Author Topic: raidiator air foils (Read 20280 times)

Hawaiiysr · « **Reply #15 on:** January 23, 2015, 02:07:05 PM »

If your trail riding as slow as you are describing, with little to no air flow, you might as well get off and walk. You can't tell me your not cruzin in 2nd or 3rd gear. Moving even in the lower gears will create air flow. The shrouds are ment to direct the flow of air as little as it may be. Like I said every sport quad has shrouds. They are there for a reason. You like slow trails? Toss the shrouds install a fan and call it a day. Installing of fans have been covered on the forums also. Now your quad will be beautiful without the ugly shrouds. But then you'll have an ugly fan and some extra doodads to deal with.

rablack21 · « **Reply #16 on:** January 23, 2015, 05:14:41 PM »

Quote from: JesseA420;49210

i am confused by that last post of mostly run-on thoughts.

its really a simple model to understand. think of the radiator as a giant filter that lets air through. it has an amount of restriction to it like filters do, due to how close the fins are. its easier for the air to just go around it rather than go through without the funneling effect of the shrouds. of course some will go through, but some will also just push out and around to take the path of least resistance. with the funneling effect the shrouds create, instead of the air just pushing out around the radiator, the incoming air is already inside the shrouds and pushes the air in front of it through the radiator because it has no where else to go.

there is too many other factors that are going to determine the operating temp of your motor to be able to know on your setup, and the operating conditions how having them on your motor or not will effect your overall operating temp, but i think if you put a radiator in a flow tunnel with and without the shrouds, you would see more air going through and not around.

You are on the right track, Jesse. Except that the air fins can handle a lot more air flow through them than we can achieve even with shrouds and going 85 mph down the highway. So having shrouds can be a good thing to add additional air, but only if they are forcing the air through the fins. Like you said, air takes the path of least resistance. So if you are trying to force more air through the fins and there is a gap between the shroud and the radiator, then your path of least resistance is the gap and not the air fins. The key is to give the air no place to go except through the fins.

F-Red · « **Reply #17 on:** January 23, 2015, 08:01:10 PM »

I'm not so sure Ryan. I could be totally off my chair, if I keep drinking! I believe the shrouds are designed to bring air to the side of the radiator. Enough air is flowing through the coils, with or without the shrouds. Angle the shrouds so air will be directed and pass by the sides. Cooling that area as well as the front. More surface area cooling, the cooler the contents. The gap between the shrouds and radiator, let's the air pass and not be trapped. Just thinking out loud. Next!

Tbone07 · « **Reply #18 on:** January 23, 2015, 08:58:47 PM »

Personally I think that we aren't getting 100% of the possible volume of air flowing through the radiator at any given time.

I'd want the shrouds with little to no gap whatsoever, to force as much air through the radiator as possible. I don't think there's any way we're getting 100% of the cooling capabilities of the OEM radiator without them

rablack21 · « **Reply #19 on:** January 23, 2015, 10:14:00 PM »

I see what you are saying Fred, but the side tanks are not meant for cooling, just a little extra capacity and to incorporate inlets and outlets. Think about it compared to anywhere you see shrouds used, especially on vehicles. The shroud butts right up to the fins and typically don't cover the tanks. That's why the tanks are usually plastic on vehicles. Because the cooling takes place in the tube and fins.
I agree with what tbone said 100%. I designed the cooling package on the last 2 bulldozer designs that I worked on including the shroud and seals,and I can tell you with certainty that the shroud can play a big role in the cooling performance. And gaps in the shroud package also makes noticeable changes in performance.
I don't know personally, but I think someone one paid close attention to how the shroud was designed in the Walsh radiators. You'll notice the air scoops were aimed directly at the air fins and the shrouds were pushed up against the radiator and foam seals used, thus making sure all the air goes through the fins.

rablack21 · « **Reply #20 on:** January 23, 2015, 10:27:24 PM »

I will add this, Fred. What you are saying is true. Air that passes over the tanks does cool them some, but only a very small amount compared to the air passing through the fins. My guess is the factory radiator was more than capable of cooling the stock engine without any assistance and at a very low speed, so the oem shrouds were used more as a deflector than an actual air guide. Now that we have more big bores floating around, we need as much airflow as possible.

rablack21 · « **Reply #21 on:** January 23, 2015, 10:35:41 PM »

Here's a couple pics of the Walsh shrouds. Notice how they butt up right to the side of the rad and the scoops point right into the air fins.

mandom250r · « **Reply #22 on:** January 23, 2015, 10:43:08 PM »

^^^^^ show off :lol:

rablack21 · « **Reply #23 on:** January 23, 2015, 10:52:29 PM »

I'm afraid the pics are not of my 250r, Mandom. Lol

mandom250r · « **Reply #24 on:** January 23, 2015, 10:57:28 PM »

ok im sorry lol

4WHLr · « **Reply #25 on:** January 23, 2015, 11:33:47 PM »

Thats one setup there that I've always wondered about. You seem to lose the straight forward airflow, and rely more on the deflected air from the side shroud.
I would think the angled screen part does a good job of protection from mud and roost though.
Nobody mentioned it just looks cool and is a good place to hang a couple of stickers. :p

F-Red · « **Reply #26 on:** January 24, 2015, 06:58:54 AM »

I'm totally on board. It would be hard to argue against Walsh engineering. :victorious::victorious:

udontknowme · « **Reply #27 on:** April 18, 2015, 10:23:17 PM »

i was reading something the other day about airscoops. no scoop at all is a bad idea like you guys already mentioned. alot of the air just goes around the rad without going through. having the scoops pointed outward to much may be bad as well as some of the air may have a easier time being pushed back out and around the scoops. straight or slightly inward pointed scoops should be best as this would make it most difficult for air to come back out and around the scoops. i know it sounds opposite of what some people think but it makes perfect sense to me. i been around a ton of different mx bikes and most of them have outward pointed scoops. the only bike i ever seen with scoops facing straight ahead was ktm and i always wondered why but i think i know the reason why now

broken1 · « **Reply #28 on:** April 18, 2015, 11:12:13 PM »

OEM trx scoops are pretty much straight too.

udontknowme · « **Reply #29 on:** April 18, 2015, 11:30:08 PM »

i never seen the oem scoops but ill take your word that theyre mostly straight on. mister honda was probly pretty smart. these little things like this is were alot of the aftermarket companies fail