Melting rotor housings
06-08-04, 02:17 AM
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Melting rotor housings
Ok so our housing is made out of aluminum, which melts at 1218F. Racingbeat also makes end plates out of aluminum. What confuses me is that our exhaust temps are around 1700F at the header and a even hotter in the combustion chamber. Do you see what I’m getting at. Anyone care to discuss this?
06-08-04, 03:24 AM
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i thought about that, but i mean the wall on the inside have to get hotter then 1200 when they are right next to something that is 1700. you would think.
06-08-04, 04:13 AM
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Originally posted by pinkfloyd
i thought about that, but i mean the wall on the inside have to get hotter then 1200 when they are right next to something that is 1700. you would think.
i thought about that, but i mean the wall on the inside have to get hotter then 1200 when they are right next to something that is 1700. you would think.
06-08-04, 04:13 AM
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Originally posted by pinkfloyd
i thought about that, but i mean the wall on the inside have to get hotter then 1200 when they are right next to something that is 1700. you would think.
i thought about that, but i mean the wall on the inside have to get hotter then 1200 when they are right next to something that is 1700. you would think.
the metals conduct the heat to the water/oil fast enough to keep from getting very hot
06-08-04, 12:00 PM
#6
the exhaust gas reads hotter farther away from the
outlet.
if you were to put egt probes in the exhaust stream
you would see lower temp close to the motor and
higher as you move away then as you get farther it
starts to go back down again.
don't believe me try it for your self
so what i am saying is that the exhaust temp is not
that high before it leaves the motor.
matt
outlet.
if you were to put egt probes in the exhaust stream
you would see lower temp close to the motor and
higher as you move away then as you get farther it
starts to go back down again.
don't believe me try it for your self
so what i am saying is that the exhaust temp is not
that high before it leaves the motor.
matt
06-08-04, 05:04 PM
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Originally posted by now
the exhaust gas reads hotter farther away from the
outlet.
if you were to put egt probes in the exhaust stream
you would see lower temp close to the motor and
higher as you move away then as you get farther it
starts to go back down again.
don't believe me try it for your self
so what i am saying is that the exhaust temp is not
that high before it leaves the motor.
matt
the exhaust gas reads hotter farther away from the
outlet.
if you were to put egt probes in the exhaust stream
you would see lower temp close to the motor and
higher as you move away then as you get farther it
starts to go back down again.
don't believe me try it for your self
so what i am saying is that the exhaust temp is not
that high before it leaves the motor.
matt
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06-09-04, 04:58 PM
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The combustion temps aren't 1500F and the actual housing temps inside the engine are surprisingly low. I wish I had some of the old published R&D data mapped out on the engine, but it's quiet surprising. Heat from the turbos has to transfer through water and oil cooled areas that lower the temps substantially.
06-09-04, 05:34 PM
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Originally posted by ArrX7ahh
Inefficient compared to other power units. Very large combustion surface area as well.
Inefficient compared to other power units. Very large combustion surface area as well.
06-09-04, 06:06 PM
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Originally posted by Fatman0203
I would swear I read our engines are more efficient than a piston (in the essence of power per displacement).
I would swear I read our engines are more efficient than a piston (in the essence of power per displacement).
06-09-04, 10:31 PM
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Originally posted by Fatman0203
I would swear I read our engines are more efficient than a piston (in the essence of power per displacement).
I would swear I read our engines are more efficient than a piston (in the essence of power per displacement).
06-09-04, 11:23 PM
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Originally posted by wwilliam54
in that way they are, but thermally they are really inefficient (low gas milage) due to the large surface area/low combustion volume, more heat is transfered int the coolant
in that way they are, but thermally they are really inefficient (low gas milage) due to the large surface area/low combustion volume, more heat is transfered int the coolant
06-10-04, 01:40 AM
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Originally posted by Fatman0203
Ahh I see so an efficient engine would be one that could get rid of the heat instead by exhaust correct? Im guessing the porche boxster engine is really efficient since they use to be air cooled.
Ahh I see so an efficient engine would be one that could get rid of the heat instead by exhaust correct? Im guessing the porche boxster engine is really efficient since they use to be air cooled.
06-10-04, 12:38 PM
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Originally posted by Fatman0203
Ahh I see so an efficient engine would be one that could get rid of the heat instead by exhaust correct? Im guessing the porche boxster engine is really efficient since they use to be air cooled.
Ahh I see so an efficient engine would be one that could get rid of the heat instead by exhaust correct? Im guessing the porche boxster engine is really efficient since they use to be air cooled.
*30% is kinda on the high side....
06-10-04, 12:40 PM
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Originally posted by wwilliam54
30mpg that long ago is pretty good
30mpg that long ago is pretty good
06-10-04, 12:46 PM
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Diesels are in the 40%+ range. Ideally, an engine would not need a cooling system, as if it were 100% efficient, all the energy going into the system, would produce 100% work.
At one time, rotarys did produce more bhp/liter than piston engines. Not so much the case anymore. Toss in the 1.1-2.2 and 1.3-2.6L discussions, and the bhp/L advantage drops even more.
That written, I still love my RX-7!
At one time, rotarys did produce more bhp/liter than piston engines. Not so much the case anymore. Toss in the 1.1-2.2 and 1.3-2.6L discussions, and the bhp/L advantage drops even more.
That written, I still love my RX-7!
06-14-04, 06:04 PM
#20
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Just because EGT's are high, doesn't mean your internal engine parts "see" that kinda temps.
Due to coolant cooling (rotor housings) and oil cooling (rotor), the surfaces of these parts will never see even close to what the core EGT's are.
If you don't believe me, pour some water into a styrofoam[sp?] cup. Put this cup in the middle of a fire. It's common sense that the cup should easily burn and melt at anything resembling a flame. So why doesn't the cup melt?
-Ted
Due to coolant cooling (rotor housings) and oil cooling (rotor), the surfaces of these parts will never see even close to what the core EGT's are.
If you don't believe me, pour some water into a styrofoam[sp?] cup. Put this cup in the middle of a fire. It's common sense that the cup should easily burn and melt at anything resembling a flame. So why doesn't the cup melt?
-Ted
06-14-04, 07:48 PM
#21
Originally posted by pinkfloyd
i thought about that, but i mean the wall on the inside have to get hotter then 1200 when they are right next to something that is 1700. you would think.
i thought about that, but i mean the wall on the inside have to get hotter then 1200 when they are right next to something that is 1700. you would think.
anyway, i also thought that that's why they chrome the housing, not just for a better sealing surface, but also to reflect combustion heat. the rotor turns so fast, even at idle, that the combusted gasses are expelled quickly - out the exhaust - fast enough that the water/coolant will be enough to remove enough of the radiated heat to keep the aluminum from being damaged.
at least ... that's my take.
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