be getting near 20 psi any time soon, so you think an internal wastegate should work fine for me? whats the average cost of an internal one and is there anything in specific i should look for when i purchase one?

 
Rep Power: 511

can anyone else help me with this??

 
Rep Power: 0

Internal WG's are built into the turbo. Most Garrett turbos are internally gated, but Turbonetics aren't. It depends upon the manufacturer.

For 3-8~10 PSI the general rule of thumb is internally gated will be fine. The addition of a good EBC will aid in avoiding boost creep. The Profec Spec B is a very easy to use EBC with easy install. Several members have run that and still do.

For any PSI > 10, an external WG is recommended. They are easier to fine tune and generally are more reliable than internal. They can be controlled by an EBC as well. Tial makes excellent external WG's. Pretty reasonably priced at $225 for a 38mm.

Even at low boost pressure for tuning use and reliablility, external WG's are better IMO.

 
Rep Power: 0

Good post and good answers.

 
Rep Power: 0

Here;s a pic of an "internally wastegated" turbo..... like it's been mentioned before, an external wastegate isn't really necessary if you're boostin 10psi or less. But you can do it.....it's not a no no or anything.

 
Rep Power: 511

do you have a pic of an external wastegate turbo as for comparison?

 
Rep Power: 0

External wastegate there. See the difference?

that's a supra btw.

 
Rep Power: 511

ya. thanks.

 
Rep Power: 0

Can an internal wastegate ever be converted to an external or would you just have to get another turbo with an external attached to it? I'm trying to get a T25BB but it has and internal wastegate, and I want to be at 20psi before the ned of the year so I got to think ahead, could I just remove the T25BB and alter it for the external or would I have to go T3 with an external ???

 
Rep Power: 0

You can have the flapper door inside the turbo welded shut. This will allow you to use an external wastegate.

 
Rep Power: 481

Is that even a safe practice? What if the welds break and get spun in the turbines of the turbo? You now have a shiny hunk of metal for a doorstop.

 
Rep Power: 0

Yes it's safe, as long as it's done correctly - DSM's have been doing it for years. ALL my 20g turbos had their flappers welded shut so I could use an external and I never had a problem.