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Old 10-23-2000, 04:27 PM   #1
AaronB
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Question Internal or External Wastegate?

Would an internal or external wastegate be better for a low psi (less than 10) turbo RS?

Why is one better than the other? Any reason besides the external is more expensive?

Trying to understand all of this turbo info.

Thanks,

Aaron http://www.azscooby.com
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Old 10-23-2000, 04:41 PM   #2
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If you use a good quality external wastegate, it will most definitely be better then any internal wastegates. External wastegates allow more precise boost control and better response. Internal wastegates are cheap in looks and construction.
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Old 10-23-2000, 04:44 PM   #3
Tim Prudence
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External wastegates create less backpressure by reducing turbulence in the exhaust stream. External wastegates are better, but the benefit would be very slight especially on a low pressure setup.

If I were you I'd go for the internal wastegate, unless you are really serious about making big power.
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Old 10-23-2000, 04:57 PM   #4
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I don't think you can choose to use an internal wastegate, it is either there or it's not. Internal wastegates are build into the turbo housing(exhaust side). If your turbo doesn't have one, then you don't have one.
However, you can add an external wastegate to any turbocharger, just disable the factory wastegate(if there is one).
I think an external wastegate is better no metter what boost level you plan to run, good boost control is always desireable. It's just like the head lights of a car. It doesn't metter if you are driving at 200 mph or 20 mph, the brighter they are the better you see the road.
If you are on a budget, then it's a different story.
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Old 10-23-2000, 05:22 PM   #5
Tim Prudence
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Yes, external wastegates are always better. I don't disagree, but the cost/benefit of running an external wastegate on a low boost system just isn't very favorable. Boost control on an internal wastegated turbo shouldn't be a big issue, unless you are running a very small turbo with the 2.5 liter engine. I'm running a small IHI-RHB5 on my RS and I never had a boost control problem while relying only on the wastegate for boost control.

The main benefit of running an external wastegate is to give waste gases there own flow path. They meet up with with main exhaust further downstream so there isn't a huge amount of turbulence just behind the turbo (which deprives the turbo of power). I don't think boost control should be a big determining factor, because most of us will end up running aftermarket boost controllers anyways.
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Old 10-23-2000, 05:54 PM   #6
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>>>>I don't think boost control should be a big determining factor, because most of us will end up running aftermarket boost controllers anyways.<<<<<

Tim, what does a aftermarket boost controller control ? Yes! the wastegate, internal or external. How else can you control boost if not via a wastegate ? Am I missing something here ? All an aftermarket boost controller does is very the amount of vacuum that the wastegate diaphragm sees, therefore giving you boost control.

And for your information, you can still make the wastegate gases meet up further down stream of the exhaust(to reduce turbulance) for a turbocharger with a internal wastegate setup. You just have to make a new flange where the turbo meets the downpipe. The new flange will have two holes with two pipes connected to them, one being the main exhaust pipe and the other for the wastegate.

You are right though about the cost issue and low pressure situation. I wouldn't spend the money for low boost applications too.
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Old 10-23-2000, 06:06 PM   #7
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So do you guys consider less than 10 psi low boost?

Thanks for the info so far!
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Old 10-23-2000, 06:24 PM   #8
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For a high compression engine, 10 psi is not that low actually. Most of the turbo ej25 guys here run around the 10 psi range +/- several psi. I think 5 to 6 psi would generally be agreed upon as low boost.

What turbo kit are you running or planning on running ?
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Old 10-23-2000, 06:51 PM   #9
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Hi guys!
I'm using a T28 Ballbearing with internal wastegate. It does a nice job. I personally think and internal unit will do, up to say 15psi, after that there's only one choice. I use to drag race a 1990 Eagle Talon (..back in 91-92) & used an HKS RageGate unit with a Mitsubishi TDO6-20G turbo @ 25psi. It made 15 passes a weekend being a 12.35@119mph the worst!!

For us with a RSt with 10psi, I think an internal unit is fine.

Also, if you are planning on using an external unit, in order to make it work at it's best, built a separate exhaust system for it with a tiny muffler or resonator AND NOOO!!! , it WON'T BE STREET LEGAL!!!

Just my 2.5 cents, PEACE!!!
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Old 10-24-2000, 01:57 AM   #10
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Hi guys,

As has been stated, if the turbo comes with an internal one, use it. If it doesnt, you havent got much choice and have to use an external.

Eg Garrett = External, IHI = Internal

In most cases internal will be fine, only under high flow/pressure would an external one be required to replace the internal one.

You can be looking at a lot of $$$ for a top notch external one

You can easily run 30psi using an internal... but will depend on the actual wastegate, its actuator and the size of the turbo.

Basically.... what I'm trying to say is that an internal one (if built into the turbo) will be fine for the 2.5 *blanket statement*

J.
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Old 10-24-2000, 03:01 AM   #11
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Boostup, you are correct in saying all an aftermarket boost controller does is varies the amount of vacumn(boost) a wastegate sees. That's exactly the point in getting one! With an EBC or even a good MBC like the Hallman or Joe P controllers, they do not let the wastegate see any boost until the actual boost level has been met at the controller, then the controller lets the wastegate see it. If you are simply relying on the wastegate to controll your boost, the wastegate is ALWAYS having boost trying to push it open, and in some cases, in BEGINS to open before the actual boost setting is met, resulting in slow, laggy spool up time.

Not to mention the fact that you have no back-up if the wastegate should ever fail.

You should always use a good boost controller.
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Old 10-24-2000, 04:46 AM   #12
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The wastegate is the only thing that prevents the turbo going BOOM!... An ENC/MBC still relies on the wastegate functioning correctly..

I know you know this.. you just didnt make it very clear..

