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Fermin
06-29-2003, 12:53 PM
Recently read or heard something about not running a thermostat for racing and was wondering if anybody had any input on this topic.

Thanks for any input!

Fermin

Jeff Grant
06-29-2003, 01:04 PM
I inquired about the same thing when I raced my 99 Gixer750 last year. I was told not to do this with fuel injected bikes (has to do with how the computer reads the engine temp and how it effects performance).

With carb'ed bikes, I've heard of some doing this... some say it made a positive difference. The other side to that coin is that without the thermostat, the circulating water does not stay in the radiator long enough to cool down, ergo, cool the engine... and can actually make it run a lot hotter.

Then again, why was it supposedly working on other bikes?? If you're not having a cooling issue now, I wouldn't mess with it. My $.02

Jack Giesecke
06-29-2003, 01:46 PM
GPs don't have thermostats. We control temp with the race tuners most useful tool, duct tape, as in on the radiator on a cool day.

The point about water flow in the radiator is true. There was a thread a while back about this subject. This point came up and in order to test it, I pulled the thermostat in my old Gold Wing for a ride. Sure 'nuff, the temp was measureably higher on a real hot day. Put it back in, and normal. The way to get around that is to make an orifice plate to replace the thermostat or cut out the bimetal spring thingy that opens the thermostat and braze it open perminant. It's really a lot of trouble, though, when thermostats don't go bad that often anyhow. When they build GP stuff, they just build it around the fact that they're not going to have a thermostat. On a street bike, why would you bother? Hell, the water pump is a lot more apt to go bad than the thermostat and heck, you could replace the thermostat every off season if you're that paranoid of it.

Fermin
06-29-2003, 02:58 PM
Thanks for the input. Where ever it was that I read this was not specific with details such as fuel injection. Good info to have. Thanks again.
Fermin

Jim Cambora
07-01-2003, 10:42 PM
Remove the T-stat, remove the spring and guts. Reinstall the T-stat frame. The cooling system must have a restriction in order for it to work properly.

Any questions, call me!
Jim 817-465-4393

Jim Cambora
07-01-2003, 10:43 PM
Sorry, don't know my own number! 817-512-4393

Nate Weber
07-02-2003, 07:52 AM
Not trying to bash on anyone, but this is a misconception and is totally false!

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body"> The other side to that coin is that without the
thermostat, the circulating water does not stay in the radiator long enough to cool down, ergo, cool the engine... and can actually make it run
a lot hotter. </div></div>This would be like saying you need to limit air flow through the radiator fins to allow the air to heat up more.

Removing the thermostat will make the cooling system act as though the thermostat is merely open. Yeah you'll have less pressure loss through that section of the cooling system which may result in a slight increase in coolant flow, but now you'll have no control of engine temp. Controlling engine temp is a good thing because you don't want to run too cool. There is a direct correlation to operating temp and cylinder wall wear and when graphed it is a J curve. The lower the operating temp. the HIGHER the cylinder wall wear. At a temp of 160 F the cylinder wall wear is something like 3 times that at 190 F. Any lower than 160 and the wear increases astronomically.

Removing the thermostat will NOT significantly increase the cooling capacity of your bike. There are basically 3 feasible areas to address if you're want to increase cooling capacity. 1.) Increase coolant flow (which is the intent of removing the thermostat). 2.) Increase Air flow. 3.) Increase radiator size. I'm sure there are other things that you are thinking of, but they are small gains.

Saying that. The stock systems on these bikes seem to be very adequate. If you're having cooling issues, I would look at all of the small things and try to optimize them because there may be allot of them which are crippling the capacity of the stock system.

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body"> The cooling system must have a restriction in order for it to work properly. </div></div>Jim is absolutely right. Many engines have internal circuits of some sort and if you remove all restriction created by the thermostat then like the old saying goes, water flows in the path of least resistance. Most of the water will go into the radiator and those internal circuits may not get adequate coolant flow, possibly like with the Gold Wing. i.e. some of its engine cooling circuits are escentially being bypassed resulting in little flow and causing increased temps. (I don't know this for sure about this bike, but I do know cases with other engines where situations like this or the opposite occur. ex 351C)

I have an SAE Powertrain and Cooling analysis report that I wrote for Motorcycle engines in Formula SAE applications if any one is interested. It's good night time reading material if you're having problems sleeping. Email me if you want it.

