# Dual radiator setup



## IBBruin

My theory of running dual radiators. Excuse the crude drawing, I'm using poor man's CAD (paint). I don't think we have a thread discussing this exclusively so lets discuss it here. 










I have never done this but I THINK this is how it should work. In the parallel example on the left, both fans should kick on and off at approximately the same time since they are both receiving the same amount of heat from the engine.

In the series example on the right, the stock radiator fan should come on first and the aux radiator fan should only come on if the stock radiator can't keep up with the heat.

Ideas? Pro's? Con's?


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## bayou_boy_22

Nice bruin. 

i think it would work the best in series so that it is forced to work through the two radiators before returning to the engine. if you run it in parallel you will just split your coolant up into the two radiators. one would cool better than the other but if you ran it to the lower one first then the upper one or vise versa you would have two different stages of cooling with alot more area to travel creating more cooling. thats just my opinion.


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## gchroniger

Our ATV group went on a ride two weeks ago and two of us had our quads overheating after going through a couple mud holes. My brute was one of them. One of the guys actually suggested this same thing. I looked at mu buddys Can Am rad and the fins were much wider apart and was less clogged than mine. And the fact that his was not overheating said a lot. So I think a better quality rad and or a second rad would definitely help bring the temp down especially when the primary is getting clogged. My only concern was cost. I did not want to invest $400 for a rad upgrade. I also do not like the look of the relocated rad. And I even took off my front rack. I was wondering if I could put a second smaller rad in front of the stock probably lower.


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## gchroniger

bayou_boy_22 said:


> Nice bruin.
> 
> i think it would work the best in series so that it is forced to work through the two radiators before returning to the engine. if you run it in parallel you will just split your coolant up into the two radiators. one would cool better than the other but if you ran it to the lower one first then the upper one or vise versa you would have two different stages of cooling with alot more area to travel creating more cooling. thats just my opinion.


Agreed:haha:


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## bayou_boy_22

Dont know if you would be able to fit a second one that would do any good under there. might have to relocate your aux one for big rides and leave your stock one down low. i dont see me doing this as i dont have the overheating problem since i put it on my rack. but like you said if you leave your stock one down low and put a smaller one up high it may work our for you.


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## IBBruin

Here's an extremely simple way to wire up the aux fan. This is assuming the temp sensor is mounted in the radiator. There are many ways to do it, this is just one way.


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## IBBruin

gchroniger said:


> I was wondering if I could put a second smaller rad in front of the stock probably lower.


It would benefit you a little to have a second radiator in the same location but consider the drawbacks. 

1. The second one is still low and prone to clogging with mud.

2. If you are going to one fan to pull air through them both, you'll be pulling the hot air from the front radiator directly onto the rear one.

3. If they both get clogged, it'd be difficult to get them both clean if they were kind of stacked together.


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## hoover

In a series for sure, i would probably add an electric auxiliary water pump to assist in getting the water through the stock radiator on up to the racked radiator


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## IBBruin




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## IBBruin




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## Injected

Why not run a larger rad,instead of 2? Something out of a ....say ford escort?


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## IBBruin

I sure that would work also. Depending on the size and mounting locations available. I guess if you didn't care how it looked, you could mount a radiator out of an F250 on the rear rack. LOL


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## Injected

I was using the escort rad as an example. I paid less for the 4 core in the race car, then what kawi wanys for a replacement


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## IBBruin

Yea I know, I was laughing with you not at you. No doubt about it, unless you can run across a good deal on one, having two radiators would be expensive.

:beerchug:


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## elpinto88

i like the idea of the series but what if instead of trying to push water to the top (left image) why not let gravity push it down (right image) through the radiators back to the engine


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## IBBruin

Yep, that would work also, maybe even better. That would change your primary rad to the top one. It would come on first and if it couldn't keep up, the bottom one would kick on and help.


