captain chaos Posted May 27, 2014 Share Posted May 27, 2014 Guys, I have a radtec (45mm) core radiator. The cooling is fine when on the move but as soon as I hit traffic the temp climbs quite quickly to 88/90 deg. The fan then cuts in, but if it's a warm day, the temp will climb, quite slowly up to 100 deg +. A recent enforced rebuild left my engine builder advising that he would like to see the motor run cooler when being worked hard or stuck in traffic. i dont do alot of miles but I did get caught in a terrible jam around brussels last year which saw me pulling over a couple of times due to high temps. (I was runnning the 82 deg stat) So, what are the rest of the Vx modified owners seeing as temps?....which Radiator are you running? I would appreciate some feedback as to what temps you are seeing in normal road/traffic use? Spoke to Radtec today...they have stopped making the caterham extreme radiator (was 68mm core) and are now making a 58mm model which they feel would suit my purpose. I am getting hot water in the expansion tank and the rad hoses are nice and warm when i close up the system. comments appreciated... Link to comment Share on other sites More sharing options...
Mavic82 Posted May 27, 2014 Share Posted May 27, 2014 Not sure I can be much help but for info.... I run a calibra hot climate stat with a small drilled bypass hole. A standard radtec radiator with self bleed back to the header tank. I also run a restrictor in the bleed hose from the top of the manifold. Heater is in the circuit. Car runs around 85 most of the time rising to around 95 in traffic then fan brings it back down. No issue in 30 plus ambient in queuing traffic. I do have a fan over ride switch in case and the biggest fan I could cram in that flows the most air I can get. Keeps it all stable. Cheers Guy Link to comment Share on other sites More sharing options...
captain chaos Posted May 27, 2014 Author Share Posted May 27, 2014 Thanks.... I think I may need the bigger rad to increase capacity as the fan will not control things on its own (with higher ambient temps) ... I'll see if the other vx boys are lurking and see what others are experiencing ... Link to comment Share on other sites More sharing options...
Area Representative Golf Juliet Tango Posted May 27, 2014 Area Representative Share Posted May 27, 2014 Not a VX driver but... In my opinion: fit a bigger/higher powered fan. You know the radiator is big enough because the normal cooling is ok. So when the conditions are against you, you need to draw more air across it. You may also wish the fan to cut in at a lower temp (or to be able to switch it in as soon as you see the temperature is rising beyond your preferences). Link to comment Share on other sites More sharing options...
Mavic82 Posted May 27, 2014 Share Posted May 27, 2014 Yes I agree, that is what I was alluding to. I measured the biggest fan diameter that would fit in front of the rad and then searched all the fan companies to find the highest flow. Much better than a caterham fan in both size and flow. On a normal day it pulls the temp down very quickly. Link to comment Share on other sites More sharing options...
captain chaos Posted May 27, 2014 Author Share Posted May 27, 2014 Hi guys Thanks again ... Will certainly look at this ... I think the fan unit could be an nice bigger overall... Are they rated in terms of airflow? Link to comment Share on other sites More sharing options...
captain chaos Posted May 27, 2014 Author Share Posted May 27, 2014 Just checking fans and I suppose it's obvious they will be (doh!) ... Looking at the info on DT site it seems there can be quite a difference too... Link to comment Share on other sites More sharing options...
Area Representative Golf Juliet Tango Posted May 27, 2014 Area Representative Share Posted May 27, 2014 Quoting captain chaos: Hi guys Thanks again ... Will certainly look at this ... I think the fan unit could be an nice bigger overall... Are they rated in terms of airflow?Yes. I did this for the 21 (K Series VHPD so high temperatures make me very jumpy), and the Demontweeks website had fan airflow details. Mavic: glad we agree. Link to comment Share on other sites More sharing options...
Lee Fowler Posted May 27, 2014 Share Posted May 27, 2014 I run the larger Radtec with the upgraded fan for a similar problem and have just looked at the Invoice but all it says is Caterham Radiator but does not give the size of the rad! Sorry Lee Link to comment Share on other sites More sharing options...
captain chaos Posted May 27, 2014 Author Share Posted May 27, 2014 Lee... What's your motor ? Link to comment Share on other sites More sharing options...
Nigel Riches Posted May 28, 2014 Share Posted May 28, 2014 Hi Captain. Have a look at this, http://www.spalautomotive.com/eng/products/default.aspx Sorry not much good at techno stuff, I have been wondering if my set up will cope with the zetec installation using the rad and fan as installed, and could I possibly fit two smaller fans to increase airflow? I presently have a rad from CC from 1995, supposedly for a 2L Vauxhall motor, Cov Rad item, P/N 57530, however with a look at Coventry Heat Transfer web page no mention of these radiators Nigel. Link to comment Share on other sites More sharing options...
