Divided manifold to single wastegate

[Canadian_CD9A]

I'm making a separate thread to ask this since the manifold thread I started months ago won't get much attention.

I have this 4G63 manifold that I'm very attached to and want to use it on my car. The problem, however, is that the wastegate flange is in such a spot that the wastegate would interfere with the turbine housing, there is no way to mount both. So I'm trying to decide the option that is the lesser evil.

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I have both a 7-blade and 8-blade Holset HX35 with 12cm divided T3 housings teed up, with a T4-T3 adapter plate to make it work. My issue is with boost control - my first option is to either weld a divider to the wastegate flange and bolt on a block-off plate, and run a Holset on its internal wastegate. I know this isn't great for power production, might creep due to the 19mm size (see the housing on the right for port size), Holset wastegate springs run high pressures and the wastegate only vents one pair of runners, so a pair of cylinders might run lean.

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My other choice is this little pipe that bolts to the manifold and moves the wastegate off to the side - tight fitment, but possible. The issue here, is I don't know if I would lose the twin scroll effect by having a shared route to the wastegate. I would still weld the wastegate port to the divider, but use the pipe to a 38mm Turbosmart Ultragate that I have sitting around.

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I know I could slap a IWG T4 EFR on it and make magic, or a tubular manifold that divides the pulses completely, but I'm a broke student (I did buy $159 and $100 found-in-a-dumpster-Holsets, after all), and I believe this manifold can really shine. Response is huge to me, and a cast manifold can probably outspool a tubular manifold by a good margin due to the shorter runners, the stored heat in the cast piece and possibly smaller diameter runners. My setup is ready to go otherwise.

What do I do?

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[GST with PSI]

Meh. You're going to lose the twin scroll effect with a single gate no matter how you cut it (given the 2 options you listed). Like you said, the best option would be to swap in a manifold that allows for dual gates. But, we're picking the lesser of the two evils you listed...

I'd use the pipe that relocates the wastegate. Running either turbo on the internal gate would be the worst option IMO.

 

[Canadian_CD9A]

Yup, I'm slowly realizing that the EFR is the only way to do this properly. So close but so far with this thing, thanks for the input.

 

[agentorange313]

OOOOOOO is that an original HKS cast?