air flow under the plastic and dumping heat

[Chris09]

I thought I'd start a thread about air flow / cooling / air impingement / ventilation of components / radiation / conduction / convection / fan cycling / actual cfm / actual air flow / velocity at zero speed vs velocity under way... and all that stuff.
Before getting underway with my own ST this summer, I did a bit of experimenting with it after servicing and verifying that I've got a clean / clear / unobstructed / unfouled radiator with everything as it was designed, all the fairing parts, foam bits, seals and gaskets correct.
Last year I had highway pegs protruding through cut engine guard covers; I think the air leakage through those deprived the engine sides and pipes of the correct ventilation.
The OP provided me with new engine guard covers which I will be using this year, my belief is that once the forward portion of the bike is sealed, the radiator fans will force air as designed; across and down through the inner plastic,

 

[Bmacleod]

Good luck. There have been as many threads about air flow / cooling / air impingement / ventilation of components / radiation / conduction / convection / fan cycling / actual cfm / actual air flow / velocity at zero speed vs velocity under way... and all that stuff , as there have been threads about oil, with little success.
Seriously, I hope you come up with something.
There was one guy from Idaho mounted a couple of computer case fans, with "velocity stacks" to the sides of his fairings to evacuate the hot air.

 

[SMSW]

Good luck. There have been as many threads about air flow / cooling / air impingement / ventilation of components / radiation / conduction / convection / fan cycling / actual cfm / actual air flow / velocity at zero speed vs velocity under way... and all that stuff , as there have been threads about oil, with little success.
Seriously, I hope you come up with something.
There was one guy from Idaho mounted a couple of computer case fans, with "velocity stacks" to the sides of his fairings to evacuate the hot air.

And the guy who made what he called the Redneck ventilation system out of vacuum cleaner hose, plastic scoops, and pvc fittings. He did not post the results of an independent study of the efficacy of his system for peer review.

 

[Chris09]

Well I began with the back fairings off, the little bits over the heads off, the guard covers off, and the lower fairings off. On the centre stand, when the fans kick in man, they boot air, blast it out pretty good, got me thinking

these fans as small as they are, have to moving 800 cfm

can't help but wonder if we could get some bigger fans in there

not bigger in the conventional sense of the word

The exhaust pipes imediately out of the engine are [I see no manifolds; almost like my horrible Jeep 3.6] are encased / concealed / enclosed, it can't get harder from there.

... you gotta move air across it, but, you gotta hit it with air; impingement I think is a big part of this engine; without it, ventilation isn't gonna help you

call it a hunch

 

[Kevcules]

The rad fans aren't running all the time so we can't use that to determine heat dissipation/reduction function.
I've also thought about how we can somehow direct the hot air out to atmosphere from below, instead of baking your legs as it exits from the forward sides.
Keep us posted on your experiments.

 

[Chris09]

Well one of the things is, why not keep the fans running continuously during high ambient temperatures; if you can run accessories off the later unit alternators surely the fans could run continuously at some given OAT

with all the stuff on, it seems to me that air moves through the rad, across the the engine, then down, maybe at some OAT, more [bigger fans] air, running continuous;
it's an alusion to imagine that this assy, cools itself, it's a mechanical heat rejection machine, I just don't get why it hasn't been addressed sooner

In the absence of the fairing parts, you can not keep the air against the engine

 

[Chris09]

rebuttal

 

[Andrew Shadow]

Well one of the things is, why not keep the fans running continuously during high ambient temperatures; if you can run accessories off the later unit alternators surely the fans could run continuously at some given OAT

At higher speeds, the fans do not come on because there is more passive air flow than is needed and more than the fans can produce. The fans only operate a lower speeds when there is insufficient passive air flow, and more air flow is required.

Even if the fans were on continuously, due to being a liquid cooled engine, the thermostat will maintain the same engine temperature just as it does when there is an excess of air flow at high speed. This means that the fans come on when they are needed, and when they don't come it is because they are not needed and that they would provide no benefit at that time.

 

[TerryS]

I have no issues with the ability of the 1300 engine/cooling system to regulate it's own heat, but I do think the designers have made a poor compromise of keeping the rider isolated from the result. My old ST1100 had a very similar layout/engine so presumably pumped out the same heat as the 1300, yet I never ever noticed it doing so. I think the tube frame/plastic shell of the 1100 allowed most of the heat to vent out under the panels to the rear and isolated the rider from it, where the tight packaging of the alloy frame/secondary tank/seat etc prevents this from happening and traps the heat in the rider contact areas. If I was dreaming of a modification, it would be some system to extract hot air from the area below the main fuel tank rear, maybe a fancy venturi-creating duct under the bike. As is, I make sure to always wear decent textile pants and then move to a cooler bike when it is really hot. My Yamaha MT-10 or VFR800 are perfectly pleasant under 30+ temperatures.

 

[Andrew Shadow]

If I was dreaming of a modification, it would be some system to extract hot air from the area below the main fuel tank rear, maybe a fancy venturi-creating duct under the bike.

Redneck nut cooler | Staying Cool

Heading across South Dakota with 100 degree temps soon... No need to get fancy...

www.st-owners.com

 

[NVDucati]

rebuttal

There is a company Exair which works in industrial air movement including entrainment. They sell off-the-shelf bells as small as 2 inches at reasonable prices.
@TerryS makes the correct point that cooling the radiator further won't help. However, evacuating air from the just right spot, might. It would be interesting to have someone in a car use a thermal temp gun ride beside you to see where the most heat is.

