Electric superchargers...

[woody]

Anyone had a look at these before or have any opinions/feedback?

http://badassmotors.co.uk/shopDisplayProduct.asp?pId=694

[MatsHolden]

Rubbish mate.

[woody]

I have noticed there are a number of electronic variations to the standard supercharger all promising 4 - 10 HP gains on power all stating they are used in some race form or another. Just would like an opinion of someone who has had some experience with one or knows someone who has. What is your opinion based on Matsholden?

[woody]

nevermind.. have done additional reading on the matter... for those of you who are interested why it's not a good idea...:

http://www.wildweasel.ca/j-body/HowTo/eturbo.asp

[Don]

[quote=woody]Anyone had a look at these before or have any opinions/feedback?

If you do some calculations you will find that these electric superchargers will not work unless they have variable speed and then power losses similar to mechanical superchargers.

Lets take say the Vectra 2.5litre V6.
Capacity is 2500cc
One revolution takes in 1250cc (Otto cycle 4 stroke) and based on full throttle.
Idles at say 650rpm = 812500cc/min
Rev engine to say 2000 = 2500000cc/min
Rev engine to 5000 = 6250000cc/min
This is a large dynamic range change. The value for 5000rpm may be less than this as the volumetric efficiency of the engine will fall off with the higher rpm. Most engines have peak volumetric efficiency at peak torque rpm. These figures above are to just keep up with the engine and not provide any additional pressurisation.
Also bare in mind that if the electric supercharger cannot speed to that necessary to cope with engine demand (electric motors resist overspeeding) then the fan/impeller will act as a closing throttle on the intake.
One of the versions I have seen on Ebay draws 35 amps which would make quite a hole in the alternators output.

[woody]

Yeah i read up on it and basically the only version of an electronic supercharger that does work is a race bred version which provides maximum boost for a short period of time in situations such as drag racing.. these would cost you thousands and require serial batteries to provide the required charge which would require a recharge once discharged over the 1/4 mile course.

[btm]

why is there no cheap and easy way to anything... :D

[blueraven]

Sure there is :D

a cheap and easy way to set fire to your car will cost you one match :D:D:D


i think what you meant is there is no cheap & easy way to more power ;) :)

[woody]

i've just spent the best part of an hour reading up on these things and man did the guy who is trying to sell them get his ass handed to him on a plate.. at one point someone said that his stats defied physics and therefore could not be true... he responded with "facts are facts, if the theory doesn't match the facts then the theory must change" yeah cos physics needs to change!

BTM one quick way to screw up your engine - add an eturbo!!

[stevedee3]

I'd never even heard of an electric supercharger, but I guess some people will try anything to flog some rubbish.

Using an electric compressor motor requires:
Converting the mechanical energy into electricity (alternator)
converting electricity into mechanical energy (compressor motor)Both of these steps introduce energy losses. Why on earth would you go this way instead of just using a conventional supercharger???

[Clint]

i just saw these a few days on ebay for the first time, i didnt think it would work either, i wasx thinking the exact same thing as steve was.

physics laws state energy cannot be created. a combustion engine turns fossil fuels into kinetic energy by a number of processses, but the electric supercharger uses energy created by the engine to power a 40,000rpm turbine which in turn is 'supposed' to give the engine more power, it draws 40 amps which is quite a bit of power considering the total output of the alternator is 110amps on my car, maybe more or less on the other models.

is it possible that it could work but i dont know. the one on ebay claimed to produce 15bhp gains.

it also said that it will give additional gains on a turbocharged engine if you place it after the intercooler and before the engine intake.

i am a little doubtful it will work but im completely against it, i suppose it could be possible, but im more leaning towards it not working.

[MatsHolden]

I have noticed there are a number of electronic variations to the standard supercharger all promising 4 - 10 HP gains on power all stating they are used in some race form or another. Just would like an opinion of someone who has had some experience with one or knows someone who has. What is your opinion based on Matsholden?

There's been many articles around on these things. They aren't just a new development, been around for a while. Tests have been carried out and prove they do not work. Suggest electronic supercharger to someone like Ron Harrop and they'd laugh in your face.

[Mr T]

An electric S/C would work but its applications would be limited due to the power required to run them.

This particular system that gives you stuff all boost is a waste of time to start with.

If you had two systems side by side (one pulley driven S/C or Turbo and Electric driven S/C) that were running the same boost, the electric driven S/C would produce more power.

Reason: the S/C would not be draining energy directly from the engine to power it.

Downside: where do you get, and where do you store the energy required to power this system?

[Don]

An electric S/C would work but its applications would be limited due to the power required to run them.

This particular system that gives you stuff all boost is a waste of time to start with.

If you had two systems side by side (one pulley driven S/C or Turbo and Electric driven S/C) that were running the same boost, the electric driven S/C would produce more power.

Reason: the S/C would not be draining energy directly from the engine to power it.

Downside: where do you get, and where do you store the energy required to power this system?
To comment on your post.
1] An electric supercharger would have to be variable speed to work. As you would have seen in my post earlier the amount of air needed at low speed is a small fraction of that required at high speed. There are many variable speed electric motors but they are not efficient. This is to do with magnetic pole shift as the motor speed increases.
2] An electric supercharger will require electricity from the alternator and in the region of 40amps (480watts) at 30% efficiency for the ones on the internet. A mechanical supercharger also requires power to drive and at least 2bhp will be lost in just the belt drive alone.
3] A turbo charger though on initial look appears to not require energy from the engine it in fact does use energy from the engine by creating more backpressure. Of the 3 systems the turbo charger is the most efficient.
4] Most turbocharged and supercharged engines need to have a reduced compression ratio to avoid excess cylinder pressures once boost comes on to avoid engine failure caused by detonation or even pre ignition (they are not the same by the way)

In summary the electric supercharger as described on the ebay ads is not able to deliver engine requirements as needed by a naturally aspirated engine let alone supply extra to cover that needed to produce a boost pressure. Sure if you fitted one and the engine was idling the throttle would be closed and you would probably measure a pressure before the throttle greater than was there before fitting if you were to open the throttle wide under load I think you would find that there was a negative pressure between the supercharger(electric) and engine which means it is not supplying boost. The example engine of 2.5 litre had a dynamic air requirement from idle to 5000rpm of 5000 times!