Mike C. Posted October 9, 2006 Share Posted October 9, 2006 My Superlight (R300 spec) has the Caterham C/F Airbox and Triple Pass (R500) Rad, with the cooling fan mounted at the front. I've mentioned before that the fan, in this location, is quite noisy. But it can't be fitted elsewhere. At the moment the fan cuts in at 85 degrees, which seems a bit low. What would be the highest temperature I could safely set the fan to cut in? (Temp is set on the ECU). Mad Manx Link to comment Share on other sites More sharing options...
Allen Payne Posted October 9, 2006 Share Posted October 9, 2006 According to Minister engines the coolant shouldbe 75deg +/- 5deg here Edited by - Allen Payne on 9 Oct 2006 18:06:55 Link to comment Share on other sites More sharing options...
Peter T Posted October 9, 2006 Share Posted October 9, 2006 Mine is set to come on at 93 degrees.I did have it set at 85 but felt the range was too low . R500 Mango Madness Link to comment Share on other sites More sharing options...
MAK Posted October 9, 2006 Share Posted October 9, 2006 In with both feet. I thought the thermostat in a cooling system was intended to stabilise coolant temperature, and that K series in particular have a reputation with HGF. If you set a fan temp significantly above this set temp I would think you are more likley to get HGF. Malcolm Link to comment Share on other sites More sharing options...
Myles Posted October 9, 2006 Share Posted October 9, 2006 MAK - same here. Can't see any reason for letting the temps get outside the smallest possible range. 🙆🏻 🙆🏻 🙆🏻 🙆🏻 🙆🏻 Alcester Racing 7s Equipe™ 🙆🏻 🙆🏻 🙆🏻 🙆🏻 🙆🏻 Alcester-Racing-Sevens.com Link to comment Share on other sites More sharing options...
F355GTS Posted October 9, 2006 Share Posted October 9, 2006 But if you set it too low the fan will cut in before the thermostat Mark Link to comment Share on other sites More sharing options...
simonbell Posted October 9, 2006 Share Posted October 9, 2006 On my duratec it comes on an 94 and off at 90...........stat is at 82, fan only ever comes on after sitting in traffic for a bit Simon Bell - Caterham 7 Duratec R I`ve seen the future.....and it`s powered by duratec Check out the website here Link to comment Share on other sites More sharing options...
Support Team Shaun_E Posted October 10, 2006 Support Team Share Posted October 10, 2006 Standard K series setup is to have the fan come on at around 96 degrees and off again at 92 ish (I can't remember the exact figures). I have mine set the same albeit controlled by the Emerald and I'm using an 82 degree stat. I guess if you have the R500 stat (74 degrees ?) then your setting should be OK but if you are using an 82 degree stat then it is way too low as the fan will be coming on not long after the stat has opened. Yellow SL #32 Link to comment Share on other sites More sharing options...
MartinWoodham Posted October 10, 2006 Share Posted October 10, 2006 IIRC the temp switch for the fan is mounted in the rad itself. So setting a lower temp than the thermostat isn't a prob because the water in the rad won't be warm until the thermostat has opened. But to answer the question, I would have thought 85 deg is quite high enough. Do you know why the fan is noisy/ is there anything to be done about it? Martin Aero'd Roadsports B with a garage slowly filling up with upgrade parts Link to comment Share on other sites More sharing options...
Mike C. Posted October 10, 2006 Author Share Posted October 10, 2006 Martin The system I have is the same as the R500 - a Caterham c/f airbox and triple pass rad. The ducting for the airbox prevents the fan from being located behind the rad, where the noise would be subdued. It is therefore mounted in front of the rad, behind the grille, and it is quite noisy (sounds like a Dyson vacuum cleaner). Apparently, it's quite normal with this set up. 'Ruff Seven' suggested a smaller, quieter fan made by a company called Cyclone, but I haven't located a uk source yet. However, as the cooling system is now so efficient, I thought it might be possible to raise the operating temperatures. Hence the question. Mad Manx Link to comment Share on other sites More sharing options...
Peter Carmichael Posted October 10, 2006 Share Posted October 10, 2006 According to Minister engines the coolant shouldbe 75deg +/- 5deg here Think of a number. Any number. If you have any concerns about a K-series being a bit hot, just drive it gently until the airflow brings the temperature down. Asking a fan to keep temps very low asks a lot of your alternator... besides making an awful racket. Link to comment Share on other sites More sharing options...
Peter T Posted October 10, 2006 Share Posted October 10, 2006 Overcooling can havea drastic effect on your engine also. R500 Mango Madness Link to comment Share on other sites More sharing options...
MAK Posted October 10, 2006 Share Posted October 10, 2006 Perhaps I am getting confused here. The thermostat in a cooling system attempts to maintain a reasonable stable coolant temperature, once it starts to open. The temperature rating for a thermostat is usually the temperature at which it is fully open. Under normal operting conditions I would expect your coolant temperature to be no greater than this "fully open" temperature.- Surely if its above this you have a cooling system that is not properly controlled. eg you may have a radiator with insufficient performance for the ambient conditions and the heat generated by your engine.- or possibly your radiator fins are blocked and no doubt many others. If you set the fan switching temp a few degrees above the Thermostat fully open temperature, it should only switch on when there is insufficient cool air flow for the thermal load, such as sitting in traffic. If you set it significantly above the fully open temperature you are allowing the engine temperature cycle to be greater under these conditionswhich I would think more likely to cause HGF. I think its preferable to have an alternator working more frequently than to encourage HGF. Malcolm Link to comment Share on other sites More sharing options...
Myles Posted October 10, 2006 Share Posted October 10, 2006 Malcolm. Still with you on this one... I don't have an adjustable fan switch (well, I have a manual override...) - I have both the R500 stat and switch. The stat is rated for 74 degC (mine opens fully a little below that) and the fan switch triggers at an indicated 81ish. That's a fairly reasonable range IMHO and fairly close to what Minister recommend. 🙆🏻 🙆🏻 🙆🏻 🙆🏻 🙆🏻 Alcester Racing 7s Equipe™ 🙆🏻 🙆🏻 🙆🏻 🙆🏻 🙆🏻 Alcester-Racing-Sevens.com Link to comment Share on other sites More sharing options...
Peter Carmichael Posted October 10, 2006 Share Posted October 10, 2006 The thermostat is rated at its "opening temperature". The standard K-series thermostat starts opening at 88 degrees. It is only the rubbish Caterham gauges that leave us thinking it is running the car at ~80 degrees. If you attempt to run the coolant at lower than sensible temperature, you are ultimately doomed to failure. Heat dissipation relies on a heat differential compared to ambient temperature. If there is a reduced heat differential, there is a reduced ability to dissipate heat. Once the lower spec thermostat is fully open, the temperature will climb to the same equilibrium temperature anyway. The scenario we often witness is the cooling system modifier expressing concern at the uncontrolled temperatures and attempting to fit an even lower thermostat... It is a bit like this ... "but heat kills!" yelled Councillor Prescott Link to comment Share on other sites More sharing options...
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