running without thermostats??
#21
05-07-2012, 12:52 PM
wow.
im well versed on superchargers i dont need your rudimentary explanation.
its wrong anyways and ill tell you why.
1. a roots supercharger does not compress air.
2. .
3. The reason a supercharger has such high delta temperatures is because of the engine temperature (which is directly related to coolant temperatures). a hot engine will cause the rotors to reach schorching temperatures at higher rpm's, which exponentially increases the heat of the delta air within a fraction of a second. a bench top supercharger rig, will produce very little heat.
4. weve achieved 3-5% gains on our 3800 engines by blocking the coolant passages (see my original post) & using throttle body shielding.
go back to your s-type forum. maybe they will believe you.
EDIT: let me mend point no 2 to say that although compressing air to 150 psi in a compressor might yeild a given amount of heat, the act of pressurizing a manifold to 6-10 psi has virtually no increase in heat. and the act of releasing compressed air cools it. such as releasing air from a compressor. so in theory, the act of depressurizing air into an open cylinder should effectively reduce any initial increase in air temperature.
im well versed on superchargers i dont need your rudimentary explanation.
its wrong anyways and ill tell you why.
1. a roots supercharger does not compress air.
2. .
3. The reason a supercharger has such high delta temperatures is because of the engine temperature (which is directly related to coolant temperatures). a hot engine will cause the rotors to reach schorching temperatures at higher rpm's, which exponentially increases the heat of the delta air within a fraction of a second. a bench top supercharger rig, will produce very little heat.
4. weve achieved 3-5% gains on our 3800 engines by blocking the coolant passages (see my original post) & using throttle body shielding.
go back to your s-type forum. maybe they will believe you.
EDIT: let me mend point no 2 to say that although compressing air to 150 psi in a compressor might yeild a given amount of heat, the act of pressurizing a manifold to 6-10 psi has virtually no increase in heat. and the act of releasing compressed air cools it. such as releasing air from a compressor. so in theory, the act of depressurizing air into an open cylinder should effectively reduce any initial increase in air temperature.
Last edited by M90power; 05-13-2012 at 05:15 PM.
#22
05-07-2012, 02:44 PM
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1. a roots supercharger does not compress air.
2. the act of compressing air cools it. hence the water, condensation etc.
EDIT: let me mend point no 2 to say that although compressing air to 150 psi in a compressor might yeild an insignificant amount of heat, the act of pressurizing (not compressing) a manifold to 6-10 psi has virtually no increase in heat.
2. the act of compressing air cools it. hence the water, condensation etc.
EDIT: let me mend point no 2 to say that although compressing air to 150 psi in a compressor might yeild an insignificant amount of heat, the act of pressurizing (not compressing) a manifold to 6-10 psi has virtually no increase in heat.
I'll ignore your rude comment, have fun. See ya!
Last edited by Mikey; 05-07-2012 at 02:50 PM.
#23
05-07-2012, 07:03 PM
Veteran Member
Compessing air absolutely increases its temperature - put your hand on the output pipe of your air compressor when its been working - you will most likely burn it.
Water is an inherint product of air H2O as the air cools it allows the water vapor to fall from the air, to put is simply cold air is denser because it drops its excess water vapor. This is why ALL panel shops run air cools on their compressors to cool the air thus removing the water.
Exactly the same princinple for superchargers as they compress the air they heat it Root are especially ineficcent at compressing hence they induce more heat into the outlet charge. Yes there will be some heat soak that will contribute to outlet temp but this will be less than the heat generated by compressing the air.
Water is an inherint product of air H2O as the air cools it allows the water vapor to fall from the air, to put is simply cold air is denser because it drops its excess water vapor. This is why ALL panel shops run air cools on their compressors to cool the air thus removing the water.
Exactly the same princinple for superchargers as they compress the air they heat it Root are especially ineficcent at compressing hence they induce more heat into the outlet charge. Yes there will be some heat soak that will contribute to outlet temp but this will be less than the heat generated by compressing the air.
#24
05-07-2012, 07:42 PM
Veteran Member
Back to the OP's original question - If your car running too hot you need to look at radiator and cooling fans first.
If it is running hot while driving at speed then the radiator needs to be cleaned, could also be crud between the rad and AC condensor.
If it running cool at speed and overheating when stationary then the fan is most likely at fault.
