airflow

[f22cb7accord]

What is the stock airflow ratings (cfms) on the intake side of the JDM F22b DOHC? Does any one know? Also what would those numbers rise to with say a t3/t4 setup or a T27bb turbo running @ 8psi? Thanks

[f22cb7accord]

Excuse me typo T25BB i meant. Thanks

[Accord R33]

Engine volumetric flow (EVF)= (engine CID/1728) * (RPM/2)
= (134.25/1728) * (RPM/2)
=(134.25 *RPM)/3456
so at say 5500rpm
= 738375 / 3456
= 213.65 CFMs

EDIT: 240.9 at 6200rpms

next we want airflow. (N).
p = absolute pressure
T = absolute temperature (about 130. add 460 to make it "rankin")

airflow = [(P) x EVF x 29]/(10.73*T)
airflow = [(14.7 + 8psi) x 213.65 x 29]/(10.73*590)
airflow = 140645.8/6330.7
airflow = 22.2 lb/min

EDIT: 25 lb/min at 6200 rpm

every 10lb/min is about 144.72 CFMs so:
airflow = 321.27 CFMs at 8psi. and 5500 RPMs
multiply this by the engines volumetric efficiency, which i dont know what it is for the F22, but assume 85%

you get 22.2 *.85 = 18.9 lb/min
or 321.27 * .85 = 273.6 lb/min

EDIT: 21.25 lb/min @ 6200rpm
307.5cfm @ 6200rpm



so you need to get a turbo that can support that

im assuming you want this info for compressor map purposes. so ill continue. you need 2 things for the compressor map. pressure ratio, and airflow (some use lbs/min some use CFMs

assume 1.5psi for intercooler pressure drop
Pressure ratio = (boost + 14.7 + intercooler pressure drop)/14.7
PR = (8psi + 14.7 + 1.5)/14.7
PR = 1.6

so we have

airflow = 18.9 lb/min or 273.6 CFMs
PR = 1.6

so lets take the t4 .57 trim compressor.



look at the X-axis. and find 18.9 lb/min (or 21.25 for 6k)
look at the Y-axis and find 1.6

find there meeting point and you can see that they meet right in the turbo Max efficiency "circle" if you will. which looks like 76% therefore..the t3/t4 .57 trim is a very good choice!

NOTE: the intersection line is very close to the 76% efficient line. this is because i did the calcs for 5500RPMs. i probably should have done 6k, it will be a little more inside the circle.


I couldnt find a compressor map for the T25..so ill do the 14b



you can see that the intersection is only in the 70% efficiency range at 8psi and 5500rpms (this time look for 273.6 [or 307.5 @ 6k] on the x-axis)

NOTE: again, if calcs were done for 6000rpms the intersection point would be farther to the right...and even farther from the max efficiency range

EDIT: I redid the calcs for 6200rpms, a little closer to redline so you can see the difference

i hope all my calcs and formulas are correct, if anyone has anything to add please correct me..its late and im tired lol

[b00stingsx]

wow, someone got an A+ in math heh...

[f22cb7accord]

wow

WOW once again R33 pulls through with his wealth of knowledge. Thanks man its going to take me awhile to totally decifer that but from looking at that what you figured out was the total engine airflow and what I was looking for maybe i wasnt specific enough is Just the Head flow. I know there is math to figure that out like port diameter times runner length..... I know some heads flow more then others do you know the math for that or did I misinterprit what you gave me. I plan on using the T3/t4 now. So there ya go. I have a few other forced induction questions im posting a new thread please check them out too man you awsome. Where do you get all this knowledge from are you a automitive teck or just a tunner that reads alot like me. Ive only been in serious for 2 years and all my brains comes from reading books the net and people like you. Thanks your a great teacher.

[Accord R33]

WOW once again R33 pulls through with his wealth of knowledge. Thanks man its going to take me awhile to totally decifer that but from looking at that what you figured out was the total engine airflow and what I was looking for maybe i wasnt specific enough is Just the Head flow. I know there is math to figure that out like port diameter times runner length..... I know some heads flow more then others do you know the math for that or did I misinterprit what you gave me. I plan on using the T3/t4 now. So there ya go. I have a few other forced induction questions im posting a new thread please check them out too man you awsome. Where do you get all this knowledge from are you a automitive teck or just a tunner that reads alot like me. Ive only been in serious for 2 years and all my brains comes from reading books the net and people like you. Thanks your a great teacher.

oh shit..sorry man i answerd a completely different question than you were asking haha. woops. oh well, hopefully it will help someone else out in the future...anyway i dont know the equations for head flow, mabye wikked or midnite can chime in hear. i know wikked is into the whole port and polish thing so mabye he knows.

[iamanonymous]

ok question....
small 16g=505 cfm
big 16g=550 cfm
14b=405 cfm
quick, easy, done
and an answer..............for my own question