Asin Eaton Type Supercharger.

Intend to use an Aisin SC14 supercharger on 3.8 litre enging in low boost (<10psi) application. My calculations indicate that although this unit was fitted standard to 2 litre engines it should be suitable for my requirement.

It has a swept volume of 85 cf/rev (1420cc) that should provide the required airflow rate of 427 cfm however the flow data I have managed to find for this supercharger sets the max flow rate at 375cfm at pressure ratio 1.8. As the car in question is a day to day drive, I will very rarely run the engine to max power (just want more low speed torque) and therefore believe the available flow rate at a pressure ratio of 1.6 will be adequate.


Are my assumptions reasonable.

You mention max flow rate for the sc; this would for a given speed of SC rotation. From what you tell us I assume you would have a smallish pulley to increase the flow for the bigger engine at daily drive speeds.

You could look at other OEM installations of the SC to see what else has been tried.

James

Data has Max flow rate at 9000 rpm & I have a pulley ratio that will reach this speed at desired engine speed. My calculations prove an 85 cfm supercharger run at 9000 rpm will meet my air flow requirement, but the air flow data for the SC14 says it falls short no matter how fast it spins. Must be the characteristic of the SC14.

Question I have is what affect, if any, the slightly less that ideal max flow rate will have on the anticipated engine output, specifically low/mid range torque which is where I want the best effect. I would expect none, just limit topend HP.

Other similar applications for this supercharger either say "its great at 12 psi" or "it will not work at any engine bigger than 2 litres" but no one provides a mathematical proof for either statement.