bigger radiator test

[katze300rr]

I´ve just bought a pair of cheap eBay Chinese radiators. The main purpose was to have them as a spare part for a long desert and mountain raid I’m having next month. Also got a Chinese silicone hose kit, and a Trial Tech digital temperature gauge with a hose sensor.

To my surprise, the rads look really good, much better than expected for the money (good welds, thick walls, thick body, but crappy cap). Also, had some good comments about their better cooling ability due to more capacity, since they are 40mm instead of the 23mm or so from OEM rads.

I always thought this bikes run a little bit too hot, specially at low speeds or hot enviroment (desert, wind form behind, hi-reving in mud or deep sand, etc) , and I think that some extra cooling would help in engine durability, reliability and efficiency., so I decided to kill my curiosity and test them.

First installed the temperature gauge right after the engine water exit.

Then run the test with OEM rads, from a totally cold engine, one day in the morning. After that, installed the CHN rads and run the same test in the afternoon, also form a totally cold engine and almost same conditions (same spot, about same ambient temperature, etc)

The test I run was very simple, home-made-non-scientific. First the “static test”: start the bike and keep it completely idle for 10 minutes (not a single gas turn). Take temp readings every 30sec the first 5 min, then every 1 min. At minute 10, turn it off and keep reading for another 5 min. After that, the “dynamic” test: run the bike hard for 3 minutes. After stopping, read the current temp and then again 1, 3 and 10 minutes after that.

After that, installed the CHN rads and hoses, and repeat the test. (kept the OEM cup)

Here, the results. (The temperature is in Celsius, sorry Fahrenheit fans)

My interpretation and oppinion:

They cool a little more (about 2 ºC) when the bike is heating up, up to a certain temperature when them both cool the same. When riding, the also cool 2-3 ºC more. When stopped, the CHN get cold faster 4ºC).

They look stronger. Couldn´t test that yet, we´ll se after a few falls if that´s true ?

They are heavier (rads+coolant weight like 0.5Kg more)

They don´t fit so well: the shrouds needed some hard pulling to get in place.

My general conclussion is that they seem to run a -little- better, specially when running and after stopping.

Not worth the replacement for performance reasons, but a very cheap replacement choice.

General data:

Bike: 08` WR450f with stock water pump and exhaust pipe. OEM rads non bent nor hit.

Altitude: sea level

Coolant: water with no special coolant (there´s a reason for that)

Env: 24-25 ºC, no wind, cloudy

Next step:

Try them in the desert raid.

Install a fan cooler and run the test with different coolants (i think THERE will be a difference)

Install a hi-flow water pump.

Best regards, from Argentina.

[n16ht5]

Wow, this should be a magazine article. Thanks!

[katze300rr]

to any ADMIN: this topic was unintentionally posted twice, please delete one copy. Ty.

[Troy35]

Thank you for the time that you put into this test! I was considering the bigger radiators for a cooling upgrade, but I'll hold off on that and only use them if I crack one. Please follow up if your opinions on the cooling difference change with a more prolonged test or ride.

[still2smokin]

I find this very interesting , I had thought that the bigger rads would produce way lower temps.

I wonder how much more cooling would be acheived with an aftermarket/high flow waterpump combined

with the larger Chinese rads.

BTW.... nice write up .

[MANIAC998]

Very nice write up!!! The static findings are about what I expected. It doesn't matter how wide a radiator is while sitting still. It's all about how much surface area there is that can shed that heat to the atmosphere, and this is the same on both. Now moving is a different story! If we assume all things being equal, which they rarely are, then the wider Chinese radiators should cool quicker than the OEM's. Will they run cooler than OEM? Hmmmmmmm.............that I don't know!

One benefit that might be getting overlooked is that they hold more fluid, so if they do boil over, they will still be holding more fluid than a boiled over OEM radiator, and this might be enough to keep from causing engine damage. Just my thoughts.

[miweber929]

Great findings but unless I mis-read your high stress was 3 minutes of hard running? My thought would be a better gauge of performance would be more running than statically testing like Maniac said.

Sitting and cooling is one thing, but a 15-20 minute loop with air flowing (or not flowing) might provide better ideas how the shed "overheat" and not just "normal temp heat".

Just a thought, and thanks much for doing this.

[katze300rr]

I find this very interesting , I had thought that the bigger rads would produce way lower temps.

I wonder how much more cooling would be acheived with an aftermarket/high flow waterpump combined

with the larger Chinese rads.

BTW.... nice write up .

Thanks everyone for the good feedback

I think that the hi-flow pump is the key to the difference. That´s the opinion for example, of Mauricio "Paco" Gomez, a guy from here who run 2 Dakar Rallys with a private WR450. He did it with a Boyesen Pump, OEM Rad and silicone hoses. He had ambient temperatures over 50ºC and rides at 4.000m high (water boils around 80ºc there) This year he had an Official Yamaha France YZF so he didn´t care any more about mechanic nonsense ?

miweber is right: 3 minutes hard run is not much. Should have run more. But what worried me most and made me try to do this was "near-static" running.At had speeds, CHN may or may not run cooler, but OEM run just fine. Hi-reving at slow speeds in sand, sliding the back wheel with no grip in mud at 5 km/h, etc., that´s what i care most...

maniac says " It doesn't matter how wide a radiator is while sitting still. It's all about how much surface area there is that can shed that heat to the atmosphere, and this is the same on both". The surface part is right: when moving, the bigger radiator has more surface in contact with air to radiate. Static, the surface is almost the same. but don´t forget the water volume (mass) is bigger (about 30%) So it has a bigger "heat inertia", it takes longer to heat. A little longer, as seen in the test.

I´ll keep testing and keep you briefed, but unfortunately no more comparison will be made because I ´m keeping the CHN. Maybe if someone else has the TT gauge installed at the radiator intake can post their numbers, and we can make sort of statistic or reference values

Best Regards from Argentina

. JM

[MANIAC998]

Have you installed any radiator guards? This is the primary complaint with the larger radiators, in that most of the time it's nearly impossible to fit radiator guards to them.

[katze300rr]

Have you installed any radiator guards? This is the primary complaint with the larger radiators, in that most of the time it's nearly impossible to fit radiator guards to them.

Nope, tried Work Connections but it won´t fit, but it seems they can be adapted. I´ll work on it this month.

[DeepPurplishBlue]

Just tried to put a set of the china rads on a 2005 WR450 and they don't fit worth a darn... the hose fittings on the left side rad stick out too far, and on a rad that is already a lot thicker than the stock rad this results in clearance issues. The fuel tank hits the large vertical hose. Shimming the rad with a bunch of washers was the only way to get it to go and still not really happy with it. Also the stock plastic radiator guard fits very loosely. Same problem with two different sets of china rads so it seems to be a design/production issue rather than a one-off manufacturing error.

The china rads fit without major issues on my WR250s though so go figure... also got aftermarket radiator guard to go in without major issues.

[panda38]

put a set of china rads on my 07 wr450 and the fit was good except for a little work needed for the plastic rad guards. They didn't do much when the bike was standing still but made a huge difference when underway. We ride mostly tight single track 1st and 2nd gear stuff.

[Yzfracer]

http://www.amazon.com/EVANS-POWERSPORT-Evans-Powersports-Coolant-Gallon/dp/B005DGZLQE/ref=sr_1_5?ie=UTF8&qid=1362003431&sr=8-5&keywords=waterless+coolant

This stuff works great also!!