[mech]

Hey guys,



I know I post a ton of questions, but its fun <img src="/forum/images/smilies/968/smile.gif" class="smilie" alt="" />



Im going to helping a friend install an eletiric water pump on his 13b motor, which has got me wanting to do it on my car, I don't know when the previous owner changed the current pump so its time to at least replace it.



here is the eletric unit im looking at



http://www.daviescraig.com.au/main/display.asp





looking at this image







no belts will haft to be altered, but here the question



Does the current pump mount against the engine, or are there internal connections that im going to need to deal with, from this picture it does not look like it







I know there will be only a small performance gain but the big gain should be reliability



what do you guys think

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[flash]

i know a few people who have done this kind of thing - they have all since gone back to mechanical pumps or one reason or another



on the topic of additional power, i think i would have to do some math - need to know current draw of the pump so i could calculate horsepower to run - and then i would need to figure out how much horsepower the stock pump uses



as for reliability, not so sure i would trust an electric pump - i would need to know things like flow rating of the exisiting pump, flow rating of the electric pump, and the electric pumps ability to adjust flow for rpm



the mechanical one has only the bearing and seal to worry about - the electric one has those AND a motor AND wiring AND a fuse



because i am running underdrive pulleys, i couldn't do this



check this one out carefully - a lot of things to consider and change for 3 or 4 horsepower

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[Greimann]

Replacing the existing pump with an electric one is pretty much impossible. The pump pulley is driven by the timing belt and re-engineering this setup would require a major revision to the entire front of the motor. Your picture of the belts crops out the actual pump and pulley.

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[flash]

just to be clear - the people i was talking about did it on different cars - not a 968



the internals are a nightmare to be sure, though i'd love to see somebody do it successfully - it would put me one step closer to a chain instead of a belt in there

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[mech]

[quote name='Greimann' date='Apr 13 2005, 10:21 PM']Replacing the existing pump with an electric one is pretty much impossible. The pump pulley is driven by the timing belt and re-engineering this setup would require a major revision to the entire front of the motor. Your picture of the belts crops out the actual pump and pulley.

[right][post="3223"]<{POST_SNAPBACK}>[/post][/right][/quote]





i did not see that, but it increases the difficulty more than I anticipated...



i could gut the current waterpump and leave just the pulley assembly, that would keep the timing belt properly set, but i have to see how its pulley is connected to the turbine, this might introduce other problems, anyone got a old pump they wanna pull apart and take picture of the internals?



i originally got the idea from this page when looking for info for my friend,

http://www3.telus.net/haywire/RV-9/13b_r...ngine1.htm



this is for a 13b in an airplane, so reliability is an issue



the pump and controller

http://www.daviescraig.com.au/main/display.asp?pid=8

are pretty cool, the cost of both is a little under 350, but then the pump is only 200 after that which would reduce later costs



here is a review, the controller alters flow based on a specified engine temperture which can be adjusted via a knob, this system can be used as a supplemet to the current system, which is also interesting





http://www.fordmuscle.com/archives/2000/08...ump/index.shtml



specs on the pump

Technical Specifications:



Operating Voltage  4V DC to 14.5V DC



Maximum Current  7.5A



Flowrate20L to 80L/min, (300 gal to 1300 gal/hr) 13.5V DC



Operating Temperature  -20C to 130C (-5 F to 270 F)



Pump Design  Clockwise centrifugal with volute chamber



Motor Life  2000 hrs continuous at 80 C (180 F) and 12V DC



Pump Weight 900 grams (2lb)



Pump Material Nylon 66, 30% glass filled



Maximum Pressure tested to 50 psi



Fits Hoses Sizes 32mm to 50mm (1-1/4" to 2")

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[Greimann]

Put it this way, if you are good enough to pull this off, we have a little headlight project for you next <img src="/forum/images/smilies/968/smile.gif" class="smilie" alt="" />

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[mech]

[quote name='Greimann' date='Apr 13 2005, 11:55 PM']Put it this way, if you are good enough to pull this off, we have a little headlight project for you next  <img src="/forum/images/smilies/968/smile.gif" class="smilie" alt="" />

[right][post="3229"]<{POST_SNAPBACK}>[/post][/right][/quote]



ill give it my best, i cant help tinkering...



i need an old waterpump if someone has one they are willing to part with, that would be a great start, if I can get that prepared I dont think the other stuff will not be too difficult



I was going to get an MSD multispark iginition, but this project is more interesting

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[flash]

i still wonder how they plan to slow the pump down at lower rpms - that really needs to happen in a street car

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[mech]

here is the pdf about the system

http://www.daviescraig.com.au/documents/...%20Res.pdf

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[rustech]

What did you say Dave? Take lots of pictures? <img src="/forum/images/smilies/968/biggrin.gif" class="smilie" alt="" />

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[Greimann]

I certainly don't want to discourage anyone from tinkering. Heck, I have learned more from tinkering and having it go terribly wrong, than I would have if the effort was never put forth in the first place.



