12 replies to this topic

[MK1russ]

I'm currently in the procress of overhauling the cooling system on my mini as it's been running a bit warm recently. I've throughly flushed out all the rust and sludge and fitted a new 3 core radiator, 82c thermostat, and a large impeller type water pump.

 

I'm now at the stage of putting it all back together and i've got both the small water pump pulley (that was originally fitted) and a larger A+ pulley. Which one would be the better one to use with the cooling setup i'm using? Should the large impeller pump be used with the larger pulley?

Edited by MK1russ, 27 June 2018 - 11:22 PM.

[nicklouse]

the engine is a?

[Spider]

Mostly what sort of driving do you do?

 

eg, around town with a lot of lower revs and lots of idling, or all motorway stuff?

[MIGLIACARS]

a larger pully will slow the flow down.

keeping it in the rad longer

On my race engines iI use the big pully, there are 3 types

small med large

[MK1russ]

The engine is a standard 998 with a stage 1 kit fitted.

I'm mosting driving on A roads, with a bit of town use, so i'm mainly travelling at speeds of around 60mph which is around 4000rpm on the rev counter.

[mini13]

unless your racing or pretty much constabntly at high revs fit the smaller pulley. The large ( production) pulley was fitted to 998's which ran a shorter final drive.

 

contrary to what some people belive, decreasing mass coolant flow rate does not increase cooling capacity, what is  generally the bottle neck is getting the heat out of the water, and generally spinning the fan faster helps especially at low speeds.

[MK1russ]

I'll stick with the original small pulley then I think.

[RooBoonix]

The bigger pulley helps prevent cavitation at high revs, where the water pump just cuts through the coolant rather than actually pumping it. I'd use whatever was standard on your engine for road use and only worry about that sort of thing when you're looking at racing or very fast road.

[Midas Mk1]

Larger one. I found the smaller one caused way more engine drag than the larger one too.

[Retroman]

Its a lot less than the 3 MPH drag switching the air con on a 1 litre Vauxhall Corsa....

 

They are a real gutt-less piece of 3 cylinder crap

[Ethel]

I'd try the large one*. It uses less power and makes less noise, so assuming you can live with changing back if it doesn't work out....

 

The objective is to cool the engine, not the contents of the radiator - the hotter the water the greater the temperature differential with the air and the more heat will be transfered between them.

 

The specific heat capacity of water is about 4000 times that of air and water's around another thousand times more dense. In short, moving the air through the rad is way more important. That said, the main function of a car is to move itself through the air, at least do what you can to make sure you're not hindering the air that would naturally through the radiator. 

 

*pumps and pulleys were selected to work together.

[Steve220]

Unless you're racing, and your engine spends most of its life at high rpm, then I'd stick to the larger pulley.

[MK1russ]

I've gone with the original smaller one for now and everything is back together and back up and running.

 

I had the engine running at idle for about 20 mins today and once fully warmed up, the temp guage is sitting over halfway (about 2 'needle notches') it was pretty hot outside too.

 

I'll see what its like driving it about tomorrow and see where it sits on the temp gauge whilst driving.