Electric Superchargers from eBay etc

[old-git]

 

[RobBentley]

hahahaha. Somebody must be re packing USB desk fans as superchargers.

 

[old-git]

But people believe the hype and buy them. Say it load enough with glossy packaging and the gullible will believe you.

 

[old-git]

But people believe the hype and buy them. Say it load enough with glossy packaging and the gullible will believe you.

Also, the clever thing is to not sell it cheap. By putting a reasonably high price ($3oo dollars in this case) on the item people think it must be much better than the obviously useless cheap ones.

 

[obi_waynne]

Rob - if I got one of these would you need to alter the performance map for me to cope with the extra intake pressure and would I get another 40bhp from it?

 

[RobBentley]

Rob - if I got one of these would you need to alter the performance map for me to cope with the extra intake pressure and would I get another 40bhp from it?

Just fit it - you'll get another 40 placebo powers... That good enough?

 

[old-git]

And you don't need to pay Rob to remap it

 

[davalav]

Dont belt driven superchargers spin at over 500,000 rpm? How can a fan match that!?

I am glad MCM did a video on this. Stop idiots buying them and wrecking thier engines.

 

[old-git]

No They are powered by the crank and their speed is governed by the difference in gear teeth numbers between the crank and compresser pulleys. They normally run faster than the engine but not a 100 times! I'm no expert on these but my guess is between 2 and 4 times crank speed.

 

[jarrus]

depends on the superchargers, generally larger ones won't be able to do the RPMs of the smaller ones, but the larger ones can flow more air (you already knew that)

saw this video ages ago and I kind of knew what the outcome would be.....
That said these guys did something similar and made an increase in power.... was it worth it? no but they did for the crack...

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[st24]

Might buy 6.
If they are no good on the car they will sure get rid of the leaves in my garden.

 

[800jer]

A super charger will normally take around 80+bhp drain on an engine. But the gains are fantastic. A little fan wont do diddly squit and if its an axial flow compressor it would have stages of rotors and stators to compress the air down which it does not.

 

[HDi fun]

An electrically driven compressor is possible but the losses wold be greater than those for [a conventional] one which is directly mechanically (ie belt) driven. Whatever electrical load the motor presents to the alternator will in turn load up the engine. The greater problem is practicality. If a conventional 'charger saps 80bhp then an electrical one will do the same.

80bhp = 59.7 kW (59.68 to be exact)

Let's assume a nominal 13 volts DC system.

Moving on: Ohm's law gives us Power(watts) = VI (volts x amps)

So divide 59680(watts) into 13 volts and we need over 4500 amps to drive the supercharger motor. That's ten times the current required to operate a standard 12 volt starter motor.

The alternator would be huge. The cables would be huge. The supercharger motor itself would be huge.

 

[800jer]

Plus when you are changing from one power type to another then to another eg mech to elec then back to mech you always lose in the change overs. The Coeficiency of Power. Standard physics.

 

[HDi fun]

That was my first thought [hence, my first sentence] - the frictional heat losses and electrical heat losses would be huge. Thermodynamics gets in the way of so many things.

Superconducting magnets and superconducting cables would solve most of this, but let's try and guess the load that cooling things cryogenically would present. Far more than 60kW

 

[800jer]

Unfortunately there are many widgets and gadgets that claim to make your car more efficient or more powerful and they are all snake oil. Another famous one is the Hydrogen gadget that you pop in the engine bay and by electrolosis you split the atoms in a pint of water and make your car more efficient. lol

 

[HDi fun]

^^ yes, loads of stuff like this ^^ it's not new. We had the Slick50 rubbish in the 1980s. I never use oil additives. Fuel additives have a place possibly.

 

[TCJBOLDIE]

[QUOTE="old-git, post:
Also, the clever thing is to not sell it cheap. By putting a reasonably high price ($3oo dollars in this case) on the item people think it must be much better than the obviously useless cheap ones.[/QUOTE]

Reminds me of the time a neighbor placed some furniture on the footpath with a sign FREE and after a few days it was still there so put a new sign on it saying "for sale $50.00" and it was gone overnight

 

[claymore]

http://autoweek.com/article/car-news/volvos-new-electric-supercharger-explained

 

[800jer]

Yes the Idea here will work but a much larger capacity alternator would have to be install to generate the power required to keep it running. There will also be a bigger load on the engine to turn such an alternator.

 

[obi_waynne]

http://autoweek.com/article/car-news/volvos-new-electric-supercharger-explained

That's an interesting development, i'd need more technical information to really comment but a large car maker wouldn't be doing this unless it worked.

The twin charge arrangement is where the benefit lies as the charge is compressed twice this has the effect of compounding giving larger gains that just doubling the boost. Will it last the distance though, electric motors have a habit of burning out especially when you think of the high rpms it will need to generate!

 

[old-git]

The principle of electric superchagers has never been in doubt, they work the same way as the exhaust driven variety - requiring very high RPM and a properly designed compressor impeller. A tin impeller turning at a few thousand RPM just isn't going to work , no matter how glossy the box is.

 

[HDi fun]

It's more likely that the engine vacuum will snap the blades off. Guess where they're going!!!