Those with experience with tunnel coolers on the bikes. Without radiators what size tunnel cooler/heat exchanger is adequate without being more than necessary? Again, no rads, I want to eliminate the convection effect and cool entirely with the tunnel cooler. This would be on 450ish 4s. Catsledman1, you have a pm?..
More tunnel cooler talk.
- Thread starter dooman92
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My friend had his first ride with 1 rad and it was a tad cool on the road out. I bought the same cooler and we are both going to go no rads. I'm waiting on hose adapters and about 2 feet more snow before I can report back. 
This is the used cooler model we got. 1998 ARCTIC CAT PANTHER 550 Front Heat Exchanger
This is the used cooler model we got. 1998 ARCTIC CAT PANTHER 550 Front Heat Exchanger
I have the same cooler. More than adequate. Only use my right radiator has a coolant bottle. Tunnel cooler/scratchers on the skid doesn’t take much.My friend had his first ride with 1 rad and it was a tad cool on the road out. I bought the same cooler and we are both going to go no rads. I'm waiting on hose adapters and about 2 feet more snow before I can report back.
This is the used cooler model we got. 1998 ARCTIC CAT PANTHER 550 Front Heat Exchanger
On my RIOT/KTM 500 I am running a 6" x 11" heat exchanger I made 6 years ago for a old MH kit. Made from the heat exhanger extrusions that WAHL bros racing sells in bulk. So 66 sq inches of heat exhanger but thats bolted to my bare aluminum pan which also becomes a heat sink. From building custom sleds and going through this same ritual 30 years ago, sleds do best with heat exhanger mounted as far forward in the tunnel as possible. So mounted to the front right in my RIOT tunnel. Pic on the forum here of that set up last year.
On my last old sytle TS kit, I welded up two little heat exchangers that fit within the area between the side panels and the center pan.
Two 3 1/2" x 6 heat exchangers. Ran them for three years. 42 sq inches of heat exchanger. AS a test, I blocked one of the heat exchangers out of the system and ran just the 21 sq" of heat exchanger. Worked great, never an overheat. Way back a guy with a KTM 300 and TS kit had me weld appropriate fittings on a little cylindrical finned transmission cooler and mounted it on top of the tunnel ahead of the brake system where snow kicks up
. I was skeptical, never a problem, ran that for serveral years.
I haven't done it yet, but am considering running a couple lengths of thin wall aluminum tubing in my tunnel for a heat exhanger.
Won't be quite as efficient because of the thick mass of fluid flowing in the center of the pipe,
1" od pipe has 3 sq " of exposure for every inch of pipe. So being conservative and use 60 sq" of exposure as a goal. Two 10" pieces of pipe might do the job, or go twice that, still cheap, the only real weight added is the anti freeze.
After fooling with heat exhangers and needing to get our temps up, we dumped our left radiators, better. The last couple of years we used late 90's cat radiator cap filler pipes and drumped our right hand radiators. Slimmer lower center of gravity bike.......all good.
On my last old sytle TS kit, I welded up two little heat exchangers that fit within the area between the side panels and the center pan.
Two 3 1/2" x 6 heat exchangers. Ran them for three years. 42 sq inches of heat exchanger. AS a test, I blocked one of the heat exchangers out of the system and ran just the 21 sq" of heat exchanger. Worked great, never an overheat. Way back a guy with a KTM 300 and TS kit had me weld appropriate fittings on a little cylindrical finned transmission cooler and mounted it on top of the tunnel ahead of the brake system where snow kicks up
. I was skeptical, never a problem, ran that for serveral years.
I haven't done it yet, but am considering running a couple lengths of thin wall aluminum tubing in my tunnel for a heat exhanger.
Won't be quite as efficient because of the thick mass of fluid flowing in the center of the pipe,
1" od pipe has 3 sq " of exposure for every inch of pipe. So being conservative and use 60 sq" of exposure as a goal. Two 10" pieces of pipe might do the job, or go twice that, still cheap, the only real weight added is the anti freeze.
After fooling with heat exhangers and needing to get our temps up, we dumped our left radiators, better. The last couple of years we used late 90's cat radiator cap filler pipes and drumped our right hand radiators. Slimmer lower center of gravity bike.......all good.
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I'm putting the filler cap on mine also. Debating if it will ever get hot enough to need a catch bottle. Simple enough to make a small gatorade type bottle, but I see there are a few small ones or some used ones for sale.
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Catsledman, thanks for that post. That was the info I thought I read in prior posts. So, in the right location, anything over 40 sq inches is probably just extra with little benefit unless cement and no scratchers? Currently working on my 450fx/mototrax. Do you run the bypass on your thermobob? I'm thinking about just adding another small bleed hole in thermostat and plugging bypass. That is essentially how my ktm/c3 setup is when my bars are shut down.
