AudiForums.com - Turbo/Supercharger

Quote:

Originally Posted by eurotrip (Post 1479072)

LOL right.... all i have to say is psi vs cfm will answer 90% of your hypothesis

Here goes the cramping fingers...
When engaged in a discussion about the efficacy of boost systems the volume portion of the discussion is left off for the very simple reason that it is assumed to be the same for all the systems being discussed. One would not compare the horsepower boost achieved in a 2.0 liter ( volume of displacement ) turbo V4 with that achieved in a 6.2 liter supercharged V8. While it is possible for one system to be great in a smaller displacement engine and not as good in a larger one that is not the discussion I started. I assumed everyone would know that the displacement would be considered a "scientific constant" along with all the other parts of a motor with the only variable being the boost system. Both turbo charged and supercharged cars are equipped with a "boost" gauge on the dash instrument panel which measures the current boost achieved in PSI. Nitrous oxide systems inject liquid nitrous oxide so pressure is not mentioned. The only reason compression ratios are ever discussed at all is due to the simple fact that ANY combustible material will explode with greater force when greater pressure is applied but that is compounded when the material also has more oxygen atoms to react with. Higher PSI = more oxygen atoms hence a turbo building boost to 30 PSI prior to entry into the cylinder is forcing more oxygen atoms into the cylinder. With the exception of Nitrous Oxide injection systems the ONLY relevant measure of a boost systems efficacy is PSI of boost they can generate how quickly (turbo lag) and at what cost.