[Irace86.2.0]

Originally Posted by FR-S2GT86

Although the variable pulley supercharger is an interesting design, seeing the technology already being used in vehicle transmissions with somewhat iffy reliability results, (I'm thinking Jatco CVT's in Nissan vehicles) I would have serious doubts about the overall reliability of that particular technology within the Procharger over an extended period of time. But time will surely tell once they are out on the market. Maybe they'll be more reliable than the Edelbrock kits, maybe they'll be worse. I can almost guarantee you that they won't be as reliable as our Harrop kits. One thing for certain is that they WILL cost even more than their standard supercharger as the rep stated in the video you provided.

Another thing I see about the variable pulley supercharger, is that whenever boost is needed, and wherever in the RPM band, parasitic draw on the engine will still always exist. Low demand for boost, like in a standard fixed pulley supercharger, will mean a low draw, and high demand for boost will mean a high draw. What I'm proposing would reduce the draw on the engine completely (ideally) at high demand. This would have the added benefit of less strain on the engine internals.

You are correct in pointing out the higher cost, which I pointed out already, but the two combined technologies I'm proposing are already tried and true and have been for decades. There is already an understanding of both out in the field of how they work and what things to expect to have to deal with when using them, with the exception of mounting a drive pulley to the gearbox instead of a compressor, but I would think that would simplify the build somewhat. And with the higher cost will come higher reliability, not only of the engine, but the bolt-ons as well.

I seriously think my idea would be much more reliable in the long term than any type of electronically-controlled variable pulley drive system, as long at it is designed properly. I doubt those rollers or electronic actuators inside the Procharger will hold up to years of even just normal wear and tear.

The good thing is, the standard Procharger supercharger is a tried, tested and reliable design, and its gearbox would be a good candidate to modify in the set up that I'm describing. The desired final supercharger drive shaft speed could be as simple as experimenting with different combinations of gearbox, pulley size, belt size and possibly overrunning clutch pulley size. It will certainly take time in developing, but what good product doesn't?

Maybe you didn’t notice, but that video is 7 years old. They have been on the market. They do cost more, but they do more, so it is what it is. It allows for more boost down low with a flatter torque curve up high for people who have a fuel/boost/block-strength limit all while being more efficient and while generating less heat and this reducing the chance of knock.

I think the biggest obstacle for your design would be mounting the exhaust turbine to an exhaust manifold with good tolerances and then having that interface with a pulley in a good packaging situation. I don’t know if you were thinking that there would be a custom output shaft mounted at a distance to a gearbox or if it would be mounted to the turbine like a centrifugal supercharger, but if it is the latter then there may be heat concerns for the components. It is an interesting idea.