Clawmark423@hotmail.com

Fermin
07-02-2003, 08:41 AM
Thanks again for the additional input. Not currently having any cooling issues (temp is around the 200 degree mark when coming off the track) but was mostly wondering because of the 100 degree temps that will be upon us soon and I this is my first season to race so was unsure.
Fermin
Am #509

Steve McNamara
07-02-2003, 09:09 AM
Damn Nate,
Impressive!!!
I just thought you were a racer. :-)

Nate Weber
07-02-2003, 09:29 AM
It's kinda my job here at work. Thanks though.

Anyhow, I'd rather just be an impressive racer. I guess that means I'm gonna have to get to allot more of them Lonestar Track days to work on that. /ubbthreads/images/%%GRAEMLIN_URL%%/wink.gif

Jeff Grant
07-02-2003, 10:26 AM
<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">Originally posted by Nate Weber:
Not trying to bash on anyone, but this is a misconception and is totally false!</div></div>d000d... you're totally bashing man!! That was just what I was told! (heh-heh) /ubbthreads/images/%%GRAEMLIN_URL%%/wink.gif

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">Originally posted by Nate Weber:
water flows in the path of least resistance. Most of the water will go into the radiator and those internal circuits may not get adequate coolant flow ....some of its engine cooling circuits are escentially being bypassed resulting in little flow and causing increased temps.</div></div>I think this is probably the issue I had heard about. Makes sense.

Texasoilman44
07-02-2003, 01:01 PM
Increased cooling water flow will remove more heat from the cooling circuit. However, if the radiator cannot handle the extra load, the coefficient of heat transfer is actually less so you either do not gain anything or actually lose. If you can increase the cooling water flow and the air flow across the radiator or the surface area of the radiator (installing a bigger radiator), then the coefficient of heat transfer will increase and therefore more heat can be displaced.

The one thing to remember, is that the engineers that design these things, in all of there infinite wisdom do know what they are doing. They design the cooling capacity based on the BTU output of the engine. If you are having cooling problems, I would look elsewhere.

Regards,

Kevin

To the pessimist the glass is half empty. To the optimist the glass is half full. To the engineer the glass is twice as f*!%?ing big as it needs to be.

Jim Cambora
07-06-2003, 09:05 PM
My post was not an effort to repair or enhance cooling system capabilities. The only reason to remove a T-stat as I described is to eliminate the possibility of a part failure. I have tested the cooling systems on a dyno with the thermostat frame and without. There is a noticeable difference. Nothing worse than spending $2000 or $3000 to go to Pocono, qualify 3rd in the FUSA superbike class, run your warm up lap for the race and the bike overheats due to thermostat failure. Who was watching? A big name owner? Was that your shot that misfired for about $25.00? It doesn't matter because you didn't race. Race prepping a machine is not only performance based. It's also to eliminate possible future problems. These changes I make when building a race bike are based on experience. If the bike can't make the race grid as mentioned in the scenario above it reflects directly on me as a mechanic and tuner.

E. Templet
07-06-2003, 11:07 PM
<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">Originally posted by Nate Weber:
Not trying to bash on anyone, but this is a misconception and is totally false!

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body"> The other side to that coin is that without the
thermostat, the circulating water does not stay in the radiator long enough to cool down, ergo, cool the engine... and can actually make it run
a lot hotter. </div></div></div></div>Wrong-O Nate.

The thermostat is an orifice and required for proper cooling. The only time removing the orifice would make a system more efficient would be if the design engineer missed the boat on his calculations.

Any refrigeration mechanic could enlighten you on the differential inlet and outlet temperatures being the determining factors concerning proper heat absorption and maximum efficiency.

If you have ever seen a thermostat up close, how could you state that the system would only react "as if the thermostat is open"?

For my dollar I'd just as soon leave the thermostat alone. They go 100k miles plus in automobiles..... no reason why they can't go a season (100 hours) in a motorcycle engine.

I understand Jim's point, as he is looking for less parts that can shut down his bike. And besides, he is a professional and makes his living doing this stuff.

In the end, be very careful about advice you take concerning your motorcycle. Seemingly insignificant changes can have fatal consequences to your engine and ruin your day and perhaps season.

Nate Weber
07-07-2003, 07:56 PM
Hey Gene,
Just thought I'd clear up a few things about this post and statements made.

1) I'm NOT wrong!

2) This is not an air-conditioner! A Vapor cycle needs an orifice to cause a pressure drop resulting in a refrigerant vapor flash, but we are not using freon nor are we dealing with a Vapor cycle!!!! Be careful of your analogies because there is a huge difference between these two systems, anyone that's taken Engineering Thermodynamics can tell
you this!

2a) The thermostat does not act as an orifice in an engine cooling system as it does in a refrigeration system. In a engine cooling system it's main purpose is only to limit flow to the heat exchanger, period! Also, I never said removing the thermostat would increase the efficiency of the system, I said it would result in a slight increase in capacity, there's a difference. I'm against removing the thermostat, leave it in!

