Why even run a thermostat?

[Sjorge450R]

I was talking to my dad the other day and we were thinking. Is it nessacary to run the thermostat in our quads? I mean especially use with the grounded out fans. I mean it couldnt be that much of a difference eliminating it, cause all that would mean is that my coolant would always be flowing.

Like I mentioned, Im not sure on this and thats why i am making this post. Just thought i would see what others think about this

[300ex_#387]

This is the way I see it, but I could be wrong. The Thermostat is set to open at a certian temperature, and close at a certian temperature. I would think that quad would run better at a warmer temp, rather than running at a cooler temp all the time with the thermostat out. I could be wrong, but that is what I think.

[bloodmoney23]

any motor will run better cooler hence the reason for turbo chragers. But with such a small engine, they are made to run at a certain temp. i would leave the thermostat on it.

[Hammer trx450r]

The thermostat will also slow the flow down just enough to let it cool in the radiator

[Hammer trx450r]

Originally posted by bloodmoney23
any motor will run better cooler hence the reason for turbo chragers. But with such a small engine, they are made to run at a certain temp. i would leave the thermostat on it.

What does that mean?????

[rt20ps]

Cooler isn't always better. These engines only make peak horsepower when properly warmed up.

Too hot or too cold and your loosing HP.

That being said, we are usually trying to find ways to keep them cooler, unless your ice racing or racing in extreme cold temperatures.

The dirtbike engines do not have thermostats.

[bloodmoney23]

Originally posted by Hammer trx450r
What does that mean?????

it means leave the thermostat on it....if you want to run cooler buy a better fan and oversized radiator.....

[pro-rider46]

yeah the thermostat, by passes the cold coolant so it keeps it circulating through the engine, if you didnt use one, it would take a long time to warm up, and cause the quad to run rich, and it could eventually get so hot it would just over heat. so i think that it would be the best to keep the thermostat,

[Sjorge450R]

see this is excatly why i asked on here before i did anything. I wasnt sure if the quad made its best power when hot or when it was cooler.

Just with these responses, answered my question greatly and by the amount of people that responded, i can tell im not the only one that ever thought about this...lol

[Hammer trx450r]

Originally posted by bloodmoney23
it means leave the thermostat on it....if you want to run cooler buy a better fan and oversized radiator.....

I meant the "hence turbo charger" statement

[bloodmoney23]

Originally posted by Hammer trx450r
I meant the "hence turbo charger" statement

turbos are designed to help make something run cooler. the cooler the air through the turbo the faster a car or bike will go which is why it is able to run more fuel. and say a cold air intake will also increase hp on a car becuae it is cooler. the cooler it runs the better a car will run. But since the motor on a 450r is so small....it is actually worse to run it too much cooler. but anyway, that was offtopic and glad everyone could help you out sjorge

[4bidden]

Originally posted by bloodmoney23
turbos are designed to help make something run cooler. the cooler the air through the turbo the faster a car or bike will go which is why it is able to run more fuel. and say a cold air intake will also increase hp on a car becuae it is cooler. the cooler it runs the better a car will run. But since the motor on a 450r is so small....it is actually worse to run it too much cooler. but anyway, that was offtopic and glad everyone could help you out sjorge

lol....I think you need to read some books! You have no idea what you're talking about.

First off...Turbos produce excessive intake air temps which is why most setups have to run an intercooler to cool the intake charge.

Second...The additional power is due to the air being FORCED into the engine from the turbocharger which then requires more fuel. And more fuel (bigger injectors) + more air to match (compressed in by turbo) = more power.

We're way off topic. But some people seem to think they know more than they do!

[Hammer trx450r]

Originally posted by 4bidden
lol....I think you need to read some books! You have no idea what you're talking about.

First off...Turbos produce excessive intake air temps which is why most setups have to run an intercooler to cool the intake charge.

Second...The additional power is due to the air being FORCED into the engine from the turbocharger which then requires more fuel. And more fuel (bigger injectors) + more air to match (compressed in by turbo) = more power.

We're way off topic. But some people seem to think they know more than they do!

