Radiator Efficiency

[Chino886]

What I want to know is what determines the cooling effect on our 450cc motors (450R)?

I know there are companies that claim that their radiators will help keep your bike cool, at a very pretty price, 30% better then the OEM radiator. Why do these cool better, just cause their bigger, prettier, and cost more? Bah hum bug!

Now what determines that? Is is the cooling tubes (the design or diameter of the tubes that sweep back and forth), or is it larger fins?

Also, is there a point where the coolant pressure or delivery is compromised. I think I kind of understand how the cooling system works and all.

Let me see if I have it correct:

- We have coolant stored in the head and in the cylinder which dissipates some of the heat.
- We have a fan that draws air past the radiator fins to aid in cooling the liquid as it passes through.
- Now, the thermostat controls when the fan kicks on (at a predetermined temp on our 450Rs).
- The water pump makes the coolant flow through the motor and back again.
- The reservoir stores extra coolant and captures any boil over that may occur.
- The whole system is under pressure, hence the pressure sensitive radiator cap.

Now, someone or anyone please shed some light on my unmechanical arse.

I only ask cause I bet I could find a small radiator for half the cost, yet be bigger then what the OEM radiator is and mount the SOB on our quads.

Now what do you all think to this!


Thanks for reading my uneducated dissertation!

[ss440ex]

So what your saying is thier a little over priced???

I agree!!!

I`ve seen an all aluminum radiator for a pro-street big block
New for $195.00....6x the size.

You would think some out there would be able to manufacture
one....

[wykyd450R]

I figure because the radiator is bigger, it holds more coolant. More coolant would mean more material for the heat to dissipate into. I figure it would take longer to heat 5 gallons of water, than it would 4. Then you would also have more fluid passing thru the radiator,taking longer to get back into the engine. While it has a longer time out of the engine, it has a chance to cool a lil better....All this is what I think. LOL

[cincy250R]

this is what i think about this but not sure,

i think the manufactures of the aftermarket make them thicker and that make more surface area for the air too hit therefore making the heat exchange greater cooling down the coolant more effeciantly(spelling) than the stock radiator

i think kinda like dual core radiators and single core radiators for cars....that is my guess

as for the price i would guess that since there are WAY more people with cars than people with quads they know they will sell more of the car radiators cause there are 10x more people too buy them....

just my .02 cents

[TRX450RACER174]

You pretty much have it correct, I have never seen a aftermarket rad but my guess is they are twin row cores cause the stocker is a single row, basically the added capacity of the rad helps it keep the coolant cooler lowering the temps of the coolant as a whole, but here is the kicker the 450r's thermostat is set at a pre determined heat range so it's still going to hold the coolant in the motor until it reaches the optimum temp to open, so really without a lower range thermostat imo the higher capacity radiator really does no good, yes it holds more coolant and it cools more but if the coolant is not flowing the engine is still running the same temp, if someone can find a thermostat that opens a little sooner it would run cooler.
Now here is a little food for thought the thermostat starts to open at 176deg and is fully open at 203deg but the thermoswitch
does not turn on the fan until i believe 210 well over the thermostat temp so ideally if you want your bike to run cooler you need to find a switch that will operate at 195deg and i have found one but have not installed it yet here it is.
http://www.spal-usa.com/

got to the fan section and click on atv then fan accessories.

[bloodmoney23]

Alll of you arwe pretty much correct. I have the fluidyne oversized radiator that cost me $400.00. And a SPAL a/m cooling fan and the CV4 rad hoses.

-Oversized radiators have more surface space for air to hit which in turn give you a faster cooling rate.
-SPAL Fans have an aluminum shield on the back which will stop the air at the radiator and pull the air to the fan gaurenteeing a cooling effect. They also have more blades in turn pulling more airflow through (CFM's) which assist with cooling
-CV4 radiator hoses are multiple layers of material instead of a standard hose which is just one big piece. The multiple layers make it easier for temps to disperse.

[400exrider707]

Though a larger radiator can help and does in most cases, dont forget that you can run the risk of keeping it too cool as well. Your motor was designed to run at a certain operating temperature and everythign was designed off of this. As we all know metal expands with heat, so that certain temp is actually quite critical to your engine. If you cool too much, you wont ever get your motor up to temp! Granted this is a highly unlikely situation but never the less, something else to think about.

