The engine fan, coupled with the radiator shroud draws air thru the radiator and aids cooling. This fan uses a viscous (oil filled) coupling, which in turn is driven by the fan belt. By removing the viscous fan, and its coupling back to the drive pulley behind, about 140mm of free space is available between front and the radiator. My new radiator setup will be using a modified PWR twin pass radiator, with a custom alloy shroud and 16'' SPAL thermofan. Space is limited so stock fan has to go. Will removing the stock fan and viscous coupling cause any imbalance to the drive belt system on the engine? With a smart setup like i will be using, i anticipate that cooling myths about thermofans should be made redundant. Cooling could now be run independent of engine use, allowing cool-down routine and variable speed based on engine speed. Stay tuned.
It's fine removing it, infact it will free up a tiny bit of power but no e-fan is going to beat the stock engine fan as far as how much air it will push.
I will be pulling air. How much flow is the standard fan capable of? From what ive been researching, a fan that flows 1200CFM will be its max flow, but the efficiency of the fan is just as important. To be efficient it needs to have a good seal with the surrounding shroud, to create the maximum amount of 'suck' from the fan. The shroud i will be running is going to be quite efficient, running the largest post-radiator air resevoir i can manage, and a hefty thermofan. With little to no air loss around the fan, i predict the cooling efficiency of the unit will be much greater than stock. See below: Different radiator, similar concept.
Stock is at least 4,000CFM. E-fan setups can and do work, it's not rocket science but it's still not as effective as the stock unit no matter how you try and spin it. Twin 10" davies craig fans would do the trick.
I'm running a 56mm rad with a twin pass mod, 16" Spal electric fan with an 85' on 80' off thermoswitch located just below the inlet pipe on the hot tank. works absolutely fine, has plenty of cooling ability and most of the time with normal street use the fan doesn't even come on. When pushed hard at the track it normally takes around five to ten minutes before the fan switches off when in the pits idling, this is easily fixed by running a Nismo thermostat to lower the engine temp a little further away from my switch temp. (not a big deal so I haven't bothered) Burnout displays might be a different story (have not yet tested in that environment yet). To be honest that fricken windwill on the front of the standard engine is a huge pain in the arse and you will never look back once you have ditched it. I have seen people try and install electric fans and then go back to the windmill as they can't get the e fan to cool properly. This is installer error not a inherent fault in the design/theory. If it is done rite you will have no trouble at all. WARNING!: I advise to run two switchs and relays with separate power supplies so if one system fails the other will still run the fan(s). Also consider running a LED on the dash hooked up to the backup switch system to let ya know if the first one has failed resulting in the backup kicking in.
Good thinking mate. Despite all the trash people talk about electric fans, I agree that when used properly, they can work really well. Example: The radiator i aquired had the thermofan bolted straight to the alloy core. BAD IDEA since the weight of the fan and vibrations can bust a cooling tube and lead to disaster. This method also only effectively draws cool air thru the 16'' diameter where the cooling fan is in contact. A radiator shop suggested screwing a sheet of flay alloy to the rear of the radiator, with a hole for the thermofan. This helps draw air thru fan only, but lack of an air resevoir inhibits mass air flow (limits the capability of the fan). Speaking to an intercooler manufacturer, he suggested a custom shroud box, as the drag and sprint cars use. This seems the best option so far, and is what i will be running with. just goes to show how different options of setting a fan up can change its effectiveness, and alter peoples opinions of them.
So here is the setup I'll be running with: Custom shroud covers the majority of heat exchange area, utilizing the full capacity of the fan to facilitate airflow across this surface. Depth of shroud limited by fan pulley, and height of the 16'' SPAL thermofan that will be attached. Overall 'depth' of the radiator was kept to below 130mm to keep clearance. Also shown is the modified top mounting points, changing the TT to NA pin mounts. Also cleaned up the daggy PWR ends with a clean, polished alloy section. Looks tops- no need for bling here 4x M5 mounting bosses are attached to the shroud section, allowing easy removal of fan assembly. 16'' fan sits nicely over the whole heat exchange area, seeing this setup outside of the drawing phase, indicates high-speed airflow, such as highway driving, should not be a problem. while this is only an 'eyeball' assumption, testing of this in weeks to come will give valuable answers.
