so we've probably seen the split downpipes. My question is... is there one out there for a 2nd gen. that divides the wastegate and exhaust from the turbine?

Would it be worth it? Or is it useless because we can just port the wastegate anyways? But it does inhibit the flow of exhaust leaving the turbine.

Are there any out there? I've seen one that was full custom welding a new backing plate onto the turbo.

The idea sounds interesting, and I know it's been done before, but can't really find any rx7 information on it... including dyno results, boost response, and all the goodies

 

It could be done but I don't think there's much demand for it, or at least enough to justify a production run. Like you said it would require a custom backplate.

 

There isn't one available. Better off putting an external wastegate on a S4 turbo setup.

 

My knightsports hybrid has a divided set-up. It uses the stock backplate and has a sleeve punched into the turbine outlet. The wastegate door has a hole right behind it on the stock backplate and has a resonated screamer. I will try to find some pics and post them up, seems rather easy.

 

Sorry forgot to mention it is a s5 turbine

 

Yes! Glad to hear they are using the sleeved turbine outlet.

I divided mine with a machined block between turbine outlet and wastegate outlet and years later thought of the sleeve idea.

The stock backplate has a machined lip that matches the turbo and the rest is rough cast- this should also be addressed.

So, remember to simply have the backplate receive the sleeve as well instead of machining it to the turbo only and then realizing you will have this slight leak unless you machine the backplate flat.

 

I had my s5 exhaust housing machined to accept a 2.5" press fit slieve. I then had my mate port the exhaust housing right at the turbine wheel smoothly out to the id measurement of the 2.5" slieve.

The external wastegate was drilled out and plate welded over the top of the 2 holes.

I then had the hole where the wastegate shutter welded. 2 external wastegates were installed, one in each runner of the aftermarket divided exhaust manifold.

with the gates open it sounds like a pair of chainsaws running inside your head.