With a re-cored radiator my car runs on the thermostats at 100km/h. You can actually seen the temperature cycle between N and 1/2 way to C. But would over heat in traffic. Turning the car off the old fan kept turining at least 4-5 turns.
Also my car has no front spoiler and all of the foam missing around the radiator and I live in a walm climate so get the radiator running right then fix the little things like foam around the radiator etc.
If it is running hot while driving at speed then the radiator needs to be cleaned, could also be crud between the rad and AC condensor.
If it running cool at speed and overheating when stationary then the fan is most likely at fault.
With a re-cored radiator my car runs on the thermostats at 100km/h. You can actually seen the temperature cycle between N and 1/2 way to C. But would over heat in traffic. Turning the car off the old fan kept turining at least 4-5 turns.
Also my car has no front spoiler and all of the foam missing around the radiator and I live in a walm climate so get the radiator running right then fix the little things like foam around the radiator etc.
#25
05-07-2012, 08:35 PM
Compessing air absolutely increases its temperature - put your hand on the output pipe of your air compressor when its been working - you will most likely burn it.
Water is an inherint product of air H2O as the air cools it allows the water vapor to fall from the air, to put is simply cold air is denser because it drops its excess water vapor. This is why ALL panel shops run air cools on their compressors to cool the air thus removing the water.
Exactly the same princinple for superchargers as they compress the air they heat it Root are especially ineficcent at compressing hence they induce more heat into the outlet charge. Yes there will be some heat soak that will contribute to outlet temp but this will be less than the heat generated by compressing the air.
Water is an inherint product of air H2O as the air cools it allows the water vapor to fall from the air, to put is simply cold air is denser because it drops its excess water vapor. This is why ALL panel shops run air cools on their compressors to cool the air thus removing the water.
Exactly the same princinple for superchargers as they compress the air they heat it Root are especially ineficcent at compressing hence they induce more heat into the outlet charge. Yes there will be some heat soak that will contribute to outlet temp but this will be less than the heat generated by compressing the air.
#26
05-07-2012, 08:41 PM
m90-
I've not responded to your posts directly because of your aggressive approach. That's not what this board is about.
If you're wondering why there's a dramatic temperature increase in air temperature in a supercharger, it's due to the act of the air being compressed. Simple as that, look up 'ideal gas law' and 'Boyle's law' as proof. If a person is not familiar with basic level physics such as this, debating more complex topics such as Otto cycle thermodynamics is rather pointless.
If you wish to question the amount of heat transferred into the intake ductwork, please contact the author of the document. He's the OEM and is far more vrsed and experienced than either of us. I have no reason to dispute his practical findings or the theory behind it.
Referring to a previous post claiming that a 3HP gain was achieved by pointing a fan at the radiator, and putting aside such a modest deviation is well within the range of standard deviation from one run to the next, it's more likely that the fan lowered the air intake temps somewhat, and had nothing to do with coolant temps. If the fan had lowered the coolant temps, the thermostat would have simply restricted coolant flow to maintain a constant temp.
Given that a 10*F reduction in intake temps gives a 1% increase in power output, a 3 HP gain on a 300(?) HP engine is quite possible and easy to achieve.
I've not responded to your posts directly because of your aggressive approach. That's not what this board is about.
If you're wondering why there's a dramatic temperature increase in air temperature in a supercharger, it's due to the act of the air being compressed. Simple as that, look up 'ideal gas law' and 'Boyle's law' as proof. If a person is not familiar with basic level physics such as this, debating more complex topics such as Otto cycle thermodynamics is rather pointless.
If you wish to question the amount of heat transferred into the intake ductwork, please contact the author of the document. He's the OEM and is far more vrsed and experienced than either of us. I have no reason to dispute his practical findings or the theory behind it.
Referring to a previous post claiming that a 3HP gain was achieved by pointing a fan at the radiator, and putting aside such a modest deviation is well within the range of standard deviation from one run to the next, it's more likely that the fan lowered the air intake temps somewhat, and had nothing to do with coolant temps. If the fan had lowered the coolant temps, the thermostat would have simply restricted coolant flow to maintain a constant temp.
Given that a 10*F reduction in intake temps gives a 1% increase in power output, a 3 HP gain on a 300(?) HP engine is quite possible and easy to achieve.