Thanks u saved me some typing

[bloodmoney23]

ok so my turbocharged car with a GT35R ball bearing turbo and perrin oversized intercooler that runs at 165º has nothing whatsoever to do with the turbo. Im pretty sure that the 35r, which i run normal at 18psi would create enough heat to kill someone then according to your statement. I know what a ****ing turbo does douchebag, its called forced air induction. and since this is my 3rd t/c car i think i understand quite a bit. henceforth air is cooled down by a intercooler which in turn cools the air before it gets there which my friend creates cooler air going into the motor. cooler air into the motor makes the car run cooler. but i dont know ****...... ill admit it. I dont i just talk out of my *** all day. Its actually quite fun to do cause you get the know it all asshoels that think they are god to sit and talk **** instead of saying hey, your wrong this is what it really does. So in everything said. A turbo car will run cooler, and perform better. but regardless. my point was that if you make the 450r run cooler it will not run peak performance.

[Hammer trx450r]

Thats called EGT's (exhaust gas temp):rolleyes:

[NJ450rider]

Turbochargers run off of exhaust gas and that gets them hot. super hot!! intercoolers exsist to cool the charged air going into the cylinders. and even then it really only cools so much. You can have a turbocharged vehicle without an intercooler. than you wouldnt be able to turn the boost up much because of detonation. And lastly turbo cars dont run off of outside air temps. And my srt-4 will boost higher once it warms up and gets to the right temp.

So either way running too cool is bad for an engine.

[pro-rider46]

cold air is denser than hot air, so cold air that goes through a turbo then becomes super dense, adding the extra fuel makes a lot more hp.

[KEVIN132]

well i dont run one in mine.i have an oversize radiator. my bike is a falicon 531 with the crf ignition and i run no fan. it does get hot if your playriding in woods. but on mx never have a prob!!:D

[toxicd]

ok getting back to the original question. the reason why you run a thermostat is because like someone said you do not want the water passing through the water jackets and cooling the cylinder at all times, especially on startup. the reason is not only because of the proper operating temps for horse power, but mainly because like every other thing on the planet with atoms, metal expands when hot, especially cylinders and pistons!!!

if you heat up the piston much quicker than the cylinder (which usually happens because of the combustion and the fact that aluminum dissipates heat much quicker then steel) then guess what, your piston expands and your cylinder does not creating more friction and wear on your components.

any mechanic or any joe blow who has put a 160 degree thermostat in a chevy 350 v8 that didnt really need it knows first hand what will happen. the front cylinders, especially the passenger side i believe, will eventually catastrophically fail resulting in severe engine damage. i have seen this first hand on at least a half a dozen occasions.

[400exrider0004]

don't take out the thermostat. Just like a car it is in there for a reason. A thermostat isnt just for allowing water into the jackets at a certain temperature it also regulates the temperature. If you were to take out the thermostat it would take you a good ten minutes for the bike to warm up to the recommended temperature. It will get to the recommended temp. (lets say 160 degrees) for a minute and then shoot past it or dive back down again because there is nothing regulating the coolant flow. Dont take it out.

[KEVIN132]

im just stating what i run. i race mx so im not out there long. i have never had a prob with motor at all .

i just think that if it gets to the point of opening whats the diffference if its open already. its keeping the motor cooler before it has to open.

[86250rrider]

SO DEN R U SAYING A TURBO IS LIKE HOT AIR NITROUS ? HES GOT NOSSSSSSSSS...... BOOOOOOMMMM !!!LOL:rolleyes:

[400exrider707]

Originally posted by bloodmoney23
ok so my turbocharged car with a GT35R ball bearing turbo and perrin oversized intercooler that runs at 165º has nothing whatsoever to do with the turbo. Im pretty sure that the 35r, which i run normal at 18psi would create enough heat to kill someone then according to your statement. I know what a ****ing turbo does douchebag, its called forced air induction. and since this is my 3rd t/c car i think i understand quite a bit. henceforth air is cooled down by a intercooler which in turn cools the air before it gets there which my friend creates cooler air going into the motor. cooler air into the motor makes the car run cooler. but i dont know ****...... ill admit it. I dont i just talk out of my *** all day. Its actually quite fun to do cause you get the know it all asshoels that think they are god to sit and talk **** instead of saying hey, your wrong this is what it really does. So in everything said. A turbo car will run cooler, and perform better. but regardless. my point was that if you make the 450r run cooler it will not run peak performance.

