So, how is this different from the electric superchargers? It's more complex than an electric supercharger. It places turbo wheels in the path of the exhaust just to create electricity for a completely separate electric system in a car that already has a battery and alternator for producing and delivering electricity. Engine builders used to not only seek to get more air/fuel delivered, but also scavenge exhaust most efficiently. Putting turbo wheels into the exhaust path is contra efficiency. Having worked on VWs & Porsches back in the day, this just seems like German over-engineering and over-complicating matters.

 

Not being an engineer myself, I will not attempt at arguing the specific design efficacy one way or another. I am glad to see engineers tackling the turbo lag issue as our governments have forced the manufacturers to develop more fuel efficiency in their fleet. this is why the V6 engines will increasingly become a rarity. I am amazed at how the Ascent 4 has so much power for such a large vehicle (lag or no lag).

 

I believe that the turbo used in the Ascent (and Outback XT) spools at a very low RPM, so that may mean less lag than systems that wait a bit. There's been some previous discussion about that if my memory isn't flawed.

 

The Ascent also uses a dual spool compressor which is very efficient and gets moving very quickly.

 

The Ascent's turbo is a "Twin Scroll" design, which matches the exhaust manifold's pulses into discrete inlets on the hot side. This reduces lag by not having the hot gas pulses competing against each other as they enter the turbo.

 

The Ascent's turbine is also sized according to the exhaust flow in the desired rpm range. This is what helps the turbo spool so quickly, but also what limits the flow at higher rpms.

It seems Porsche is taking the idea of a turbo and splitting it up, kind of genius in a way, removing the compressor makes the turbine more efficient and removing the turbine makes the compressor less dependent on RPM. If it works correctly, which I'm sure at this stage it will, it could be a step for ICE to electrification. The turbine uses waste energy to power the compressors exactly like a standard turbo without lag or unnecessary heat transfer.

 

The Ascent's turbine is also sized according to the exhaust flow in the desired rpm range. This is what helps the turbo spool so quickly, but also what limits the flow at higher rpms.

It seems Porsche is taking the idea of a turbo and splitting it up, kind of genius in a way, removing the compressor makes the turbine more efficient and removing the turbine makes the compressor less dependent on RPM. If it works correctly, which I'm sure at this stage it will, it could be a step for ICE to electrification. The turbine uses waste energy to power the compressors exactly like a standard turbo without lag or unnecessary heat transfer.

A quantum leap up from the electric $50 "superchargers" sold on ebay, but in a way a refinement of the concept. I wonder what parasitic losses are encountered by the exh turbine powering a generator/alternator to charge the battery pack which powers an electric motor which drives the compressor?? It seems to me that the current direct drive (common shaft) setup would be more efficient, altho subject to lag.

 

I love turbos,the louder the better. I wish I could get my Ascent to sound like this. Maybe if I loosen the banjo bolt on the hot side.....no that would be to loud. I'll think of something? You might wanna turn your volume down......quite a bit. She's a screamer.

 

I don't think there is much turbo lag on our cars, more so transmission lag. Also these electric turbos currently cost more than our engines. Garrett who is the manufacturer of the turbo on our engines is at the forefront of electrified turbos in pass cars. With that being said all major turbo manufacturers are already or have working electric turbo systems. They are the future or at least until the ICE is obsoleted.

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