Not sure if this helps, but my Low Pressure Turbo for my MX5 runs about 5 or 6 PSI. Which adds about 40 to 50 bhp to a 120bhp engine I can't give exact figures as I only rolling roaded it when it was at 9 PSI & giving 208 BHP, funnily enough I turned it down :-)
My top two low pressure turbos only generate 50psi, then they feed boost to the 'normal' one at the bottom which pushes this up to 90psi boost - hope this helps. Can't get it to fit under the bonnet of my Tam though....
My top two low pressure turbos only generate 50psi, then they feed boost to the 'normal' one at the bottom which pushes this up to 90psi boost - hope this helps. Can't get it to fit under the bonnet of my Tam though....