It's simple physics. PV/T. If volume remains constant and you increase pressure, temperature increases as well. A turbo will make your car run hotter. It does NOT cool the motor at all. This is easily verified with an EGT gauge. What are you measuring 165 degrees at? Coolant temp? Oil temp? An EGT gauge is what you want to be using.



Again to the original poster, without a thermostat, your quad would take forever to warm up, and may actually never get to operating temps.

[bloodmoney23]

Originally posted by 400exrider707
It's simple physics. PV/T. If volume remains constant and you increase pressure, temperature increases as well. A turbo will make your car run hotter. It does NOT cool the motor at all. This is easily verified with an EGT gauge. What are you measuring 165 degrees at? Coolant temp? Oil temp? An EGT gauge is what you want to be using.



Again to the original poster, without a thermostat, your quad would take forever to warm up, and may actually never get to operating temps.

that 165º would be my cars coolant temp. the bigger the turbo the cooler it ran, with stock turbo it ran 210º and i still have stock thermostat, radiator, hoses, water pump, fan....but i dont know like i said i just talk outta my *** and dont know anything. and for once your wrong. w/o a thermostat his bike would probly overheat and blow the motor. it would constantly flow and never give the coolant a chance to cool down in radiator getting hotter and hotter as you ride id give it about 2 hours in 90º weather before it would blow.

[TRX450RACER174]

WOW did this get off track

Keep the thermostat in and either run a oversize rad or Engine ice but don't take out the thermostat.

[400exrider707]

Originally posted by bloodmoney23
that 165º would be my cars coolant temp. the bigger the turbo the cooler it ran, with stock turbo it ran 210º and i still have stock thermostat, radiator, hoses, water pump, fan....but i dont know like i said i just talk outta my *** and dont know anything. and for once your wrong. w/o a thermostat his bike would probly overheat and blow the motor. it would constantly flow and never give the coolant a chance to cool down in radiator getting hotter and hotter as you ride id give it about 2 hours in 90º weather before it would blow.


Coolant temp at 165? Your thermostat wouldn't even be opening. Which means your car isn't even getting to temperature. Something else is probably wrong then. Is your new turbo running less PSI than your stocker? Or are you disproving phsyics? Pressure, volume and temperature are all related. Your volume (cylinders) are staying constant, so if your temperature is dropping, then your pressure is dropping too (less boost) If you're running more boost like you say (18psi) then your temperature increases. There are no if ands or buts about this. If everything is working properly you are running more temperature. An intercooler would certainly help, but to say it's bringing your coolant almost 50 degrees cooler seems ridiculous. I would say there is somethign wrong with your gauge. Try an EGT gauge, it will be WAY more accurate. Install it pre turbo and then post your results.


I never said the quad wouldn't blow up. It would work both ways. In really hot weather you are probably right. In really cold weather it may never warm up properly and could seize due to the piston expanding far more rapid than the cylinder will allow. We would both be right on that, as we are agreeing to leave the thermostat in. If you think I'm wrong, then whatever I'm wrong.

[300ex mxracer]

Originally posted by bloodmoney23
ok so my turbocharged car with a GT35R ball bearing turbo and perrin oversized intercooler that runs at 165º has nothing whatsoever to do with the turbo. Im pretty sure that the 35r, which i run normal at 18psi would create enough heat to kill someone then according to your statement. .I know what a ****ing .turbo does douchebag, its called forced air induction . and since this is my 3rd t/c car i think i understand quite a bit. henceforth air is cooled down by an intercooler which in turn cools the air before it gets there which my friend creates cooler air going into the motor. cooler air into the motor makes the car run cooler. but i dont know ****...... ill admit it. I dont i just talk out of my *** all day. Its actually quite fun to do cause you get the know it all asshoels that think they are god to sit and talk **** instead of saying hey, your wrong this is what it really does. So in everything said. A turbo car will run cooler, and perform better. but regardless. my point was that if you make the 450r run cooler it will not run peak performance.

