real electric supercharger?

[rocket2050]

Is there such thing as a real electric supercharger? There are alot of ebay ones which sell for $30+ and I looked at some of the seller's feedbacks and it looked like most people were satisfied about what they bought. I also googled Electric Supercharger and found this supercharger selling for $199. How would I know which one works and which one doesn't? Thanks

[spit144]

basically all the electric superchargers are is a fan that forces air into your intake. Yes it will give you some extra hp, but not all that reliable. The ones I have seen you have to wire it to a switch and turn it on when you want the extra power, it doesn't automatically come on and off.