Quote:
Originally Posted by pope
You could somewhat replicate a turbo's boost-by-X tuning by running a wastegate on the intake tube with an electronic control or an electronic control on the internal bypass (if the blower is equipped) and smallest pulley for the upper limit of desired boost.
I haven't seen this in some years and I don't have the impression it was widely used, but back in the early/mid-oughtes when turbos were really starting to take over from superchargers in the 5.0 Mustang community, some SC users realized they could mimic the broad, linear powerband of a turbo by installing a small wastegate on the intake tube to dump excess psi. By targeting, say, 10 psi and running a 20 psi pulley, they could make 10 psi a couple thousand rpm lower in the torque curve and hold it through redline instead of making 10 psi near redline with a 10 psi pulley.
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I'm aware, but the reason this is less common is because the supercharger is essentially over-spinning once the bypass is activated, which isn't good on fuel economy or on the life of the supercharger, and it produces a lot of extra heat. I also don't know if the bypass is large enough or if there would be some boost creep, but I doubt that is an issue. A turbo wouldn't have this issue because it would just not spin as much. For the Harrop kit, the smallest pulley is 65mm, which is around 18 psi. I think Harrop needed to use a larger crank pulley to achieve 20+ psi. Even then, the car is only making 10 psi at 4k, which a turbo could be far above that. Just saying.