914/V8 Fan Operation, Conversion Cooling Options

[tyler]

Can you conversion guys tell me how your electric fans operate and if you've modified the air dam?
Put in my 15.5x28 Griffin radiator with 944 Turbo fans on a shroud. Crusin at 70 on the freeway the temp starts at 170 for 6 miles and creeps up to 195 when the fans come on and bring it back to 170. This continues to cycle like this both on the freeway and around town. I'm using a 160 Tsat until the cooling system is done. I ran with the lid off so I know the cuts in the wells are ok. So I figure I'm either blocking the airflow with the fans/shroud or the air dam need to channel the air in somehow. It doesn't seem to me like the temp should cycle like this. I'd like to hear how yours run.
Thanks,
Tyler
'70 914/350/4 webers

[John2kx]

QUOTE (tyler @ Jul 25 2005, 07:45 AM)

I have a top cover and there is complete sealing to avoid recirculation. After looking at the Renegade pics, I did some testing and found that the side plates to channel the airflow in (removing turblence) and a little air dam in front to force the air up towards the radiator make a major difference. Ran for ~30 miles (about 80 outside)right on 185, fans never came on. I'd like to see pics of what anyone runs for an air dam since I just used a short piece of sheet metal and there must be something nicer looking and more efficient. I didn't see anything in the Renegade pics.

Tyler,

I thought you had the top cover on shroud removed and hood off at the beginning of this thread. If you installed it AND added a small wing to your air dam, I'd be willing to bet the addition of top cover on shroud as reason for improvement. Please clairify.

The switch used to activate fans provided by RH is mounted 6" or so below top radiator hose on radiator. I questioned the on/off temperatures selected for this switch as well and can only say that the boys in Vegas have quite a reputation when it comes to cooling v8 914s. There on/off numbers were selected through much testing in some of the worst conditions. If I was going to follow someones lead, it would be them.

Since the fans don't provide any cooling above 45 mph or so (according to RH), and you have a adjustable switch, you could lower your "fan on" trigger until you reach a point where the fans never come on when in cruise mode. The lower the point the fans come on when you start slowing down or entering bumper to bumper traffic, the faster cooling takes place in addition to providing more consistant water temperature. Also known as the snowball effect, or how to avoid it.

One other note when performing similar tests: always make sure conditions are the same or close. Make the duration/route/driving style the same. Results will be different when driving in 80F vs. 90F weather.

It looks like your armed with all the right tools (fan on/off indication, adjustable fan switch) and are not suffering from high water temperatures. I'd continue to make changes until you see optimum results while experiencing high outside temperatures.

Good luck,

John