Science of speed 10 psi going to 13 psi
05-23-2019, 08:36 AM
#11
You are correct...11.0 on the F20 and 11.1 on the f22. 11.5 was the Japanese F20.
The difference between 91 octane and 93 octane would only show if the timing was running up against the knock sensor. Pump gas itself has some variation. With E85 your limitation will be the supercharger and the pistons (lightweight, high-compression NA pistons aren't made for high-boost environments).
SOS says it uses the Novi 1220 (Vortech SCi) and the Novi 1200 (Vortech Si). The compressor map for the SCi only goes to about 15psi (pressure ratio just over 2). The Si goes all the way to 2.8 pressure ratio, maybe 28psi. https://vortechsuperchargers.com/pages/compressor-maps However, the compressor map goes to 55k rpm while the spec says 52k is the spec'd peak and further says 23psi which would be a 2.6 pressure ratio.
Unlike turbos and positive-displacement superchargers (see the BoostFab and IMT units coming out in the Whipple thread), the centrifugal superchargers only make peak boost at or near peak rpm, so the piston issue may be smaller. I have no insights into this. Of course, that comes at the expense of a lot less power under the curve. Note that the Lysholm 1600AX used by BoostFab and the Eaton TVS 1300 used by IMT will only hit 17psi-19psi. They are probably at their best on 91 octane pump gas with low compression pistons.
ID has a calculator to size the injectors: Fuel Flow Calculator - Injector Dynamics.
The difference between 91 octane and 93 octane would only show if the timing was running up against the knock sensor. Pump gas itself has some variation. With E85 your limitation will be the supercharger and the pistons (lightweight, high-compression NA pistons aren't made for high-boost environments).
SOS says it uses the Novi 1220 (Vortech SCi) and the Novi 1200 (Vortech Si). The compressor map for the SCi only goes to about 15psi (pressure ratio just over 2). The Si goes all the way to 2.8 pressure ratio, maybe 28psi. https://vortechsuperchargers.com/pages/compressor-maps However, the compressor map goes to 55k rpm while the spec says 52k is the spec'd peak and further says 23psi which would be a 2.6 pressure ratio.
Unlike turbos and positive-displacement superchargers (see the BoostFab and IMT units coming out in the Whipple thread), the centrifugal superchargers only make peak boost at or near peak rpm, so the piston issue may be smaller. I have no insights into this. Of course, that comes at the expense of a lot less power under the curve. Note that the Lysholm 1600AX used by BoostFab and the Eaton TVS 1300 used by IMT will only hit 17psi-19psi. They are probably at their best on 91 octane pump gas with low compression pistons.
ID has a calculator to size the injectors: Fuel Flow Calculator - Injector Dynamics.
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