bennygoodman Posted April 21, 2015 Share Posted April 21, 2015 Luckily I fitted an electric fan last Friday because I was taking my GT6 for it's first longish run on Saturday and got stuck on the East Lancs for about 30 minutes in this glorious weather we're having.I have fitted the fan on the outside of the radiator and have it drawing air from outside towards the engine but I'm wondering if I could make the interior of the car a bit cooler if I swap it to draw air from the engine towards the outside of the car through the front of the bonnet, the fan is only in use when the car is stationary as it does not overheat when on the move. Quote Link to comment Share on other sites More sharing options...
stevegt6 Posted April 21, 2015 Share Posted April 21, 2015 I've always had mine fitted on engine side of rad - keeps air flow to the max through rad.....fitting fan on front of rad will block about 15-20% in surface area.Just my thinking anyways :) Quote Link to comment Share on other sites More sharing options...
JohnD Posted April 21, 2015 Share Posted April 21, 2015 You want to draw air past the radiator from inside the bonnet, where that hot engine and exhaust pipe will have got it nice and warm first?Kind of you, but it won't help the radiator to cool the engine.And if by doing so you do cool the inside of the car, then you have:Lots of unsealed holes in the bulkheadNo seal of the gearbox cover onto the floor.To which you should attend first!JOhn Quote Link to comment Share on other sites More sharing options...
1300dolly Posted April 21, 2015 Share Posted April 21, 2015 I would fit a thermostat switch so it comes on at a set temp, you say the car doesn't overheat but it might be getting too hot. Quote Link to comment Share on other sites More sharing options...
piman Posted April 22, 2015 Share Posted April 22, 2015 Hello Steve, ".fitting fan on front of rad will block about 15-20% in surface area."Fitting the same fan on the engine side of the radiator will block 15 - 20% of the surface area also. The air needs to exit as well as enter, no real difference.Alec Quote Link to comment Share on other sites More sharing options...
Andy Flexney Posted April 22, 2015 Share Posted April 22, 2015 I had the same theory as Alec but when I put the fan to the engine side of the radiator it came on later than when it was in front so it does appear to make a difference. Don't ask me why.AndyF Quote Link to comment Share on other sites More sharing options...
Rallyspit Posted April 22, 2015 Share Posted April 22, 2015 Some electric fans are pushers, some are pullers. Testing one fan by fitting it either side of the Rad would probably give different readings anyway as the aerodynamics for the fan blades would be all wrong working in the reverse direction. I fitted a pusher in front of the full width rad, after making sure all the radiator gills were straight and not clogged up with insects and other debris. Quote Link to comment Share on other sites More sharing options...
rlubikey Posted April 22, 2015 Share Posted April 22, 2015 That's a really interesting idea bennygoodman. An under-bonnet thermostat to suck air forward when it's hot - i.e. when you're not moving. But, as JOhn et al point out, changing to the conventional (blow) direction when the *coolant* thermostat says the engine's too hot so it gets maximum cooling. :)A couple of things; The fan won't work as well when it's running in the wrong direction, as the blades aren't symmetrical. Also, sucking air isn't as effective as blowing - unless there's a cowling to duct the air. (You don't get so cool standing *behind* a desk fan)Give it a try! Maybe have an on-off-on switch in the cab while you're experimenting so you can reverse the direction if the engine's getting a bit :oRichard Quote Link to comment Share on other sites More sharing options...
bennygoodman Posted April 22, 2015 Author Share Posted April 22, 2015 The fan works in either direction by just changing the live and earth terminals over on the motor so it is a two minute job to do.My thoughts were thoughts were to suck air out as it only overheats when stood, never when on the move to keep the cabin a bit cooler, surely even if the air is hot that is being drawn through the radiator it will still cool it sufficiently to stop it overheating as the hot air will still be cooler than the boiling water? Quote Link to comment Share on other sites More sharing options...
esxefi Posted April 23, 2015 Share Posted April 23, 2015 as above,any decent fan will have contoured vanes that work one way only,much like a sail on a yacht.some fans can be inverted with a polarity reverse on the motor to make it a sucker or blower.a fan should only need to be used when stationary or moving below 20-30 mph.any overheating apart from this indicates a problem elsewhere,in front should be fine.the blades rotate anyway when moving so the obstruction to the matrix is less than you think.the biggest improvement you can do with an electric fan is shroud it or at least seal the perimeter against the rad otherwise you will get the hot air just recirculating back through the matrix which is bad for heat dissipation.I've seen a triumph on youtube with 2 fans that are fitted approx. 8" in front of the rad.how inefficient is that? :-/ Quote Link to comment Share on other sites More sharing options...
markcro Posted April 23, 2015 Share Posted April 23, 2015 I have wondered this as well. But the Kenlowe fan that I fitted it specifically designed for the front of the rad. And as said above, blocking the front or the back of the rad has the same effect. Quote Link to comment Share on other sites More sharing options...
stevegt6 Posted April 23, 2015 Share Posted April 23, 2015 It would appear the best solution is to drive fast and not stop ;D Quote Link to comment Share on other sites More sharing options...
