How our supercharger works.


By GA Projects



An electric superchargerIn this section we detail how the GA Projects team managed to squeeze out so much boost from so little input


We didnít set out to build a supercharger but a simple humorous observation started us thinking about one. Young Ryan (one of our technicians) had just built a proof of concept model of a 600 mm (24Ē) radial compressor when he joked that it would make a great supercharger for his bike. This sowed the seed of an idea that eventually led us to build an electrically powered supercharger.


Big G (our boss) suggested we used an automotive heater fan to power the charger. Initially this concept was greeted with howls of derision but when we began to think about it the idea grew on us. What if we ran it at 24V or even 36V? And how  Supercharger during constructionefficient could we make it by using a diffuser? As these questions were answered it became ever more apparent that an effective supercharger could be built from a cars heater fan assembly.


The electrical side of things turned out to be easy even at the relatively high voltage/current loads that are required and heater fan motors have generally proven to be incredibly resilient. 24 and 36 volts are achieved by electrically switching additional batteries into series with the superchargers motor. On disengagement the auxiliary batteries are switched back into parallel with your vehicles main battery for recharging. Note that the remainder of your vehicles electrical system remains fully isolated from raised supercharger voltages and cannot be harmed by them.Our electric supercharger is engaged by a throttle body mounted switch and does not operate at idle or light load. During development we had the supercharger idling through a ballast resistor when not engaged to prevent induction impedance. Further testing showed that this was not necessary as the supercharger does not form a sufficient airflow barrier to justify corrective action.


Supercharger showing diffuserDesigning an efficient yet easily built diffuser turned out to be more of a challenge than expected. After wrestling with all sorts of complex curved vanes we eventually came up with a simple flat vaned diffuser that for our purposes worked just as well as the others. A diffuser is a static set of vanes (yellow coloured ring in photograph left) that redirects gas flow and causes a pressure wave to build up. The difference between a supercharger and a fan is its ability to generate pressure as well as gas flow. Our diffuser effectively turns what was originally a fan into a supercharger.


One difficulty we had to overcome during development was insufficient volumetric efficiency. To put it another way our early superchargers could develop pressure but did not displace enough air to keep up with the engine. Mounting an impellor fan in the superchargers inlet solved this problem.


Designing a casing for the supercharger is simplified by the fact that heater fans are barrel shaped, we just had to work out what materials to use and how to seal it.


Naturally we donít want to give too much information away or we wonít have anything to sell.Full details are available in our illustrated 27 page construction manual.





Click here to order Ė just $10



Previous article

Next article

Supercharger home page

GA Projects home page





Easy projects for the home handymanGA Projects specialise in designing low cost projects that any practical individual with basic handyman tools and ability can build. We avoid the need for special machinery or skills (e.g. welding) and ensure all our projects are made from readily available parts and materials. All projects are easy to build and are carefully scrutinised for quality and safety. We supply comprehensive, illustrated plans and construction manuals to guide you through every step of the way.


You can contact the GA Projects team at

Or view the GA Projects home page to see our full product range, just CLICK HERE






GA Projects links

Build a Solar Pool Heater for under $100 The project that got us started.

Kids Electric Go Kart This project is a synch for the home handyman or handywoman.

Discover electricity and basic electronics Comprehensive introduction to these subjects for just $6.99c

Build a Kids Ride On Army Tank Easy to build and cheap too, kids will love this one.


Recommended links to other companies.



At GA Projects we individually select each link (no automated link farms here). We are a family orientated company that will not link to inappropriate material or companies pedalling unsuitable products (porn, drugs, gambling etc.) Should any such links slip through our nets then please let us know so that the offending material can be deleted.


CLICK HERE to view links


Site Map


Home | Poolheater | Go Kart | Understanding Electronics | Tank | Supercharger


Contact us at