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## tacoma_2002

Since the bottom radiator (in mud) is deemed useless anyway...I would think make the rack mounted radiator the Primary cooling unit and let it go through the stock radiator for shigs and tiggles.

I agree with pushing water up to the top radiator and letting it flow down rather than "pushing" water through both units. The usage of more coolant will aid in heat reduction as well.

Just my .02


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## DTX

tacoma_2002 said:


> Since the bottom radiator (in mud) is deemed useless anyway...I would think make the rack mounted radiator the Primary cooling unit and let it go through the stock radiator for shigs and tiggles.
> 
> I agree with pushing water up to the top radiator and letting it flow down rather than "pushing" water through both units. The usage of more coolant will aid in heat reduction as well.
> 
> Just my .02


 :agreed:


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## badazzbrute

If you are going to use 2 radiators, why not put them in series and mount them both on the rack side by side sorta angled off from each other. As far as bringing on the fan, you could use just one sensor to bring on both fans. Use a sensor mounted in the second radiator that the coolant hits. If the coolant makes it through the first radiator, and is still too hot at the bottom of the second, then let the system bring on both fans. With this set up, both radiators would have be able to drop the temp of the coolant before bringing on a fan which would keep your fans off longer. What do you think. I know two radiators would take up loads of room on the rack, but it looks good on paper. :34:


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## elpinto88

^you would still have to push coolant thru both radiator

i would like to see the look of two radiators on the rack


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## Injected

Im not sure the stock propeller will have enough umph to move that much volume


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## FABMAN

Your not adding more load to the pump just quantity it will evaluational move. The stock pump will have no problem. It would be no different then taking your input and outlet on the engine and putting it in a lake. Just like a boat. Just because your on a bigger lake don't mean the pump will worked harder! Its been designed to move X gallons in X time at X rpm and that's it. If you do decide on running an electric water pump you might as well remove the propeller on the stock pump to free up HP. That's what we do with race cars. But you need to be careful not to move the coolant too fast or it will not have enuf time to cool in the radiator and/or time to cool the engine, and not to move it too slow it may get too hot in the engine spending too much time in there. I had these problems in a 84 pro street Dodge Daytona with a 440 once. I had to mess around with pulleys to get it right.


Now as far as series or parallel. If you run a series set up the water will flow at X speed in the engine and radiator's. But if you run a parallel set up the water will run at the same speed in the engine as before but 1/2 the speed in the radiator's thus allowing the coolant too cool longer per radiator. however the series set up has the coolant run threw 2 radiator's before it gets back to the engine. So the time coolant spend in the radiator's or radiator should be the same. in a perfect world they both should cool the same however if mud or dirt get in/on one radiator and not the other the series may have a slight but small advantage. Keep in mind that both set up's series or parallel will have less cooling capabilities if one radiator is dirty. Also keep in mind heat rises and cold likes to go down so use that to your advantage by running the hot up top and the cold at the bottom of the radiator's.


Something you guys have not thought of yet is the 2 radiator caps you'll have by running 2 radiator's. If the cap on the bottom purges before the top one does, you'll loose allot of coolant! It will literally drain all the coolant that is above the cap that purged! like the hole radiator! let's just say the stock cap on this bike is a 7lbs cap. The caps now days are not that good and can vary quit a bit. So you will need to run 2 different cap lbs like a 13lbs on the lower and a 7lbs up top. this should combat that problem. Also if you plug the lower radiator's overflow port should fix that as well. But for a safe measure id do the different cap lbs thing and cap off the overflow port.

Now the fan's. Id run the stock fan set up but the power running to the stock fan id run to 2 relay's to trigger it and run a power of appropriate gage from the batt to the relay's at that point the power will split at the relays to power both then fuse the power going to the fans. so both fans run at the same time and if one blows the fuse the other will still work.

That's my 2 cent. If you don't like it keep the change! lol


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## bayou_boy_22

Nice Fabman did not think about the caps and overflow. Makes sense.


