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MS-75 Regular Location: Adelaide Registered: June 2002	Re: thoughts on barrel coolers??? Thu, 10 February 2005 07:59 Hi there 6BOOST, sorry for the delay-I just needed to find time to put a decent response together to fully explain why restriction is important in a centrifugal pumping system. Here goes- Just slowing the pump down won't have the same effect as generating some pump outlet pressure. Centrifugal pumps require some pressure head to work properly. In an engine cooling pump the system resistance is provided by the thermostat general cooling circuit-although the design of many factory water pumps is truly terrible. (In many factory cooling systems as soon as the engine temp comes up and the engine is given any decent revs the impeller is just cavitating in foam. You can see this by taking pressure readings before and after the pump, and once cavitiation begins the outlet pressure drops through the floor. This is why the external electric water pumps work so well-they are not controlled by engine revs and so you can avoid the high pump speeds that cause the impeller to cavitate. They also have good curved type impellers like a turbo, not the shitty straight pressed steel cavitation specials fitted to many factory cars. All the sharp edges are what cause small regions of low pressure in the hot moving fluid which then causes the fluid to boil instantly-known as cavitation-and the engine pump doesn’t pump a foamy froth too well at all…………&am p;#8230;. Anyway-I digress) Keep the pump running flat out, and then slowly increase the restriction post pump outlet by slowly closing a valve (1/2 or 3/4 inch black poly watering system tap). As a test, have the system operating open circuit with water, and have it emptying into a bucket (at the same level as the pump inlet-and don’t have the pump pulling from an elevated source as this can disguise results). Measure the flow rate, and you should see a rise as the restriction increases up to a point, and then it should fall away again as the resistance begins to hurt flow rate. The max flow is at the pumps max efficiency point for the given pump speed-just like a turbo(ie a centrifigal pump) If you have a look at a centrifugal pump curve (ie turbo comp map), you will see that trying to run a pump with a massive pressure ratio and incorrect mass flow will put you over the surge line. At the same time however, you’ll notice from the graph that running a pump with too little pressure ratio will also put you way outside the efficient operating range for the pump. (I only know this boring crap as I did a lot of pumping stuff at uni for my mining degree-there is a lot of shit to be pumped about at mines.) Aaaanyway, the lack of restriction diagnosis seems logical to me here at the end of a keyboard, but the proof will come with your testing. From what you described it sounds like the barrel cooler has a reasonable internally finned set-up giving a decent area, and you are running it in a counter current configuration which maximises temp differential and hence rate of heat transfer between the two fluids. It should work better than it does, and a bit of dicking about should bring the performance up a fair bit. Once you have the flow rate checked and maximised start taking temp difference measurements on the water inlet/outlet and air inlet/outlet just as SHINYBLUESTEEL mentioned before. Once you have a measured and proven flowrate it should all be a lot more clear what is going on. Are you using a radiator for the coolant in the system or a coil and ice bucket set-up? Send me some pics if you can, I’d be interested to see the setup, the inside of the core etc. Keep me posted if the restriction works-otherwise I’ll put together a few other suggestions and start crunching some numbers for you. I’m curious as I’d like to set one up on the crown in the next 6 months or so to make the intake charge temp less variable with atmospheric temp variations. Take it easy Sean PS-My big cube turbo engine is about to really get a wake-up-I take posession of an 800hp GT-42 in a couple of weeks. Fun fun fun fun…………&am p;#8230;…… [Report message to a moderator]

	Subject	Poster	Date
	thoughts on barrel coolers???	jcmunga	Wed, 02 February 2005 07:32
	Re: thoughts on barrel coolers???	YelloRolla	Wed, 02 February 2005 07:44
	Re: thoughts on barrel coolers???	jcmunga	Wed, 02 February 2005 07:55
	Re: thoughts on barrel coolers???	shinybluesteel	Wed, 02 February 2005 07:46
	Re: thoughts on barrel coolers???	680OST	Wed, 02 February 2005 11:29
	Re: thoughts on barrel coolers???	jcmunga	Wed, 02 February 2005 11:38
	Re: thoughts on barrel coolers???	680OST	Wed, 02 February 2005 11:35
	Re: thoughts on barrel coolers???	Allan	Wed, 02 February 2005 11:43
	Re: thoughts on barrel coolers???	jcmunga	Wed, 02 February 2005 11:46
	Re: thoughts on barrel coolers???	oldcorollas	Wed, 02 February 2005 11:55
	Re: thoughts on barrel coolers???	thechuckster	Wed, 02 February 2005 12:17
	Re: thoughts on barrel coolers???	shinybluesteel	Thu, 03 February 2005 04:07
	Re: thoughts on barrel coolers???	Allan	Wed, 02 February 2005 11:52
	Re: thoughts on barrel coolers???	YelloRolla	Thu, 03 February 2005 05:24
	Re: thoughts on barrel coolers???	680OST	Thu, 03 February 2005 22:34
	Re: thoughts on barrel coolers???	680OST	Thu, 03 February 2005 22:43
	Re: thoughts on barrel coolers???	shinybluesteel	Thu, 03 February 2005 23:45
	Re: thoughts on barrel coolers???	Joshstix	Thu, 03 February 2005 23:55
	Re: thoughts on barrel coolers???	680OST	Fri, 04 February 2005 02:14
	Re: thoughts on barrel coolers???	oldcorollas	Sun, 06 February 2005 11:40
	Re: thoughts on barrel coolers???	MS-75	Fri, 04 February 2005 20:38
	Re: thoughts on barrel coolers???	680OST	Sun, 06 February 2005 11:15
	Re: thoughts on barrel coolers???	shinybluesteel	Sun, 06 February 2005 11:42
	Re: thoughts on barrel coolers???	fatboy	Mon, 07 February 2005 06:42
	Re: thoughts on barrel coolers???	YelloRolla	Mon, 07 February 2005 06:56
	Re: thoughts on barrel coolers???	fatboy	Mon, 07 February 2005 08:00
	Re: thoughts on barrel coolers???	680OST	Wed, 09 February 2005 08:36
	Re: thoughts on barrel coolers???	jcmunga	Wed, 09 February 2005 08:57
	Re: thoughts on barrel coolers???	mrshin	Wed, 09 February 2005 12:14
	Re: thoughts on barrel coolers???	MS-75	Thu, 10 February 2005 07:59

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