GTM Performance Engineering: MHI Twin Turbo Official Release

G37sHKS

Go with external wastegate. my boost gauge was reading 8.8 PSI while the internal wastegate spring was 7 PSI.

1.8 PSI of boost creep is a lot if you ask me. Im not so sure if going with .86 housing will eliminate the boost creep or will just minimize it (which is still not good)

So just to be in safe side. go with external wastegate. you will have better boost response, better flow, more power, and last but not least, it will extend the life of turbo.

Yes you heard me right it will extend the life of turbo and will give better power and more power.

Please watch this video to learn more about external and internal

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Chuck33079

Yep. Other than cost, external is always better.

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2011 MB Touring-Sport-6sp-Nav/GTM TT/FI TT TDX/JTran/Kosmic/Eibach/Hotchkis/SPC/CSF/RPS/SoThatsWhereAllMyMoneyWent

esfourteen

Every factory turbocharged car in the world comes with internal wastegates, for the obvious reasons of: cost, weight, and clearance/space issues, so aside from those, I would say its a good idea to run externals just because internals have certain limitations.

Since the volumetric efficiency of our engine is so high, I would say if you have the extra money just go external so you avoid any boost creep issues with our engine. However, claiming that external wastegates are safer and give "better power" (whatever that means) and more power is just a joke.

The biggest problem typically encountered with internal wastegates is controlling higher amounts of boost (> 20psi). Theres 2 reasons for that, first most factory actuator springs are in the range of 7-14psi, so with an EBC solenoid at max duty cycle (about 90%) that would mean a maximum of 14-28psi. The second issue is the size of the wastegate openings. Internally gated turbos wastegate opening is limited by the size of the turbine housing itself, external wastegates do not have this limitation. This is why the .64 AR suffers from creep issues while the .86 does not.

I currently run 15psi and have no issues holding that to redline on internal gates with .86 housings.

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Build Thread | GTM TT Install Thread | Engine Build Thread

megalapagas

Thx now I'm SET FOR SURE.

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GTM 34 Row Oil Cooler | K&N Drop Ins w/ Z1's Post MAF Tubes | F.I Non-Res'd 2.5" T.P w/ CF CBE | Axis Wheels | Piecing together My Own Custom T4 Top Mount Single Turbo Kit *Still in the works* |

showme99

Very informative video. Thanks for sharing.

Mr.Squeeze

Nice video

For the amount of money that is spent on a turbo kit especially your going to upgrade down the line witch at some point we all do. It is just better to get the External Gates and not have to deal with the issue that come along with internal gates.

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Driven Motorsports Single Turbo 7675 T4 1.32 A/R 995WHP 780TQ

Chuck33079

Exactly. Don't paint yourself into a corner right off the bat.

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2011 MB Touring-Sport-6sp-Nav/GTM TT/FI TT TDX/JTran/Kosmic/Eibach/Hotchkis/SPC/CSF/RPS/SoThatsWhereAllMyMoneyWent