3) I have done the Engineering analysis and mathematical calculations for both a water to air heat-exchanger thermal system, and a refrigeration
system, and I have them in report format if you would like to view them.

4) If you have some calculations yourself I'd love to compare work and if you can find error in mine and prove me wrong that would be great, because I will have learned something from it.

5) I've got experience in this discipline too. Work and University studies and graduate projects.

6) Some of my comments may not have been the clearest and that is why I offered to share my studies with anyone interested.

7) I'm through posting on this topic, no one has to believe me if they don't want to. I've
seen so many people argue over this subject that it's gotten old to me, yet no one ever puts forth any empirical data! Hopefully I can change that.
I'm not posting to try to prove any points, you can agree with it or disagree with it, I just want to help the club and race.

Thanks

David Hirsch
07-07-2003, 08:18 PM
Nate, You may reply as an email if you would like. Also I would like to read your report if you want to email it to me at bibmen@bibmen.com.
I have always gone with Jims method and I never had any problems other than using duct tape on the radiator if it was too cool out.

ysr612
07-07-2003, 08:28 PM
I have not looked at the bike cooling system (never gave me problems) but in a car the thermostat is a diverter valve and if you take it out you need to put something in to send the water the way you want it to go. In some auto system with it out it will go 90% around the block so it overheats with it out in some 90% to the radiator so it never warms up with it out.

Nate is correct on what he said. I am trained as a chem E. (never did it but I took thermo II ) Jim is also correct. they do not contradict.

E. Templet
07-07-2003, 11:22 PM
<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">Originally posted by Nate Weber:
Hey Gene,
Just thought I'd clear up a few things about this post and statements made.

1) I'm NOT wrong!

2) This is not an air-conditioner! A Vapor cycle needs an orifice to cause a pressure drop resulting in a refrigerant vapor flash, but we are not using freon nor are we dealing with a Vapor cycle!!!! Be careful of your analogies because there is a huge difference between these two systems, anyone that's taken Engineering Thermodynamics can tell
you this!

2a) The thermostat does not act as an orifice in an engine cooling system as it does in a refrigeration system. In a engine cooling system it's main purpose is only to limit flow to the heat exchanger, period! Also, I never said removing the thermostat would increase the efficiency of the system, I said it would result in a slight increase in capacity, there's a difference. I'm against removing the thermostat, leave it in!

3) I have done the Engineering analysis and mathematical calculations for both a water to air heat-exchanger thermal system, and a refrigeration
system, and I have them in report format if you would like to view them.

4) If you have some calculations yourself I'd love to compare work and if you can find error in mine and prove me wrong that would be great, because I will have learned something from it.

5) I've got experience in this discipline too. Work and University studies and graduate projects.

6) Some of my comments may not have been the clearest and that is why I offered to share my studies with anyone interested.

7) I'm through posting on this topic, no one has to believe me if they don't want to. I've
seen so many people argue over this subject that it's gotten old to me, yet no one ever puts forth any empirical data! Hopefully I can change that.
I'm not posting to try to prove any points, you can agree with it or disagree with it, I just want to help the club and race.

Thanks</div></div>Gee, I don't think I yelled or used on exclaimation point in my whole post. /ubbthreads/images/%%GRAEMLIN_URL%%/smile.gif

Yes, you are wrong because removing the thermostat will "not" make the cooling system "act as though it is merely open". The thermostat does act as an orifice/flow restrictor/flow deverter. You even acknowledge this in one of your other statements. You contridicted yourself in your agreement with Jim concerning this.

I made no reference that the motorcycle cooling system is anything like a refrigeration unit in it's operation or design. I only refered to a referigeration tech as a souce of system efficiency measurements.

Why can't people have a conversation or discussion without getting all ruffled up? /ubbthreads/images/%%GRAEMLIN_URL%%/confused.gif Reason, it is the false self, that needs recognition, approval, status, and esteem among peers. In life it doesn't matter who is right, only what is the truth. That should be our goal...only that, and there will be no losers.

Our lesson for the day /ubbthreads/images/%%GRAEMLIN_URL%%/smile.gif

Take care and ride safe.

E. Templet
07-07-2003, 11:29 PM
Actually, this thread should have been posted in the tech section. /ubbthreads/images/%%GRAEMLIN_URL%%/laugh.gif

Jim Cambora
07-08-2003, 12:41 AM
Sorry to cause any poop! For most racers the best way is to leave the T-stat installed unaltered!