Refreshing to see someone who understands physics. The supercharged engine does not knock when running cooler is partially because the mixture is enriched at lower coolant temps. He probably should install an intercooler and have his ECM tuned and more than likely install different injectors.
Running a car without thermostats or cooler thermostats does not prove anything. It will burn more fuel for sure. I never understand why people don't just fix the real problem.
The following users liked this post:
Mikey (05-08-2012)
#27
05-07-2012, 08:53 PM
wow.
im well versed on superchargers i dont need your rudimentary explanation.
its wrong anyways and ill tell you why.
1. a roots supercharger does not compress air.
2. the act of compressing air cools it. hence the water, condensation etc.
3. The reason a supercharger has such high delta temperatures is because of the engine temperature (which is directly related to coolant temperatures). a hot engine will cause the rotors to reach schorching temperatures at higher rpm's, which exponentially increases the heat of the delta air within a fraction of a second. a bench top supercharger rig, will produce very little heat.
4. weve achieved 3-5% gains on our 3800 engines by blocking the coolant passages (see my original post) & using throttle body shielding.
go back to your s-type forum. maybe they will believe you.
EDIT: let me mend point no 2 to say that although compressing air to 150 psi in a compressor might yeild an insignificant amount of heat, the act of pressurizing (not compressing) a manifold to 6-10 psi has virtually no increase in heat. and the act of releasing compressed air cools it. such as releasing air from a compressor. so in theory, the act of depressurizing air into an open cylinder should effectively reduce any initial increase in air temperature.
im well versed on superchargers i dont need your rudimentary explanation.
its wrong anyways and ill tell you why.
1. a roots supercharger does not compress air.
2. the act of compressing air cools it. hence the water, condensation etc.
3. The reason a supercharger has such high delta temperatures is because of the engine temperature (which is directly related to coolant temperatures). a hot engine will cause the rotors to reach schorching temperatures at higher rpm's, which exponentially increases the heat of the delta air within a fraction of a second. a bench top supercharger rig, will produce very little heat.
4. weve achieved 3-5% gains on our 3800 engines by blocking the coolant passages (see my original post) & using throttle body shielding.
go back to your s-type forum. maybe they will believe you.
EDIT: let me mend point no 2 to say that although compressing air to 150 psi in a compressor might yeild an insignificant amount of heat, the act of pressurizing (not compressing) a manifold to 6-10 psi has virtually no increase in heat. and the act of releasing compressed air cools it. such as releasing air from a compressor. so in theory, the act of depressurizing air into an open cylinder should effectively reduce any initial increase in air temperature.
Compressing air cools it?? I hope you are kidding. Have you touched your air compressor lately? Never saw ice hanging off it. So if compressing air cools it then why have an intercooler? It should be an interheater then?
A supercharger is forced induction just like a turbocharger. Is builds air pressure, which when the intake valves opens forces air into the cylinder. This gives you more oxygen which allows you to add more fuel. More fuel equals more power.
The point of running coolant to the throttle valve (throttle body) is to keep it warm so that water does not condense on it and in freezing ambient temps this condensation can freeze and cause the throttle plate to stick open.
#28
05-07-2012, 09:42 PM
and once again, roots blowers dont compress anything. theyre just an air pump. technically speaking theyre an external compression blower, meaning that the air coming out of it is the same volume as the air going into it. you build boost once the delta air builds up in the manifold, unlike a twin screw which actually does compress air.
which is why i specified that the roots blower pressurizes the manifold.
The supercharged engine does not knock when running cooler is partially because the mixture is enriched at lower coolant temps. He probably should install an intercooler and have his ECM tuned and more than likely install different injectors.
So there's a difference in 'pressurizing' air and 'compressing' it
Last edited by M90power; 05-07-2012 at 11:05 PM.
#29
05-08-2012, 06:02 AM
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#30
05-08-2012, 06:18 AM
#31
05-08-2012, 12:24 PM
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#33
05-09-2012, 02:21 AM
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...
Using the ubiquitous GM small block once again as another example, thermostat temps were bumped from 160 to 180 to 195*F over the years to keep up with pollution regulations and to take advantage of advances in coolant and oil technology. There was no accompanying reduction in any engine durability parameter. There's my line(s) in the sand.
