A couple years back Audi invited me to drive a prototype A6 TDI that was equipped with an electrically-driven centrifugal compressor.

In this car the s/c was added in series with the turbo, just downstream of the intercooler. It wasn't sized to handle the max airflow requirements of the engine, just to fill in way down low in the rev range and during transients, switching off once the turbo was huffing in earnest. Because this was a diesel, the electric s/c wasn't just a performance adder, it was also an emissions helper.

It worked great. The engine had heaps of torque right off idle and pulled like a freight train.

The downside? The electric supercharger used a dedicated 42 volt bus to keep the current draw to a reasonable level. Cost on top of cost.

You see a similar situation with the electrically assisted turbo stuff. Realistically they all need a high voltage bus, making them suitable for use only use on hybrid vehicles. And hybrids are inherently costly, what with having two powertrains on board already, so adding zoomy turbo electrons is a hard sell.

 

I recall a compound set up has the smaller turbo compressor inlet connected to the compressor outlet of the larger turbo? So, for a compound set up with this Phantom turbo, would you set it up as follows?

1. Outlet of turbo compressor feeds the intake of phantom turbo.

2. Outlet of phantom turbo to hot side of intercooler.

3. Bypass valve between between turbo outlet and phantom turbo (which opens at optimal pressure ratio of the phantom turbo) and bypasses the Phantom turbo completely. Whenever bypassed or not called on for boost, the Phantom motor is turned off and it's battery is recharging.

4. Tune

5. Very little turbo lag?

 

You'd want them in parallel. But even still. We have near zero turbo lag options for the BP up to 500hp. Why would you want more than that?

 

My EVOIII 16G, small as it is, still does not really get going until ~4000 rpms. Sure, it could be overkill. But, just thinking, that's all. It would be easier to set up with no need to plumb up another hot side.

Why would parallel be preferred over compound?

 

You're not going to have the electric on all the time.

Your evo 3 16g isnt even ball bearing. Install EFR, remember that nothing belower 3000rpms really matters for going fast, profit.

 

EFR would be too easy, lol.

 

This thread seems pretty old but I stumbled across it. While I did not use an electric supercharger to spool up a turbo. I did use two electric superchargers in sequence. I guess you can say my car is twin E charge. If you're wonder these are the phantom superchargers which I believe were meantioned somewhere on the thread. So do they work absolutely they do. How do the twins compare to a single one. Well I have my two Dyno graphs from when I was running a single to twins. If you're wondering how they work you can look up phantom electric supercharger on YouTube or look up torqamp they are currently building and developing electric superchargers just like the phantom I would argue even better than the phantom. One thing you'll notice is these electric superchargers don't make a lot of hp. But they make a good amount of tq and you feel the difference.


In this image the green line was on 91oct and the red on e85.

In this image the blue line was with stock front pipe. And the green line with catless aftermarket front pipe.

 

There's functional parts but there's no competition so they are expensive. Better off just getting a centrifugal supercharger and bolting a starter of some kind to it.