I'm fitting twin fans, on a two stage switch.
Would shrouding them in make much of a difference, or is it OK just to have them like this ?
Without.
Idea
[Edited on 15-5-10 by ken555]
Just how much a difference do they make ?
I'm fitting twin fans, on a two stage switch.
Would shrouding them in make much of a difference, or is it OK just to have them like this ?
Without.
Idea
[Edited on 15-5-10 by ken555]
yes it will make a difference; cannot give you any figures.
the fan will blow/suck air through the part of thje radiator that is equal to its are but with a shroud, that can be increased substantially - will
help lots when stationary.
you will find production cars have shrouds and it stands to reason they would not go to that trouble and cost if there was no point.
cannot see what is happening in second picture but in effect you need to construct a pyramid, then chop the top off parallel to the base and fit a
cover with hole for the fan.
Are they just for cooling while the car is stationary or does it not get enough air when moving?
If it's just when sitting idling etc then I think they'll be fine as the engine won't be making much heat then anyway. Looking at your
first pic the fans touch the top edge of the rad, do they touch the bottom edge too? That would mean all of the cooling tubes of the rad cross the fan
at some point so all of them would at least get some benifit from the fan's airflow.
I ran a rear mounted rad on my front engined grasser, it was a 2l Sierra rad with 2 fans from a Nissan Sunny mounted side by side like yours but with
the shrouds from the Sunny too. As luck would have it the two shrouds side by side were a perfect fit for the Sierra rad. If I forgot to switch the
fans on it'd be cooking in 2-3 laps but with them it never got hot & this was a 2l 8v turbo & later a 2l 16v N/A working hard not sitting
idling in traffic.
quote:
Originally posted by hillbillyracer
Are they just for cooling while the car is stationary or does it not get enough air when moving?
In my experience shrouding is most effective in front of the radiator, directing the air through to a 'puller' fan which kicks in while in
slow traffic.
Your top picture would be the best solution IMO, without any shrouding blocking the airflow like the bottom picture - that will just build up pressure
in front of the fans and prevent natural airflow.
[Edited on 15-5-10 by RazMan]
Over cooling is a lot easier to adjust than over heating
First of all the fans should only work when stationary
Shrouds are only useful when the fans are working and are used in production cars to get the most from cheap inefficient fans
Your car cools perfectly well with the 1 'scrap yard' fan
You want the maximum air flow when under load as in when being driven, a rear 'fan shroud’ can only inhibit air flow.....
In short forget a fan shroud, if anything I would duct the air into the radiator from the inlet from the front of car like most 'race cars'
employ
If it over cools use card to block off part of the radiator cores on cool days and if it gets warmer remove the card or alter it to suit the
conditions
quote:
Originally posted by ken555
quote:
Originally posted by hillbillyracer
Are they just for cooling while the car is stationary or does it not get enough air when moving?
Just for stationary.
If anything the radiator overcools the car when moving.
This was the previous set-up and never had a problem with it.
quote:
Originally posted by 02GF74
ah, you didn't say that or post the photo .... a quick glance shos the area swept by the fan blades is comarable if not slight bigger than the single fan so you should be ok.
quote:
Originally posted by ken555
If My Maths serves me right the ratio is 50 to 36. (2x10" to 12" ) so a 1.4 times improvement.