Supercharger for 203 or 403?

luthier said:
I have one of these and might be interested in selling it if anyone is sufficiently interested. Or if I find some good info I might decide to fit it myself afterall.
It needs to run on an accessory belt I think , as it previously used a timing belt arrangement but this wouldn't stay on.
So if anyone knows what the best belt arrangement is that would be very helpful. As I say I think an accessory belt might work best as a timing belt needs more perfect alignment. In fact a double V would be the most tolerant of any slight misalignment.
It comes with a manifold that replaces the plate on the side of a 203 or 403 head and it uses a small solex downdraught carby that sits on top.
It looks like a Constantin but seems to be a generic copy in the Garrett style I think. I'll get some photos later if anyone wants to see.
It was last mounted on a standard 203 and was going exceptionally well up Mt Ousli overtaking everything when it threw the belt. Nothing was damaged but it was never refitted.
I was told it mounts straight on by virtue of the manifold but I would personally fabricate support brackets from the engine block as it is fairly hefty and there's a lot of force being exerted when it's running. It also comes very close to the bonnet but I'm told that it does fit without modification. Maybe a pancake filter could squeeze in there too but not sure.

Cheers.
Click to expand...
Hi, is it for sale ? thanks
 
luthier said:
I have one of these and might be interested in selling it if anyone is sufficiently interested. Or if I find some good info I might decide to fit it myself afterall.
It needs to run on an accessory belt I think , as it previously used a timing belt arrangement but this wouldn't stay on.
So if anyone knows what the best belt arrangement is that would be very helpful. As I say I think an accessory belt might work best as a timing belt needs more perfect alignment. In fact a double V would be the most tolerant of any slight misalignment.
It comes with a manifold that replaces the plate on the side of a 203 or 403 head and it uses a small solex downdraught carby that sits on top.
It looks like a Constantin but seems to be a generic copy in the Garrett style I think. I'll get some photos later if anyone wants to see.
It was last mounted on a standard 203 and was going exceptionally well up Mt Ousli overtaking everything when it threw the belt. Nothing was damaged but it was never refitted.
I was told it mounts straight on by virtue of the manifold but I would personally fabricate support brackets from the engine block as it is fairly hefty and there's a lot of force being exerted when it's running. It also comes very close to the bonnet but I'm told that it does fit without modification. Maybe a pancake filter could squeeze in there too but not sure.

Cheers.
Click to expand...
I've fitted many superchargers to many things and I think most people would be quite surprised how much a Roots style blower pulls down towards the drive pulley under boost, regardless of how rigid the mounting system appears to be. This flexing is often the reason why a belt comes off rather than from any static misalignment. I've used V belts, polyrib belts and toothed belts all with great success.
One thing to remember with toothed belts is they have a no "give", a decent backfire can potentially snap the blower's input shaft.
My Reliant is actually set up with a polyrib pulley welded to the water pump pulley. The water pump is driven off the crank by a single A belt and the blower is driven off the polyrib pulley on the water pump via a 3PK belt (up to 10psi).
I've run this setup for about 6 years and never had a belt come off. I had the same water pump blower drive setup on an A15 Nissan motor for a few years as well, and again no belt problems.
In one setup I've seen they had a little snout on the front of the blower pulley and another on the crank pulley. Then they had an adjustable bar with a high speed bearing on each end that slipped over the snouts, the inner races locked onto the snouts with grub screws. This way the pulleys can't get out of alignment and the blower can't flex down, so the drive belt can't go slack.
I always try and run a dedicated supercharger belt and have the tensioner on the back of the belt to maximise belt wrap around the pulley/s.
With polyrib I try and use pulleys with more ribs than the belt has so if the belt does "walk" for whatever reason it will just creep to the next groove rather than get onto the edge of the pulley and damage the belt, or worse the belt actually comes off.
 
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