Throttle Body Upgrade Confusion
#1
Throttle Body Upgrade Confusion
So I've been researching some performance upgrades for my 5.9 and a common one seems to be 52mm throttle bodies.
What is confusing to me though, is how can people report an increase in performance when the stock throttle body flows 635cfm(source: hughes) but the stock intake manifold only flows 180cfm(source: allpar intake shootout) and the stock heads only flow 199cfm (source: mopar action magazine)?
What is confusing to me though, is how can people report an increase in performance when the stock throttle body flows 635cfm(source: hughes) but the stock intake manifold only flows 180cfm(source: allpar intake shootout) and the stock heads only flow 199cfm (source: mopar action magazine)?
#2
So I've been researching some performance upgrades for my 5.9 and a common one seems to be 52mm throttle bodies.
What is confusing to me though, is how can people report an increase in performance when the stock throttle body flows 635cfm(source: hughes) but the stock intake manifold only flows 180cfm(source: allpar intake shootout) and the stock heads only flow 199cfm (source: mopar action magazine)?
What is confusing to me though, is how can people report an increase in performance when the stock throttle body flows 635cfm(source: hughes) but the stock intake manifold only flows 180cfm(source: allpar intake shootout) and the stock heads only flow 199cfm (source: mopar action magazine)?
Consider, the engine is just a giant air pump. It 'displaces' 360 cubic inches of air per two revolutions. So, about .21 cubic feet. Figure a redline of 5500 RPM, and that works out to max flow of 577.5 CFM. Well below what the 52mm throttle body supplies.
Of course, that's figuring 100% volumetric efficiency, which these engines don't even come close to. I think if you get 75-80%, you are doing really well.
#3
Throttle body is total flow, Manifold, and head flow is for ONE cylinder/runner.
Consider, the engine is just a giant air pump. It 'displaces' 360 cubic inches of air per two revolutions. So, about .21 cubic feet. Figure a redline of 5500 RPM, and that works out to max flow of 577.5 CFM. Well below what the 52mm throttle body supplies.
Of course, that's figuring 100% volumetric efficiency, which these engines don't even come close to. I think if you get 75-80%, you are doing really well.
Consider, the engine is just a giant air pump. It 'displaces' 360 cubic inches of air per two revolutions. So, about .21 cubic feet. Figure a redline of 5500 RPM, and that works out to max flow of 577.5 CFM. Well below what the 52mm throttle body supplies.
Of course, that's figuring 100% volumetric efficiency, which these engines don't even come close to. I think if you get 75-80%, you are doing really well.
With your calculation though, wouldn't the stock throttle body be more than sufficient and thus upgrades wouldn't provide any performance advantage?
#4
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#9
250 seems way too much to spend. It seemed a little more able to rev, maybe.
What happened to dakrt?? he used to sell the ported ones on ebay for 100 bucks. That was a bit more tolerable.
There is a guy selling some on ebay for 200. Still a bit high if you asked me.
What happened to dakrt?? he used to sell the ported ones on ebay for 100 bucks. That was a bit more tolerable.
There is a guy selling some on ebay for 200. Still a bit high if you asked me.
Last edited by Ugly1; 06-19-2017 at 11:17 PM.