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2011-2014 Mustangs
Engine/Tuning
Cobra Jet manifold reworking
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<blockquote data-quote="SmokeGreyHatch" data-source="post: 13351073" data-attributes="member: 45470"><p>While researching and engineering the correct CAI diameter, I went through the following calculations to see where the true bottleneck is and what’s really required based upon it. Obviously airflow through a pipe is dependent upon the surface area of that pipe, so I decided to do a comparison of various throttle bodies – actual surface area of airflow. What I found was pretty astonishing; the SCJ TB is in a league of its own for serious flow area. The 4.5 inch seems to be the best combination of flow, drivability and nicest transition to the 5 inch OD on the TB without restriction. 5 inch is overkill based on the TB constraint. The 4 inch and 4.25 inch should theoretically make the same power as the 4.5 inch, but it’s more of a step down at the TB. I can clearly see now why the 4.5 inch made 10 more hp than my JLT. I’d also like to bet that the CJ dual 65 with any CAI being at 9 square inches is 10-15 hp less than the SCJ and 4.5 inch CAI. I’m glad I went with the SCJ. </p><p></p><p>Throttle body intake side surface areas:</p><p></p><p>GT500 Dual 60mm = 8.77 sq in minus throttle plate rail area (1.18 sq in) = 7.59 sq in</p><p>Dual 63.5mm = 9.82 sq in minus throttle plate rail area (1.25 sq in) = 8.57 sq in</p><p>For reference: Single 90mm = 9.86 sq in minus throttle plate rail area (0.88 sq in) = 8.98 sq in</p><p>CJ Dual 65mm = 10.29 sq in minus throttle plate rail area (1.27 sq in) = 9.02 sq in</p><p>SCJ Mono-Blade TB = 13.78 sq in minus throttle plate rail area (1.45 sq in) = 12.33 sq in</p><p></p><p></p><p></p><p>CAI round pipe surface areas:</p><p></p><p>5 inch = 19.63 sq in</p><p>4.5 inch = 15.90 sq in</p><p>4.25 inch = 14.19 sq in</p><p>4 inch = 12.56 sq in</p><p>2010 JLT at tightest spot = 10.01 sq in</p></blockquote><p></p>
[QUOTE="SmokeGreyHatch, post: 13351073, member: 45470"] While researching and engineering the correct CAI diameter, I went through the following calculations to see where the true bottleneck is and what’s really required based upon it. Obviously airflow through a pipe is dependent upon the surface area of that pipe, so I decided to do a comparison of various throttle bodies – actual surface area of airflow. What I found was pretty astonishing; the SCJ TB is in a league of its own for serious flow area. The 4.5 inch seems to be the best combination of flow, drivability and nicest transition to the 5 inch OD on the TB without restriction. 5 inch is overkill based on the TB constraint. The 4 inch and 4.25 inch should theoretically make the same power as the 4.5 inch, but it’s more of a step down at the TB. I can clearly see now why the 4.5 inch made 10 more hp than my JLT. I’d also like to bet that the CJ dual 65 with any CAI being at 9 square inches is 10-15 hp less than the SCJ and 4.5 inch CAI. I’m glad I went with the SCJ. Throttle body intake side surface areas: GT500 Dual 60mm = 8.77 sq in minus throttle plate rail area (1.18 sq in) = 7.59 sq in Dual 63.5mm = 9.82 sq in minus throttle plate rail area (1.25 sq in) = 8.57 sq in For reference: Single 90mm = 9.86 sq in minus throttle plate rail area (0.88 sq in) = 8.98 sq in CJ Dual 65mm = 10.29 sq in minus throttle plate rail area (1.27 sq in) = 9.02 sq in SCJ Mono-Blade TB = 13.78 sq in minus throttle plate rail area (1.45 sq in) = 12.33 sq in CAI round pipe surface areas: 5 inch = 19.63 sq in 4.5 inch = 15.90 sq in 4.25 inch = 14.19 sq in 4 inch = 12.56 sq in 2010 JLT at tightest spot = 10.01 sq in [/QUOTE]
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