Flow Bench Test Results

[Jim Allen]

The "puckering" only occurred when tested at 20" of H20, not at 10". The actual airflow is then converted via a graph to 28". In the case of the 10" tests, there is less air actually flowing through the unit, so the puckering was not apparent. Still, the unit flowed better without the rubber when tested at 10" of H20. The corrected 10" reading were 607cfm with, and 642.5 cfm without the rubber. At 20" the readings were 586.69/632.5. That says to me that the rubber over the bell mouth of the adapter is doing something to the airflow.

[kd4crs]

Sorry I have been absent, our family is on vacation this week and have not been monitoring the forums. First, thanks for testing the various setups and posting the results. I wondered about the flexibility of the PVC downspout adapter and you confirmed what I suspected, that it might bow inward with high flow. That is not good for airflow. I will see if there is anything else that can be substituted or if the downspout adapter can be modified, perhaps by shortening the length of the leading edge will reduce or eliminated the bowing effect. The lip of the downspout adapter is what actually holds the unit in place so cutting it off entirely would not work. Further research will be needed. In the meantime the best alternative is the reduced straight PVC/ABS pipe into the fender. Thanks again for the testing and the results.

[kd4crs]

I just got around to purchasing the alternate rigid 3 inch tubing that fordmt08 on f150online.com used for his intake modification and it looks like it will work well installed a couple of different ways. The tubing required is made by Spectre Peformance. It is part number 8741 for the black color (8742 is Red, 8746 is Blue, 8748 is Silver) and it is called: 3" Flexible Air Duct. It is priced ~$20 and should be available at O'Reilly Auto Parts and Autozone stores. I installed it completely collapsed using one of the two connectors that come with the kit to go into the fender inlet and using the downspout connector to connect to the stock flexible section. It fits perfectly and does not require any hose clamps. I will be testing it out with my Gryphon Custom 87 performance and Custom 87 towing tunes this week. This variation completely eliminates any possibility of the downspout connector collapsing or getting sucked inside out.