Jonmurgie 2 Posted August 15, 2006 No idea where to find this information out but hopeing someone may know! Basically I'm sizing up an aftermarket fan to fit onto my lowered rad and it looks like I'm going to ahve to go with an 8" fan, which seems tiny! However, size isn't everything... it's about how much they can blow/suck So, does anyone know what the CFM rating for the standard OEM single fan setup in a 205 is? If I can get that figure (or a rough guestimate) then I can select a fan that is rated around the same... Hope someone knows! Cheers Jon Share this post Link to post Share on other sites
engine killer 6 Posted August 15, 2006 sorry for a little off-topic i haven't got a clue about the rating but as for my friend's experience, an effective cowling is a must to make the fan useful. he tried different settings (with and without cowling), cowling and diverting panels (thin alu sheets routing between front grill service area and radiator service area, he mainly uses pull type fan to increase efficiency as he said) made a huge difference. since we are in south east asia, cooling plays a very major role if we want to finish the race. Share this post Link to post Share on other sites
j-16 1 Posted August 15, 2006 (edited) Can you not just use the lower temp fan sensor, so the standard fan will come on earlier? Sorry, just re-read and you don't actually want more cooling! Edited August 15, 2006 by j-16 Share this post Link to post Share on other sites
Jonmurgie 2 Posted August 15, 2006 correct, and I'm not USING the standard fan! So I'm still looking for any idea of the CFM of the OEM fan Share this post Link to post Share on other sites
Jonmurgie 2 Posted August 16, 2006 bump... am I right in saying this is an un-answerable question?! Share this post Link to post Share on other sites
veloce200 3 Posted August 16, 2006 (edited) bump... am I right in saying this is an un-answerable question?! possibly. if I were you i'd buy the fan you are looking for and switch in on early and off late that way you'll never have a problem in traffic, at least you have the luxury (like me ) of ECU control! It shouldn't ever activate on track if it does other cooling mods required (not that you'd notice it switch on with your TB's at full blare! Edited August 16, 2006 by veloce200 Share this post Link to post Share on other sites
Rob_the_Sparky 9 Posted August 16, 2006 I guess the power of the motor and size of the fan are probably easier to come by and may give an idea of the rating. Share this post Link to post Share on other sites
smckeown 1 Posted October 14, 2006 (edited) what CFM rad did you go for in the end Jon ? I'm going to cut up the spare cowling I have and weigh the fan. But having a lightweigh fan that has a good enough CFM may mean the fan is on less, therefore less time sapping power. As always Julianhas something interesting to add. It is a good point that while driving you want the rad to get as much air as possible, so the fan doesnt need to come on. I'll keep an eye on water temp a lot more closely in the future; may try and use KMS logging to tell me what temp the water goes up to after some spirited driving. Makes you think about the power runs/mapping sessions when usually the fan is blarring probably even on high power, making the results even more inaccurate Sean Edited October 14, 2006 by smckeown Share this post Link to post Share on other sites
Jonmurgie 2 Posted October 14, 2006 I went for the Pacet Thinline TCF1011 which is a 10" fan providing 902 CFM. The 205 radiator is so very short that a 10" fan is all I could get to fit no idea if it's good enough, only time will tell Share this post Link to post Share on other sites
Henry Yorke 269 3 Cars Posted October 14, 2006 Sorry Jon, not much help but I have a Spall fan straight onto my Nissens ally rad that has been lowered. This kicks in on the lower temp switch and is only single speed. As has been said before, the fan only ever comes on in traffic. F1 cars don't have fans IIRC which is why if there is a delay at the start, they all get pretty nervous. Ditching the fan cowling does ad a weight saving and allows more air into the engine bay if the rad is dropped. What is often overlooked is how to get the hot air out. An Integrale style bonnet vent at the back may be ideal. Old Skoda Felicias have a plastic one that may do the job as well. Also have a look at a T16 bonnet and the massive hole for the post-rad air that they used. The other air out method may be to have some NACA ducts in the bonnet that create a venturi effect to suck the air out from inside. Share this post Link to post Share on other sites
Rippthrough 98 Posted October 14, 2006 (edited) Problem with losing the cowling is that a good cowling can increase the effiecency of a fan by a substantial amount - as can fitting it as far back from the radiator as possible. A pure track car may get away with dropping the fan altogether though. Edited October 14, 2006 by Rippthrough Share this post Link to post Share on other sites
smckeown 1 Posted October 14, 2006 I'm thinking that you want as much cold air as possible to hit the rad, the cowling and fan are restrictive. This would result in the fan actually running less in the first place. Also by putting a slimline fan bihind the rad and sucking will also allow the rad to be cooled by air as much as possible. Share this post Link to post Share on other sites
Rippthrough 98 Posted October 15, 2006 I'm thinking that you want as much cold air as possible to hit the rad, the cowling and fan are restrictive. This would result in the fan actually running less in the first place. Also by putting a slimline fan bihind the rad and sucking will also allow the rad to be cooled by air as much as possible. Stick a voltage controller on the fan, see how low you can go voltage wise, that'll show you (roughly) what cfm you need to keep the car cool in traffic, then you can switch to a smaller less obstructing fan. You only need one when you're stood, and you have a rebuilt cooling system, so you might get away with a puny fan - say 240cfm, which could be done with a tiny 120mm fan. Share this post Link to post Share on other sites
