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MG MGB GT V8 Factory Originals Technical - Water pumps
|Anyone know what the throughput in gallons per minute of a standard V8 water pump is?|
Anyone know of souces of high performance water pumps - especially in the UK?
Anyone know of sources of electric water pumps - especially in the UK?
How do electric water pumps work? Do they replace the mechanical one? If not, doesn't a double pump setup mean one of the pumps is impeding the other?
I have looked into this hoping to find an electric water pump that would protrude less toward the radiator with no luck. None are made for the BOP/Rover, just Chevrolet and Ford and even then the electric motor extends further forward than the standard unit. On one of the other BBS subjects someone pointed out this manufacture of a universal electric water pump. http://www.daviescraig.com.au/ It plumbs between the radiator and the existing water pump after removing the impeller.
|George - here's another site which has an electric pump which is apparently made for the Buick small block and so which should fit. On the other hand, I don't know whether its external dimensions are too big http://www.centuryperformance.com/detail.asp?Product_ID=MZE-WP125 I understand the additional advantages of electric pumps but what I still don't know is what is the throughput of water on a standard mechanical pump? On the Century Perfromance site above, they are claiming 35 GPM for their standard pump and 55 GPM for their high performance one. The mechanical ones done by Stewart appear to reach as much as over 100 GPM at some revs!|
It all doesn't mean a great deal to me without understanding what it is I am trying to improve on.
Also, I imagine that if one starts increasing throughput, then one is increasing pressure and therefore putting stress on other parts of the system, such as hoses.
I believe Real Steel sell an electric pump (no web site) but advertise in Kit Car (I have the tel no at home).
Good test of coolant system today.
|I was on the telephone to Real Steel anyway, as it happens but they don't sell an electric pump. On the other hand, Demon Tweeks does, made by Craig Daivies in Australia. The throughput for that one is claimed to be about 250 gallons per HOUR. It is £120 plus £80 for a thermostatic controller. Compared with Stewarts mechanical fans which reckons over 100 gallons per MINUTE at 4000 revs or 55 gallons per MINUTE for an electric one by Meziere from Century Performance Center, I'm getting quite confused and worrried about the colossal differences in performance. As I've asked on another related thread, what are the throughput figures for the stock mechanical water pump? No one has come up with a response and there appears to have been no discussion of this recorded in the archive. I don't have the knowledge or the equipment or the place to start making my own measurements. Overheating seems to a problem that is signicant in the V8 MGB world. I'm quite surprised because it seems to me that this approach could produce a permanent scientific fix.|
|For some reason I thought electric water pumps were _strictly_ for race cars. Not so? I like that Century Performance place -- the owner is very knowledgable and helpful -- but they are quite expensive.|
By the time you rig an electric water pump and one or more electric fans to boot, I guess you're talking about a bigger alternator almost by definition. Anyone know of one that just pops in to a factory-type setup?
|My understanding now is that:|
1) The quicker the coolant is shunted around the system, the more cooling takes place.
2) High pressure is essential to the cooling as pressurised water can hold more heat. Once it becomes steam (at its vapour point) then it stops cooling the system
3) When the engine is switched off, there is a short while during which there is no circulation of coolant but residual heat is still building up around the cylinders. This is called heatsoak and apparently can go to very high temperatures. This can cause damage but I suppose it is quite rare. Anyway, an electric pump will continue to circulate the water after the engine has stopped thus avoiding heatsoak.
4) When electric fans continue after the engine has been swtiched of, they are merely cooling water in the radiator and this does not prevent heatsoak without an electric pump working alongside.
Those Stewart figures seam dubious even if US Gallons, surely they must mean per hour.
I've been checking cooling fans - The 16inch Rainbow Products fan is 3000cfm compared to Kenlowe at 2320cfm, but is Rainbow Products fan for 24 volts?.
Recent thread - Upgrading Factory V8 Alternator gives some alternatives.
I agree that the figures seem incredible, but they use Gallons per minute throught out their website. Even the electric pump by Meziere is quoted in gallons per minute both by the manufacturers and by suppliers. I really don't know what to make of it. I agree that the figure will be US gallons, but that only accounts for an aprox 13% difference. Anyway, the figures for the demon Tweeks pump may also be in US gallons for all I know and that would put us back to point zero.
What is the diameter of the Kenlowe? is it as large as 16"? Is it possible to fit 2 16" fans in front of a V8 radiator? Anyway, Fans are only useful up to a certain speed. After that it seems to me that they might impede airflow. I don't know what that speed might be but it wouldn't at all surprise me if it was quite slow - 20--30mph. After that, the fan should be switched off and in an ideal fan, there should be electronic braking to prevent it freewheeling. I don't think that any fans have electronic braking and I don't know how it could be introduced. I don't know whether this is a modification which could be made or whether this feature has to be built in.
The DT pump at 250per hour is about 4 per min. I reckon my outside tap is about 1 per min so this seams reasonable.
The Kenlowe dimension wise is the same but has a higher consumption 20.2 amps.
|Well I managed to get a look at the Demon Tweeks pump manual and the specifications as published. The flow rate is much higher than the DT staff told me on the 'phone. According to Davies Craig, the pump runs with an electronic controller which varies the speed of the pump commensurate with the cooling required. The flow rate apparently is from 300 GPH to 1300 GPH!! - and when you aren't using the car, you can use it to fill your swimming pool, I suppose. Anyway, that's a bit more in line with the other rates claimed for both high performance mechanical and electric pumps - although still much less as at top speed the DT pump is only doing about 21 gallons per minute. Small beer in the cooling world.|
All of this still leaves me wondering what the flow rate of the stock V8 pump is. I must say that the silence is deafening. I really had expected Roger Parker to come by now with the answer.
Roger, can you help?
Just checked Summit Racing site - They have a remote pump at 15GPM and others at 20GPM so I think Stewart missed a decimal point.
|Paul, I've posted a message onto Stewarts board - http://bbs.cartserver.com/bbs/a/4600/index.cgi asking them to confirm their rates. We'll see in a day or so.|
|"Stewarts flow rates should be in GPM like 80 gpm, which they are. It could be advertised as gph but it should be about 4800 gph to be comparable to 80gpm. fuel pumps and some elec low flow water pumps are in GPH flow rates." |
.. so now we know!
|... and here's the reply ...|
| "I'll take a guess that a stock pump is only in the 12 GPM at idle, up to about 30 GPM at cruising RPM" ....|
I suppose that the answer to overheating becomes fairly obvious, doesn't it. Here we are getting very high tech about engines, exhausts, brakes etc but when it comes to cooling, all we seem to do is to change the insualtion and add a bottle of water-wetter or cut a few holes on the bonnet. Very Neanderthal all of a sudden. Maybe overheating simply isn't sexy and cooling is just er, well just uncool.
|... and from the supplier of Meziere ...|
This thread was discussed between 23/06/2001 and 27/06/2001
This thread is from the archive. The Live MG MGB GT V8 Factory Originals Technical BBS is active now.