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I am trying to plan my turbo system for the SPI I am putting in.

My question is regarding internal vs external wastegates.

Internal would save alot of space. But external seems to provide better performance.

Which way should I consider or does it rally matter.
 

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Running a exsternal just makes thing's more complacted and exspensive. There nice to have, usally you have more controll and less spikes and creep's, but I have'nt had any issues with my internal. Internals can be modified to run pretty much what ever boost you want anyways.
 

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External wastegates were designed for high boost applications, if you have a internal wastegate the flap that opens is usually the biggest I have seen is 36mm and that is on a big t3/t4 hybrids, 20g mitshu turbos.

Meanwhile a external wastegate are made huge 36mm+, allowing more exhaust to bypass the turbo with less creep and spikes like Jeffescortlx said.
 

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Yep - an external wastegate is nice but unless you really pour some money into the SPI and build it up, you won't ever be able to run enough boost to really notice the difference.
 

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external is better for boost levels over 15psi. tho an internal can handle it. an external can be made in sizes in upwards of 50mm+. the smallest ones i have seen are like 38/40mm. not many internals are larger the 32/34 that i have seen.

easiest way to figure it out is think of a BOV. the bigger you use means you are running more boost. a small DSM one is only good til low 10's in boost with out modifing. just like an internal gate needs to be ported at times to be able to control the higher boost.

NEUMAN
 

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neuspeedescort said:
the bigger you use means you are running more boost.
It's just the oppisite. The larger the waste gate, the more energy that can bypass the turbo.
A waste gate with a large valve will do better at controling low levals of boost. While a high boost turbo system when very little energy is being bypass and most of it forced through the turbo, a smaller wast gate can be used.
 

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Jeffescortlx said:
neuspeedescort said:
the bigger you use means you are running more boost.
It's just the oppisite. The larger the waste gate, the more energy that can bypass the turbo.
A waste gate with a large valve will do better at controling low levals of boost. While a high boost turbo system when very little energy is being bypass and most of it forced through the turbo, a smaller wast gate can be used.
true to a point. how much CFM are you pushing along with your high boost numbers? like a smaller turbo (call it type1) that peaks at 17-20psi is going to not be a big deal with an internal. but when you are pushing a larger turbo (call it type2) at 8-10psi making that same CFM as the "type1" you would be ok. but what happens when you get the right a/f ratio to push like 13-15psi or more on "type2"? its going to make your CFM levels jump and the internal wastegate that is 32mm can no longer keep up with the demand of the boost levels. so this would make you want to plug off "type2's" internal and get a nicer 38mm or 42mm external.

see where i am coming from? jeff you know alot just as i do. just i think we are saying the same thing twice. heheheh

NEUMAN
 

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id rather have an external one with its own down pipe. the sound they make is worth the extra cash.

mostly guys use them on huge turbo setups. they get rid of the internal because of its small ness. the amount of exhaust is too much for the little flap inside so they still over boost.

as far as accuracy, theyare just as acurate as your MBC they are exactly the same thing...prety much. theres a piston in a cylinder that moves under boost pressure.


and the best part about them..they sound badass
 

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there are a few of the wrx guys in my club running them. i would definately do it for just the sound if i had the cash to do it...

ppppttshhh tshhh tsshhh it sounds like someone sweeping a concrete floor but echoing.
 

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Onegimp said:
marclar said:
id rather have an external one with its own down pipe. the sound they make is worth the extra cash.
Thats a stupid reason for wanting one.

And if you don't want to over boost, just get a pop off valve.
siragan said:
Um... I think some of you guys have your priorities in the wrong places.
agreed.
 
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