We're putting in the new radiator. Debating whether or not to build a fan shroud and mount the fans to it leaving a 1 or 2 inch gap between the fan and the core, or build a bracket to bolt the fans <5mm from the core.
Im curious to see if anyone has any recommendations or pitfalls...
Cheers.
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Green Sally up. Green Sally down. Lift and squat, gonna tear the ground.
We run a skeleton shroud on ours. It is only the fans with no shroud at all really. It lets the air flow through the cores at all times. The engine runs at 83 degrees all race and the fans only come on when we are on the form up grid.
Cheers
VQs run hot so whatever you can do wouldn't be a waste of time,we run a shroud, temp sits at 80/90 then the fans come on, we have a big radiator that Cools the g/ box also running a heat exchange for engine cooling, never had a problem with it, I would fit a shroud Gaz,
Fans pull from the lowest pressure differential. As such if you just have the fans sitting on the surface they will tend to pull air from the sides of the fan rather than through the core.
Always shroud the core, seal it against the sides of the rad.
I developed a moulded glass shroud. It seals tight against three sides of the rad and it only requires two simple bolts to hold it in place (given the friction o the sides of the rad).
-- Edited by RedMist on Thursday 24th of April 2014 05:55:03 PM
As far as I'm concerned. If you need a fan, than it's not an efficient enough system? Except at low speeds? I was informed that a fan cannot exceed a vehicle traveling above 60kmh wind speed, so therefor it should really only cut in on the start line IMO
It is very true, however what do you do when below 60kph? If you spend a majority of your time above 60kph then remove the fan (it'll increase flow).... but is more airflow through the core above 60kph essential to remove the BTU's you generate in engine operation? In my case.... not.
Fan is essential for low speed.
I believe there is a lacking of flow understanding in radiators for use in offroad racing. it's often that I see a poorly shrouded fan that allows a good deal of air to be sucked from the sides of the fan (and not through the core). And it's very very unusual that I see anyone correctly duct the front of the fan to ensure that air does not bypass the radiator. Pushing air through a rad core increases pressure that does not exist at the sides of the rad, as such a good portion of air will simply flow over the top, bottom or sides of the rad. In order to get as much air through the core as possible you must.... logically.... force as much air through the rad as possible.
I lock all air that passes beside the car, through the cabin, so that it can't do anything but pass through the core. It's sealed between roof, side scoops and fuel cell/floor.
The Latest Radiators i have seen have rubber flaps built into the shroud, When the fan is sucking they are pulled closed, and when the road speed is high, they open and allow air to escape.
