Gus Posted December 6, 2021 Share Posted December 6, 2021 Apologies if this has been discussed previously, but when you fit a rovatec electric fan, can you remove the pulley fan or is it best to leave in place? Quote Link to comment Share on other sites More sharing options...
yorkshire_spam Posted December 6, 2021 Share Posted December 6, 2021 (edited) My Dolomite 1850 runs without the mechanical fan with only the electric one. It cools just fine. I think in most cases squeezing BOTH in the space available would be a problem, pretty sure standard practice is one or the other, not both. Edited December 6, 2021 by yorkshire_spam Quote Link to comment Share on other sites More sharing options...
sparky_spit Posted December 6, 2021 Share Posted December 6, 2021 As said above, my Spitfire has had just an electric fan, with no mechanical fan in place, for many years now and has been absolutely fine, even in 34deg heat in the south of France. I use a manual switch to control it rather than a thermostatic switch, but that's just my preference. You may even get a tiny amount of extra BHP due to the engine not having to power the fan 😉 Quote Link to comment Share on other sites More sharing options...
Gus Posted December 6, 2021 Author Share Posted December 6, 2021 Thanks folks. I watched the Rimmers bros video and they left the mechanical in place, which did not seem to make sense to me. I will go with your advice. Quote Link to comment Share on other sites More sharing options...
glang Posted December 6, 2021 Share Posted December 6, 2021 I suppose, if theres room, the one advantage of having both is that if the electric packs up for whatever reason you'll still have some cooling. Then with a thermostat you certainly shouldnt get any over cooling and, as Sparky says, the power absorbed is miniscule... Quote Link to comment Share on other sites More sharing options...
Ed H Posted December 6, 2021 Share Posted December 6, 2021 Leaving the original fan in place negates one of the main reasons to go electric--eliminating the load of the mechanical fan on the engine. Ed Quote Link to comment Share on other sites More sharing options...
glang Posted December 6, 2021 Share Posted December 6, 2021 Well thats been talked about a lot in the past and as I say it seems to be almost negligeable given that the load depends on how much air is actually being moved by the fan. So even if its not a viscous type it comes down to what work the fan is doing when the air is already being forced through by the action of driving along. You could almost argue that the blast of air pushs the fan round and helps reduce engine load😂 Quote Link to comment Share on other sites More sharing options...
RobPearce Posted December 6, 2021 Share Posted December 6, 2021 40 minutes ago, glang said: You could almost argue that the blast of air pushs the fan round and helps reduce engine load Not really. It's certainly true that the blast of air pushes a free-spinning electric fan round if it's mounted in front of the radiator but if an engine driven fan is to do anything useful at idle then the air flow behind the radiator is not going to be fast enough to even significantly reduce the extra load caused by the fan. I'm sure you were being facetious in proposing a perpetual motion machine, though. Quote Link to comment Share on other sites More sharing options...
glang Posted December 6, 2021 Share Posted December 6, 2021 Alright youve caught me out there😁 However there is the question why manufacturers went to viscous fan drives or was it to reduce the noise of a solid driven fan at speed? Quote Link to comment Share on other sites More sharing options...
RobPearce Posted December 6, 2021 Share Posted December 6, 2021 Noise was certainly part of it. The viscous coupling does reduce the wasted energy (and you can see that the air flow isn't doing anything because the viscous coupling does continue to slip when driving) as well as allowing a bigger fan to get more cooling when it's actually needed (at idle). Of course the bigger fan makes more noise, so there's a bit of swings and roundabouts. The main driver for electric fans was the adoption of sideways mounted engines, of course. Quote Link to comment Share on other sites More sharing options...
Ed H Posted December 6, 2021 Share Posted December 6, 2021 This video might be relevant to this topic. https://drivemag.com/video/cooling-fan-shoot-out-engine-masters-ep-20 Ed Quote Link to comment Share on other sites More sharing options...
glang Posted December 6, 2021 Share Posted December 6, 2021 Trouble is those tests are done static so without the air forced through by driving at high speed which Im postulating reduces the energy used to drive a mechanical fan.... Quote Link to comment Share on other sites More sharing options...
Rosbif Posted December 7, 2021 Share Posted December 7, 2021 Based on that video my 13/60 is losing 30% of its power due to the mechanical fan . . . Or not. This subject is getting more and more interesting. Quote Link to comment Share on other sites More sharing options...
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