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Discseven Discseven is offline
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Join Date: Oct 2012
Location: Miami, FL
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Must be flow data is relative to the manifold being tested. I say this because while cc flow is mentioned, nothing is said about what vacuum force is being applied. Obviously that vacuum must be the same for a single manifold. But could be different from one manifold to the next. And different shop to shop---unless there is an applied standard. Posted vid as some ref to how this is done---I had no idea.


Loosing sleep over the math on hand, calculations on paper are called for. Am going at this slightly different than Sal. And this is to play with numbers---am not seeking Nobel calculus prize here. And certainly not competing with Sal. Curiosity that's got hold of me is the air flow delta side-to-side in my 3.2 intake. Without Gliding Serpent's ("Glider's") air flow figures, I'd not be at this---TY Glider. Never mind how his numbers were arrived at, or what the reality of air flow is in a working engine, or the potential infinite variables involved, am plugging numbers in to see what comes of it...

Question being, can we do the math and sort out what injector flow rate is wanted for one side of an engine when we already know the air flow rate, AFR/Lambda, and flow for injectors already in an engine? This assumes there's an imbalance in O2 side-to-side and the goal is to improve O2 balance. Not saying this is necessary to do or not... doing it to see if it can be done. Empirical stuff.
Added each side's cfm per Glider's data:

1-2-3 = 764
4-5-6 = 731.5

Total up both sides:

764 + 731.5 = 1495.5

Calculate each sides percentage of 100%:

100 x 764 = 76400
76400 / 1495.5 = 51.08659

Side 1-2-3 = 51.08659 %

100 x 731.5 = 73150
73150 / 1495.5 = 48.91340

Side 4-5-6 = 48.91340 %


Calculate 4-5-6 side’s cc fuel flow based on existing 24 lb. 260cc Bosch 158 injectors:

48.91340 (Side 4-5-6) x 260cc (side 1-2-3 cc) = 12717.48579 / 51.08659 (side 1-2-3 %) = 248.9398

Target injector cc flow for 4-5-6 = 248.9398

24 lb. 255 cc injectors should arrive later today. (Ordered these injectors a few days ago based on "dirty" Lucas test results.) Will install them tomorrow morning and run a log. IF... and that's a big "IF", all the numbers applied work, the result would be an AFR/Lambda which brings 4-5-6 O2 closer to the 1-2-3 side than the last log with all Bosch injectors installed. But 4-5-6 O2 will not go above 1-2-3. So 4-5-6 will still be slightly richer than 1-2-3. A speculative prediction. Am fully prepared to eat crow.
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__________________
Karl ~~~

Current: '80 Silver Targa w /'85 3.2. 964 cams, SSI, Dansk 2 in 1 out muf, custom fuel feed with spin on filter
Prior: '77 Copper 924. '73 Black 914. '74 White Carrera. '79 Silver, Black, Anthracite 930s.

Last edited by Discseven; 12-13-2024 at 08:57 AM.. Reason: changed "our 3.2 intakes" to: my 3.2 intake
Old 12-13-2024, 08:18 AM
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