[Steve C.]

"I would think that the fuel injection set up would not be as finicky to the placement height of the throttle body vs a carburetor which operation is in direct relation to the air flow passing through it and the air+fuel within the intake.... The Carb will respond with changes in spacing however I dont believe a "throttle body" which only flows air is as responsive to the throttle body height as it is to velocity within the intake runners."

I had a discussion with the the fellow who did the work on my intake regarding the modification with the Brodix carburetor adapter. In short, he felt the same as your statement. It's air and not air/fuel mixture and the F.I. set up would be less sensitive to the impact.

Almost all my different engine combinations have been tested on a engine dyno but I've never had my car on a chassis dyno. I hope to do so soon with the current 505 and the now converted fuel injection set up. For interest, plus I want to know if my small air cleaner assy has a significant impact on the performance. My Trans Am does not have a functional shaker assembly. The car has the saftory shaker scoop molded to a fiberglass hood. The air cleaner assy sits up inside the scoop, thus I cannot go larger. What I have is a K&N filter that measures 2.875" high x 9" diameter, with their 9" dia X-Stream filter top. When I talked with K&N tech they stated those two items used together would flow approximately 710 CFM and suggested my 505 / 650 hp engine needs approximately 1100 CFM for operating at 6000 rpm where it made peak power on the engine dyno with the carb set up. I then asked at what lower RPM will the above 710 cfm be adequate for ? The answer, based on their calculations, a 505ci engine at 4000 RPM would require approximately 710 CFM. WHAT ! I'm having a HARD time understanding this and now want to test on the chassis dyno with and without the current air filter assy.

I'm curious how the K&N numbers differs so much based on my dyno sheet with the carb set up that indicates 866 scfm at the 6000 rpm. Then the formula below that suggests 867.9 cfm. Note, almost the same as my dyno sheet

( For the calculation I used 0.99 for the volumetric efficiency. However at 6000 rpm on my dyno sheet it indicated 106.9 VE)

6000 x 505 = 3030000
3030000 divided by 3456 = 876.73
876.73 times .99 = 867.9 cfm

https://itstillruns.com/calculate-en...e-6393767.html





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