THE throttle body mod thread (with airflow data)
11-27-07, 05:17 PM
#26
final data!
here is the completed and accurate official chart
throttle bodies are typically flowed on a bench with no elbow on them and measured at WOT and typically flowed at a pressure of 1.5" of HG (mercury)
so I have that on the chart now. so if you see like a 650CFM carb thats what its tested at 1.5" Hg. Considering the more pressure you force air through a given orifice, it will yield more flow. so I could have it tested at an even higher level of inches of water and get more CFM but 25" is the magic number it seems for when people are comparing things to another such as intake manifolds, heads, headers and etc...
this test was basically to see the difference in using a bolt to fill the hole or JB weld and see how P&P affects airflow etc etc. there is a very minimal difference in CFM for the JB weld fix or using a bolt, hell if you dont have a thread and tap kit you can fill it with jb weld then run a bolt through it heh, but that would be redundant.
the velocity was all measured at WOT on the bench with no elbow
you gain more velocity through a smaller port with the same pressure so widening the throttle body lowers the velocity through there but it gives more CFM, its kind of a trade off but looking at the results a ported and polished throttle body is definitely an upgrade in comparison.
so use JB weld or a threaded bolt, your not going to be able to tell the difference (unless you end up screwing up and get a leak :P )
throttle bodies are typically flowed on a bench with no elbow on them and measured at WOT and typically flowed at a pressure of 1.5" of HG (mercury)
so I have that on the chart now. so if you see like a 650CFM carb thats what its tested at 1.5" Hg. Considering the more pressure you force air through a given orifice, it will yield more flow. so I could have it tested at an even higher level of inches of water and get more CFM but 25" is the magic number it seems for when people are comparing things to another such as intake manifolds, heads, headers and etc...
this test was basically to see the difference in using a bolt to fill the hole or JB weld and see how P&P affects airflow etc etc. there is a very minimal difference in CFM for the JB weld fix or using a bolt, hell if you dont have a thread and tap kit you can fill it with jb weld then run a bolt through it heh, but that would be redundant.
the velocity was all measured at WOT on the bench with no elbow
you gain more velocity through a smaller port with the same pressure so widening the throttle body lowers the velocity through there but it gives more CFM, its kind of a trade off but looking at the results a ported and polished throttle body is definitely an upgrade in comparison.
so use JB weld or a threaded bolt, your not going to be able to tell the difference (unless you end up screwing up and get a leak :P )
Last edited by fidelity101; 11-27-07 at 05:25 PM.
11-27-07, 06:00 PM
#27
Red Pill Dealer
iTrader: (10)
I just want to say: Thanks!
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