Radiator Cooling

[Anonymous]

The thermostat is just a device that regulates temp. to a given set point or set point range. It’s basically a simple valve and does this by restricting flow around the cooling system by opening and closing. If it remains closed, flow is stopped and therefore the temperature is increased, conversely, if the engine is hot the valve will open to increase flow and reduce the temperature of the engine.

The thermostat converts a measured temperature of the cooling system and uses this to modulate the valve to control the flow of coolant. The thermostat can ‘ask’ for whatever temperature it wants but the system can’t regulate to that temperature if the radiator can’t flow enough coolant and/or the design is insufficient to dissipate the heat.

In short, a really large system (big radiator) with a large flow capacity can cool a system quicker due to the larger volume of coolant it can flow through the radiator cores. The radiator cores dissipate heat in the same manner as simple heat exchanger using the differential temperature of the ambient air passing along the core.

Large systems are great but are limited by size and weight. An engine will have an optimal working temperature range and it’s the thermostat’s job to regulate that temperature by increasing/decreasing flow as covered earlier.

An engine working at optimal efficiency will perform better than a hot engine suffering from ‘heat soak’. Therefore, in most common engine based applications (particularly performance based cars and motorbikes) having a bigger of higher flowing radiator improves performance as the engine doesn’t run too hot.

By increasing the core size of the radiator you expect to increase the amount fluid it will hold and therefore add to it’s cooling capacity.

If your engine is hot or suffering from ‘heat soak’ under duress then an upgrade of your cooling system is required for best performance and safety of engine operation. This results in increases in power, or the ability to use the intended power of the machine before the heat build up in the engine reduced the ability of the machine to generate power.

In general a improved cooling system will flow more coolant and/or provide a larger surface area to dissipate the heat generated. This can be seen by a reduction in measured engine operating temperatures under load also in a power increase in the vehicle in question (assuming the standard cooling system was not sufficient).

If an aftermarket radiator does not do this then there is little point in upgrading.

Moto

[dennis da menaceMember]

and just to add to that point moto, too large a radiator can also be bad for the engine.

thermostats are not designed to keep opening and closing, especially in hi-po engines. they are engineered into the system to keep a constant-ish temp throughout the engine under standard load/running conditions. their primary function is really on warm up.

if too much flow goes through an engine with a thermostat, it will heat and cool the water jacket to much leading to unwanted heat cycles, that arent really good for an engine.
an inrush of cooler water into the head/barrel will cause the parts exposed directly to the cooling system to expand and contract. the parts not directly in contact, ie; piston etc will not expand and contract the same leading to excessive engine wear over time.

the problem is finding the balance as to keep the engine temp constantly in its green zone, while also preventing overheating under extreme loads, like climbing big arse hills.

but since we are talking agricultural engines, none of this really matters, and it all comes down to whats Phat looking and how far you can piss :laugh: :laugh:

after all “PWR” just sounds tuff, doesnt it

[dennis da menaceMember]

and whatever you do, dont take the thermo out…..

too much cavitation will occur :ohmy:

[GregMember]

Everything you said menace was on the money also, right up until the final two sentences :laugh: :laugh: Be that as it may it will be an agricultural engine with F1 technology as you pointed out

Everything Moto has said above is correct enough in basic terms and Menace also but its only what was said elsewhere like in Motocool etc. All that aside a stand alone thread is awesome, I will see if I can add some pictures also that we use when I get a minute. Thanks Moto and Menace

When I get the new ones I will take some photos of the standard and the new ones for the peanut gallery

TB

[Anonymous]

Good points Menace

[Anonymous]

Why don’t you do dyno runds with both standard and PWR rads. You need to tune you’re bike anyway don’t you? I’m sure you said somewhere you wanted to go to Fathead and get it sorted.

I’d like to have a proper play on the dyno and see what jetting changes effect performance and in what way etc.

[dennis da menaceMember]

i thought they we turning up today, maybe the posty rides an XR too :laugh: :laugh: :laugh:

if so, give it a week.

[GregMember]

I havent been to Penrith today, been busy

TB

[Anonymous]

Found this for a KLR650, basic but does the job

[GregMember]

Moto wrote:

Quote:

Found this for a KLR650, basic but does the job

Perfect explains everything said today

TB

[Anonymous]

What are those 2 grey things at the top of the cylinder? I thought only farm machinery had them?

[TrentMember]

Moto wrote:

Quote:

Why don’t you do dyno runds with both standard and PWR rads.

You do know that he crushed one of his stock cores right? Hence the reason for needing new ones. :huh:

[GregMember]

Moto wrote:

Quote:

What are those 2 grey things at the top of the cylinder? I thought only farm machinery had them?

Should have posted this in tech help then it would have been only sensible posts, oh wait that would of been discriminating against you Moto :laugh:

TB

[Anonymous]

Austblue wrote:

Quote:

Moto wrote:

Quote:

Why don’t you do dyno runds with both standard and PWR rads.

You do know that he crushed one of his stock cores right? Hence the reason for needing new ones. :huh:

Yes, but I’m sure he can get hold of a standard one for a test.

[Bruce CurtisMember]

Moto wrote:

Quote:

What are those 2 grey things at the top of the cylinder? I thought only farm machinery had them?

you forgot large heavy earthmoving equipment too Moto….

Now do you reckon this thread could evolve into some really in depth discussion on problem areas.. if we prod it and poke it enough?

BC

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