Since we are Supercharger Performance, I knew that I’d have to talk about this topic sometime…I didn’t want to get into it though, without emperical evidence.
I am an engineer, I understand the math, I understand the arguements and the counter arguements about electric superchargers…One day I do wish to see a universal supercharger that doesn’t require beltwork… but for now, for most of us , we just need to SEE things to understand once and for all weather they work or not.
I mean it’s very hard to describe how a throttle pedal works in equations… how the angle pulls the cable and opens up the butterfly which causes more air to go into the engine, which makes it rev up…. but give a car to a chimp (not even a human) and after a while the chimp will figure out that more gas = more revs.
That’s imperical evidence for you and it comes from humans impressive ability to understand things that are so complex by just being able to witness them.
So away from the religious-philosophical aspect of things, the root of supercharger, turbocharger and nitrous oxide performance is overfeeding the engine with more air than it would naturally breathe. This takes the motor from being naturally aspirated to being focedly induced. The physical measure of forced induction is ‘boost’ or pressure differential and every engine that is turbocharged or supercharged or nitrous injected will have higher pressure in its manifold than atmospheric pressure because the turbocharger or supercharger is both overfeeding it with air, and that over feeding is causing the air to get compressed and the manifold pressure to rise.
So, do electric superchargers work ?
Everyone dances around this question but the difinitive answer to it is this:
CAN AN ELECTRIC SUPERCHARGER INCREASE MANIFOLD PRESSURE ?
This is not a complex question, if you put a 30 dollar boost gauge on a car and add an electirc supercharger you will know right away weather these things work or not. If the needle goes past 0 psi (atmoshperic pressure) into positive boost then yes electric superchargers work, if the needle is stuck at 0 psi just as it would be without the supercharger, then no the engine is not being force fed, there is no boost, and the thing does NOT work.
It’s such a simple question that you’d think EVERY e-charger manufacturer would prove to you (in something as simple as a youtube video) that with the engine running and the car moving, that their charger can create boost and is thus overfeeding your engine with more air. More air + more fuel = more power and that’s how things work.
Yet these videos don’t exist… (weird, right?)
I came across this on youtube and I applaud him being the first that I know of to debunk the axial fan supercharger… He’s using a Forceflow X4 which is supposedly the MOST powerful axial, and the ‘blower’ is claimed to flow i believe up to 800 CFM which should be able to pressurize a 3.0 liter nissan V6. However axial fans are known to have very low block off pressures (they are unable to trap air properly like a centrifugal does by expelling air at a 90* angle with it’s blades or a positive displacement does with a similar no-direct-return path for the air once it exits the blower)….
httpv://www.youtube.com/watch?v=8-hlFQ0RDl8
Imperical evidence… no need for math… there is NO boost…
If any manufacturer disagrees with this post … then I have one thing to say:
SHOW ME THE BOOST!










Wesley HS wrote:
I know you are allowing comments to your article “Electric Superchargers
– Emperical Proof.
July 6th, 2009″ – However while that article debunks the axial fan
electic superchargers, there are several companies that have developed working
electric superchargers. I happen to have 2 examples – both based on converted
Eaton Superchargers – a m62 and m90. They are ESC units from Thomas Knight over
at http://www.boosthead.com/home.php
I have used some of his other superchargers as well – the BDT units.
Further – his units have been installed on a host of vehicles, are proven to
work both electric and non-electric and he holds a few patents.
The most tantalizing evidence can be found at:
http://www.turbomagazine.com/tech/0406tur_knight_turbo_electric_supercharger/index.html
Which is turbo magazines right up on his old altima.
There are of course a few other companies that have designed and built various
units. But I have yet to see one that doesnt in some way infringe on his
patents.
He has both centrifugal and roots style units – I have played with both, all I
will say is they are impressive.
Their limitation is the amount of power they consume, which limits maximum
continous opperation.
I suspect you may have come across them in the past. The important thing I
think is to distinguish the difference between a bilge pump or rc airplane motor
in a plastic tube and a true electric supercharger.
Also – a take not of one thing – a cheap boost gauge typically lacks the
sensitivity or range to detect smaller changes in manifold pressure.
Every OEM intake system for an ICE I have ever seen. Is operating at a slight
negative – in the range of 1/2 a point of boost do to restrictions and the
nature of its design and optimiazation for a given rpm range. Pressurizing the
intake stream, can even if of a limited range – make a difference as you have
erased the negative pressure – which is a possitive pressure gain – but marginal
at best – but still a gain. Of course to explore that you would have to get into
flow dynamics, intake velocity and optimization, etc.
This isn’t to say an electrical supercharger COULDN’T exist, just that the $20 dollar ebay specials aren’t good enough.
In fact I think some auto manufacturers looked at the idea of E-superchargers in conjunction with moving cars up to 48V electrical systems. However, the 48V idea got canned, and so did a true e-supercharger.
Case in point :
http://www.treehugger.com/files/2009/09/electric-supercharger-hybrid-boosts-torque-better-mpg.php
axial fans have very low ‘block off’ pressure. they can’t really trap air so they can’t really create boost.
Turbines are a little different, due to a much higher RPM and multiple layers of ‘fans’ to create block of.
An electric supercharger is going to almost definately be some sort of air trapping device be that centrifugal (airflow outlet is 90* to the inlet) or some sort of positive displacement pump (pumped air has no way to flow back)…. and even then u need a lot of current.
The link posted above is promising but it caps out at 70,000 rpms (of a turbine’s possible ~120,000 rpms) and at ~7psi of boost instead of 15+ and that specfic unit if u scrutinize the dyno graphs provided i estimate to be flow limited to 140hp @ 7psi.
So i can see one of these on a bike… say a Yamaha R6… and that was probably going to be my next blog post
Thanks for reading