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## Rack High

I completely agree with Bayou Boy 22, Badazzbrute and Elpinto 88. They must be installed in series or the 2 radiator system won't work properly. I'm wondering whether the stock water pump would be able to overcome the added fluid volume (added fluid volume equates to added resistance). That pump would have to work awfully hard to push the addition.


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## bayou_boy_22

but like stated above if you running a racked rad. you just go from there down to the secondary one. this would save you from having to pump coolant through both rad. one would be fed by the water pump and the second would be gravity fed from the primary.


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## rmax

what about the heat an water coming off these rads when the fan comes on, an as for the 2 rads on the rack double the fun. i installed a plexiglass shield behind mine to let the heat an water defect around me ,works like windsheild on motorcycle, have a problem with leaving fan switch on, then wash the thing get back on turn key an here comes the water ,now the shield gets it not me, also noticed diffrence trail riding with the heat deflected away from me


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## bayou_boy_22

rmax said:


> what about the heat an water coming off these rads when the fan comes on, an as for the 2 rads on the rack double the fun. i installed a plexiglass shield behind mine to let the heat an water defect around me ,works like windsheild on motorcycle, have a problem with leaving fan switch on, then wash the thing get back on turn key an here comes the water ,now the shield gets it not me, also noticed diffrence trail riding with the heat deflected away from me


I would like to see pics of your set up. i dont care for the heat when it is 100 degrees out side and you have the hot air from the rad blowing on you. love it in the winter.


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## Guest

:haha: Yep...Gotta post some pics rmax!


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## FABMAN

The teryx has a bigger radiator compared to the brute and allot more radiator hose. but yet they use the same engine with the same water pump impeller. Oh and the teryx radiator is $200 ceeper too!
2010 750 teryx cooling sys parts brake down 
http://www.ronniesmailorder.com/fic...egory=ATVs&make=KAWASAKI&year=2010&fveh=38133
2010 750 brute cooling sys parts brake down 
http://www.ronniesmailorder.com/fic...egory=ATVs&make=KAWASAKI&year=2010&fveh=38222
look for your self!


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## bayou_boy_22

that dont make any sense.


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## meangreen360

I dont see the point in running to rads. One on the front rack is plenty. If you like your space on front rack,buy the hl one and be done. No need for 2 imo.


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## tacoma_2002

I agree and disagree with that.

This could be useful for the higher performance bike...turning them from strictly a pit bike to a reliable trail bike as well. You could however use one large radiator on the front rack, but then you have a big bulky unit on your front rack killing any cool looks it might have had before.

It also could be used on the more modified trail/mud bikes that have a tendency to run a little hot on those 100* days out working on the farm.

Two radiators on a stock bike with mods such as lift and tires = useless....Dual Radiators on a heavily modified bike with a BBK, cam, clutch kit and 32" backs = useful


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## jctgumby

I just wanted to throw my 2 cents in here for the people that say they don't want the radiator on the front rack...I might be the only one that thinks like this I don't know but I like the way it looks on the rack...In my own opinion if you don't use your rack for serious work I wouldn't hesitate to move it up, cause the fact is whether you ride alot of heavy mud or not it does cool much better...And if you don't want to lose room for your radio then just do a split pipe audio system that is what I am about to do...Sorry for the rant just wanted to throw that out there


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## badazzbrute

jctgumby said:


> I just wanted to throw my 2 cents in here for the people that say they don't want the radiator on the front rack...I might be the only one that thinks like this I don't know but I like the way it looks on the rack...In my own opinion if you don't use your rack for serious work I wouldn't hesitate to move it up, cause the fact is whether you ride alot of heavy mud or not it does cool much better...And if you don't want to lose room for your radio then just do a split pipe audio system that is what I am about to do...Sorry for the rant just wanted to throw that out there


I agree completely gumby. The radiator fan doesn't seem to run as much with the radiator racked. Tells me it's cooling better up there in the direct flow of the air.


