24 replies to this topic

[nicklouse]

I also use a Craig Davis pump with a front mounted radiator, when its cold weather I have to put a thermostat in because it wont get up to temperature. And I have a controller fitted which slows the pump right down to get the engine up to temperature quicker.
The car is a 1460 turbo track car which does generate plenty of heat. Water cools the turbo which also acts as a bypass. In warmer conditions it's perfect with the thermostat removed and a sleeve in place.

as you dont have a mech pump fitting the sleeve is pointless. but i would always run a stat.

[Curley]

MED did a video about dry decking in which Steve said the standard water pump was loosing 5HP at full chat.

 

Mini7 rules require that a charging system be retained.

 

I measured the Bosch pump today at 1AMP constant.

[paulrockliffe]

Those sort of figures sound like complete rubbish though don't they?  There's no way you could feed 5 hp into the pump and then dissipate that energy into the water supply.  1 Amp at 12V is nowhere near 5hp.

 

With a nifty controller, maybe some extra cooling capacity, and some thought you could eek out some lap time by disconnecting the alternator and cooling off the battery at full throttle, with the alternator coming back in off throttle.  Like F1 ERS to run the ancillaries so the engine can send more energy to the wheel when needed.  Doubt it's legal though.

[PoolGuy]

Minis Spares claims, "Recent testing has seen the growing popularity of electric water pumps. These have to be the ultimate answer, as their pumping capacity remains constant, as they're completely independent of engine speed. Consequently cooling efficiency is far greater. The only two drawbacks being their initial cost, and installation, as adaptors have to be made up to blank-off the water pump mounting hole. Both, however, are well worth it - the results are outstanding. Not to mention the fact the water pump consumes power to drive it and reduces accelerative power output - to the tune of 4 bhp on a small-bore engine and 2 bhp on the large-bore ones! A further benefit is that the pump can be left running with the engine off after a race/hot/long journey to reduce the problems associated with the 'heat-sink' effects of non-circulating coolant at stand-still."

[sonscar]

I find it difficult to understand the pump needing twice as much power to drive it on smaller motors,or are larger motors filled up with bigger horses?.Steve..

[OzOAP]

With a nifty controller, maybe some extra cooling capacity, and some thought you could eek out some lap time by disconnecting the alternator and cooling off the battery at full throttle, with the alternator coming back in off throttle. Like F1 ERS to run the ancillaries so the engine can send more energy to the wheel when needed. Doubt it's legal though.

Through a brake light switch.
Alternator only charges when you brake.

Edited by OzOAP, 10 September 2020 - 07:04 PM.

[paulrockliffe]

Do people do that?  

 

Doesn't that still leave the alternator spinning though?  Ideally you would would stop the alternator being turned at all.

[OzOAP]

Do people do that?

Doesn't that still leave the alternator spinning though? Ideally you would would stop the alternator being turned at all.

If alternator is not charging there is no load

[Spider]

Ha ! Ford introduced that system in many of their recent cars - 'Smart Charger' - they call it, only it would have to be the dumbest idea on Earth if you live in a place like Australia, where it's very easy and not uncommon to drive for 3 - 5 hours (and longer) without using the Brakes. A Mate found this out after buying a Ranger and then heading off to Lake Eyre and having a dead battery before the day was out and it only got worse from there,,,

 

Anyway, we aren't talking about those kinds of situations here.

 

The advantage of an electric pump is it can run in concert with water flow requirements rather than directly proportional to engine speed, which is not at all related to engine heat and coolant flow needs.

 

I think the 1 Amp figure Curely quoted might have been with the Pump unloaded? If you made a closed circuit, with a valve in it and run it again so you can adjust rates and pressures with a restriction in the system, I think you'll find more real life current draws. 1 amp at 12 volts is only 12 Watts. Ignoring losses here, that's only 0.018 HP. The stock pump with 3.75" Pulley fitted drags about 2 HP from the the Crank in a 'peak loading' situation, where the Pump is spinning at it's optimal speed which for these pumps (depending on which one you have) is usually between 2000 and 3000 Pump Shaft RPMs. Above and below those speeds the power needed is less and also, the power needed at any speed will only be (kinda) proportional to any restriction of the pump's (capable) flow rate. If it's open ended, then the power needed is going to be next to nothing and as they are a Centrifugal Pump, even when totally shut off is not when they are loaded the most, that occurs at is optimal operating RPM and peak flow rate (as will be set by restriction in the system). It's not at all straight forward.

 

Given the small numbers of power involved here, for a street car, I feel it's not worthwhile if only considering perceived power savings, which may or may not occur. As some guys touched on, while it won't be directly driven from the Crank, it actually still is, only via the Alternator. If the losses were nil, the power absorbed to run the Pump would be the same, but as the Alternator and the Electric Motor of the Pump will have losses, the power is in fact more.

[Curley]

Correct, that was a front mount rad with no thermostat, flow restrictor or bypass circuit. The flow restrictor does not fit MPI castings. I'll have a look tomorrow to see if I have the bits to set up a bypass circuit and thermostat to retest.

 

The rules don't say what charging system to use & took some time looking for an alternator with a clutch. Modern cars ECU can disengage the alternator drag under W O T but couldn't find anything small enough to fit the space I had.

 

EDIT: Note, figures quoted were taken from a cold engine having hot wired the pump & pressure tested for leaks.

Edited by Curley, 10 September 2020 - 10:31 PM.