[GREG O'Brien]

I still wouldn't use CFM when there are much better equations layed out in the above links

[Turbopit]

Originally posted by Rara:
The CFM calcs can be used to get a decent ballpark figure for a turbo (hardly something to rely on, but close enough for an educated WAG )

We can get that close without doing any actual math.

[Rara]

Originally posted by Turbopit:

Originally posted by Rara:
[b] The CFM calcs can be used to get a decent ballpark figure for a turbo (hardly something to rely on, but close enough for an educated WAG )

We can get that close without doing any actual math. [/b]

certainly, provided you have a little bit of experience . . . I don't particularly like using cfm methods regardless, mass airflow is really far more important. Just simply pointing out that the cfm equation could be just as useful for N/A as it could be for forced induction, lol.

[67King]

Originally posted by Rara:

Originally posted by Turbopit:
[b]

Originally posted by Rara:
[b] The CFM calcs can be used to get a decent ballpark figure for a turbo (hardly something to rely on, but close enough for an educated WAG )

We can get that close without doing any actual math. [/b]

certainly, provided you have a little bit of experience . . . I don't particularly like using cfm methods regardless, mass airflow is really far more important. Just simply pointing out that the cfm equation could be just as useful for N/A as it could be for forced induction, lol. [/b]

Before y'all get too busy pissing all over each other, you should know that y'all are two of the three parties involved in my trying to work out something for 'Pit to get a front bumper cover and possibly a set of smooth cladding. :eek:

BTW.....did you end up with the car, or what?

[Turbopit]

hehe, :pat: :offtopic:

[TurboRay]

Good stuff, Greg. THANX for "being there" to help turbo-sizing illiterates like myself!! [Image: biggrinjester.gif]

C'ya - RAY

[GREG O'Brien]

it gets better - Cozz is working on something that blows away the work I have done - it will help EVERYONE (including myself)... hopefully he will finish it and post soon

[T.TREPANIER]

Hi Greg:I've been readying all the info you've posted on this site and it's excellent!I Hope you can help me with my Turbo choice..I understand the comp. maps,but don't know how it relates to RPM'S..My car is an automatic,so i want the boost to come in ASAP,This thing shifts at 5000K,and is street driven with the stock T-3..ATR header,Volvo I.C.,big valves etc..thanks DADDY DOG

[GREG O'Brien]

what you are going to need to do is calculate the air flow at the different RPM points and plot them across the map to get an idea of what you are looking at...

so basically you would:

1) pick your lowest point where you expect full boost (say 3000rpm@15psi or a PR=2.0) - calculate #/min airflow and plot it.

THEN

2) calculate and plot airflow in #/min at the highest rpm point you expect to operate at... in your case say 5500rpm@15psi or a PR=2.0.

3) Draw a line between these two points and that is the operating range of you motor.

4) If you are concerned with crossing the surge limit too much - then you could calculate your airflow a few hundred rpm BEFORE boost onset assuming a pressure ratio of PR=1.0 (or atmospheric pressure/no boost or vacuum). So figure hypothetically - PR=1.0 @ 2700rpm. Draw diagonal line from this base point up to your first point - this represent the building of boost over those 200-300rpm.


Now the automatic complicates things a little because convertor can have alot of DIFFERENT effects on boost onset... so you'll have to take that into account too.

[GONRACIN]

Originally posted by Honda Eata:
[QUOTE]Unfortunately, Turbine maps don't exist publically for T3 or T4 exhaust sides :banghead:

67King, you work at Ford! Does Ford have any turbine maps in their vaults?

See! no one ever believes me about the conspiracies! The truth is out there! but anyway, great info...I always enjoy trying to work out stuff like that :thumbup: