Originally posted by twinturbosaleen
you can easily run 12 - 15 psi depending on the quality of gas in your area. Completely safely.
long as your runing 8.5-1 and a aluminum headed engine.
if you have good heads.. 500 horses can easily be surpased with only 8 psi boost on a 8.5-1 motor anyway so you wont need to run to much boost.
How can you make hp claims in relation to boost? I dont want to start a war but...
The output of an Otto cycle engine is directly related to MASS FLOW, not boost. Mass flow=pressure*volumetric flow. Volumetric flow = area*velocity.
In order to state how much boost is required to make "this much" HP you need to know a number of things. Adibatic efficiency of the compressor, intercooler efficiency, etc. It doesn't matter how good your heads flow, if the mass flow in is not increased you will not make any more hp.
If the mass flow rating on my turbo is only 550 kg/hr @8psi of boost and a given engine requires a mass flow of 800kg/hr to make 500hp, you will not make 500hp with 8psi with THAT turbo.
If the same turbo moves 800kg/hr @12psi of boost then 500hp is attainable at 12psi and no less.
Make sense? Im not trying to be a jerk, i just dont like the hp per psi of boost relationship people talk about. Boost is a measurment of RESISTANCE to flow, not flow. Mass flow holds air quality and quantity into account.
Lemme know if i missed anything, i typed this while doing my thermodynamics homework...