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If I want ~ 450 to 475 Crank HP on a RB25DET with the these upgrade:

Exhaust cam gear

Metal head gasket 1.6 mm (to lower CR to ~ 8.5)

3" exhaust

Water/Air intercooler

Water injection

T3/T4 , GT30 or GT25R Not sure yet...

Is it necessary to have a external one? I know that for high boost it's much better..but if I plan to boost 20 psi max (1.35 bar) Do I need it?

If I go for external...is there any company that make manifold for RB25DET without spending too much ? (which one do you recomend?)

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I think in an ideal world where money isnt always such a restriction, go the external wastegate.

On merit they give you better boost control, superior flow, and typically are used in conjunction with more effecient/better flowing exhaust manifolds.

That said there are plenty of people making good power with intenal gate turbos, on factory manifolds, and looking at the power you are chasing, people in Aus have made such power with such setups.

As for who to buy the exhaust manifold off, HKS/Trust/Apexi all make nice stainless steel manifolds for their turbo setups.

Doenst really answer your question though does it? As im spending your money, go a HKS kit 3037 or 3040, manifold and gate. Bit pricey but will get you the power you need

Originally posted by MattR

im at the stage now where 268 with a td06 and standard manifold is at its limit. The acuator cannot take anymore and I have to go for external to get more power.

Hey MattR, what sort of turbo setup are you running? A TD06-17c? Bolted on to the standard manifold? You have 268 rwkw? Sorry, just curious as to your trust setup.

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