this is one thing i have yet to understand... why does the motor need a load to give boost?

just wondering.

thanks
mark

 

when you drive, the weight of the veh is present... for example... I can drive at 45mph at a certain rpm... if I push the pedal down to the floor, boost can build.... when sitting still the engine has no load.. it's free to just rev... kind of an easy way to put it.

I guess you could compare yourself running on foot across flat ground at a certain speed compared to you running up a hill at that same speed.

 

I ---- you not, but once I saw a DSM, rev up at idle, and hit 14psi, lol.. It was crazy, he had problems with his wastegate

 

When my friend revs his GST, his BOV goes WOOOSH!.. He doesn't have a working boost gauge, so I dunno if it had time to build up a little pressure.

 

I can make my BOV go off in neutral. I don't think it really builds boost though. I try not to do that too often.
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you are still building boost when you keep the motor in neutral and rev the motor (which is why you saw the DSM'er have his BOV go off when he revved at idle) it's just that you aren't making AS MUCH exhaust gas, you are making it for a shorter period of time, and it's less than while in gear so you aren't spooling the turbo as well.

while the engine is in gear it's making the exhaust gasses for a longer period of time....so you're making more exhaust because the engine is revving slower giving the turbo more exhaust gas to spool it, letting it spool fully.
at least im pretty sure thats what it is.

 

my brother in laws dsm will hit 18psi in neutral.. its because they ahve extremely small turbines.. Something around or below a .48 ar I believe.