Scotty Posted June 25, 2005 Report Share Posted June 25, 2005 I have a question however, do the fans blow in toward the engine or outward? I asked my radiator shop what they thought about adding a fan blowing in and they said, that I should have it blow out, does that make sense? I would have thought that the fan I install in the front of the radiator facing in should blow IN... because of the ram air effect of the simple act of driving forward.. While I was riding today I was thinking of this. I was thinking that I would need to get a fan that was small enough to fit between the cross member that is there. If it were small enough to fit, would the fan do anything as it was too small.. Then I was thinking I could add two small fans one on each side.. Then what crossed my mind was whether these fans would obstruct air flow when not in use. Then what about the additional power to drive them, how much current would they draw? Since I would only use these Rube Goldberg fans when I was in traffic what would be the consequence of using them on high speed in terms of current draw, heat created by the alternator, physical drain on the engine and maybe my alterntor would be stressed by it and not be able to provide enough current and I would drain my battery.. I have seen low charging rates at night with Lights, wipers, HVAC fans... add the additional fans and I could be looking for trouble.. Then I sat back and thought about Guru and how he said the 222 to 235 range and probably 240 ranges is not really a big deal, that cars are driving everyday in places like Phoenix and Las Vegas and survive... So I am going to replace my hoses and ignore my temp guage this summer... Link to comment Share on other sites More sharing options...
JasonA Posted June 25, 2005 Report Share Posted June 25, 2005 Scotty, the fans ALWAYS blow "in". You either have a "pusher" fan mounted in front of the radiator pushing air through it, or you have a "puller" fan (like we have) mounted behind the radiator pulling air through it. I've never ever heard of someone mounting a fan so it pushes air out the front of the radiator. In fact, that's generally a check on the overheating troubleshooting charts I think...is the fan installed correctly...so that it's not trying to push against ram air. Jason(2001 STS, White Diamond) "When you turn your car on...does it return the favor?" Link to comment Share on other sites More sharing options...
Scotty Posted June 25, 2005 Report Share Posted June 25, 2005 Scotty, the fans ALWAYS blow "in". You either have a "pusher" fan mounted in front of the radiator pushing air through it, or you have a "puller" fan (like we have) mounted behind the radiator pulling air through it. I've never ever heard of someone mounting a fan so it pushes air out the front of the radiator. In fact, that's generally a check on the overheating troubleshooting charts I think...is the fan installed correctly...so that it's not trying to push against ram air. Thanks that is what I thought also, maybe I misunderstood my AC guy, maybe he thougth I intended to put a fan on the inside... Link to comment Share on other sites More sharing options...
Ranger Posted June 25, 2005 Author Report Share Posted June 25, 2005 Ranger, What are the 1999 specifications for other temperatures and humidity levels? Just over 300 psi is consistent with my observations during a prolonged idle, high blower, recirculated air, and 90-95 F at over 50% humidity, however, the 1997 vent temperature is likely a worst case scenario figure (extremely high initial interior temperature, severe heat soak). The only way to get 200 psi high side under those conditions is to spray water on the condenser or start the test with a VERY cold car. WarrenJ, A 30-40 F drop is reasonable within a certain humidity range (as you noted), but with one big assumption - no recirculated air. If you feed 80-90% "interior air" to the evaporator, you will reduce the load significantly and achieve a must lower vent temperature at some point. KevinW, Maybe Sunday morning I can get my daughter to help me scan and post both charts. I would think both charts are based on the same premise, ie: temp, humidity, heat soak, recirc or vent air etc. Link to comment Share on other sites More sharing options...
JIMDTS Posted June 25, 2005 Report Share Posted June 25, 2005 Here's an interesting chart A/C Performance Table Ambient Air Temperature Relative Humidity Service Port Pressure Maximum Left Center Discharge Air Temperature Low Side High Side 16°C (60°F) 0-100% 228-269 kPa (33-39 psi) 1000-1207 kPa (145-175 psi) 11°C (52°F) 21°C (70°F) Below 40% 228-269 kPa (33-39 psi) 869-1076 kPa (126-156 psi) 11°C (52°F) Above 40% 241-283 kPa (34-41 psi) 890-1096 kPa (129-159 psi) 12°C (56°F) 27°C (80°F) Below 40% 276-317 kPa (40-46 psi) 1048-1255 kPa (152-182 psi) 16°C (60°F) Above 40% 290-331 kPa (42-48 psi) 1069-1276 kPa (155-185 psi) 16°C (60°F) 32°C (90°F) Below 40% 324-365 kPa (47-53 psi) 1283-1496 kPa (186-217 psi) 19°C (67°F) Above 40% 352-393 kPa (51-57 psi) 1310-1517 kPa (190-220 psi) 21°C (70°F) 38°C (100°F) Below 40% 345-386 kPa (50-56 psi) 1427-1703 kPa (207-247 psi) 19°C (67°F) Above 40% 372-414 kPa (54-60 psi) 1455-1731 kPa (211-251 psi) 21°C (70°F) 43°C (110°F) Below 40% 372-414 kPa (54-60 psi) 1572-1848 kPa (228-268 psi) 22°C (71°F) Above 40% 421-462 kPa (61-67 psi) 1655-1931 kPa (240-280 psi) 24°C (75°F) 49°C (120°F) Below 40% 462-503 kPa (67-73 psi) 1820-2096 kPa (264-304 psi) 26°C (79°F) Link to comment Share on other sites More sharing options...
Northstar Posted June 26, 2005 Report Share Posted June 26, 2005 undefinedI understand all the variables, well most of them, but I think you guys are missing my point. The numbers I listed in the original post can right out of the '97 & '99 service manuals. Why such a big difference? Same engines, same basic systems. Probably same compressors, though I am not positive about that. They are different compressors, in 1998 they went to a Scroll type compressor. Link to comment Share on other sites More sharing options...
Ranger Posted June 26, 2005 Author Report Share Posted June 26, 2005 I have figured out that the '99 does have a "scroll type" compressor as opposed to the '97 with an "axial type" compressor. Maybe that explaines the different pressures and duct temps at any given ambient temp and humity. I am having trouble trying to scan and post the two charts (I hate computers). Link to comment Share on other sites More sharing options...
KevinW Posted June 26, 2005 Report Share Posted June 26, 2005 The vent temperature figures that JimDTS posted appear more 'reasonable' (presumably from a 2001 manual). The volumetric efficiency of a scroll compressor increases roughly in a linear fashion with respect to RPM, which is almost the opposite of a piston-based compressor. As such, one of the biggest problems is ensuring enough compressor RPM for adequate idle performance (observe the much smaller diameter of the pulley), while not running into an over-speed condition at the engine's red-line, as well as managing quick transients. The beauty of the piston compressor is that its efficiency drops off sharply at high RPM and there's little worry about rapid build-up of pressure on sudden acceleration. I would expect the performance of a 'scroll' to be below that of a 'piston' at idle, everything else being the same. ___________________________________________________ Link to comment Share on other sites More sharing options...
Matt Posted June 26, 2005 Report Share Posted June 26, 2005 Again this was very interesting info even though our car years vary greatly. Link to comment Share on other sites More sharing options...
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