thegreatestben Posted July 10, 2009 Share Posted July 10, 2009 Sorting out the AW11's setup. I'm using the ST205 celica intercooler, I have the exchanger for up front but it's actually too big to fit between the chassis rails of my car. few q's Pumps: Can't find a stock Celica st205 one for a reasonable price. Have looked through alot of different options. Bosch, davies craig and some bilge/boating pumps. Gonna give this one a go because it's A) price effective recommended and tested by frozenboost.com who sell alot of set ups (not cost effective for me due to overseas shipping and shit economy etc) Link to frozenboost pump here The pump has more than enough oomph going by numbers (it out performs the davies craig unit) and it has the correct in/outlet size. But as brock-lee mentioned I don't want the water to be travelling around the system too fast. Could this could be over come by wiring so I can adjust speed of motor? If so can someone with electrical know how recommend a circuit layout? Next question is the exhangers, I've had a few suggestions, best so far is motorbike radiators. I'm looking at these I could look at running both, having one up the front of the car and another in the engine bay infront of the gearbox. Thoughts on that? Other suggestions or does anyone have anything suitable, I don't have measurements right now but needs to have 3/4" in/out preferably both on the same end. Chur Quote Link to comment Share on other sites More sharing options...
Simon Posted July 10, 2009 Share Posted July 10, 2009 Those bike rads look good. I was just going to put the small honda radiator from my corona in there in front of the normal one. Im also interested in this Quote Link to comment Share on other sites More sharing options...
BobbyBreeze Posted July 10, 2009 Share Posted July 10, 2009 I think you'll find the faster the flowrate the better. No matter what, more mass-flow = more heat transfer rate. Quote Link to comment Share on other sites More sharing options...
RUNAMUCK Posted July 10, 2009 Share Posted July 10, 2009 water to air is FTW. A mate of mine makes them, he borrowed my shitfiro last weekend an let me use his sw20 mr2 with full custom water to air unit. Fuck it's just plain scary how well it goes. sorry i can't contribute anything of real help, but I'm drunk and want to post something Quote Link to comment Share on other sites More sharing options...
Spencer Posted July 10, 2009 Share Posted July 10, 2009 Run it on meth and no cooler Quote Link to comment Share on other sites More sharing options...
danger Posted July 10, 2009 Share Posted July 10, 2009 Considered using an old heater core? Quote Link to comment Share on other sites More sharing options...
thegreatestben Posted July 10, 2009 Author Share Posted July 10, 2009 considered running a brand new heater core but couldnt find anything big enough Quote Link to comment Share on other sites More sharing options...
84_S12 Posted July 10, 2009 Share Posted July 10, 2009 I think you'll find the faster the flowrate the better. No matter what, more mass-flow = more heat transfer rate. Actually in truth the heat exchanger will have an optimal water flow rate for maximum heat transfer/rejection, but you're partly right in that a greater flow rate of the secondary heat exchange medium (ie air) over the heat exchanger will reject more heat Quote Link to comment Share on other sites More sharing options...
BobbyBreeze Posted July 10, 2009 Share Posted July 10, 2009 Actually in truth the heat exchanger will have an optimal water flow rate for maximum heat transfer/rejection, but you're partly right in that a greater flow rate of the secondary heat exchange medium (ie air) over the heat exchanger will reject more heat As far as i know, the forced convection heat transfer coefficient should increase as the mass flow increases. This means you'd get better cooling by increasing both the air and the coolant mass flow rate. Why would increasing the air flow rate increase the heat transfer, but increasing the water flow rate not? Happy to be proven wrong. Quote Link to comment Share on other sites More sharing options...
danger Posted July 11, 2009 Share Posted July 11, 2009 what size you after? Have a aircon core lying around thats like brand new would do the trick Quote Link to comment Share on other sites More sharing options...
eke_zetec_RWD Posted July 13, 2009 Share Posted July 13, 2009 water takes time too cool and if its forced through the cooler too fast then its going back to intercooler 2 warm, and if its too slow then it will be getting too hot in the intercooler. so there will be a optium flow rate. a bigger radiator will always help and more cold air flow will always help Quote Link to comment Share on other sites More sharing options...
xsspeed Posted July 13, 2009 Share Posted July 13, 2009 water takes time too cool and if its forced through the cooler too fast then its going back to intercooler 2 warm, and if its too slow then it will be getting too hot in the intercooler. so there will be a optium flow rate. a bigger radiator will always help and more cold air flow will always help yep there will be an optimum flow of the primary fluid through the radiator, will depend on factors such as coil size/fin size, how many passes etc. Can't remember theory off the top of my head, should have something at work about it Quote Link to comment Share on other sites More sharing options...