Can you point me to a specific document that contradicts this? General statements that rubber and plastic stuff lasts longer when it's cooler are rather obvious in nature but again, if the field data indicates that there's no real problem, what's to gain?
Using the ubiquitous GM small block once again as another example, thermostat temps were bumped from 160 to 180 to 195*F over the years to keep up with pollution regulations and to take advantage of advances in coolant and oil technology. There was no accompanying reduction in any engine durability parameter. There's my line(s) in the sand.
Can you point me to a specific document that contradicts this? General statements that rubber and plastic stuff lasts longer when it's cooler are rather obvious in nature but again, if the field data indicates that there's no real problem, what's to gain?
So, citation for "no accompanying reduction in any engine durability parameter" ?
Preferably peer reviewed.
#34
05-09-2012, 04:02 AM
Veteran Member
Goodness me !
A supercharger is an air compressor used for forced induction of an internal combustion engine. (Wikipedia).
It doesn't matter if the air is compressed inside the supercharger or, as with a Roots, in the intake manifold because the blower is pushing more air into the manifold than the engine can swallow at atmospheric pressure.
Before the intercooler this is essentially isentropic compression so the air temperature must rise.
Hot air going into an engine is bad because
1. It is less dense so contains less oxygen so can burn less fuel
2. It will get even hotter when compressed by the piston so is more likely to cause pre-ignition
3. It is already hot so expands less when heated by the burning fuel
so it goes through an intercooler.
The hotter the intercooler the less well it does its job.
Inside the cylinder there are conflicting requirements
4. Keep the fuel/air mixture cool for reasons 2 + 3 above
5. Don't cool the mixture after combustion (because petrol + oxygen > water + CO2 which would occupy less volume than the original petrol/air mix at the same temperature). All that pushes the piston down is the rise in pressure produced by the heating of the combustion gasses.
So, running the engine hotter has a deleterious effect on every stage except 5. which happens so quickly that a few degrees difference in engine temperature doesn't matter.
Here ends the lesson......
A supercharger is an air compressor used for forced induction of an internal combustion engine. (Wikipedia).
It doesn't matter if the air is compressed inside the supercharger or, as with a Roots, in the intake manifold because the blower is pushing more air into the manifold than the engine can swallow at atmospheric pressure.
Before the intercooler this is essentially isentropic compression so the air temperature must rise.
Hot air going into an engine is bad because
1. It is less dense so contains less oxygen so can burn less fuel
2. It will get even hotter when compressed by the piston so is more likely to cause pre-ignition
3. It is already hot so expands less when heated by the burning fuel
so it goes through an intercooler.
The hotter the intercooler the less well it does its job.
Inside the cylinder there are conflicting requirements
4. Keep the fuel/air mixture cool for reasons 2 + 3 above
5. Don't cool the mixture after combustion (because petrol + oxygen > water + CO2 which would occupy less volume than the original petrol/air mix at the same temperature). All that pushes the piston down is the rise in pressure produced by the heating of the combustion gasses.
So, running the engine hotter has a deleterious effect on every stage except 5. which happens so quickly that a few degrees difference in engine temperature doesn't matter.
Here ends the lesson......
#35
05-09-2012, 04:22 AM
Also bear in mind that, besides old fashioned overheating, improper coolant *flow* and air pockets have caused many a dropped valve seat on V12s. Air pockets in the heads will create hot spots even the the actuall coolant temp....in the areas where coolant is actually flowing....isn't very high.
Cheers
DD
Cheers
DD
#36
05-09-2012, 04:54 AM
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#37
05-09-2012, 05:38 AM
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#39
05-09-2012, 10:44 AM
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Why? The gist of the response was that you habitually dismiss anything that you do not like using the ploy of asking for a citation. Yet, citations do not accompany your own assertions.
So, citation for "no accompanying reduction in any engine durability parameter" ?
Preferably peer reviewed.
So, citation for "no accompanying reduction in any engine durability parameter" ?
Preferably peer reviewed.
" If the goal is component longevity, then keeping it cool is not a "myth". It is good engineering with proven results in the real world."
In the context of operating an engine below design temps, I can find no evidence that this is true. As always it's easier to prove that something exists than doesn't exist, so you have the advantage in backing up your statement.
#40
05-11-2012, 06:45 AM
theres aboiut 50x more where that came from.
/thread.
