Ok I'm jumping into the pool.

I believe that there it's absolutely possible to make a gas engine have more power by electric supercharging. But it's not easy, especially if you are looking for significant improvements or for any extended duration. It can definitely be done, but at what cost.

Lets face it, there are electric motors that can put out way, way more power than needed to supercharge a LS engine. Diesel trains and transatlantic ships are driven by electric motors.

So the $64k dollar question.....Has this motor/compressor combo been tested and has a table or chart with boost, flow, RPM, voltage, current been created? Without that, you have no way of knowing if all the effort you're putting into this is going to give you 1 extra HP or 500 extra HP or the results you want.

BTW, what are the results you're expecting?

What RPM do you need to spin the Esupercharger at to get your desired flow/boost?

I noticed the motor you have has no gearing. So that means that you're going to have to drive it at high speed. That gets expensive. You see, in theory, no problem, just switch the coils faster and more often. In reality, not so easy.
1) As you switch a coil faster and faster, an inductive component begins to come into play making the coil effectively have a higher resistance. With a higher resistance, you need a higher voltage to get the required high current. That means you need a higher supply voltage.

2) High current switching circuits don't like high switching speeds, especially at high voltage. It can be done, but it's not easy and usually not cheap. Once you get to a certain RPM requirement, you may be better off with gearing.

A couple of more observations. When just driving around and not in boost, the compressor is going to restrict airflow. So you're going to need a bypass or to run the Esupercharger all the time, although at lower power. Also I think I noticed an intercooler in the mix (I could be wrong). I wouldn't bother with that unless you're going to be in the 10 PSI or greater range, Less flow losses.

 

You would be surprised, as long as you don't care about inputting noise to the motor I don't think you would have too much of an issue.

 

i want to point something out to you. Cruising around you can’t the throttle blade open, what, 5%-10%.......which if you look at the throttle blade at that percentage, the area the air is flowing through is quite small, I would not figure the compressor blade would hinder anything. And if it’s throttle position activated like the one that cleetus tested that is grossly over priced and under sized, then it won’t be a problem under moderate acceleration. Just a single observation.

 

In the first video I make reference to a 2-way valve system that allows N/A and boosted modes without any losses. Time will tell whether this can be implemented in practice. The mechanics have been less than enthusiastic about rigging this up for me on my terms.

The inductance of the motor is all part of how it's wound. There's nothing wrong with what you said but the guy who built this S/C for me already took all that into consideration and found an appropriately wound motor that would work at 25V. This means the windings are capable of creating the magnetic flux needed at that voltage and at 300A, which is the trade-off you need to make to get power at low voltage.

I'm making my power tables according to energy equations, which simplifies things a great deal. Instead of worrying about RPMs, voltages, etc, I just look at the electrical power, factor in the efficiency and take that net power and make it equivalent to gas enthalpy. By doing that, I can determine how much mass-air-flow a given electrical wattage will result in. This also makes it easy to know how to drive the motor to get that flow. You just need to determine the duty needed to get the power level you desire based on the airflow you desire. I already have an array of duty values in my program which correlate to commanded power levels.

Quite right about losses. At most throttle positions there would be none. The throttle "response" would be laggy... instead of getting 50% HP at 50% throttle (I'm just making up numbers) you might get 50% HP at 60% throttle. This only becomes a problem once you get up to 100% throttle but at that point the S/C is more than making up for pumping losses so it's no longer a problem. If the S/C is off you might notice a bit of power loss at 100% but that's all.

 

Id think a larger displacement unit like a roots blower would be better for this sort of thing. Wouldn't need the RPM to push alot of air. Ive seen a honda setup that used 3 starter motors to spin a jackson supercharger up and it worked really well. That or even buying a self contained centri blower unit and adapting an electric motor to spin it. Trying to use a actual turbo adds alot of complication IMO. Violates my KISS mentality! lol... but cool none the less!

 

That image is from Thomas Knight Superchargers, the same guy who built mine. You have a good point re: the RPM but roots are so inefficient I guess he decided it wasn't practical. Centrifugal yield more from the batteries and the motor can be made to accommodate those high RPMs if you select the right one.

 

I may have missed it, but are you oil/water cooling that motor?

 

No, the motor is normally air cooled and rated 10kW. At maximum battery load I'm running maybe 7 kW so I doubt there's a motor cooling issue.

 

Looking at the dyno charts from the electric turbo's VS the roots type though, it seems like the roots can keep up with the engine RPM to redline. I've yet to see a centri style unit maintain boost to Redline. Even with 2 60mm elec. turbos feeding a 2.0 liter. I just don't see a 76mm turbo keeping up with the engines needs. Look at Centri blower design. They run 120mm+ impellers at 65,000+ RPM. I want to see what your doing work, I really do! Why reinvent the wheel on the power unit though? Why not retrofit an electric motor to an existing used small blower?

 

It's kind of a long story but the short answer is I tried my best to request a product that would be perfect for my engine and what I received was the size of a kitchen garbage can. Frustrated, but not wanting to upset the manufacturer who put a lot of effort into it, I worked with him to find a solution and he offered me another unit that he had already made that would work on the car. Much smaller, more practical but the boost map wasn't exactly perfect. I believe it will work on the LS3 but is a bit on the small side so likely it just means I will have a power curve that is skewed to the lower RPMs and I won't get much up top.