CSR water pump question
03-13-2008, 09:08 PM
#17
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Location: Central Cali.
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A stock mechanical waterpump does outflow a the CSR while driving. The CSR flows a static 37GPM, a stock mechanical pump under load will flow around 45gpm or a little more depending on your RPM range. The mezierre pump I believe is rated at a higher gpm. I noticed this on my car as well, at idle it runs cooler, but under load it is a little warmer.
On the highway my cars turning 2500-3200, I'm not sure what the stockers putting out at that rpm but I'll bet it's more than 37gpm.
Maybe the people that say it runs the same don't run steep gears?
03-13-2008, 09:39 PM
#18
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I am so happy to see I am not the only one who understands this.
03-13-2008, 09:53 PM
#20
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you make no sense.
get an exchange if you think it's not right. you should be cooler or better than stock. check your rad for buildup, check your t-stat and make SURE it's working...put it in boiling water. check your stat housing for crap in there that can cause a blockage.
it's been known that t-stats are bad in the box...could be your prob. also, anything electronic MAY be bad from the box. ya never know. but if you tested the unit with a switch directly and it worked, you probably have other problems........
you havent tried any 'home remedy trix' like eggs or pepper have you? i'll go ahead and call you an idiot now IF YOU DID... otherwise, keep troubleshooting.
get an exchange if you think it's not right. you should be cooler or better than stock. check your rad for buildup, check your t-stat and make SURE it's working...put it in boiling water. check your stat housing for crap in there that can cause a blockage.
it's been known that t-stats are bad in the box...could be your prob. also, anything electronic MAY be bad from the box. ya never know. but if you tested the unit with a switch directly and it worked, you probably have other problems........
you havent tried any 'home remedy trix' like eggs or pepper have you? i'll go ahead and call you an idiot now IF YOU DID... otherwise, keep troubleshooting.
troubleshooting what? Can I call you an idiot for either quoting the wrong person or just not making a dimes worth of sense? What's with this "don't say anything at all..." bit when no one is bickering other than you?
I have no probolems with the cooling of my 396 and have not noticed any difference in temperature fluxuation while driving.
03-14-2008, 12:52 AM
#22
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Location: Seattle, WA
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Stock pump flow rates can be found in the SAE paper on LT1's published in the mid 90's. I think I have a copy...
this data was unusually helpful to open road racing guys who do sustained runs above 6000 rpms. It seems the stock pump increases flow rates linearly with RPM until about 5500 rpms, flat lines a bit later (until ~6000 I think), and then flow rates start to drop due to cavitation.
A SINGLE e-pump is a poor solution for these guys due to the lower flow rates, although I have heard them talk about an e-pump with a booster pump in line with no thermostat (to ensure constant radiator water flow). Not sure if anything came of it, but they were also talking about fitting a less aggressive impeller that could flow a bit less and avoid cavitation up to 7000rpms.
this data was unusually helpful to open road racing guys who do sustained runs above 6000 rpms. It seems the stock pump increases flow rates linearly with RPM until about 5500 rpms, flat lines a bit later (until ~6000 I think), and then flow rates start to drop due to cavitation.
A SINGLE e-pump is a poor solution for these guys due to the lower flow rates, although I have heard them talk about an e-pump with a booster pump in line with no thermostat (to ensure constant radiator water flow). Not sure if anything came of it, but they were also talking about fitting a less aggressive impeller that could flow a bit less and avoid cavitation up to 7000rpms.
03-15-2008, 11:22 AM
#23
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The SAE document is where I got the info.
Also important to not the electric flow rates are free flow not restricted as they would be on the engine. At 6000rpms on the engine the stock was about 66gpm, by 3000rpms it is like 32gpm as restricted by the engine.
Also important to not the electric flow rates are free flow not restricted as they would be on the engine. At 6000rpms on the engine the stock was about 66gpm, by 3000rpms it is like 32gpm as restricted by the engine.
03-15-2008, 12:17 PM
#24
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If you are referencing SAE 920673 "New Generation Small Block V8 Engine", the charts for water pump flow are plotted as a function of pump RPM, not engine RPM (e.g. - 11 GPM @ 1,000 RPM; 20 GPM @ 2,000 RPM; 31 GPM @ 3,000 RPM; 40 GPM @ 4,000 RPM; 51 GPM @ 5,000 RPM; 64 GPM @ 6,000 RPM).
What is the ratio of water pump RPM to engine RPM?
What is the ratio of water pump RPM to engine RPM?
