So, I have a 318 magnum, and want to run low-boost on it, about 5psi or so, looking at a GT35 or a T3/T4 hybrid single turbo maybe, but then I started looking at centrifugal superchargers, and that led me on a rabbit hole of weird Ebay stuff. Lo and behold I find the AMR500, a $100 500cc-per-revolution supercharger for KEI cars.
Now obviously one of those on a 1:1 gear ratio would not make boost, but they are supposedly rated up to ~18,000 rpm
So doing a bit of quick math if I used two of them with a ratio of 3.5:1, meaning at the 5100 rpm my automatic slushmachine likes to top out at the supercharger would be spinning at ~17850 to 18200 so riiiight at the top of what the AMR500 is rated at.
At 3.5:1 two 500cc superchargers will displace 3.5L of air per revolution, well over the "50% displacement rule" for superchargers.
Not including losses or volumetric efficiency (which I thiiink I would actually gain boost from because the engine doesn't perfectly suck in 5.2L of air every two revolutions) I would be seeing a pressure ratio of 7/5.2 == 1.346 giving me a boost of (14.5*1.346)-14.5 == 5.07
Am I missing something or is this just about the simplest and cheapest way to make ~5psi of boost?
Now obviously one of those on a 1:1 gear ratio would not make boost, but they are supposedly rated up to ~18,000 rpm
So doing a bit of quick math if I used two of them with a ratio of 3.5:1, meaning at the 5100 rpm my automatic slushmachine likes to top out at the supercharger would be spinning at ~17850 to 18200 so riiiight at the top of what the AMR500 is rated at.
At 3.5:1 two 500cc superchargers will displace 3.5L of air per revolution, well over the "50% displacement rule" for superchargers.
Not including losses or volumetric efficiency (which I thiiink I would actually gain boost from because the engine doesn't perfectly suck in 5.2L of air every two revolutions) I would be seeing a pressure ratio of 7/5.2 == 1.346 giving me a boost of (14.5*1.346)-14.5 == 5.07
Am I missing something or is this just about the simplest and cheapest way to make ~5psi of boost?
There's also sc12 and sc14 superchargers they made for toyotas that displace 1200cc and 1400cc respectively, they're more expensive, but they might be better/less change of outright failure from the supercharger
Where are you going to put both of them and figuring out the mounting and belt placement/piping? Plus twice the drag to run them. I'd opt for twin turbos, Can't beat to sound when the spool up! 
Quote:
I thought about doing that I bought the manifolds off eBay! I honestly believe that hardest part is figuring out the intakeOriginally Posted by Moparite
Where are you going to put both of them and figuring out the mounting and belt placement/piping? Plus twice the drag to run them. I'd opt for twin turbos, Can't beat to sound when the spool up!
Turbo(s) require headers, crossover, exhaust AND intake work, and for the small amount of boost I want to make I'm not sure it's cost-effective. I was just wondering if the dual AMR500's would have any obvious issues working in this context, or if I had messed up the math somewhere.