Small Turbine, Small A/R & Large Compressor

[Lextreme II]

I talked to JBrady few days ago when we were discussing the SSTT issue. He suggested Small turbine, small A/R & Large Compressor. The small turbine will spool up faster, however it will be restrictive and large compressor will provide mass air flow. How would this solve the restriction problem? Everyone want to have low end torque. JBrady suggest the restriction can be moderate by two or more wastegate. Basically, the WG will bypass the excessive exhaust flow to prevent over spin of the turbine and restriction.

Its an very interesting idea and looks bright in it cocepts. Here is a picture of this example:

The WG is the primary gate control to moderate the exhaust flow and turbine speed. Aside from the concept, which turbo (turbine/compressor) would fit into this application of our engines?

FYI: I did not come up with this concept, the credit goes to JBrady.

 

[turboandrew]

I think this has been applied to rally cars, small exhaust, big compressor, big WG. The only problem I can think of is surging. That WG looks like an HKS one, but I can't tell what size. I had a pretty small hot side on my HKS twin kit (on the Supra), 0.61 A/R on 2835R turbos, and had twin 50mm WG's, no boost creep with those WG's

 

[Trvln Nalzmn]

I agree entirely. The turbine has much more rotational inertia than the compressor because of the materials they are made out of so if you can make the turbine smaller then its much better. That header and wastegate setup looks perfect to me. The path to the wastegate is straight and it looks nice and large and all 4 cylinders can vent out the wastegate. Once the turbine in spinning fast enough to supply power to the compressor to make the required boost then the rest of the exhaust can go out the wastegate.