Water temp drop through radiator

Allan Litten · Joined: 29 Nov 2006 Posts: 53

I have read somewhere that the water pump takes 0.3 hp to run at max rpm but I cannot remember where I read it.

Was that you Ian?

Ian Harrison · Posted: Thu Oct 11, 2012 10:30 pm Post subject:

Hi Guys

If you look at an electric pump that does the same job you can more or less imagine the figures for the engine pump.

I've used this exact pump and it's awesome!!

http://www.demon-tweeks.co.uk/motorcycle/water-pumps/davies-craig-ebp-electric-water-pump

click on specification and benefits:

Voltage 9-15V
Max Current 1.3 Amps

Max Wattgae - 19.5Watts

19.5 watts = 0.026 horsepower

i.e.e Not a lot!!

Even this monster only draws a max of 7.5 Amps = 112 Watts = 0.150 horsepower
http://www.demon-tweeks.co.uk/motorcycle/water-pumps/davies-craig-ewp80-water-pump

Is that better Andy Wink

Best Regards

Ian Very Happy

_________________
Ian Harrison
Viper Racing UK
www.viper-racinguk.co.uk
sales@viper-racinguk.co.uk
+44 7984 225 564
+44 161 343 2009
Championship winning Superkart race team 1997-2012

Andy Kiker · Posted: Fri Oct 12, 2012 5:49 am Post subject:

Glad to see you are back on top of things Ian.
That pump you listed was a little slow for us. We went to the one I list below. It draws more juice but has much better flow and is cheaper.
Cheers! Very Happy

http://www.siliconeintakes.com/product_info.php?cPath=12&products_id=1001&osCsid=5470a83850cc182863db156fb6b704dc

Not sure how I did the double post? Embarassed

_________________
Andy Kiker #24

Anderson Karts
WiWa GasGas
Powrpad

Ian Harrison · Posted: Fri Oct 12, 2012 10:01 am Post subject:

Greg Lindahl · Joined: 13 Jan 2011 Posts: 267

Still want to know: What's the temperature drop from rad in to rad out, for any application. A round figure would help... I'll know after the Sonoma race on T'day weekend but I'd sure like to know now.

Ian Harrison · Posted: Sat Oct 13, 2012 4:49 am Post subject:

Hi Greg

Best I can give you off my dyno this morning is 55 deg C in the normal top hose temp sensor towards the back rad and 35 deg into the engine water pump (Anderson/CR250).

I put the second temp sensor into the bleed screw hole on 'U'-Pipe that feeds into the intergral pump inlet (CR250).

However, this is a twin rad setup (rear and side) and the cooling is nothing like as good on the dyno as it is on the racetrack at speed.

Obviously as the engine gets hotter and the ambient air gets cooler, the temperature gradient gets steeper and heat transfer is more rapid.

Best I can do in the time. Hope it helps Very Happy

Best Regards

Ian Very Happy

_________________
Ian Harrison
Viper Racing UK
www.viper-racinguk.co.uk
sales@viper-racinguk.co.uk
+44 7984 225 564
+44 161 343 2009
Championship winning Superkart race team 1997-2012

Greg Lindahl · Joined: 13 Jan 2011 Posts: 267

Thank you Ian.
That's very helpful. A 20C increase while passing throught engine is quite significant, and the infeed side is quite cool. Both load size and how cool the return water is are interesting...

Erik Maxfield · Posted: Tue Nov 20, 2012 10:29 pm Post subject:

.02
I was thinking strongly about adding restrictions to the outlets of my 125 a couple of years ago. I was thinking primarily around reducing pumping losses (horsepower to drive the pump. I made some REALLY conservative calcuations around hydraulic horsepower and found that it was a silly pipe dream.

Adding restrictors in the return lines backs the pump on the curve and keeps it from cavitating (with an increase in RPM or a decrease in backpressure the flow goes up- the Net positive suction head required (NPSHR) of the pump goes up with increased flow rate)
That said,
I run with a giant barndoor in the wind (roadracing a 125) and was strongly considering building a diffuser box on the inlet side of the radiator to better reduce parasitic drag (much like most of the 250 brigade out here runs). That should help for a couple of MPH for use (we run into a wall around 106-108 MPH).
_________________
Erik
The early bird gets the worm.....
The second mouse gets the cheese....

Stock CR125.
Chassis-FrankenKART
Intrepid/ITAL combination

Chris Reinhardt · Posted: Wed Nov 21, 2012 5:23 am Post subject:

Greg Lindahl · Joined: 13 Jan 2011 Posts: 267

Hi Erik and thanks for the ME input WRT pumps, cavitation and losses: THAT explains why I found what was noted in the message above about choking flow and reducing temperature while experiencing no performance improvement.
On the subject of aero drag from the radiator; I've tested many inlet/outlet ducts to no real affect. However, I'm not finished with ideas and will continue testing until I either find a measureable drag reduction or determine that it's not worth the effort.
For this weekend, I have the radiator in full parachute mode and am gathering data for a winter project looking for an improvement in drag loss.
Come chat in garage 10...
Greg

Erik Maxfield · Posted: Wed Nov 21, 2012 9:49 pm Post subject:

Greg Lindahl · Joined: 13 Jan 2011 Posts: 267

I'll be measuring flow speed at the backside of the radiator on Saturday. Would like more channels on my Evo IV so more measurements could be made. I measure five temperatures and that isn't enough and must move the inputs around to gather all I want and still miss some...
See you Saturday, and, we've met a few times before.

Jeff Pickel · Joined: 14 Mar 2009 Posts: 84

you would be surprised on the cylinder jacket pressue with out a head gasket and with one. It depends on your overall system set up.