_ethrty-Andy_ 2122 Report post Posted March 10, 2014 (edited) So most of you know i have my V12 E34 when in traffic, being a big engine in a small engine bay it gets a wee bit warmer than i would like, and would like an auxilary fan that i can control, just to be on the safe side, last thing i want is to replace two headgaskets! currently only has the waterpump pulley mounted fan, as most of the aircon stuff including auxilary fan is deleted. Am I better off to run two small fans, or one big fan? and also curved blades or straight blades? cheers edit: by the way, have gone through and replaced all the water pump and thermostat etc not that there was anything wrong with them, just to be on safe side and so i know its done. Edited March 10, 2014 by _Ethrty-Andy_ Quote Share this post Link to post Share on other sites
yng_750 247 Report post Posted March 10, 2014 Usually one big one works best. Big pusher 16" will do it. You can get a thermostatic switch and relay setup. Which is good because you can then add a switch override. Square radiators dont fit well with dual fans. Older style ones fit two sude by side ok. Quote Share this post Link to post Share on other sites
_ethrty-Andy_ 2122 Report post Posted March 10, 2014 (edited) Usually one big one works best. Big pusher 16" will do it. You can get a thermostatic switch and relay setup. Which is good because you can then add a switch override. Square radiators dont fit well with dual fans. Older style ones fit two sude by side ok. yeah have found a relay diagram for it, just need to work out the resistances etc and how i want to control it, may even get real keen and run it off a microcontroller yet, say switch on at factroy temp 88C or whatever it is and not turn off till 80 or so, and also a manual override three pole switch, OFF AUTO and ON etc. but more worried about choice of fan at this point. Edited March 10, 2014 by _Ethrty-Andy_ Quote Share this post Link to post Share on other sites
yng_750 247 Report post Posted March 10, 2014 I used one of the thermostat kits from davies craig and put a 16" puller in an e36. Replacing the factory fan completly. Their kit has a dial to set temp on. And like you say it doesnt turn off until about 5,c lower than activation temp. This saves constantly turning on and off . In practice it comes on after a hard drive for 20 seconds every two mins or so while stationary. You could run duel stage with a resistor for different speeds but i wouldnt bother if its an additional helper rather than the only fan. Usually i avoid putting a switch in that can cause you to accidentally switch it off entirerly though not critical if its a secondary fan. Only other option i have seen is hard wiring it to power. Downside is it can run the batt flat if it has the relay stick on. But upside is it can continue to cool after the ignition is off and the system is soaked with heat. Mini coopers run this way without issue I did see a guy hook one.up to a turbo timer so he could leave it running for 5 mins after a track session to keep air flowing through the engine bay. Sent from my GT-I8160L using Tapatalk 2 Quote Share this post Link to post Share on other sites
yng_750 247 Report post Posted March 10, 2014 Thickness is a big one. I used the calibre fan from.sca but it fits by a hair in the space the factory fan used. So in front of the radiator will be even tighter Sent from my GT-I8160L using Tapatalk 2 Quote Share this post Link to post Share on other sites
_ethrty-Andy_ 2122 Report post Posted March 10, 2014 I used one of the thermostat kits from davies craig and put a 16" puller in an e36. Replacing the factory fan completly. Their kit has a dial to set temp on. And like you say it doesnt turn off until about 5,c lower than activation temp. This saves constantly turning on and off . In practice it comes on after a hard drive for 20 seconds every two mins or so while stationary. You could run duel stage with a resistor for different speeds but i wouldnt bother if its an additional helper rather than the only fan. Usually i avoid putting a switch in that can cause you to accidentally switch it off entirerly though not critical if its a secondary fan. Only other option i have seen is hard wiring it to power. Downside is it can run the batt flat if it has the relay stick on. But upside is it can continue to cool after the ignition is off and the system is soaked with heat. Mini coopers run this way without issue I did see a guy hook one.up to a turbo timer so he could leave it running for 5 mins after a track session to keep air flowing through the engine bay. Sent from my GT-I8160L using Tapatalk 2 thats a really good idea, i might do that, if i open the bonnet after just driving (like coming back from getting dinner just before) its big heat wave. Quote Share this post Link to post Share on other sites