That said, I can think of several reasons why this is a bad idea for a street car and can't think of any reasons why this is a good one.



One is, a mechanical water pump is a very reliable device. No wires, motor, fuses to add to the complexity of a mission critical system. I think I have 99k miles on my original. They state that the motor life is 2000 hours. Lets say a lifetime vehicle speed average of 30 MPH, running 2000 hours takes you to 60,000. That average is a guess, but you can see the comparable life.



Two, they say you have to remove the thermostat. A thermostat performs two important functions: It establishes the minimum operating temperature of the engine and, it serves as a flow limiting orifice to create a dynamic pressure head in the system. This second function is important because increased pressure at high loads (and RPM) help to prevent steam bubbles at hot spots. The flow from the water pump backs up against the thermostat to create this pressure. Removing it can actually cause overheating.



Three, you have to remove the impeller. While it might be possible to do this, my guess is it may take some machine work beyond just getting out the grinder.



Afterall this, you still are only picking up 1-2 HP after figuring the electric motor uses .13 hp at full load. Think of it this way: do you think your lawnmower would have much trouble, given the right gearing, spinning the water pump to 7000 RPM? I don't think my 6.5 hp LawnBoy would break a sweat.

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[flash]

glad to see i'm not alone in my reservations - well said

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[mech]

thanks for all the great comments, they help a ton, I did not know that the thermostat keeps pressue in the system, if you have 90k on your water pump its time to get a new one <img src="/forum/images/smilies/968/biggrin.gif" class="smilie" alt="" />





i have found 3-4 more pumps with much higher flow and life span(anywhere from 30-55 gpm and some rated up to 7000 continous hours), i have been reading that an electric water pump is less likely to cause cavitation in the working fluid, a booster pump might be required to to keep the system at an acceptable pressure



there are defintly some issues to be worked out



im helping a friend out who is swapping a 13b rotary into a 914, , the cooling system is going to be one of the more difficult parts , we are still looking for a radiator to mount in the front of the car...



Once we get cooling system(including the electric pump) in the 914, which should be in the next month, ill be in a better situation to figure out how to work it out on my car



I have some huukups in a machine shop, once I can get an old waterpump to work with Ill tare it down and see how the impeller is attached to the pulley axel...

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[flash]

contact 968gene - he did this kind of thing with a 215 V8 in a 914 - he found a cool radiator setup

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[mech]

[quote name='flash' date='Apr 14 2005, 01:16 PM']contact 968gene - he did this kind of thing with a 215 V8 in a 914 - he found a cool radiator setup

[right][post="3252"]<{POST_SNAPBACK}>[/post][/right][/quote]





thanks! I just pm'ed them...



The swap we are doing will hopefully result an amazing car, its a 13b turbo rotary with ~270 HP (not much torque) into a 914...

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[Cloud9...68]

Very interesting discussion, but I would tend to agree with Dave and Flash that an electric water pump is probably a lot more work than the tiny horsepower gain would justify.



To me, a mod with much more bang for the buck would be an electric AC. Not only would it reduce a ton of drag from the motor, but it would enable the use of a supercharger without sacrificing AC. Hybrid vehicles are already using electric AC, and it sounds like a much more straightforward mod in principle.



Another interesting concept (to me, at least) is electric power steering. This is beginning to be offered in several new cars, and I've read that it will completely replace its mechanical counterpart in a few years. This would probably be much harder to retrofit to a 968, and would have less impact on engine load than electric AC, but it's interesting nonetheless.



Nice to see there are people thinking about ways to keep the 968 cutting edge <img src="/forum/images/smilies/968/smile.gif" class="smilie" alt="" />



Andy N

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[KensCab]

OOOoooo, a 'water pumper' 914... that should have some of the oldtime purists rolling over.

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[mech]

cloud9

I have been toying with the a/c compressor idea, I think the new hybrids use a 144 volt eletrical system, but i havent looked in more depth, but I might be able to get one from a previous generation



kensCab - the 914 will be a really interesting car when its done

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[Greimann]

One thing about looking to reduce parasitic loss on the AC compressor, you can also simply turn it off under full throttle with a micro switch. Afterall, that is the whole point of tweaking for power, WOT.

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[Cloud9...68]

[quote name='Greimann' date='Apr 15 2005, 08:21 AM']One thing about looking to reduce parasitic loss on the AC compressor, you can also simply turn it off under full throttle with a micro switch. Afterall, that is the whole point of tweaking for power, WOT.

[right][post="3287"]<{POST_SNAPBACK}>[/post][/right][/quote]



Hmmm... You mean a switch that's activated by the gas pedal when it's floored? Interesting idea...



But I'm more intrigued by the concept of an electric AC as a means to allow supercharging without "losing your cool." Not that I'm planning on adding forced induction anytime soon; right now I'd just be happy to get rid of the hesitation I'm experiencing.

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