Home   Tips and Tech notes.

Autolite 4100 CFM Ratings

I've gotten tried of all of the arguments about the CFM capacity of the Autolite 4100s.  In December 2002 I took five of them in a local speed shop and put them on Superflow 1020 flow bench.  One 4100 had the small 1.08 primary venturi and the rest had the larger 1.12 primary venturi.  The small one flowed 441 CFM, the larger ones flowed 503 to 528, averaging 520.

These results were very close to what I expected for the 1.08 but 50 CFM higher for the 1.12.  Still the 1.12 does not flow 600 CFM as claimed by some vendors.

The testing was done at Charlie's Automotive in Apex, NC.  They are an engine builder for the local NASCAR guys.  The tests were done on a Superflow 1020 flow bench which is computerized and automatically corrects the output data to standard temperature and pressure.  The flow testing was done at the SAE standard for 4 BBL carburetors - 1.5 inches of mercury, which is the same standard used by Holley, Edelbrock and Carter.

Tag or ID Number Primary Venturi Primary Bore Secondary Venturi Secondary Bore CFM test Results
C6AF-E 1.08 1.437 1.18 1.437 441
EDT 84D 1.12 1.562 1.18 1.562 503
EDT-17BR 1.12 1.562 1.18 1.562 523
C4SF-B 1.12 1.562 1.18 1.562 526
C4AF-DG 1.12 1.562 1.18 1.562 528