yng_750 247 Report post Posted March 10, 2014 When i had my 750 the engine was warm to the touch when i left work. Thats after 8 hours or so. The engine bay was so well insulated. Sent from my GT-I8160L using Tapatalk 2 Quote Share this post Link to post Share on other sites
Allanw 1052 Report post Posted March 10, 2014 Be careful with an "ON" switch - if you forget and leave it on, the fans can burn out - they often have a duty cycle rating. Quote Share this post Link to post Share on other sites
_ethrty-Andy_ 2122 Report post Posted March 11, 2014 When i had my 750 the engine was warm to the touch when i left work. Thats after 8 hours or so. The engine bay was so well insulated. Sent from my GT-I8160L using Tapatalk 2 yes mine like that Quote Share this post Link to post Share on other sites
antil33t 90 Report post Posted April 3, 2014 Just buy the 318i electric fan 80/88 thermo, and install a new relay. Best to keep something that could end your car simple. Quote Share this post Link to post Share on other sites
e30ftw 396 Report post Posted April 3, 2014 I forgot to ask you but I ended up ordering a 80/88 switch from pelican the other week. Got mine setup with a relay works really well with a 16" electric fan kicking in at 80C, Keeps it right on half way constantly. Wiring is piss easy. Quote Share this post Link to post Share on other sites
_ethrty-Andy_ 2122 Report post Posted April 3, 2014 might hae to have a nosey at some stage Quote Share this post Link to post Share on other sites
Neal 512 Report post Posted April 3, 2014 Another extreme is go the full hog on Craig Davies products. Modify the factory water pump(s) by taking impeller out. Fit thermostat bypasses.Go electric and pick a pump with adjustable flow (e.g water to slow = over heating , water too fast means radiator has too little time to transfer heat out of water= overheating, just right means maximum cooling for a given temperature setting) http://www.daviescraig.com.au/Electric_Water_Pumps-content.aspx Add a controller for fine temp control of water with pump speed regulation. http://www.daviescraig.com.au/Controller_and_Switches-content.aspx Add a push / pull arrangement with two electric fans or run viscous plus electric Add a turbo timer or ignition off delay timer into the cooling circuit to cool engine after switch off for a predetermined time ( e.g 6-10 minutes) This should get the heat down and protect the battery from going flat from the cooling circuit. have been thinking of this type of setup for my turbo mini. Quote Share this post Link to post Share on other sites
_ethrty-Andy_ 2122 Report post Posted April 25, 2014 Got it all apart just now. removed aircon radiator condensor thing, and factory auxillary fan, and in the bin. My windows work so i dont need aircon. This in itself should help cooling a lot, lots of bugs and that in the aircon one with its tighter weaves, so that wouldnt have been doing me any favours. Have measured up the space, the radiator is 18" high by 24" wide, but realistically its is about 15" high due to constraints with the cross memeber the bonnet bolts to. So 15" by 24" to work with. I am running the factory BMW viscous fan clutch on the engine side of the radiator. Am I better off to buy one 15" fan, or two 10" fans? (dont think 2x12" fans would work even though its 24" wide, due to mounting constraints, body of the fan etc. Quote Share this post Link to post Share on other sites
polley 916 Report post Posted April 26, 2014 largest single fan you can fit. Quote Share this post Link to post Share on other sites
yng_750 247 Report post Posted April 26, 2014 I did a 16". Most brands go 10,12,14,16 from what ive seen Quote Share this post Link to post Share on other sites
Tidy30 38 Report post Posted April 26, 2014 Make sure you shroud the fan, whatever you decide on in the end! Sent from my Nexus 5 using Tapatalk Quote Share this post Link to post Share on other sites
