EVO III GT Exhaust Mani vs. T-25, options?

[PieEyedPiper]

I replaced my cracked 2g manifold with the turcochargers.com GT manifold. Problem is I am still on the stock T-25 and I'm now experiencing a funky power band, presumeabley, due to the mismatched outlet of the manifold and inlet of the exhaust housing of the T-25.

It spools slower and is definitely less responsive in the lower rpm's. When I finally get to about 4500rpm I almost get a whiplash effect, again presumabley, due to the higher overall flow of the manifold overtaking the turbulance created by the mismatched openings.

Is this ^^^ a correct diagnosis? How deterimental to flow and such is this mismatch? I just want to be sure I know what the problem is befire I try to fix it.

I'm looking for solutions or alternatives and even opinions.
It has been suggested to just grab a 14b, port the heck out of it and replace the T-25, or just port the T-25. Cost is a major consideration.

Also is it possible to use the 7cm sealer ring with the GT manifold? There is no step for it to seat in so I'm not sure.

 

[hopwoodp]

I replaced my cracked 2g manifold with the turcochargers.com GT manifold. Problem is I am still on the stock T-25 and I'm now experiencing a funky power band, presumeabley, due to the mismatched outlet of the manifold and inlet of the exhaust housing of the T-25.

It spools slower and is definitely less responsive in the lower rpm's. When I finally get to about 4500rpm I almost get a whiplash effect, again presumabley, due to the higher overall flow of the manifold overtaking the turbulance created by the mismatched openings.

Is this ^^^ a correct diagnosis? How deterimental to flow and such is this mismatch? I just want to be sure I know what the problem is befire I try to fix it.

I'm looking for solutions or alternatives and even opinions.
It has been suggested to just grab a 14b, port the heck out of it and replace the T-25, or just port the T-25. Cost is a major consideration.

Also is it possible to use the 7cm sealer ring with the GT manifold? There is no step for it to seat in so I'm not sure.

Your diagnosis is correct. Port out your turbo. An upgrade is always an option but, like you said "cost is a consideration". I say go ahead and port your T25 and see what the difference is. I don't believe the GT manifold was design to have a sealing ring. That is why it was cast without one. They were basically designed so that you would not need to port it. Just make sure you match your turbine housing inlet to the manifold outlet.

Do me a favor. If you do that, let me know what happens and how much of a difference that makes for you.