Sometimes you take on a project that you think is going to be great, but it turns out it just isn’t. This is one of those failed projects. Chronologically, I did this right before the EFI swap. The AMR500 is a small roots supercharger that can be found cheap, in this case on Amazon. Because it’s small, it fit right into an opening in the engine bay and could run off the v belt where the AC normally would go. With some creative bracket, tubing, and bonnet fabrication, a big TBI injector and some sealing it was ready to fire up. Ok, that’s grossly simplified, it took quite a bit more effort, but I’m not going to get too far into it.
AMR500 setup
After getting everything hooked up and firing it up, it did surprisingly move some air. I had looked up some videos of people who had put them on various vehicles and something you can’t get through a video is just how loud this thing is. It literally hurt my eardrums. It has two straight-cut 8-shaped rotors, which I think is a big part of the noise. I also had trouble getting the TBI to seal up because believe it or not, it wasn’t designed with forced induction in mind! Those two things were pretty much the nails in the coffin. I couldn’t imagine daily driving it with the noise, so I decided to scrap the project and go a different route instead of putting more time into it. It was fun and educational, but just not practical.
I have a 360ci, 1/2 inch de-stroked 426 Chrysler hemi that has wet sileeves its an old Keth Black hemi drag racing engine all aluminum with solid cylinder heads that I made during summer vacation junior year of high school.
I made 20 sets in total that Summer.
The point is I have a 14-71 drag race blower – 28% over drive at 4500 rpm it is loud.
Just shy of 6000rpm the blower is wear stripped so it may not make so much noise as a flat rotor.
I also built a hotrod with two Magnuson 110ci motorcycle blowers on a common manifold side draft ida 48 Webber carbs it was not that loud I can’t remember the ratio at idle made 5psi I never could get a pressure reading leaving the light The exhaust noise was considerable and it Was a handful to say the least I got some people to ride along just to get or watch the pressure no one could.
I would ask them when it was over and no one could remember or pay attention to the gauge.
The AMR blower I know nothing of I was looking for a picture or actual specs when I ran across this article but. From what I have read it seems like people are over reving them without dimensions they look like a Magnuson 110.
I don’t think they should turn any faster then 20,000rpm If the tips of the rotors go sonic it will make a lot of noise and probably stop pumping soon after from the shock waves just because you can do something does not mean you should.
I know from experience that PSI blower can not tolerate nitro the linear motion of the screw is fast enough coupled with the compression to detonate nitromethane the reason it works with roots blowers is the slow helix dumping chunks of atmospheric pressure air into a pressurized volume in a laminar flow pattern I can’t imagine the shock waves bouncing around the manifold it might be interesting to see a quality simulation if not a photograph we did not have such tools back in the day but the ineffincyes and loses must be insane.
All I know is it worked to make crazy power alot of noise and alot of fun and alot of work.