aftermarket radiator fans generally have the option to blow or suck

my question is :
does it make any difference to the cooling abilities ?
is one preferred over the other ?

dosnt that depend on wever it's bein mounted on the fron or the back of the rad

yes

blower in front
sucker behind

if mounted on the front then would it be rite for best to have it suck ???

surlly then this would draw heat away from rad

im total guewesing here btw

I would have thought the suck, with the fan behind the rad, as creating a lower pressure between the fan and the radiator would draw in more cooling air through the rad, especially when moving. Trying to blow air through the rad from the front would not be so efficient as it would build positive pressure between the fins and resist efficient passage of air through the rad..

sorry for some reason i was thinkin stationary been a long day !!!!!!!!

I would say suck through but it's possibly more important to recognise the importance of decent shrouds for the fans, as this will cool more of the surface area of the radiator than without a shroud.

Another consideration is that the fans are not normally operational when the car is moving because there is suficient ambient airflow, and blow through fans can impede the cooling by obstructing the frontal area of the radiator

suck.

in blow configuration the fan could act as resistance to air flowing through the matrix, in suck, the air has already done its job.

as stated though well thought out ducting, and shrouding is equally as important, as well as looking at other aspects of the cooling system

a well thought out cooling set up, works wonders......i had excellent results with mine with only a few simple alterations

different thermostat
ally radiator
twin pull electric fans, manually controlled
continuous self bleed system with greater capacity header tank

Fans on the front give you a bit of stone chip protection, but as has already said - suck.

But you have to look at radiator and fan as a complete system. The cooling capacity is a function of the rate of flow through the system, which is in turn a function of the pressure drop through the whole system. Whether you put the fan on the front or the back of the radiator it still contributes to the total pressure drop when the system is moving through the surrounding air. The shape of the fan and its containing structure may make it more efficient when air is passing through it in one direction as opposed to the other, but that apart, it really ought not to make much difference whether it is on the front or the back of the radiator.

The efficiency of a fan is affected by the inlet and outlet pressures and it may be possible to design fan profiles optimised to reduce sensitivity to either changes in input pressure or output pressure, but not both. So you can produce a fan that works better sucking than blowing, or vice versa. None of the car fans that I have seen appear to have this degree of sophistication, but I am ignorant of any work that may have been done in respect of high performance vehicles. You have only to look at the very complex shapes of aircraft propellors (and take account of their variable pitch arrangements) to know what a complex area of technology this is.

There are so many imponderables, that I would hesitate to generalise. Even if we were to measure the pressure drop through the system with the fan mounted first in front and then in the rear, the measured difference would not necessarily hold good over the whole vehicle velocity envelope from stationary to top speed.

thanks for some great new knowledge

i think i will go with the sucker