An electric Supercharger can be an effective way to gain a fairly substantial amount of horsepower for a very low cost. Conventional belt driven superchargers can be very expensive although they deliver power throughout the rev range irrespective of throttle setting.
MGB with Belt supercharger
TR6 with Belt supercharger
Not only are they inexpensive to build, they are generally easy to install and are safe for your engine if installed and built correctly. The electric supercharger installs right onto your cars intake system.
In most cases you will need at least 500cfm of power to receive a boost great enough to give you any substantial gains. If at all possible we hope to achieve a 2psi boost by building a 24,000rpm unit that will produce the needed airflow.
We are investigating fitting one to a car with twin carburetors, we have contacted the manufacturer of once such product who assures us it will work with carbs. We intend to make our own using easily available parts and think we can make one for £20 to £30 plus buying a K&N type filter for the front end.
The electric supercharger will only work at full throttle when the accelerator pedal is right to the floor and thecarburetors are fully open. A micro-switch will be used to operate the motor only when required.
E-Ram Electric Supercharger in Action
Pictures of the main Components required to build an Electric Supercharger
The high power motor is used in conjunction with the 3" fan to produce the 24,000 rpm supercharger
The 3" or 4" fans are capable of spinning up to 24,000rpm under a 12 Volt power source to the high power motor. These units will produce roughly 3 ft. pounds of air pressure or about a 1-2psi equivalent boost under most applications which we will investigate to see if the claims are true.
We have investigated further using an electric supercharger with a twin carb setup such as an SU or a Stromberg and these type of carburetors would have to be mounted upstream of any kind of electric supercharging as is the case for the belt driven supercharger. This would mean that the fuel/air mix would have to flow through the electric supercharger with its electric motor, any spark generated by the motor could ignite this mix and cause an explosion.
The only way to get round this is to change to a different type of carburetor such as a Webber or Delorto but the extra cost would make it not worth while and better performance would be achieved by fitting the Webber or Delorto's.
Where it looks like a small gains could be made is with cars fitted with fuel injection with air flow meters and the Boshe K Jetronic mechanical fuel injection system. In one review someone did some tests for his university disitation using an Audi with the Boshe K Jetronic system and found that he could get a repeatable gain of about 7bhp. His aim was to set out to prove that they did not work and was plesently supprised with the results.
I am still looking and thinking of a way to make an electric supercharger that will fit my MGB without causing and explosion!