You are correct with the statement about bleed via the wastegate. If using a mechanical or stock setup.. then the wastegate can start to open prematurely.. and bleed boost off... giving slower spool..etc.. an EBC will ensure the wastegate remains shut until the exact desired boost level is met - giving better/quicker boost build up.

J.
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Old 10-24-2000, 05:08 AM   #13
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Shik, I fully understand what a boost controller does and it is highly recomanded for any turbocharger(if you can afford it).Note: don't buy the cheap mechanical ones though, you can never trust one of those to do a good job.
All I am trying to say is that(if money is not a concern)an external wastegate is almost always better than an internal wastegate at controlling boost, even better if you use a boost controller.
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Old 10-24-2000, 07:18 AM   #14
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Jay, I know you know that I know, that's why I wasn't very clear

You are totally correct and I made an incorrect statement(forgive me, it was early and the remainder of last nights Old English 40's were still circulating in my blood stream ) For some unknown reason I was thinking if something were to happen to the wastegate, the BC would still only provide a certain amount of boost to the wastegate. But as just about everyone knows(except for me at the time ) , if the wastegate decides to stay shut, what happens before it is irrelevent. Thanks for waking me up.

Boostup, I understand what you are saying and for the most part agree. I personally didn't get the chance to use an external wastegate yet on either of my cars, so I can't comment on the actual performance difference between a stand-alone external vs. a stand-alone integrated.

FWIW, the only reason why I would change to an EBC at this point is for convenience. The Joe P controller is about as safe as they come. But thats a different topic entirely
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Old 03-18-2009, 11:14 AM   #15
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This might have been answered, but I have been searching for a good two hours... is our stock wastegate internal with an external actuator, or is the MY02 WRX wastegate fully external? I stood there looking at it for about 20 minutes, and it is odd that nothing is piped or hosed from the piston cylinder attached to the turbo's snail bracket (where a wastegate actuator ought to be), so am I right?
If so, is there any upgrade to the actuator, such as an Aluminum pushrod, bearing linkages, billet actuator body, etc.? It is hideous. I have Titanium up and downpipes, Weapon-R intake, Mid-back Borla Race all t-304 all catless. The turbo housing is polished, it was bored, and everything looks great on and around it other than the actuator (or wastegate, if I really am that out of my wits)... so is there an aftermarket for this? I mean, if we can get about 30 types of band clamp...
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Old 03-18-2009, 11:22 AM   #16
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external gates are better period. Add a boost controller and very common issues like boost creep become and non issue with the proper setup.

As for running 30 psi on an internal.....no thanks. On our bikes we experience boost creep with as little as 6 psi on internal gates.
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Old 03-18-2009, 07:27 PM   #17
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I was wondering why a mod would ask this question, but it lists back to 2000 and this mod doesn't even exist anymore.

And why is this in the Naturally Aspirated forum?
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Old 03-18-2009, 09:17 PM   #18
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Quote:
Originally Posted by impreza2.0 View Post
This might have been answered, but I have been searching for a good two hours... is our stock wastegate internal with an external actuator, or is the MY02 WRX wastegate fully external? I stood there looking at it for about 20 minutes, and it is odd that nothing is piped or hosed from the piston cylinder attached to the turbo's snail bracket (where a wastegate actuator ought to be), so am I right?
If so, is there any upgrade to the actuator, such as an Aluminum pushrod, bearing linkages, billet actuator body, etc.? It is hideous. I have Titanium up and downpipes, Weapon-R intake, Mid-back Borla Race all t-304 all catless. The turbo housing is polished, it was bored, and everything looks great on and around it other than the actuator (or wastegate, if I really am that out of my wits)... so is there an aftermarket for this? I mean, if we can get about 30 types of band clamp...

Why did you revive a 9 year old thread?
Your turbo has an internal wastegate, I don't know of any turboed Subaru that ever had an external gate.
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Old 03-18-2009, 09:19 PM   #19
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Quote:
Originally Posted by Da-Risin-Smoke View Post
I was wondering why a mod would ask this question, but it lists back to 2000 and this mod doesn't even exist anymore.

And why is this in the Naturally Aspirated forum?
What do you mean, this mod very much exists

And I'm guessing that this was the only place for this question back in the day.
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Old 03-19-2009, 03:17 AM   #20
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AS, can you kick this to the NA w/ Bolt on FI forum? Maybe the guy will actually get some answers. Or maybe just fork the recent posts to a new thread in NAwBFI?
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Old 03-19-2009, 03:44 AM   #21
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Quote:
Originally Posted by impreza2.0 View Post
This might have been answered, but I have been searching for a good two hours... is our stock wastegate internal with an external actuator, or is the MY02 WRX wastegate fully external? I stood there looking at it for about 20 minutes, and it is odd that nothing is piped or hosed from the piston cylinder attached to the turbo's snail bracket (where a wastegate actuator ought to be), so am I right?
If so, is there any upgrade to the actuator, such as an Aluminum pushrod, bearing linkages, billet actuator body, etc.? It is hideous. I have Titanium up and downpipes, Weapon-R intake, Mid-back Borla Race all t-304 all catless. The turbo housing is polished, it was bored, and everything looks great on and around it other than the actuator (or wastegate, if I really am that out of my wits)... so is there an aftermarket for this? I mean, if we can get about 30 types of band clamp...
You did all that work and youre still running a stock turbo Or do you mean a turbo with an internal wg?

If you are simply doing this for looks, you do realize you're going to have to cut and weld up your pretty dp to go external right?

And yes you can convert an internal wg turbo to external, just need to shut the internal wg closed (weld it or bracket by grimmspeed).

Finally, this should be moved to the right forum.
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