84_S12 Posted July 14, 2009 Share Posted July 14, 2009 eke_zetec_rwd sums it up Rejecting more heat thru the radiator means you increase the ΔT between the hot air from the turbo and the entering water temperature at the intercooler. Heat is not being rejected at the pump, or any of the interconnecting pipework really either, so the time spent by each litre per second of water in the heat exchanger, where again there is a ΔT between the airstream and the heated water from the intercooler is a critical figure unique to the heat exchanger used. Bear in mind too that the specific heat capacity of water is many many times higher than that of air. Quote Link to comment Share on other sites More sharing options...
Brock-Lee Posted July 14, 2009 Share Posted July 14, 2009 I had a good think about this, the cooler setup will have an optimum flow rate, if you increase the flow over this rate its not going to negativly affect the cooling properties of the system. sure it will have less time in the radiator, but it will also be exposed to less heat in the intercooler becasue its going through faster and it will do more passes through the radiator and so compensate for less time spent each pass. putting a big fuck off pump in the system wont hurt, but it wont help cool better. *waits to be told otherwise Quote Link to comment Share on other sites More sharing options...
84_S12 Posted July 14, 2009 Share Posted July 14, 2009 The pump needs to be sized for the required rate of flow and the anticipated head or it will cavitate and kill itself, or never achieve/maintain flow as required. The point of best efficiency (BEP) for a pump is smack bang in the middle of it's efficiency curve. Fans also show similar characteristics, and demonstrate very different performance running in free air or correctly ducted/shrouded. Quote Link to comment Share on other sites More sharing options...
Brock-Lee Posted July 14, 2009 Share Posted July 14, 2009 the head in a w2a system can be negated, it will be enough to keep the pump primed and thats all. Required rate of flow is a bit of an unknown as he is using a bit of a mish mash of parts. IMO it would be better to go for a big pump that you know is going to flow over the "optimum" rate and then you are safe. Quote Link to comment Share on other sites More sharing options...
84_S12 Posted July 14, 2009 Share Posted July 14, 2009 Running an oversized pump achieves greater required input power and a reduced lifespan. Nothing more. It is however possible to partially bypass the pump to reduce head pressure (This principle is commonly used in refrigeration systems to control refrigeration effect, and sometimes in jetboat jet units to maintain efficiency at differing speeds) With an undersized pump you can usually stop cavitation installing an I/R valve or flow regulator on the discharge side of the pump to bring it back on it's curve. You could then use whatever radiator is practical and adjust flow to suit based on your pump selection. Quote Link to comment Share on other sites More sharing options...
Brock-Lee Posted July 14, 2009 Share Posted July 14, 2009 agree on greater power input but when you're looking at a ~200rwkw setup 1-2hp gets lost pretty fast , why shorter lifspan? Quote Link to comment Share on other sites More sharing options...
84_S12 Posted July 14, 2009 Share Posted July 14, 2009 Please review the edited post lol Bearings take a hammering and so too does the impeller and seals. Put it this way: Energy in = Energy out so if you are putting a lot of electrical energy into a pump that is not converting that energy into water movement, where does the energy go? Heat and vibration, both pump and motor killers. I say if you are going to engineer something that is to protect what is important to you (ie the car's engine in this case) then do it right. Quote Link to comment Share on other sites More sharing options...
Brock-Lee Posted July 14, 2009 Share Posted July 14, 2009 I must be missing somthing lol. the whole reason for fitting a bigger than neccesary pump is to increase water velocity to above an optimum rate. there fore lots of energy in(big pump) = lots of enegry out(large water velocity). I agre 40000% on doing shit right, but apart from a small increase in parasitic loss I fail to see how fitting a large water pump is going to hurt this build. and to think, I started this thread with a silly comment made in spam Quote Link to comment Share on other sites More sharing options...
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