I just sold my '86 30' Sierra Sahara (name is Sara BTW) so I am unable to run the differential pressure test with a simple clear plastic manometer tube.I had planned to retrofit an underbody air scoop to increase air pressure in the engine compartment if it is a Negative pressure relative to the aft side of the charge cooler.
The 'factory' engine driven fan is grossly inefficient because it has way too much blade tip clearance and not nearly enough shroud length surrounding it. The amount of noise it makes also supports my theory of fan inefficiency.
On Fri, Jun 1, 2018 at 8:55 PM, dewey2501@... [Safarifriends] wrote:
I posted a picture a few weeks ago of the rear of my rig with 2 electric fans on the rear of the radiator to help push the air out past the fins. The anemometer I ordered finally showed up, so I have some air flow readings to show the difference so far. At idle with the meter on the fins, I'm pushing 6.1 knots of air past the meter. With the fans on, the airflow increases to 13.8 knots of air, so almost double what the engine driven fan pushes out.
I'll know more once we head out on vacation in July, but so far they are doing exactly what they were installed for - moving the air out of the engine compartment past the radiator. I did discover with them on that you have to work at it to raise the bed - you can feel the pull on it when they are running.
I tried to figure out other readings on the meter that would make more sense, but the meter is smarter than I am. I might try it again using the ft/min setting and see what it comes up with just out of curiosity.
Duane96 30' Sahara, 250hp Cat, Allison 6spdSpokane WA
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