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## eagleeye76

bayou_boy_22 said:


> Nice bruin.
> 
> i think it would work the best in series so that it is forced to work through the two radiators before returning to the engine. if you run it in parallel you will just split your coolant up into the two radiators. one would cool better than the other but if you ran it to the lower one first then the upper one or vise versa you would have two different stages of cooling with alot more area to travel creating more cooling. thats just my opinion.


I agree with the series idea. I like the double rad idea. BUT do they make Thicker rads for atvs like they do for trucks cause that would take up less room than two and provide more cooling. although a second rad infront of the other one was to get plugged you MIGHT still have enough air getting around to the back one for cooling. It looks like there might be room? just a couple of ideas. And how do you start these questions I can only reply like i am doing now. I have some Q's of my own and cant figure it out. If some one has a chance to tell me how could you send me a message please it would be GREATLY appreciated.


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## brodaddy1075

This is the first weekend I've run my dual rads and 90 degrees out it barely got over 160 with no fans. Def recommended.


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## badazzbrute

Post some pics of how you did it. Did you leave one in the factory location, one on the rack? Upgrade water pump? Come on man, give us the goods.... :rockn:


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## brodaddy1075

Left the stock in place added a gorilla mount and 2nd stock radiator on the rack and plumed them in series more less. I get some pics up this weekend.


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## phreebsd

eagleeye76 said:


> I agree with the series idea. I like the double rad idea. BUT do they make Thicker rads for atvs like they do for trucks cause that would take up less room than two and provide more cooling. although a second rad infront of the other one was to get plugged you MIGHT still have enough air getting around to the back one for cooling. It looks like there might be room? just a couple of ideas. And how do you start these questions I can only reply like i am doing now. I have some Q's of my own and cant figure it out. If some one has a chance to tell me how could you send me a message please it would be GREATLY appreciated.


when you are in a forum you want to create the thread, look for a button about 1/4 way down the screen on left side. says "NEW MSG"


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## Sbevins

brodaddy1075 said:


> This is the first weekend I've run my dual rads and 90 degrees out it barely got over 160 with no fans. Def recommended.


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## Sbevins

I’m in San Antonio and it’s gets hot I have 2008 840 brute I had moved the radiator up top on the front rack and not having any air blowing on the motor From the fan she was running hot .i moved it back down and she’s running about 25 degrees lower but still warm still pretty warm .i found another fan and radiator put it on top ran the hose from the motor looking at the bike left side the upper hose to the upper port on the radiator the lower port to the top port on the radiator under the fender to the topside so the hose is going from the low side to water pump stayed the same .i have both fans switched so I can turn off the lower one when I’m in the water /mud trail riding I run the lower fan I header wrapped the exhaust as well so far about 50 degree difference I also added additive to the radiator fluid tomorrow is the test I have had it running in the driveway for 1/2 hour it hasn’t gotten above 150 Changed the snorkels so to get max air flow for the clutch case I also changed the thermostat and impeller and complete exhaust , good lord I hope she runs


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## Sbevins

Sbevins said:


> I’m in San Antonio and it’s gets hot I have 2008 840 brute I had moved the radiator up top on the front rack and not having any air blowing on the motor From the fan she was running hot .i moved it back down and she’s running about 25 degrees lower but still warm still pretty warm .i found another fan and radiator put it on top ran the hose from the motor looking at the bike left side the upper hose to the upper port on the radiator the lower port to the top port on the radiator under the fender to the topside so the hose is going from the low side to water pump stayed the same .i have both fans switched so I can turn off the lower one when I’m in the water /mud trail riding I run the lower fan I header wrapped the exhaust as well so far about 50 degree difference I also added additive to the radiator fluid tomorrow is the test I have had it running in the driveway for 1/2 hour it hasn’t gotten above 150 Changed the snorkels so to get max air flow for the clutch case I also changed the thermostat and impeller and complete exhaust , good lord I hope she runs


They are in series


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