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Where is the best place to fit electric fan the front of the Rad or in the engine bay being under the bonnet?

Provided the airflow is in the right direction I am not sure there is a 'right' place. When my viscous fan got a bit noisy I removed the fan blades (leaving the pulley and belt) and fitted an electric fan to the front of the rad. This was partly as it would not fit on the back with the pulley in place and partly to hide the electric fan. It has never been a problem there.

It is the type with a capillary control in the top hose. I wired the power supply directly from the battery (with fuse) with a relay operated by the control box to pull it in. Also an indicator light and override switch in the car so that if the temp rises and the control needs the fan but it is not running I can switch it on manually. Wiring from the battery means it continues to run if required when the engine is switched off to help dissipate under bonnet heat, its how my Saabs work so I thought it would be good for the TR7.

Hi, I removed the complete fan and idler assembly on my 7 and installed the electric fan and shroud behind the rad. I wired mine exactly the same as saabfest and it always cooled the engine well with the temperature gauge never moving more than a fraction above the quarter mark even after longer runs on hotter days.
Rich.

I agree it doesn't matter, if the engine cooling system is in good condition, with no blockages, an electric fan can be in either place.

When having a lot of trouble with cooling the 8, I did a test, after installing air conditioning in a 7 which had never had it. I removed the fan blades to see if the electric fan blowing from infront of the condenser, infront of the radiator would keep the engine cool in our 95F plus days.

It was fine on open road driving above about 50Km/hour, but that may have been the natural air flow. Once in city stop start traffic it could not handle it.

I went the other way when I rebuilt the 7s motor, with a new stock radiator, & a new viscous fan. It holds the gauge rock steady on 1/4 everywhere, & regardless of air conditioning.

Finally found it was lean mixture on low revs low throttle opening that caused the 8 to overheat in traffic. We can now enjoy city driving in it with the aircon running flat out after correcting that. The electric fans, one behind the radiator & one infront of the air con condenser do the job beautifully.

Hasbeen

Here is one theory to consider.
Electric fan placed directly behind the radiator should suck air in through the radiator core without restriction and blow it around the fan blades causing the air to cool thus cooling the core temperature.
Placing the fan in front of the radiator the fan is in fact circulating warm air around the radiator core which in turn takes a lot longer to cool the air around the radiator.
Clever Or just my opinion........

While theoretically the body of the electric motor will block a little of the radiator core from getting a full blast of air, the air temperature will be the same as any heating of the air by the warm running fan motor is negligible. It's all arguing how many angels can dance on the head of a pin as the TR7 (not sure about TR8) has plenty of radiator cooling. I'm still using the original slip clutch fan (39 years old now) and the temp needle stays just above 1/4 and doesn't vary more than a needle width even with the hottest day and stop and go traffic one can encounter in this part of the world (85F and 40 minutes traffic). I have a good used one and a new one as spares but so far haven't needed them. If you have cooling problems, either your engine isn't running right (mine's FI so no rich/lean problems) or more likely your radiator is partially blocked and needs to be power flushed at a rad shop or recored, that's reason a new radiator solves your cooling problems, not because the old one was design defective.

As per S & S recommendations when I bought their conversion kit back in the day, my electric fan is fitted on the front of the radiator, there's not much room on the other side anyway. Never had a problem with it there.

It only comes on in stop / start traffic and there's no mistaking when it cuts in as there's quite a noise.

Put my 14" fan on the back of the rad, loads of room to the engine and controlled by a Revotec unit in the top hose.