 

[Chris09]

Yeah that's what I was thinking, try to get more air flow; thourough put; the one thing though that I did notice was that there is a intended air direction through the bike

just can't figure out what it is

more air flow equals less retained heat

IMHO

 

[Willsmotorcycle]

Some other considerations may be checking your cooling system to make sure it is operating correctly, different engine oils will have an effect as well. Possibly wrapping the headers with exhaust wrap will retain heat in the pipe allowing the ambient temperature to be lower. The Cats are at your heels, when you stop after a spirited ride and the asphalt is 140 degrees, you will undoubtedly feel warm. If you stop to close to the vehicle in front of you, their heat will be a factor. Just some random thoughts on your journey, keep us posted.

 

[klaproth]

I can tell you what DOESN'T work- I tried a lot of the "fixes" on here, up to and including talking to Igofar, who gave me a list to pursue ( Yes, I did all of the things he recommended). To this day, none of them , EXCEPT the Baker Air Wings did any good at all.

Done to date:
On Igofar's ( Larry's) recommendation:
1. Change thermostat
2. Switch to non-iridium plugs
3.Balance throttle bodies
4. Re-install inner cowls ( this DID cause more perceived heat)
( no change)
Done on my own:
1. Installed Reflectix inside the fairings ( no change)
2. Added Goldwing vents on side of upper cowls ( no change)
3. Ceramic coated headers and used pipe wrap ( very little change)
4. Added Baker Air Wings ( home made) ( made a medium difference, mostly while moving)
5. Added a wood bead seat cover, which raises one off the seat, for better air circulation.
6. Made a conscious effort not to "hug" the tank with my legs, and allow more air in there....ALA' Igofar

The ST is just a "hot" running bike. I mainly ride it in the fall and spring, to alleviate the heat. I bought a smaller, less faired bike for warmer weather. ( Honda NC700X)

 

[Chris09]

I thought the tip over covers were closed, and mine were just hacked open to accomodate highway pegs, but I looked at the new ones I have and they are substantially vented on the bottom so there's a lot of air that bypasses through the head opening and cover vents that doesn't get forced across the exhaust pipes and down.
I don't think my bike has likely ran in any real heat but I've got some blistering bubbling of the paint low along the left fairing, which has to be radiant heat from the pipes.
Another thing I imagine happens is there must be a pretty good heat soak when the bike is shut off hot; I've never noticed the radiator fans running on after shut down like some bikes do.
I noticed that idling in a cool ambient temperature, before putting the fairings back on, flow through the radiator occured mainly in the upper half, almost the entire lower half of the radiator remained cold. Maybe the thermostat was only modulating partially open and when it does get to a further point in it's gradiant more fluid will move through the lower circuits, will see if my el cheapo heat gun will tell anything along the ride tomorrow.
Wondering if the fans could be set to run continuously once a specific ambient is reached, the stat will still regulate to keep the engine hot enough, and there would be less temperature rise across the rad during this phase. Also could a colder stat with a larger bypass hole be used. The three temp bar range is pretty wide, some bikes must be running toward hotter while others are colder all displaying three bars.

 

[TerryS]

I agree with the 3rd bar comment; my guess is that it covers the full range from thermostat opening (around 78C) to well into the fan operating range (100C+). My VFR800 has a degree read out, lots of owners worry about the numbers being displayed. Back in the day when temp gauges were dials, anything less than "H" was OK...

 

[Fawlty]

I noticed that idling in a cool ambient temperature, before putting the fairings back on, flow through the radiator occured mainly in the upper half, almost the entire lower half of the radiator remained cold.

Chris, have you thought that the radiator/cooling system could need flushing? Just a thought.

 

[SMSW]

Chris, have you thought that the radiator/cooling system could need flushing? Just a thought.

If you were suggesting the radiator might be plugged, a simple flush will not clean it out. For that you would need a chemical or mechanical flush (the latter was called 'rodding' in the old days). Way back when, I remember seeing more than a few radiator shops but not anymore. Have radiators improved that much or did we simply start using coolant (anti-freeze) that does not deposit solids inside small radiator tubes?

 

[Bmacleod]

OP, try thinking of the bike as a big funnel, with a small opening/drain at the bottom. You are talking about making the mouth of the funnel bigger to take in more air, yet the drain at the other end is still too small. Running the fans all the time will only shorten their life and put a strain on the battery/charging system, but without increasing the flow THROUGH the bodywork, you should see no improvement. If you really want to think outside the box, try removing the lower fuel tank to let some air escape out the back. (Before I get flamed, understand that I am certainly kidding about removing the fuel tank, just making a point about trying to exhaust some of the trapped heat)

 

[Fawlty]

Have radiators improved that much or did we simply start using coolant (anti-freeze) that does not deposit solids inside small radiator tubes?

Interesting point. In the past I have flushed radiators with chemicals, including vinegar. You could be right about modern day coolants. Years and years ago I seem to remember that anti freeze was only used in the winter and quite often plain water was used in between times, maybe that could explain why radiators got clogged more often than they seem to these days.