RobPearce Posted April 23, 2015 Share Posted April 23, 2015 4187 wrote:The fan works in either direction by just changing the live and earth terminals over on the motor so it is a two minute job to do.Not true. See other replies.4187 wrote:My thoughts were thoughts were to suck air out as it only overheats when stood, never when on the move to keep the cabin a bit cooler, surely even if the air is hot that is being drawn through the radiator it will still cool it sufficiently to stop it overheating as the hot air will still be cooler than the boiling water?It sounds like you're intending to have the fan draw air from the engine bay and blow it out the front, in opposition to the natural flow while driving. Is that right? You said something about the fan only running while stationary, which isn't true even as a generalisation, but think about this:- You're in heavy traffic, stationary. The engine gets hot and the fan cuts in to cool it.- The traffic then clears (or you reach your turning) and you accelerate away.- At this point, the engine IS STILL HOT, so the FAN IS STILL RUNNING.What you have now is a fan desperately fighting against the natural flow of the air. The result of that is that practically no air is flowing at all. And so the engine is not being cooled and it overheats, causing serious mechanical failure and a huge bill. Quote Link to comment Share on other sites More sharing options...
esxefi Posted April 23, 2015 Share Posted April 23, 2015 ^^ you're not a fan then... ;D Quote Link to comment Share on other sites More sharing options...
don cook1 Posted April 23, 2015 Share Posted April 23, 2015 Steady on Rob. Quote Link to comment Share on other sites More sharing options...
bennygoodman Posted April 23, 2015 Author Share Posted April 23, 2015 RobPearce, the fan has a manual switch, it is only used when the engine is overheating when stood in traffic, not stood for a few minutes but for a long time as happened on Saturday on the East Lancs road, as soon as the car is moving it is turned off as the car doesn't overheat when moving.I thought I made that clear in my original post but obviously your a bit slow. Quote Link to comment Share on other sites More sharing options...
RobPearce Posted April 24, 2015 Share Posted April 24, 2015 I may be a bit slow but I'm worried that you seem to have chosen to rely solely on the driver's attention and judgement for your engine cooling. If not, then the switch-controlled fan must be only one of two, in which case it's fighting the other one and my comments all still apply. Plus you're making your life hard, requiring you to do a job that a crude mechanical sensor would do far better. Still a stupid idea, sorry. Quote Link to comment Share on other sites More sharing options...
Basil Fawlty Posted April 24, 2015 Share Posted April 24, 2015 What a load of hot air..... ;D Quote Link to comment Share on other sites More sharing options...
Clive Posted April 24, 2015 Share Posted April 24, 2015 Just to clarify, the original engine fan has been removed??I ask as many owners seem to have both fitted.As I think sombody has mentioned, the key to good cooling with an electric fan (indeed, mechanical but tricky) is to have it well shrouded. My car uses the rad off a golf, with matching vw shroud and fan. This enable the fan to draw air from the entire radiator, with very little loss. Most aftermarket fans seem to have massive losses as the gaps are huge and/or poorly designed installations. Probably the best way for an aftermarket fan to be mounted is through the core. As to getting heat out of the engine bay, the idea of a separate fan mounted somewhere (where???) to help shirt the hot air would be good. But surely throwing cool air in from the front will push more air out of the engine bay anyway?? I realise not in the ideal direction when stationary, but we can't have everything...... Quote Link to comment Share on other sites More sharing options...
BiTurbo228 Posted April 24, 2015 Share Posted April 24, 2015 I must admit, I don't think it's a fantastically good idea.The point when your car most needs the fan's cooling capacity is when it's stationary. If everything's working as it should, it should be pulling cold air from outside through the radiator.If you swap that to pull hot air from the engine bay through the radiator then you're going to severely reduce the temperature differential between the coolant and the air flowing through the radiator, hampering your cooling capacity.Not a good idea.If you're dead set on having a fan to reduce underbonnet temperatures, why not have another one attached to the firewall pushing hot air down and out the bottom of the car.Alternatively, cut some bonnet vents or install some heat shielding/sound deadening to the interior. Quote Link to comment Share on other sites More sharing options...
don cook1 Posted April 24, 2015 Share Posted April 24, 2015 Also think about what the water pump is doing at tickover, not going too fast. Electric water pump with a thermo switch would compliment an electric fan. Mechanicals...daft isn't it, when the cooling needs most help it doesn't get it, when it needs it least it has masses of help??? Quote Link to comment Share on other sites More sharing options...
Phwoar Posted April 24, 2015 Share Posted April 24, 2015 cliftyhanger wrote:As to getting heat out of the engine bay, the idea of a separate fan mounted somewhere (where???) to help shirt the hot air would be good. But surely throwing cool air in from the front will push more air out of the engine bay anyway?? I realise not in the ideal direction when stationary, but we can't have everything......I'm with Clive here. Has anyone tried using 12v PC fans to extract hot air from the engine bay. They should, at least, be reliable given the work they're expected to do?Electric water pumps should help too. Quote Link to comment Share on other sites More sharing options...
markcro Posted April 24, 2015 Share Posted April 24, 2015 GT6_Don wrote:Steady on Rob.I think he may need cooling down! Rob, you need a fan fitted! :P 8) Quote Link to comment Share on other sites More sharing options...
Richard B Posted April 24, 2015 Share Posted April 24, 2015 cliftyhanger wrote:As to getting heat out of the engine bay, the idea of a separate fan mounted somewhere (where???) to help shirt the hot air would be good.I seem to recall a Scimitar SE6 with something like that. But then on a Scimitar the front grill had no holes to let air through and the spare wheel was mounted in front of the radiator.No wonder they overheated.Re EWP big fan of this, on my Stag I have twin electric fans from a Range Rover Vogue, and a Craig Davis Electric Water Pump.But no mechanical pump or fan fitted. Both controlled electronically! 8) Quote Link to comment Share on other sites More sharing options...
James Posted April 24, 2015 Share Posted April 24, 2015 Why is this even a discussion?Fan on the engine side of the rad, sucking through the radiator — controlled by a thermostatic switch. Never need worry about anything ever again. Quote Link to comment Share on other sites More sharing options...
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