Reread what you posted. A turbo raises air intake temps, an intercooler lowers them. A turbo is called forced air induction for a reason.

[balls2da-wall]

Haha hes mad because he has a boost leak!!! His neat little gauge reads 18psi when hes really under vaccum! You said that running without a thermostat reduces the radiators effect on cooling? Are you kidding me?:huh

[300ex mxracer]

Actually a thermostat does kind of reduce the cooling effect of the radiator because w/o a thermostat, the antifreeze flows too fast through the radiator. It doesnt have to time cool before it goes back into the engine.

[bloodmoney23]

Originally posted by balls2da-wall
Haha hes mad because he has a boost leak!!! His neat little gauge reads 18psi when hes really under vaccum! You said that running without a thermostat reduces the radiators effect on cooling? Are you kidding me?:huh

actually no boost leak bud......sorry to burst your bubble. boost leaks dont get you 10 second 1/4 miles. but that is a car drop the damn turbo crap....sorry to bring it up. run no thermostat this summer tough guy and let me know when you need to buy a new engine.

[snowswife]

I have raced the Honda 450r With out a thermostat since the bike has came out, 2004 12HRS of America my bike ran the Whole race with out a stat..

I have never had an issue, Besides the YFZ does not have a Stat:o

[400exrider707]

Theoretically the fluid should go as fast as the pump pushes it. The thermostat shouldn't effect it. If it slowed flow down, the pump would be over working itself pushing antifreeze and it not going anywhere.

[300ex mxracer]

Originally posted by 400exrider707
Theoretically the fluid should go as fast as the pump pushes it. The thermostat shouldn't effect it. If it slowed flow down, the pump would be over working itself pushing antifreeze and it not going anywhere.

So is it hard on the pump when its cold since the thermostat is closed?

[400exrider707]

Originally posted by 300ex mxracer
So is it hard on the pump when its cold since the thermostat is closed?

Yeah good point, I didn't think about that. I guess it really isn't. I guess I just dont understand exactly how it all works. I understand what does what in theory, but I dont know what's actually go on.

[TRX450RACER174]

Originally posted by 300ex mxracer
So is it hard on the pump when its cold since the thermostat is closed?

No it doesn't, the pump works the same hot or cold the thermostats job is to just block the flow of the coolant to keep the motor at a consistent temperature, with no thermostat the bike would run very cold, And as someone else stated yes a YFZ does not have a thermostat but it was also designed not to have one in either the coolant passages or the oil passages so it is suppose to run that way, if it's got one in it leave it in.

[300ex mxracer]

Originally posted by TRX450RACER174
No it doesn't, the pump works the same hot or cold the thermostats job is to just block the flow of the coolant to keep the motor at a consistent temperature, with no thermostat the bike would run very cold, And as someone else stated yes a YFZ does not have a thermostat but it was also designed not to have one in either the coolant passages or the oil passages so it is suppose to run that way, if it's got one in it leave it in.

I know hot or cold antifreeze wont affect the pump, but if the thermostat is closed because the antifreeze is cold, I would think the pump would be working harder since its still pumping but the thermostat isnt letting the coolant go anywhere. I dont know how it works, just theory. Honda must have it figured it out. Maybe theres a bypass or something along that line.

[TRX450RACER174]

Originally posted by 300ex mxracer
I know hot or cold antifreeze wont affect the pump, but if the thermostat is closed because the antifreeze is cold, I would think the pump would be working harder since its still pumping but the thermostat isnt letting the coolant go anywhere. I dont know how it works, just theory. Honda must have it figured it out. Maybe theres a bypass or something along that line.

The thermostat does have a small bypass hole in it to releive pressure so the pressure is always flowing in the motor.