Molecular--Bob Posted May 28, 2014 Share Posted May 28, 2014 Not sure if this is relevant to a VX but i found that at idle my crossflow was not moving enough liquid to get the water around the cooling circuit, leading to stagnation. I found that using a few more revs in traffic allowed the fan to pull the heat out of the water. Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted May 28, 2014 Member Share Posted May 28, 2014 Quoting Molecular--Bob: Not sure if this is relevant to a VX but i found that at idle my crossflow was not moving enough liquid to get the water around the cooling circuit, leading to stagnation. I found that using a few more revs in traffic allowed the fan to pull the heat out of the water.I don't understand this. Was that with a typical thermostatically-switched electric fan? Thanks Jonathan Link to comment Share on other sites More sharing options...
Jon Stewart Posted May 28, 2014 Share Posted May 28, 2014 It's worth checking the fan is connected the right way round! Mine had been re-connected the wrong way after a refresh last year and was blowing instead of sucking and showed the same symptoms as yours. I have no issues with temps other than over-cooling and I usually need to tape up half the nose at about 15 deg C ambient temps. This is running with a standard radtec rad, 11" Spal fan here IIRC, 82 deg drilled thermostat, dry sumped with oil cooler. Link to comment Share on other sites More sharing options...
Ed White Posted May 28, 2014 Share Posted May 28, 2014 When standing you also have a slow turning water pump so water not being moved through the radiator in volume. An electric water pump might help with this. Cheers ed Link to comment Share on other sites More sharing options...
Molecular--Bob Posted May 28, 2014 Share Posted May 28, 2014 Hi Jonathan Pretty much as Ed said, the radiator and fan were working correctly, but the pump was not moving enough water through it to allow the engine to dump it's heat output, allowing the water temperature to creep up. A few more revs push the water around faster and allow more heat to be rejected, resulting in total heat in the system reducing. Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted May 28, 2014 Member Share Posted May 28, 2014 *arrowup*It was shouting "pump" at me, but now I see I'm not the only one! Jonathan Link to comment Share on other sites More sharing options...
captain chaos Posted May 28, 2014 Author Share Posted May 28, 2014 some useful commnets..many thanks! Fan is sucking rather than blowing...slight revs does not seem to make any difference although i am now thinking along the lines of improving the fan...some fans seem to perform better than others and i think I could also fit a slightly bigger unit. When moving at 30 or above the temp drops to 75....so its now about getting more air when moving more slowly as heat builds or increasing capacity to make the thermostat work harder in cooler conditions...Ive decided my first step is to sort a better fan. ... Link to comment Share on other sites More sharing options...
Lee Fowler Posted May 28, 2014 Share Posted May 28, 2014 Quoting captain chaos: Lee... What's your motor ? Same as yours but not quite as powerful. Lee Link to comment Share on other sites More sharing options...
captain chaos Posted May 28, 2014 Author Share Posted May 28, 2014 Thanks Lee... Did you have similar symptoms ?..re temps ? Link to comment Share on other sites More sharing options...
Rob Walker Posted May 28, 2014 Share Posted May 28, 2014 the radtec rad is plenty big enough, look elsewhere for your problem. Rob Link to comment Share on other sites More sharing options...
Lee Fowler Posted May 28, 2014 Share Posted May 28, 2014 Quoting captain chaos: Thanks Lee... Did you have similar symptoms ?..re temps ? Yes I did and the rad and fan seemed to have cured it. Lee Link to comment Share on other sites More sharing options...
F355GTS Posted May 28, 2014 Share Posted May 28, 2014 I used to run the std Caterham rad on my 274 VX, used to be OK but on a hot day sometimes saw temps climb after a track session to a similar 100c. I didn't ever change anything but can see the logic on here that more airflow looks like the solution Link to comment Share on other sites More sharing options...
DaveMorris Posted May 30, 2014 Share Posted May 30, 2014 Gary, my Vx, albeit of drasticvally lower power than yours, has standard Radtec Alu radiator but the largest Pacet Fan that can be fitted (with only a small amount of fettling to the plastic rim) onto the rad. It is a PF1111P and blades are ~11" across the diameter and the fan out shroud is ~12". It fits completely flush to the back face of the matrix. When it kicks in the coolant temperature tends to drop like a stone - even when stationary in traffic and with a fair amount of "heat soak" . This is rated at 1180c.f.m. / 2000m3/hr - but it is SIGNIFICANTLY more than the 10" fan that was on there (which was not a Pacet). Dave. Link to comment Share on other sites More sharing options...
Paul Deslandes Posted May 31, 2014 Share Posted May 31, 2014 Do you have a heater? If so, does turning it on plus heater fan help? Mind your feet when you try this, you won't be the first to burn your feet. Link to comment Share on other sites More sharing options...
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