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jtb0322 Member

Joined: 29 Jan 2012 Posts: 27
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Posted: Mon Feb 20, 2012 1:16 am Post subject: Water Pump Racing Modification |
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I have read somewhere in a magazine, I forget where, that circle track racers have taken the impeller out of the water pump and cut a few fins off of it to reduce drag put on the motor. I cannot find this article anywhere I look now but I know I have read about it. They said that on the track you are typically turning about 4000-6500 rpms and at that speed the water pump is actually pushing to much coolant through the motor. By eliminating some of the fins, this lightens up the stock water pump and reduces drag on the motor? Is this a good idea or not?
Also, does anyone sell a stock appearing ball bearing water pump?
Thanks!!!
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clay Moderator

Joined: 24 Nov 2002 Posts: 3209 Location: South Carolina 318129.23 points
1972 Chevrolet Nova
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Posted: Mon Feb 20, 2012 12:59 pm Post subject: |
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Not sure what you're asking about the ball bearing pump as all of them have ball bearings - no way they could survive belt tension for that long with anything else. Here in an excerpt from an article mentioning the modified water pump. You might try searching for "sealed engine" or "crate engine" as they have several tips that you might find helpful.
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The same goes for the coolant flowing between the block and the radiator. This tip isn't useful if you are allowed to use a racing water pump, but if you are using an OEM unit, you are likely pushing too much water through the block a lot faster than necessary. OEM pumps are designed to provide adequate cooling for street cars, which spend 90 percent of their time between idle and 3,000 rpm. Oval track stock cars are high-rpm monsters, and cooling during extended rpm periods at low rpm is not a concern. If you can get your water pump apart, cutting every second vane off the impeller will reduce water flow to more manageable levels-you'll just need to make sure your ducting and overall cooling system works effectively. Also, it's probably best to cut the vanes off on a milling machine. A hack job will unbalance the impeller and lead to power-robbing cavitation.
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Here is the link to the article.
http://www.circletrack.com/enginetech/ctrp_0405_legal_crate_motor_performance/viewall.html
I've never messed with modifying pumps - messing with street cars I'm' always interested in as much flow as possible at idle. Hope this helps. Clay
_________________ I have done so much with so little for so long, I can now do anything with nothing. |
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jtb0322 Member

Joined: 29 Jan 2012 Posts: 27
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Posted: Mon Feb 20, 2012 1:51 pm Post subject: |
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Thanks for the link to that article!! I knew I've read about that somewhere! Does anyone have any experience on doing this to a water pump? I'm trying to make the most out of what I have and a few little things like this can make a small improvement. I realize all water pumps have ball bearings so let me restate my question... Does anyone sell a racing quality pump inside of a stock appearing housing? Thanks for the help!
Does anyone have any other little tricks like this to reduce drag/friction on the motor and increase power?
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Big Dave Moderator

Joined: 04 Dec 2005 Posts: 2663 Location: Tampa Florida 120538.84 points
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Posted: Tue Feb 21, 2012 10:26 pm Post subject: |
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Most racers use a Stewart phase III or higher stage water pump as they move more water than stock pump (which is good) but at one third the horsepower drag of the stock pump (which is even better). It does this by using a CNC machined fully enclosed scroll instead of an open paddle wheel found in the stock pump. The Stewart pump has a larger diameter drive shaft (which requires opening the hole in your water pump pulley to BBC size) which is also used on the Corvette small block motor.
Big Dave
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motorman Newbie
Joined: 22 Aug 2002 Posts: 14 Location: Pa. 513.18 points
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Posted: Thu Dec 27, 2012 7:56 pm Post subject: |
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i remove every other fin from the impeller to prevent cavitation on high RPM race car engines
_________________ corvette owner since 1959,new vettes owned 59,62,63,64,65,66,97,99,02,05 and now 08, 08 sold waiting on a C-7. retired race engine builder and former NASCAR tech inspector |
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af2 Member

Joined: 01 Sep 2003 Posts: 5579 Location: grassvalley, ca 71896.24 points
1933 Willys Coupe
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Posted: Thu Dec 27, 2012 10:27 pm Post subject: |
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motorman wrote: | i remove every other fin from the impeller to prevent cavitation on high RPM race car engines |
So what do you do when it only has 5 impellers? Or 7 for that matter?
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motorman Newbie
Joined: 22 Aug 2002 Posts: 14 Location: Pa. 513.18 points
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Posted: Fri Dec 28, 2012 8:09 pm Post subject: |
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af2 wrote: | motorman wrote: | i remove every other fin from the impeller to prevent cavitation on high RPM race car engines |
So what do you do when it only has 5 impellers? Or 7 for that matter? | never saw that on a BBC water pump
_________________ corvette owner since 1959,new vettes owned 59,62,63,64,65,66,97,99,02,05 and now 08, 08 sold waiting on a C-7. retired race engine builder and former NASCAR tech inspector |
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Paul P Member