03-15-2008, 03:24 PM
#25
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If you are referencing SAE 920673 "New Generation Small Block V8 Engine", the charts for water pump flow are plotted as a function of pump RPM, not engine RPM (e.g. - 11 GPM @ 1,000 RPM; 20 GPM @ 2,000 RPM; 31 GPM @ 3,000 RPM; 40 GPM @ 4,000 RPM; 51 GPM @ 5,000 RPM; 64 GPM @ 6,000 RPM).
What is the ratio of water pump RPM to engine RPM?
What is the ratio of water pump RPM to engine RPM?
Is the chart rated at pump rpm or engine rpm?
Either way those GPM numbers seem low.
03-15-2008, 04:02 PM
#26
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But the pump does not turn at cam RPM. You have to take into consideration the diameter of the gear on the back of the cam sprocket, and the diameter of the gear on the pump drive shaft. Since the gear on the back of the cam sprocket is larger than the driven gear on the driveshaft, pump RPM will exceed cam RPM. Maybe they made the ratio 2:1 to bring the pump back up to crank RPM. Looking at photos of the gear on the back of the cam, and of the pump shaft gear, it looks like it may be a ratio greater than 2:1, which would cause pump RPM to exceed crank RPM... but I don't know, that's why I asked.
The numbers I quoted are out of the SAE paper, prepared by a GM engineer. They are taken from small graphs, not from tabular data, so they are probably +/- 2 GPM.
The numbers I quoted are out of the SAE paper, prepared by a GM engineer. They are taken from small graphs, not from tabular data, so they are probably +/- 2 GPM.
03-15-2008, 10:44 PM
#28
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I couldn't find a spare water drive laying around, but if you have the time to count teeth: 
I "think" I got them all:
39 teeth on the Water Pump drive unit
99 teeth on the cam drive sprocket
------------------------------------
2.538:1 ratio between water pump and cam. (99/39)
2:1 ratio between cam and crank (any 4-stroke)
-------------------------------------------------
1.269:1 ratio between LTx water pumps and crank.
11 GPM @ 1,000 pump RPM (787 crank RPM)
20 GPM @ 2,000 pump RPM (1576 crank RPM)
31 GPM @ 3,000 pump RPM (2364 crank RPM)
40 GPM @ 4,000 pump RPM (3151 crank RPM)
51 GPM @ 5,000 pump RPM (3940 crank RPM)
64 GPM @ 6,000 pump RPM (4727 crank RPM)
which is right on par with what the road racer's are seeing... GPM starts to drop due to cavitation above 6000 rpms... or 7615 pump RPMs.
One solution I guess could be a new cam sprocket and water pump gear that reduce the ratio closer to 1:1 ratio between crank and pump RPMs... but then you risk really low flow rates at idle (and good luck getting anyone to invest in tooling for such a LT1-specific piece)
e-pump is fine for everything but sustained (several minutes) high-rpm racing... a second inline e-pump and thermostat delete would be in order at that point. But really, this is in extreme examples only.
I "think" I got them all:
39 teeth on the Water Pump drive unit
99 teeth on the cam drive sprocket
------------------------------------
2.538:1 ratio between water pump and cam. (99/39)
2:1 ratio between cam and crank (any 4-stroke)
-------------------------------------------------
1.269:1 ratio between LTx water pumps and crank.
11 GPM @ 1,000 pump RPM (787 crank RPM)
20 GPM @ 2,000 pump RPM (1576 crank RPM)
31 GPM @ 3,000 pump RPM (2364 crank RPM)
40 GPM @ 4,000 pump RPM (3151 crank RPM)
51 GPM @ 5,000 pump RPM (3940 crank RPM)
64 GPM @ 6,000 pump RPM (4727 crank RPM)
which is right on par with what the road racer's are seeing... GPM starts to drop due to cavitation above 6000 rpms... or 7615 pump RPMs.
One solution I guess could be a new cam sprocket and water pump gear that reduce the ratio closer to 1:1 ratio between crank and pump RPMs... but then you risk really low flow rates at idle (and good luck getting anyone to invest in tooling for such a LT1-specific piece)
e-pump is fine for everything but sustained (several minutes) high-rpm racing... a second inline e-pump and thermostat delete would be in order at that point. But really, this is in extreme examples only.
07-30-2009, 02:11 PM
#30
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Join Date: Aug 2005
Location: Tampa, FL
Posts: 416
You need to cut 3 reliefs on the housing so the screws line up. I ran a csr for 2.5 years before it nearly started an elctrical fire in my car. It seized up because of dirt. Make sure you keep the pump clean and seal off the front cap with silicone. The outside of the pump is not not sealed and will let dirt inside of it. I went with the Mezeire HD electric pump after. With the CSR it would run about 170-195. With the HD Meziere it runs a solid 170. Both with a 160 stat
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