[Mstng2]

...And I wonder about the pressures thing, because the 24psi vs 44psi seems wrong. If the Turbo has a waste gate it will bypass and only run at a speed necessary to compound a total of 24psi. To calculate a turbo for this application is more complicated also. Boost pressures don't add. The pressure ratios multiply. The pressure ratio is the absolute pressure at the outlet divided by the pressure at the inlet, Pr = Pout/Pin

For example, if the Eaton is pullied for 10 psi w/o the turbo, that means Pout = 10 + 14.7 = 24.7, and hence, Pr = 24.7/14.7 = 1.68. If the turbo were pushing 8 psi of boost at its outlet, that means a pressure ratio of 1.54 for the turbo. Therefore, the total pressure ratio is 1.68*1.54 = 2.59, which would mean a total boost pressure of (2.59 - 1)*14.7 = 23.4 psi

So if you want a total boost pressure of 17 psi, the total pressure ratio needs to be (14.7 + 17)/14.7 = 2.16. Therefore, since the pressure ratio across the blower is fixed by the pulley ratio and eff engine & SC displacements, that means the pressure ratio across the turbo needs to be 2.16/1.68 = 1.28. Hence, the gauge pressure at the outlet side of the turbo will only be (1.28 - 1)*14.7 = 4.2 psi (rounded off), which hardly seems worth the trouble.

To size the turbo with the Eaton pullied for 10 psi, you can simply assume the turbo is feeding an engine with a larger displacement. So for a 330 cid motor, it will effectively look like 0.9*1.68*330 = 499 cid, (where I've assumed the volumetric efficiency of the engine relative to manifold conditions is, VE = 0.9)

Also the 'turbo is more restrictive because of the blower' theory doesnt make sense to me. Won't 24psi of 'turbo only' entering the combustion, be the same as 24psi of 'turbo and S/C'? (for simplicity sake). Also you could run much larger exhaust housings than would be normal for a 281 cid engine and not have the lag, but see the increased flow potential. Thus saying that the turbos are infact less restrictive in that application than a normal 24psi all turbo 330 cid engine.