Joined: 15 Aug 2002 Posts: 2454 Location: Townsend, Mass. 83266.64 points
1971 Chevrolet Chevelle
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Posted: Fri Dec 28, 2012 9:07 pm Post subject: |
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af2 wrote: | motorman wrote: | i remove every other fin from the impeller to prevent cavitation on high RPM race car engines |
So what do you do when it only has 5 impellers? Or 7 for that matter? |
Not that it matters but this is what you would do.
If you have 7 that is easy take out 3 in a triangle.
If you have 5 you are kind of screwed.
Neither would work all that well. Get a pump designed for what you want like the Stewart. As previously mentioned earlier. I have the Edelbrock I know Smoke is not a big fan but I have had good luck with it. I'm not that concerned about the amount of power it takes to turn it. Good luck I think you have enough information here to make a good choice for your application.
_________________ 2001 Focus 2.0 Zetec
stock cams, bolt-ons and tune
15.63@87 MPH 1/4mi
1971 - Chevelle 408 SBC N/A
6.59@104.03 MPH 1/8mi
10.40@127.73 MPH 1/4mi
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motorman Newbie
Joined: 22 Aug 2002 Posts: 14 Location: Pa. 513.18 points
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Posted: Fri Dec 28, 2012 9:21 pm Post subject: |
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cavitation at high RPMs is the reason because a pump designed to cool a engine at 2000/3000 RPMs cavitates at 7500 RPMS unless it is modified. now days there are after market race pumps but years ago they were not available so as a engine builder you did what you had to do to cool the race engine
_________________ corvette owner since 1959,new vettes owned 59,62,63,64,65,66,97,99,02,05 and now 08, 08 sold waiting on a C-7. retired race engine builder and former NASCAR tech inspector |
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Paul P Member

Joined: 15 Aug 2002 Posts: 2454 Location: Townsend, Mass. 83266.64 points
1971 Chevrolet Chevelle
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Posted: Fri Dec 28, 2012 11:54 pm Post subject: |
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Like one of those plate kits that can be riveted to the impeller to help cavitation. Yup I agree there are purpose built pumps that have a greater rpm range and don't cavitate.
_________________ 2001 Focus 2.0 Zetec
stock cams, bolt-ons and tune
15.63@87 MPH 1/4mi
1971 - Chevelle 408 SBC N/A
6.59@104.03 MPH 1/8mi
10.40@127.73 MPH 1/4mi
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motorman Newbie
Joined: 22 Aug 2002 Posts: 14 Location: Pa. 513.18 points
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Posted: Sat Dec 29, 2012 12:08 pm Post subject: |
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those plates are used on stamped steel impellers that late model water pumps use and i was modifying cast iron impellers
_________________ corvette owner since 1959,new vettes owned 59,62,63,64,65,66,97,99,02,05 and now 08, 08 sold waiting on a C-7. retired race engine builder and former NASCAR tech inspector |
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Paul P Member

Joined: 15 Aug 2002 Posts: 2454 Location: Townsend, Mass. 83266.64 points
1971 Chevrolet Chevelle
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Posted: Mon Dec 31, 2012 9:51 pm Post subject: |
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If I remember way back that the plates were for the older cast impellers to make them efficient like the newer plate type impellers. You can't rivet to the edge of a steel impeller. Anyway they don't sell them any more I just looked. Sort of beating a dead horse at this point.
_________________ 2001 Focus 2.0 Zetec
stock cams, bolt-ons and tune
15.63@87 MPH 1/4mi
1971 - Chevelle 408 SBC N/A
6.59@104.03 MPH 1/8mi
10.40@127.73 MPH 1/4mi
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motorman Newbie
Joined: 22 Aug 2002 Posts: 14 Location: Pa. 513.18 points
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Posted: Mon Dec 31, 2012 11:27 pm Post subject: |
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cast iron impellers were solid on the back side not open like the stamped steel ones because they bent the metal to form the blades which caused the openings
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_________________ corvette owner since 1959,new vettes owned 59,62,63,64,65,66,97,99,02,05 and now 08, 08 sold waiting on a C-7. retired race engine builder and former NASCAR tech inspector |
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Paul P Member

Joined: 15 Aug 2002 Posts: 2454 Location: Townsend, Mass. 83266.64 points
1971 Chevrolet Chevelle
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Posted: Wed Jan 02, 2013 1:27 pm Post subject: |
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That's what I was looking for and couldn't find. Thanks. I am having a senior moment. Sorry .
As a tech inspector you must have seen some stuff most of us could not even dream up. Again my apologies for my reverse thinking on the application of the old plates.
_________________ 2001 Focus 2.0 Zetec
stock cams, bolt-ons and tune
15.63@87 MPH 1/4mi
1971 - Chevelle 408 SBC N/A
6.59@104.03 MPH 1/8mi
10.40@127.73 MPH 1/4mi
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motorman Newbie
Joined: 22 Aug 2002 Posts: 14 Location: Pa. 513.18 points
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Posted: Wed Jan 02, 2013 5:52 pm Post subject: |
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no problem as at my age 78 i have CRS "can't remember s--t" some times
_________________ corvette owner since 1959,new vettes owned 59,62,63,64,65,66,97,99,02,05 and now 08, 08 sold waiting on a C-7. retired race engine builder and former NASCAR tech inspector |
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