Water Pump Modification
 

Interesting thoughts brought up by Snrub in the Canadian forum, some of which I had been meaning to ask over here.

(Special thanks to renns for the free parts :p: )


Well, I went ahead and tore apart a water pump.

Heres some pics.

(I'll be posting information with pictures, so do your best to not interrupt me until you see my last post where I will say I'm done posting pics. :p: )

Pump housing:
https://www.rx7club.com/forum/attach...postid=2023553

One thought I had would be is does anyone think there would be anything to be gained by modified fins on the pump itself?

Have a look.

https://www.rx7club.com/forum/attach...postid=2023577

(*Cough* - Better view of the fins maybe in the 1st pic.. Stupid cheap digital camera..)

Polish the surface of the fins and knife edge their backside.

Cavitation is caused by excessive turbulence- the above mentioned will cut the turbulence down.

Another thought I had was:

"YAY! I can make a pulley without the stupid bell-shape sticking out (for the clutch fan)"

https://www.rx7club.com/forum/attach...postid=2023595

But to my dismay..

No

The shape of the pulley puts the bearings in the correct position relative to the loading on them (by the belts).

I would leave that alone in fear of short waterpump bearing life if it was messed with.

Re: Water Pump Modification
 

If the forum wouldn't timeout EVERY time I upload it wouldn't be so bad.. :(

NOT done..

STUPID SERVERS.

I am forced to to use my own hosting, where they will turn to big fat X's in mere weeks. So much for having pics for anyone who uses search! ;)

OK.

http://members.rogers.com/thecheat/wpmp7.jpg

I realized that you have to retain the shape, due to the pump design itself. Not worth messing with.

:)

Just spit it out and then post pics:p:

Finally:

http://members.rogers.com/thecheat/wpmp11.jpg

The pulley (in your hand) is very light, and where it mounts is fairly thin.

Machining new one(s) wouldn't be too tough I don't think.

A larger diameter pulley would result in a slower spin, which in turn would be better for higher RPMs, right?

One important thing I forgot to mention was this is for cars who see higher RPMs than most daily drivers. Snrub noticed his car got much hotter while racing at the track, and this is how the topic came about. A more efficient pump at higher RPM.

One thing I wanted to know (if anyone knows) is what is the most efficient engine speed (in turn, making the pump speed) for the most flow? Or is anything closer to idle speed best?

Would a bigger pulley (depending on how much bigger) make a big difference? I would think that it would, however thoughts are always welcome (yep, I'm done posting pics). :)

Edit: Radical Idea. Shave off 3 of the 6 fins on the inside of the pump? :D Comments! Now! ;)

If mazdacomp made a waterpump I bet it would be suitable for higher rpms...

If they made one?

I'd much rather modify my own if possibly to improve it any.. However if modifying a stock one yeilds next to nil for results, then I would have to get another one..

^

I did some EXTENSIVE searching and found the following:


Sounds like a reasonable solution.

I don't think removing fins would be a good idea. You could end up with more turbulence than when you started. Fluid dynamics is not intuitive.

Decreasing the speed of the water pump would probably be the best way to go (if you didn't want to do the polishing thing.)

:rolleyes: I saw that.

I'm not accepting one response as "the answer". I'm looking for thoughts or input on modification.



My thoughts exactly.. I'm not sure how much the polishing would help.. but then again I'm not an expert on the topic.. any more thoughts are appreciated. :)

Underdrive pullies.

I guess if the blades were more steamlined and polished when they cut into the water they would cause less disturbance and have less resistance so it would use less power to turn? I don't know too much about this stuff so just throwing it out there and keeping post alive

:boink:

Cavitation is caused by low pressure areas behind the impeller blades. I doubt you're going to remedy that with any modification you could make to the impeller.

Rob

You find a cure for impellar cavitation and the World will make you a rich man!!!

Ya, they sell these you know....

I thought of this already. Alternatives?

Duh.. :flipoff: :)

This is not necessarily for my own application. Perhaps a replacement pulley that can be installed before going to the track, and can be replaced. Removing the pulley itself is not a tedious task.

I would have liked to hear thoughts on preventing cavatation, but looks like theres no real solution I haven't heard before this.. :(

Modifying fins was just something that popped into my head, hence "radical idea". :p: Bad idea then, I take it?

Also:

Electric water pump won't cavitate...

Since he put my post in here, I still want to know if changing the pully is going to effect the cooling if I'm boosting for prolonged periods on the highway in the 3-4k range. :)

Anyone make one? Tough to install at all?

Sounds like an excellent mod for a track car! :)

Not for street use obviously.. At least I wouldn't imagine.. could it? :scratch:

May sound silly to the rotary community (seen it done on V8 drag cars), but, how about an electric motor (mount to stock air pump location?) with a small belt to power the pump?

May be something worth looking into for anyone who drives it on the road and doesn't mind doing a quick mod before seeing the track every now and again..

Again this isn't exactly for my purposes but for anyone else who may be seeking something of the like (eg - Snrub) :)

They are fine for street use and are used all the time on piston engines (not just drag cars).

I don’t see why it wouldn’t work, seeing as thought the 13b doesn’t flow any more coolant then a large piston motor.

The problem is finding one for your car. Current draw may be another issue if you are using the stock alt and have other elc. accessories.

An electric WP for my TA runs about $150. Typically the pumps are mounted on the stock water pump housing and either use the existing impeller or come with their own.