Jim

marcus mcbain
07-08-2003, 12:56 AM
<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">Originally posted by Jim Cambora:
Sorry to cause any poop! For most racers the best way is to leave the T-stat installed unaltered!

Jim</div></div>Jim, next thing you'll be saying is that non-rivet M/L's are OK to use for racing... /ubbthreads/images/%%GRAEMLIN_URL%%/laugh.gif

Marcus

Nate Weber
07-08-2003, 11:29 AM
I'm going to try to clear this up once and for all.

Getting back to the basics of an engine. Not all engines have internal re-circulation or the need for the thermostat to help divert coolant. Saying that, and this again, the main function of the thermostat is to regulate flow to the heat exchanger to help maintain a desired operating temperature.

Engine cooling 101:
Say we did have an engine like this, with no internal re-circulating or need for the thermostat to divert flow. (which is a very realistic situation for recreational vehicles) If the thermostat were removed it would basically act as if the thermostat was stuck open, or the internals were removed. You would get additional flow too, but lets not get into that. My point is and was that you would have allot of coolant flow at all times resulting in low engine operating temp. The temp would not go up because of this.

Engine cooling 102:
Now we ad a level of complexity and assume the engine now has a re-circulation loop to aid in warming the engine up when its cold, or for possibly some other reason. If you remove the thermostat it will possibly cause cooling problems because you may not get proper flow to the heat exchanger/radiator or to the internals of the engine. If you remove the internals and install the housing it will act as if it's stuck open, and it will be similar to our Engine cooling 101 engine and will run cooler.

The statement was made that too much/fast coolant flow threw the radiator would not let the water dissipate the heat because there wasn't enough time. This is the statement that I am calling false and untrue. This is true though, (to an extent of course):
If you increase coolant flow it increases cooling capacity.
If you increase air flow it increases cooling capacity.
If you increase radiator size it increases cooling capacity.

If you remove the thermostat with the intent of increasing capacity, you may have to address the issue of internal re-circulation circuits, in which case removal of the internals would be a solution. I don't think you're going to gain much capacity though. Saying that I know that Jims intent in doing this was for reliability and that's a smart solution when allot is on the line!

Also, when I said you will get more engine cylinder wall wear from lower operating temps, that is not necessarily of concern. I doubt most race engines see that many miles, but if you ever want to put it back on the street or do that to a street bike it's probably going to suffer from premature wear.

Now to wrap this up since I'm sure everyone is bored.
Everything I said here is basically what I've said in previous posts, hopefully it's more understandable.
Gene, I wasn't ruffled or yelling in my emails. I used "!" merely to try to emphasize points I was trying to make. Nor was I personally attacking you. If you re-read all of my posts not once did I say you were wrong. I thought I was being tactful unlike some other posts. Like I said, I merely was hoping to clear up misconceptions and hopefully help the members of the club. Other opinions are always welcome though.
Jim you didn't start this poop, It would have happened regardless.

Anyhow hope there's no more confusion and we can all get along, Where's the love man
/ubbthreads/images/%%GRAEMLIN_URL%%/wink.gif
Thanks,

Eric Kelcher
07-08-2003, 12:21 PM
<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">Originally posted by Nate Weber:
The statement was made that too much/fast coolant flow threw the radiator would not let the water dissipate the heat because there wasn't enough time. This is the statement that I am calling false and untrue. This is true though, (to an extent of course):
If you increase coolant flow it increases cooling capacity.
If you increase air flow it increases cooling capacity.
If you increase radiator size it increases cooling capacity.

Thanks,</div></div>I made some of these statements and my issue was not based on actually this my argument was that the effiencey of the system is greater with a larger heat differnetial(IE the water exposed to motor was much cooler than motor and water exposed to radiator was much hotter than out side air) And when the temp differnce is greater you get better cooling. By having the T-Stat installed you slow the water flow allowing it to heat more (carry more BTU's out of engine) and cool more in radiator (release heat to atomsphere)
Then there is the whole issue with cavitation of the water pump at the sustained high pump speeds that a race motor lives at that are possible without a slight resistance which can cause heat issues.

Now if the water at high speed (sans T-Stat)acheives the same output temp as at low speed (with T-Stat) and radiator can cool that additional load then there was a mismatch from the factory on radiator/engine flow combo.

Nate Weber
07-08-2003, 12:31 PM
Good points!!! (I'm not yelling) /ubbthreads/images/%%GRAEMLIN_URL%%/laugh.gif

and that's why I included "(to an extent)"

Those are areas of concern and can be an issue. My cooling analysis report takes these items into account. Email me and I'll send it to you too.

Thanks