Author Topic: raidiator air foils (Read 19624 times)

meathead · « **on:** January 22, 2015, 05:51:06 PM »

Howdy guys Well I was just wondering about the air foils for the radiator
I mean there ugly It looks like you don't even need them It looks like you would get plenty of air without them Any body out there not using them ?

mandom250r · « **Reply #1 on:** January 22, 2015, 07:40:37 PM »

you mean the shrouds? scoops? i think everyone uses them. Engine overheating is common so big radiators, scoops, engine ice, inline billet coolers all help.

meathead · « **Reply #2 on:** January 22, 2015, 08:24:02 PM »

I'm building this thing to ride it not beat the crap out of it. I can see it overheating if your
racing or running the crap out of it. But for regular trail riding do you really think it would
overheat ? A big aluminum radiator I can see but those scoops really look redundant. I think
i'll give it a try and if it overheats i'll put them on. I've seen wheelers like this without them
For sale actually. I mean i'll open it up every chance I get I'm not gonna baby it either.

broken1 · « **Reply #3 on:** January 22, 2015, 08:48:46 PM »

Get one of those IR hand held temp guns & take a baseline on the exhaust side of the cylinder & than remove the shrouds & see how much difference there is. If it's extreme you have your answer as to weather or not there needed. Even at lower speeds I would think they help channel air through the radiator & I'd leave them on but thats just my opinion.

dem3500 · « **Reply #4 on:** January 22, 2015, 08:50:41 PM »

I'd say you need them

Hawaiiysr · « **Reply #5 on:** January 22, 2015, 10:21:56 PM »

Must be there for good reason. Every sport quad has rad shrouds.

meathead · « **Reply #6 on:** January 22, 2015, 10:39:11 PM »

Broken1 has a good idea with the hand held pyrometer. I just happen to have one of those.
I think i'll give it a try and re-post. It will be a while till I get this thing together.

rablack21 · « **Reply #7 on:** January 23, 2015, 09:21:36 AM »

The majority of the shrouds on the market today for the 250r don't really do diddly squat. They leave a gap between the radiator and the shroud, so most of the scooped air is being lost. And they tend to terminate at the back of the radiator instead of at the front where the fins are. The best example of radiator shrouds were the ones that came with Walsh radiators. Check em out, you'll see what I'm talking about. But they have long been discontinued.

meathead · « **Reply #8 on:** January 23, 2015, 10:23:19 AM »

Yeah I noticed that That and the way their shaped it looks like you really have to be moving to even get any at all air in there So I figure if you're really moving you don't need them anyhow I used to have a 86 atc 250r and I would go for a putt and just putt around and it never even got hot I could almost keep my hand on it for awhile sometimes I could. So I figure they are really aren't necessary. There just a pain in the ass.
The atc 250 r it looked like those shrouds really did something The way they are shaped
But the ones for the trx are almost in line to the air coming in so they don't really scoop anything It almost looks like they would cause a disruption of the air coming in actually
Make it swirl around instead of going through the rad freely I don't know really but it wouldn't surprise me if a temperature test like broken1 suggested yielded freaky results.
That's just an opinion So I'm gonna try that test. The problem is it wont be till summer
when I get it done Parts for this thing are expensive for the most part unless you can find a good deal on ebay which do come along once in a while. But anyways I figure a new possibly over sized rad is the way to go and leave it at that. But hey I will find out unless
someone else is real curious and wants to try that test sooner.

JesseA420 · « **Reply #9 on:** January 23, 2015, 10:33:17 AM »

i think the idea behind them isnt as much scooping more air, as it is making what air is in front of the radiator go through it, instead of the air going around it.

etccb · « **Reply #10 on:** January 23, 2015, 10:47:34 AM »

imo They are very important for trail riding as well with less speed forced air going trough the radiator.

meathead · « **Reply #11 on:** January 23, 2015, 11:28:22 AM »

I think that only so much air can go through the rad anyway so unless your using a blow
gun (without bending the fins) Your not gonna get any extra air through it at high speed
that can go through it And at low speed like I said And I mean really low speed Slow enough you want to rev it up once in a while so you make sure your keeping your cylinder and all the parts in there lubricated. Especially when decelerating with the clutch engaged. I think that the coolant circulates constantly. And I don't know for sure but in a car with
no thermostat it keeps the engine so cool that you will turn on your check engine light.
and it matters only slightly if you go real slow. So makes me think that even being a two stroke which naturally run cooler anyway due to the massive lubrication it gets, will be fine at low speed. Like I said I used to go super slow for long periods at a time almost like
trials riding And it never even came close to getting hot.

JesseA420 · « **Reply #12 on:** January 23, 2015, 12:22:53 PM »

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.

meathead · « **Reply #13 on:** January 23, 2015, 01:08:27 PM »

Sorry about that last post. But I don't think that your going to be able to force air into it at high speed because only so much air can go through it. if you try forcing air through it all your going to do is create pressure in front of the radiator and actually impede your forward motion. in reality you might be able to go a little faster without them. Of course these are only opinions. Without proper testing you will not know for sure. But I'm very curious about what the results would be. I'm sure the scoops cause some air to be directed at the radiator and some goes through there. But at high speed you really don't
need them because it seems like your getting plenty. Unless the design of the wheeler
causes the air to breakup some how and deflect it away from the radiator. Who Knows
I just thought this was an interesting question to ask. Of course all opinions are greatly
appreciated. I'm going to try it with and without. And if they happen to turn out useless
I will permanently remove them because boy are they ugly.

dem3500 · « **Reply #14 on:** January 23, 2015, 01:58:56 PM »

Op
If you already had your mind made up then why did you post the question? You obviously were fishing for the answer you wanted and that's not the answer you were given here by more than one person. If you want to run without them then run without them. Don't ask a question if you are not prepared to accept either of the possible answers.