In post 43 I summarized where I was based on the constructive input. For those interested and update follows:

From various sources, including Flex-lite tech, V8s from 500 to 600 HP are adequately cooled by a fan rated at 2,200 CFM. I chose to purchase a Flex-lite 16" straight blade fan rated at 2,500 CFM. Flex-Lite advised the fan noise won't be significantly louder, I don't care if it is, and the primary reason is that it is lower profile. The fan will fit within the existing shroud covering well over the 70% needed to maximize effectiveness. The auxiliary fan will operate as designed.

The minimum HP that will then be available is 4-5. The horsepower gain I got from Dinan exhaust was 5. The price of the exhaust was in the thousands. The price of the fan and harness was just over $200. That makes it a value. Even if the HP claims are zero, it is a value to me for the side benefits.

The reason I went with Flex-lite is twofold. The tech took the time to understand my particular application and that is the brand I have always purchased and always happen with the results. I also purchased a Spal wiring harness with a relay and an inline fuse that will allow me to activate the fan by the key, by a thermostat, through a variable fan speed controller or by an on/off switch which would be in the cabin. I did not purchase a thermostat, speed controller or on/off switch. I don't think I will need any of them but in case I do I have the wiring in place. The fan was on sale. Regular price is $179, sale price was $149. Harness was $48.

Side benefits of this change are---There will no longer be stress on the water pump bearing, there may be a mileage benefit, it was time to replace the clutch fan anyway and I would spend more for a new clutch fan and it would be less efficient.

Yesterday afternoon I placed everything about where it will be so it will look like it belongs there. I did not connect anything as yet. I found a place in the fusebox under the dash that only has power when the key is on and is not used. The hot wire will plug in the side of the socket that is hot. In my case it is the top connection. The positive wire on the fan will run to the relay, I will ground the fan 90 degrees from the fan, pulled taunt, using the same route as the positive fan wire. The wire from the relay to the fusebox will run over the top of the radiator and along the passenger side and be combined with wires I have added for other mods. All wires will be hidden by shrouds or harness covers. Any wires that are too short will be spiced with wires of the same color and gauge so that there is no load question and they will be easy to trace if need be. I will test the fan before securing putting the wiring in place.

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X5 4.6 2002 Black Sap, Black interior. 2013 X5M Melbourne Red, Bamboo interior
Dallas