An aftermarket unit helps by having larger fins (more surface area) to aid in cooling. It is physically bigger in size, height, length, width. All for more surface area. The flow inside the radiator can be improved, though I doubt it can be improved much from factory.

Has anyone tried painting one black? Now we know that a coat on the radiator could theoretically hold heat in, but if any of you guys are familiar with VW, and more specifically their early bugs, those motors are required to be painted black, to aid in cooling. The black paint sucks heat out of the engine, same way your black t-shirt burns you when the sun hits you in the summer. If you actually take the black panels off of the bugs and put the cheesy chrome looking ones on, they have been known to over-heat because of this. I wonder what the scenario would be like if a radiator got a coat of black paint? hmmm....

[bloodmoney23]

well i still have my stock radiator so i'll give it a black coat and find out. Do you know exactly what type of paint was used? or just regular high temp paint?

[400exrider707]

Originally posted by bloodmoney23
well i still have my stock radiator so i'll give it a black coat and find out. Do you know exactly what type of paint was used? or just regular high temp paint?

Has to be flat black no matter what! High temp would probably be the best.

You would need to do a lot of testing with it the way it is and get temp readings with a heat reader of some sort, and then do the same after its black. I would do one to two thin layers of paint, then bake it in the oven at like 100 degrees for 30 minutes, it helps to hold it on better.

[TRX450RACER174]

That's a good thought i would be interested to see i it works.

[bloodmoney23]

Originally posted by 400exrider707
Has to be flat black no matter what! High temp would probably be the best.

You would need to do a lot of testing with it the way it is and get temp readings with a heat reader of some sort, and then do the same after its black. I would do one to two thin layers of paint, then bake it in the oven at like 100 degrees for 30 minutes, it helps to hold it on better.

I bought a ESR temp gauge and an extra CV4 hose for it. i will run it for about a week or two as is. and then run it with stock radiator stuff with black radiator. every 30 min when im riding i will mark the readings on a chart. Who knows guys, we might be on to a new product and get rich off this....lol would be nice.

[400exrider707]

Originally posted by bloodmoney23
I bought a ESR temp gauge and an extra CV4 hose for it. i will run it for about a week or two as is. and then run it with stock radiator stuff with black radiator. every 30 min when im riding i will mark the readings on a chart. Who knows guys, we might be on to a new product and get rich off this....lol would be nice.

haha, yeah I wouldn't count on it. I think most people would just buy a rattle can and do it themselves. Who knows though.

Yes please let us know, that would be very interesting.

[bloodmoney23]

it will be a while though. I have to wait for that temp gauge to come in and my rear rim fixed then i should be good. Im looking at about 2/3 weeks b4 i can even start.

[pro-rider46]

hmm, in tech class we are going over the cooling system, i just thought that this is a little interesting, if you ever put dex cool in your aluminum engine, it will eat the aluminum, and it comes out like mud. haha only gm uses it in there vehicles,

[bloodmoney23]

yeah i know, i put it in my 95 eclipse a couple years back and that was an expensive mistake.

[TRX450RACER174]

Originally posted by pro-rider46
hmm, in tech class we are going over the cooling system, i just thought that this is a little interesting, if you ever put dex cool in your aluminum engine, it will eat the aluminum, and it comes out like mud. haha only gm uses it in there vehicles,

Actually Dex-Cool is a very efficient coolant it's when you don't do routine cooling maintenance on GM's that you have problems, i have had multiple GM trucks and only had a problem once because i didn't fix the leak when it first started, but anyways we are talikin quads not trucks sorry for getting off of subject.

[pro-rider46]

Originally posted by TRX450RACER174
Actually Dex-Cool is a very efficient coolant it's when you don't do routine cooling maintenance on GM's that you have problems, i have had multiple GM trucks and only had a problem once because i didn't fix the leak when it first started, but anyways we are talikin quads not trucks sorry for getting off of subject.

sorry, i know this is off subject, but my teacher has a drag car, and he ran it cause he was told it was the way to go. and it totally ruined his brand new block after one season, and i know its a drag car, but its only run for a couple of hours in one season. now thats what i call an expensive mistake, haha