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Originally Posted by TitaniumTT
Unfortuneately for me, I only hav the option of running one stepper motor with the Motec that I'll be using. I was going to use it for the OMP but I like the throttle body butterfly for the intake idea more. I suppose I could use an internal style wastegate actuator connected to a butterfly valve as well.
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The beauty of my setup is that the control box for the turbos is a separate box, and doesn't rely on the stock ECU; you just input your max pressures and allow it to go about it's business.
Quote:
Originally Posted by TitaniumTT
My main question would be, how would the turbo's handle working against each other? The larger T4 turbo in your example would be moving more CFM at the same boost pressure as the T3 style. Pressure is pressure and if held constant between the turbos, would the T4 over power the T3 in anyway?
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No, as long as the pressures are equal, both turbo outlets will flow freely; if one produces more pressure than the other, the reed valve on the outlet will close, preventing backflow.
If you were using a system with more secondary turbo boost than the primary, it would probably be worth using another valve to redirect air from the primary turbo outlet into the turbo inlets, basically making a loop so that the turbo keeps spinning instead of stalling out against a closed valve.
Quote:
Originally Posted by TitaniumTT
The setup I had in mind is similar. Here's the setup that I'm contemplating
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Plumbing the turbos like that isn't likely to gain you anything. The thing to remember is that a turbo is a pressure differentially operated pump. In short, it relies on the difference in pressure between the inlet and the outlet on the hot side to spin the turbine.
So, you have to run your small turbocharger first, or else the exhaust, which can freely flow through the larger turbo, gets backed up against the smaller one, which means there's no pressure differential on the larger one. Because the smaller turbo must come first, the net effect is that once the exhaust runs through the small turbo, you have the difference in pressure between the primary turbo outlet and the secondary turbo outlet to extract useful energy from; far less than there exists in the manifold. Certainly there is energy there, but you'll find your larger turbo takes much longer to spool than it would in a single turbo configuration, which necessitates a larger primary turbo, which raises your boost threshold.
Your concept would certainly work, and I believe your system of wastegates would work perfectly, too, I just don't know what the performance would be like. I would be curious to see it in action, though.
Now, running sequential twins is an option, but it requires two reasonably small turbos. I feel a small and then a somewhat larger turbo will give better top end performance, but again, I'd be very interested to run the dyno numbers on a twin sequential setup with properly sized turbos and a good manifold.
I don't know where you're at in the country, but if you're anywhere near Cincinnati, I've got my engine dyno at the shop setup to test and tune rotaries, and I'm just a bit of fabrication work away from testing my setup. I'll be testing on a stock RE motor, with stock intake and upgraded injectors, and a water to air intercooler for consistency. That way I can test several turbo setups and map them against each other in an apples to apples comparison. It'd always help to have another brain when the time comes to do it.