Supercharger boost control

[neilandbob]

I'm supercharging an Alfa 145 ts. It's a 2.0l engine that makes 155bhp as standard, i'm only looking for 200bhp, at the moment. I'll be using a Rotrex centrifugal compressor at about 4-5 psi. The unit I currently have is good for about 300-350bhp. A specialist says I should use a restrictor on the inlet to the compressor so that I can still spin it at it's most efficient rpm. I'm thinking I could take advantage of bringing boost on a little earlier in the rev range and then dump excess boost as revs climb.
I know this isn't ideal but i'd welcome any thoughts on whether I should do this and if so, what's the best method of bleeding off the excess boost, bearing in mind it has to go back in to the induction loop after the MAF.

Many thanks.

 

[1gibson]

Move the MAF post compressor?

 

[gruntguru]

The restrictor is also an effective method of boost control, allowing you to spin the supercharger harder to make more boost at lower rpm while controlling boost at higher rpm. "Spinning at its most efficient rpm" is not really the issue because the speed lines are close to horizontal near the suge line, which is the part of the map you will be using with an oversize supercharger. (I assume it's oversize although you don't say at what P.R. the compressor flows 350 hp). Anyway, if it is oversize, the restrictor will help keep your operating point away from the surge line.

Engineering is the art of creating things you need, from things you can get.