It'll either work that way, or it wont. Ive seen mixed results using shrouds like that, some setups need it to work others just impede flow through the actual radiator itself and can cause more harm than good. Hope it works out for you. Where'd you get your radiator from?
Spal fans are generally better than many other brands, although there have been a large number of Z32 owners who were less than happy with the outcome(mostly they were using straight bladed Spal fans). It seems that the crescent shaped blades are far superior to the straight ones. I can't recall ever seeing anyone who managed to attain higher CFM figures than was readily available with a stock viscous fan.
One drawback I can see with your shroud design is that it will impair airflow at high speeds. This is because all the air has to go through the spinning fan (which will actually result in a restriction). If you installed some flaps on the shroud - you would not have the same issues as the air can bypass the fan at high speeds. I love the idea of a thermo fan and I am slowly working towards making my own shroud like yours, but with flaps Another bad idea that you may see on forum examples is the use of the fan 24/7. There is no point using a thermofan if it never turns off. It would actually use more power than the clutch fan. You need to have a proper fan temp switching unit. I wish TT's had a wider radiator coz it would give us sooo many more options with fans. If the radiator was say 80cm wide instead of 50, then we could run twin thermos off a falcon and have no cooling dramas what so ever. Btw just a point of interest. Alot of ppl run thermo fans (often twin) on silvias and skylines. The stock clutch fan in these cars (even for an rb26) is significantly smaller than the z32 one. So that is probably why so many ppl can successfully use thermos in those cars. Good luck with the project. I hope it works out well.
2nded not to mention the increased engine wear from not getting up to normal operating temps as quickly as possible
That is what the thermostat is for. Running an electric fan full time will not affect the warm up time for the engine at all unless there is a problem with the thermostat etc.
yes and maybe ... Agreed that the thermostat has the greatest control over getting the engine up to normal temps as soon as possible. But if a thermo fan cools an engine down when it's at normal op temps, then what do you think it's going to do when the engine is below normal? Regardless of thermostat operation, a thermo fan constantly running IS going to keep the engine cooler for longer to an extent at any given point. And most agree that the majority of engine wear is caused by engine being colder than normal op temps. Even Nissan recognised and designed the engine clutch fan with an inbuilt mechanism to stop the fan runnng at 100% speed when cold (via an internal viscous system that is loose so the fan is not running at a true 1:1 ratio with the fan pulley) but solidifies when hot to pick up the fan RPM to close that of the pulley's.
The job of the thermostat is to close off the water circuit to the radiator until water temp is up to the desired level. By running a fan on the radiator full time all you do is keep the radiator and the water in it cool (around ambient air temp). Until the thermostat opens and allows the desired amount of water to flow through it to keep the engine at the correct temp. If the thermostat is closed (IE: while the engine is warming up) it makes no difference to the engine warm up cycle if there is cooling air passing through the radiator or not. IF however you were stupid enough to run the set up without a thermostat then yes with a fan running full time the engine would run cooler than what would be considered desirable. Just google or search you will find. Still what would I know.......
everyone that goes 2 a electric fan always comes back 2 stock (myself included) perhaps in a cold place like canada or japan electrics cut the mustard.. but in australia you have no chance!!
Hmmm I hear that too. But what's interesting is everything I read about product information on fans is that the straight bladed versions move more air, and the curved bladed ones are quieter. This could be explained I guess in saying that the big daddy Spal 3000cfm extreme fan is a curved blade design simply because is if was straight bladed it would sound like a tornado in a hurricane! So they may have sacrificed slightly more cfm in order to bring the noise down to an acceptable level. Who knows. Ben PS, Mitch, Good luck with it. If it works out for you I'll definantly have another crack at mine.
Installing the thermofan onto the shroud, using 4x M5 25mm hex head bolts. Comparison of size between stock NA radiator and aftermarket TT radiator. ...Also note differences in core thickness (stock NA is <20mm thick) Aftermarket is 42 mm (i think) Difference between stock viscous clutch fan and thermofan (overlayed) Due to depth of shroud and thermofan, removal of stock viscous coupling and shaft was needed. Overall clearance is tight, with less than 5mm between thermofan motor and adjacent accessory belts
Thats a nice setup you have there! But I wouldnt be surprised if you experience high speed cooling problems. The 16inch diameter hole in your shroud is alot smaller than the stock shroud's hole. However being NA you wont get as much heat anyway. Keep us updated when you go for test runs etc.
