Maximum safe BHP for stock 1.5 with turbo

[Evangelion335]

Originally Posted by cdydjded

9lbs on with a T28 (what Im using) is not the same as 9lbs with a GT2554R (what Garm is using)........

Can someone explain this to me?

It was my understanding that the # measurement was accurate right untill it passes trough the throttle body.

Flow is an important matter, but only because you can create a bottle-necking effect that will rob you of available o2 into the engine.

The 9lb rating is going to be 9lbs no matter what the size of the turbo is. In the same sense that you can have a gallon of water thats pressurized at 9lbs as well as having an oz of water pressurized at 9lbs. Turbo sizes are relevant to the volume of air intake the engine requires not so much the #s required (this isnt a hard an fast rule).

Smaller turbos are ideal for smaller engines because:
1: A smaller turbo has less mass at the turbine meaning that it will take less force to achieve maximum rotations and therefore less time to achieve desired pressure.
2: Because you engine is smaller (1.5l) the actual internal volume of the cylinder requires less oxygen to reach the desired pressurization.
3: a large turbo and a small turbo running at identical pressures will produce the same horsepower gains. The "power loss" becomes an issue because you have selected a turbo that is limiting your maximum flow rate and spooling time. This can wildly effect torqe curves and produce a torqe curve that will become murder on trackday.

Can someone read that and tell me if ive got the theory right?