Throttle body CFM?
Jul 19, 2010 | 04:08 PM
#1
Thread Starter
Launching!
Joined: Feb 2010
Posts: 243
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From: South Carolina
Throttle body CFM?
I am wondering if I could find out the CFM of my air intake to the throttle. I know it would go up as the engine revs higher but how much? Is there a tool or device that I could get my hands on to find this info?
Thanx to anyone who can share some info.
OH, my info is in my sig.
Thanx to anyone who can share some info.
OH, my info is in my sig.
Jul 21, 2010 | 10:26 AM
#2
A high quality scan tool/software will tell you how much you are flowing. Years ago I remember the Corvette engineers saying the 2002 Z06 would flow just under 750 cfm and they were only using about 605 cfm. to make 405 hp.
Jul 22, 2010 | 07:53 PM
#4
Joined: Jan 2006
Posts: 16,282
Likes: 438
From: Huntsville, AL
hmmm, well you could measure mass air flow and convert that from pounds/min to cubic feet per minute based on the density of the air. Except density depends on many things, but mainly temperature where this will be useful:
This is assuming that 100% of the air passing through the MAF enters the engine, which I think its pretty reasonable.
Lets say the MAF shows 25 lb/min and its 80 degrees outside, the formula would be something like
(25/0.07353) = 340CFM
Looking at one of my old HPtuners logs when I still had the MAF attached, I maxed it out at 512 grams/second which is 67.7 pounds/minute. Using the table from above that is roughly 925CFM. Using data from the performance maps of the tvs1900 and with my boost level and RPM it should flow around 1000CFM. So its around a 7% error, which isnt too bad of a guess considering it was maxed out.
Code:
Temp (F) Density(slug/ft^3)e^-3 Specific Weight(lb/ft^3)e^-2 0 2.683 8.633 10 2.626 8.449 20 2.571 8.273 30 2.519 8.104 40 2.469 7.942 50 2.420 7.786 60 2.373 7.636 70 2.329 7.492 80 2.286 7.353 90 2.244 7.219 100 2.204 7.090 120 2.128 6.846 140 2.057 6.617
Lets say the MAF shows 25 lb/min and its 80 degrees outside, the formula would be something like
(25/0.07353) = 340CFM
Looking at one of my old HPtuners logs when I still had the MAF attached, I maxed it out at 512 grams/second which is 67.7 pounds/minute. Using the table from above that is roughly 925CFM. Using data from the performance maps of the tvs1900 and with my boost level and RPM it should flow around 1000CFM. So its around a 7% error, which isnt too bad of a guess considering it was maxed out.
Last edited by Atomic; Jul 22, 2010 at 08:06 PM.
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