Outer Limits 4x4 Board

Hi everyone im curious to know if the standard water pump on a commodore v6 will still work with a rear mount radiator or will it need an inline electric pump aswell.Any suggestions would be appreciated

I imagine it would work, but depending on the size of the radiator core, and CFM ratings on your thermofans, you may need an elec pump to move the water through the core a little faster.

Alternatively you ditch the mech water pump for an electrical one now and reduce the drive loss from the crank. You'll be garanteed to get the desired flow, and you may retrieve a little power that would otherwise be lost driving an ancillary component.

JMO
Pete

I was hoping that the standard water pump would be ok as its only just been replaced.The radiator is from an au falcon with the factory dual fans which i was told would be perfect for the v6.

The otis suzuki ute that was in the 4WD monthly started with the factory water pump and rear mounted factory radiator, but was replaced with a large alloy radiator and a Davies Craig electric water pump ( from memory it was the 110? The biggest one anyway), because the factory pump wasn't effecient at moving the combined volume which ends up being something like 20l of coolant.

Yes thats true i remember reading that he had trouble keeping it cool but wasnt the radiator also mounted flat under the tray to begin with.I have spoken to a few of the local speedway guys who run the same motor with a rear mounted radiator in their street sedans and the standard pump seems to work for them but thier races arent very long.

Give it a go. I wouldn't agree with pulling out the mechanical pump, electric water pumps are not very good and I would be pretty dubious about having just an electric one.

I think you should just try it; I would expect it to work okay. One issue would be putting the rear mount too high up which would make the pump work harder.

chimpboy wrote: electric water pumps are not very good.

I'd challenge that.

I'd happily claim Davies Craig electric water pumps aren't very good, but they're not the only option.

I run electric pumps on my car with a rear mount radiator and it seems fine. I know mine is an unusual case (660cc, camry radiator) but I'm also using pretty small Bosch pumps.

There are some bosch pumps with amazing flow and durability - mine are mag coupled - no shaft seals etc and only consume about 2 amps and retail for about $180 each from memory. They are an oem part so they have oem durability. Davies Craig pumps are rated for 1500hrs life. That's about 50,000km in an average car.

Some of the large DC brushless Bosch pumps would laugh at cooling a commodore V6 with a rear mount. They are expensive though. ($800-$2K)

Steve.

Gwagensteve wrote:

chimpboy wrote: electric water pumps are not very good.

I'd challenge that.

I'd happily claim Davies Craig electric water pumps aren't very good, but they're not the only option.

I am happy to amend what I said in line with that.

yeh i put a post up similar im struggling to keep the como v6 cool so im putting a el falcon rad on my tray and using standard pump mine will be finished by sat arvo and ill let u know if it works but ive been told by many it wont have any dramas with pumping it and alough it works harder to pump the water higher it makes it good for gravity feed on the return?

The real problem will be frictional loss from all the length and bends you've introduced.

Here's my take on troubleshooting the problem:

If the temperature rises fast, inadequate water pump flow.

If the temperature rises slow - inadequate airflow to radiator.

The added volume of the hoses and larger radiator should make overheating slow - it won't "spike"- it will climb slowly.

Best test I've given mine to date is about 500m of altitude climb on a 30deg day, with a load, full throttle, full boost (12psi) 4th gear for about 6 minutes.

No increase in gauge temperature over normal flat cruising

Steve.

Would putting a larger pully on the factory pump offer any benefits?
obviously it couldnt be sized too big or the impellor would just cavitate but it may be an option.

well my take is its commonly done on saloon race cars. typically use the chassis rail as the water pipes. however they often use ford or chev which have a choice of mechanical pumps. i would have to go ask if they get away with stock pumps or not.

badger wrote:Would putting a larger pully on the factory pump offer any benefits?
obviously it couldnt be sized too big or the impellor would just cavitate but it may be an option.

I think you'd want a smaller one. But I see what you mean.

The pumps work fine , you need to make sure you can bleed the system ,

I had problems with the bleeding once sorted it worked a treat ,
i ran a range rover radiator with twin thermos , at one time one fan shid itself didn,t seem to make a difference ,




useful things for making bleed pionts = put one of those filter things in high piont of hose ,they have a cap that you can remove when filling ,
Tee pieces plastic to use on heater hose size and add a ballcock valve .

Thankyou everyone there is some very useful info there,I spoke to a guy today who has a rear mount radiator in his speedway sedan and only running with the standard pump with no problems.I have tried to keep the bends in the pipework to a minimum and the top radiator outlet is 80mm higher than the thermostat.

badger wrote:
Would putting a larger pully on the factory pump offer any benefits?
obviously it couldnt be sized too big or the impellor would just cavitate but it may be an option.


I think you'd want a smaller one. But I see what you mean.

you are indeed correct, brain fart

you could probably take the thermostat out and just use the fan to control the temp. This might stop the temp getting to hot befor the cooling system has a chance to cool it.