FE-FC Holden Discussion Forum

I'm thinking about making a supercharger along the line of a Norman or Judson type sliding vane. I have been reading as much as I can including the "supercharge" book from Aldred Norman and some bits and pieces on the net. If anyone has or knows where i could find any more information or has a Norman that I could view would be great. It seems (like most things) the more I read the more complicated it gets. One thing that I have found relates to the positioning of the inlet and exhaust ports, another is the capacity required. I intend the charger for a 186 red motor with only a small amount of boost pressure, any help will be appreciated.
I am located on the Far North coast NSW.
Rob

In regard to the positioning of inlet and exhaust ports, I think that you will find that the reference is in realtion to inlet and exhaust valve overlap, which is different. The other thing to keep in mind is that the supercharger has to fill each cylinder with air. A 186 cubic inch engine fills with air every two revolutions, so a superchager would only need to be capapble of pumping just over 100 cubic inches of air every revolution to provide sufficient boost.

Keith

Thanks Keith, yes 100 ci is what I was thinking in regard to capacity. The point of inlet and exhaust port relate to the position in the charger barrel where the ports need to be machined apparently not exactly diametrically opposed this is due to noise levels and efficiency.

Rob

Obviously the ideal would be to have a 4 valve head with individual intake runners, crossflow in design with the supercharger barrel running the length of the engine so that all port runners are the same length.

In practise, depending on the mounting point of the supercharger barrel and the construction of the intake manifold equalised length runners can be fabricated. I am assuming that you would be looking at a "Draw Through" system seeing as you are looking at a sliding vane type. The reason that I ask this is that I would think that the sliding vane type will need something to act as a lubricant.

I know that the Normans used bakelite and there are many superior materials now that could be used, but I would think that a lubricant of some type would still be required.

Keith

One of the features of vane type blowers is the fact that they have their own internal compression ratio and therefore the exhaust port opening point isn't really critical. So long as the port has sufficient area for good flow and it closes when the segment between vanes is at its minimum volume it will be ok.
The intake port generally will have a longer duration - theortically it would open immediately after reaching minimum volume and close upon reaching maximum volume. In practice you'd want to delay the opening  - the internal compression ratio mentioned earlier means that there will be some "trapped" pressure so in the interests of noise reduction the chamber is allowed to expand somewhat before the intake opens. If you use peripheral ports one of the challenges will be maintaining even wear of the vane tips.
Most vane type blowers/motors use phenolic or carbon vanes; some like the old Shorrock used a complex system to maintain a small clearance between the vane tips and the housing. Vane blowers were always regarded as being a bit less efficient than a Roots blower; I'd expect a modern Roots design such as an Eaton to be quite a bit more efficient. Sounds like an interesting project though..

The Shorrock were Air craft cabin blowers used to pressurise the cabin Stan Pobjoy ran one on his VW powered Drag Bike he was the first in Australia to run a 10 sec 1/4 mile pass and also the first to smoke the slick the full quarter mile back in 1972 he was 3rd fastest in the world on a drag bike one of our pioneers and a great guy .....FC427....

Thanks everyone for your comments,
 I have made so progress and will get back to you all soon with some details.

Thanks
Rob