I don't have all my covers off so no pictures, but I will look in my pic file, maybe something from last year. I found the bypass to flow too much, so I put an aluminum pug in the line with about a 3/16 hole, warms up faster works better.
I used a mid 90's arctic cat filler neck, its T shaped radiator cap ( 13psi) on top, leg going left, leg going straight down. Off e-bay for $10 with cap, bought new cap just to cover all bases. I had bought a 2008 M8 bottle with cap and to legs, dceided it was too bulky and unnecessary. I did put a small plastic bottle for coolant over flow.
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Per CatSledMan1's previous thread on coolers, I build one as he described. This is on a 13 YZ450, both radiators deleted. Except I had a hard time believing such a small cooler would be suitable, so I made mine a little bigger (maybe 12 to 14 inches long). I should have listened to the voice of experience. It cools a little too well, I should have gone smaller!
yeah, but erroring on the side of caution is always a good idea. An extra pound of aluminum and coolant..........all good.
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That's a Mototrax track correct?
Could you possibly post a picture of how you plumbed the inlets through the track?
Clearance looks tight with the drive shaft bar to come under the tunnel.
Texas mud taco, thanks for the photo. Looks like my current project is same, mine fx with mototrax. I'm locating something in the same area for an expansion tank. I plan to mount the cooler in same location. Waiting on a cooler. Do you get consistant temps? Is your engine open like that when riding? That would provide a lot of uncontrollable cooling even with thermo closed. Yeah, also interested in a photo of top side of tunnel. I hope to poke hose barbs thru tunnel just behind that main cross bar. Have you had it good and warm and noted how much the coolant expanded in your bottle? Nice job on that cooler! I need a tig welder!
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2018 YZ450FX with a ARO3 . Tunnel cooler and plumbing. I also run the Selkirk Armor with out the built in cooler.
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The pics from the previous post are of my Mototrax kit last year. I picked up a 2020 ARO 3 a month ago, which are what these pics are of.
I have only been out once this year, last weekend at Wolf Creek (I'm in Durango), so I was doing a bit of fiddling with things on the shakedown run, including getting my system filled properly. If you haven't done it , it takes a bunch of squeezing of the rubber coolant lines and shaking the bike while cursing at it at high volumes, to get all the air bubbles out of the system. Last year I could not believe what a great job it did in keeping constant temps, with no jacket.
A year ago I bought the fabric, grommets, and ball end bungees to make a motor jacket, but have yet to execute. I DO need to get that done... I drilled the spigot holes through the tunnel with a Unibit, like electricians use (I'm a builder by trade). I want to say those Unibits are like $50, but you can get a 1" or so hole saw for about $20 at Lowes/HD.
Just for sh!ts and giggles, I included a shot of the ugliest snow shield you have ever seen (prove me wrong???). I found a bunk bed ladder, cut it down for a support frame, and attached race car plastic, which wraps under like a skid plate. Honestly, I think its just the side "wings" that make it so ugly, but they do deflect the snow away from the bike so I don't know if I should cut them off or not. As GranPappy used to say: this ain't a f*cking fashion show.
I have only been out once this year, last weekend at Wolf Creek (I'm in Durango), so I was doing a bit of fiddling with things on the shakedown run, including getting my system filled properly. If you haven't done it , it takes a bunch of squeezing of the rubber coolant lines and shaking the bike while cursing at it at high volumes, to get all the air bubbles out of the system. Last year I could not believe what a great job it did in keeping constant temps, with no jacket.
A year ago I bought the fabric, grommets, and ball end bungees to make a motor jacket, but have yet to execute. I DO need to get that done... I drilled the spigot holes through the tunnel with a Unibit, like electricians use (I'm a builder by trade). I want to say those Unibits are like $50, but you can get a 1" or so hole saw for about $20 at Lowes/HD.
Just for sh!ts and giggles, I included a shot of the ugliest snow shield you have ever seen (prove me wrong???). I found a bunk bed ladder, cut it down for a support frame, and attached race car plastic, which wraps under like a skid plate. Honestly, I think its just the side "wings" that make it so ugly, but they do deflect the snow away from the bike so I don't know if I should cut them off or not. As GranPappy used to say: this ain't a f*cking fashion show.
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No radiators . I have a thermobob about 2 inches from head going into a 180 molded hose back too the cooler. I run Evans coolant so it is a zero pressure system no need for expansion. This is a new set up for me . Waiting for more snow to test.
00tundra, I also run Evans in both my bikes. Evans expands about 7% from cold to hot, which is slightly more than typical 50/50 mix. True it has a much lower vapor pressure and doesn't boil easily which is what causes coolant loss with the 50/50. But, it does expand and if trapped in a closed system will build pressure. If I fill my radiators above the fins at the top with Evans it will expand and push the liquid out until there is enough area to absorb the expansion. Have you had your complete system up to 200? If it started full I'm sure it would push coolant out your cap relief. I think you used a typical rad cap right?
