Topic: water pump impeller design

I have the option of two different pump designs and I don't know which one to use. The pumps spin clockwise and push water into the block. Which one would you think would push more water (flow better)? Ignore the rust and etc.

https://farm5.staticflickr.com/4674/39810380284_5a042478e5_z.jpg

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Re: water pump impeller design

Former cooling system engineer here.  The plastic one will likely flow better.  However, it is more fragile.  On a race car, doubt you'll see much difference in cooling performance between the two.  I would go with the metal one for durability.

Re: water pump impeller design

Both look to be metal?

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Re: water pump impeller design

They are both metal. So richv70, you think the top one with the closed disk impeller will flow slightly better? My thought was that the bottom one would flow more because the fins are deeper than the one on top. But honestly I have no idea.

Captain of AFART Racing - 1987 and 1988 Toyota Supras
Captain of McDads/AFART Racing -1977 Lancia Scorpion (IOE Winner Sears Pointless 2021... wait, really?? YES, REALLY!!).
Captain of 42 Hours of MeLons (2013-14) - Vattenmelon Vagn 1984 Volvo 240, B-Class Winner: Arse-Freeze 2014

Re: water pump impeller design

That flat plate will really increase the efficiency. The other one will have lots of bypass and turbulence.

6 (edited by -SDR- 2018-03-02 05:09 PM)

Re: water pump impeller design

Honda originally made the GL1000 and GL1100 GoldWings with a plastic impeller and then swapped to a metal one that looks like the bottom one in the photo. It was rumored from Honda that in addition to the plastic ones cracking the metal ones flowed better, but the plastic one "looked like" it would have flowed better.


Bill

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Re: water pump impeller design

They didn't just crack, they also then shredded their damn berings. Which coupled with a previous owner who thought "oh this hole under the water pump is dripping oil and coolant. I'll plug it up!" Equalled one long not very motorcycle filled summer for me last year while I rebuilt a replacement engine for my GL1100.

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Re: water pump impeller design

The 'new' style G/W is not perfect either.  Honda claimed that the silica in the car type coolant would eat the mechanical seal and that allowed coolant to bypass the seal.  The weep hole was designed to give any coolant that got past the water pump seal a place to go so it would not wind up in the crankcase.  Yep, lots of people would seal that hole.  Also, if any coolant drips from that hole there is coolant in the bearing, and after time it will cause the bearing to fail.  If it fails, then there is good chance it can seize, and if it does it can shear the oil pump drive.  I have had better luck buying rebuild kits for the pumps over buying new ones from Honda.

2020 I.O.E. CT #36 The Rootes Of All Evil,1958 Sunbeam Rapier Convertible (YES 1958!!) & 2019 Judges Choice NJMP
2016 Thompson Speedway #36 Sabrina Duncan's Revenge, IOE Trophy, 5th Place 'C' Class 1977 Ford Pinto
2009 Stafford Motor Speedway #16 Team Teflon, 11th Place (overall) 1997 Saturn SL2

Re: water pump impeller design

The pump on the top SHOULD flow better but like others have said I doubt its gonna be a huge difference.

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Re: water pump impeller design

My take is that at low engine speeds the "full impeller" may be more efficient but at higher speeds it won't make much difference.
I've seen  WP's with the "open" design come off an engine that is all OEM so even the OEM's use the "open" design.
If they use it, it can't be bad.

Re: water pump impeller design

One thing I forgot to note is that the depth (height?) of the impellers is also different. The fins on the closed plate one on top are about 13mm deep while the fins on the bottom open one are about 16mm. Seems to me that the bigger fins would push more water, yeah?

Captain of AFART Racing - 1987 and 1988 Toyota Supras
Captain of McDads/AFART Racing -1977 Lancia Scorpion (IOE Winner Sears Pointless 2021... wait, really?? YES, REALLY!!).
Captain of 42 Hours of MeLons (2013-14) - Vattenmelon Vagn 1984 Volvo 240, B-Class Winner: Arse-Freeze 2014

Re: water pump impeller design

How close the other side of the pump (engine block / pump back?/ pump intake?) is to the impeller also matters quite a bit.

The open fin design may fit better "into" the other side / back and may flow better.

If the block / back was mangled or chewed into from say a bad pump bearing previously, the covered style impeller may flow better.

There's also cavitation at high rpm to possibly consider if you had the means to investigate that.

You could use play dough type stuff (push little lumps in a few places in the receiving end of the impeller, install a pump w/o turning it, then remove) and see how close each impeller fits the other side. A light coat of oil on the impeller should keep the play dough from sticking to the impeller and making an unreadable mess.

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