Electric water pump on RV8

[steve-V8s]

Anybody on here tried taking the impeller out of the water pump and using an external electric unit on an RV8 ? I was gazing at the engine and wondering how I can shed a bit more weight. An obvious candidate is the alternator, with that gone the two belt idlers could go apart from driving the water pump. In addition to the weight loss the engine has less loading.

I know that may sound a silly idea but as the car is used for hill climbing it should do four runs on a single charge ok, particularly if it is started with an external battery.

[dbv8]

I see its common for trailered V8s at the drag strip to have all unnecessary belts removed and electric water pumps running.
I dont think you would want to rely on the electric pump on the road but for hillclimbing as for drag racing the electric pump is ideal and can be left running while the engine is off to aid cooling down in the pits before the next run.

[spend]

I've got a pre-serp water pump converted to run an electric pump, off a stripped lump. I guess you have a serp though?

[steve-V8s]

Yes it is a Serp. When you say converted to run electric do you mean the original pump but electrically driven or simply with the impeller removed so the external pump can feed the original casing ?

[spend]

steve-V8s said:

Yes it is a Serp. When you say converted to run electric do you mean the original pump but electrically driven or simply with the impeller removed so the external pump can feed the original casing ?

Impeller removed and all welded up as well as passages opened up. Just hacking out the impeller leaves a very restricted flow for the external pump, the one I have has had that area reasonably fettled. Just observations, no way I'd want to use one myself

[fatjon]

I have heard that the flow rate of these pumps, even the biggest Davies Craig ones, is far to low for even your average 2l plodding engine. I haven't tried one myself but it may be worth bearing in mind that the biggest one they do takes 10A at 12V so assuming 100% efficiency produces 120W of water shifting power. A standard engine driven pump consumes 5HP (ish) which is 3.7Kw!

[spend]

Try a JE alt bracket to get rid of the twirly belt rubbish..

If you are obsessed enough? swapping the water pump pulley for a larger one before competition will reduce pumping losses - but tickover will only shift a 'trickle'

[clarenceboddiger]

spend said:

Try a JE alt bracket to get rid of the twirly belt rubbish..

Can you expand on this please??

[spend]

The JE bracket allows the alt to swing to tension the belt rather than all the extra weight / belting / complexity with the tensioners, much like the pre-serp philosophy? KISS .

Several here use it with minimalistic crank / pump / alt implementations (note absence of PAS Pump, AC, extra twirly bits for belt engagement...) Graham W on one of his for sure and Ant on his Griff to name a couple..

[Guillotine]

I had this on the original race engine fitment. So left it on.

The electric pump also had a suplimentary pump to cope with capacity and the road trips (Ring/Spa and back) We got 404 bhp in that configuration, but as we had to lose power for PTW regs in the Challenge...it went.

Ran on mine for around 10,000 miles, but started p1ssing about.
The pump would stop (brushes I think) then would pick up again. I noticed it by the heater going cold but the temp gauge stayed where it was...very iffy. That was due to the water not moving so the (very) hot water from the block wasn't reaching the sender to tell you it was hot. A flow meter would be good if driving to events.
bear in mind that this was a unit that been sat around for a while.

It'll be good for a sprint car...got to be worth 5-10bhp besides the weight gain.

Andy
BTW, I had the original pump in there with the blades machined down.