Turbo Air pressure Myth or fact?

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kornshadow097
Posts: 35
Joined: Mon May 24, 2010 2:25 pm
Location: South San Diego

Turbo Air pressure Myth or fact?

Post by kornshadow097 »

I hear all the time about turbo's being measured in PSI and then some say flow is more important than the pressure that is put into the engine...

I'm not sure how else anyone would measure the output of a turbine... I mean you have PSI and a flow rate... like CFM (Cubic Feet Per Minute) But I thought that the flowrate just came naturally and wouldn't really be controlled andwas just dependent on the RPM... Which makes sense...

So is there more variables to look into besides PSI and Spool up time (lag)? I mean lets pretend a turbo is instant with no lag time... PSI I'd think is the only way thigs like a BOV keep pressure down... i doubt any measure CFM..

So is it about PSI or CFM?
antedc5-s
Posts: 7
Joined: Sun May 16, 2010 12:54 am

Post by antedc5-s »

waste gates control boost not the bov. bovs just release boost after the throttle is closed and it has no where else to go. mant different turbos out there. bigger turbos usually flow more cfm obviously and also other things like the impeler/ fin design all have to do with flowing more cfm than the next turbo. from a tuners standpoint i'd say is where the psi comes into effect. just my .02
kornshadow097
Posts: 35
Joined: Mon May 24, 2010 2:25 pm
Location: South San Diego

Post by kornshadow097 »

Yea you're right I meant the wastegate. But it's the same thing they
both regulate pressure usually using pressure springs. It's just one
is to the turbo and one is away from the manifold or throttle plate
out of the other end of the turbo.

I get that a bigger fin would make more cfm but have the trade off of
higher lag time or spool time.

The thing is how much cfm does a turbo make at 6psi? Give me any
examples of any turbo, I just see hp ratings n psi ratings... So if
cfm matters so much why don't turbo kits or turbo's list the cfm?

Is the engine limited to a certain cfm or boost pressure? Cuz I'd
think pressure would be the down fall since too much compression
would damage the engine.. While too much cfm could build up pressure
if not at a high enough rpm...

Anyone have a calculation for how much cfm flow can fit in a 2.0L
engine at a given RPM? And does psi even go into account?
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