Will the Hondata gasket overheat the Head?
05-20-2002, 02:06 PM
#1
Former Sponsor
Thread Starter
Will the Hondata gasket overheat the Head?
I have a Hondata insulator / gasket installed between my head and intake manifold. It really helps allot on the hot days, by keeping the intake manifold cool, but I am concerned that it will cause my valve train to overheat.
I am concerned because the head is designed to use the intake manifold as a heat sink. It is bad for performance, but it is definately an effective way to cool the head. By replacing the stock gasket with the Hondata gasket, the heat is trapped in the head. There is no way that the head would not get hotter than it did with the stock setup. Does anyone know how much hotter the head gets? Have any of you noticed your spark plug insulators turning pink? Mine have.
I am concerned because the head is designed to use the intake manifold as a heat sink. It is bad for performance, but it is definately an effective way to cool the head. By replacing the stock gasket with the Hondata gasket, the heat is trapped in the head. There is no way that the head would not get hotter than it did with the stock setup. Does anyone know how much hotter the head gets? Have any of you noticed your spark plug insulators turning pink? Mine have.
05-20-2002, 03:10 PM
#3
Registered User
rylan, yes it is still cooled by coolant, but you also eliminate the coolant coming back to the throttle body (which is a good thing for us folk down south who don't need the warm TB).
05-20-2002, 03:35 PM
#5
Former Sponsor
Thread Starter
Keep in mind that there is nothing in the intake manifold or throttle body that generates heat, so it all comes from the engine. Any reduction in the temperature of the intake will result in an increase in engine temperature (if the cooling system is unchanged). It may not be measurable, but a cold air intake would also increase the engine temperature, since the heat that you are avoiding in the intake, came from the engine.
I am willing to bet that all these mods to reduce intake air temperature will even increase the exhaust gas temperature, since the cooler air will be more dense, leaning out the mixture and burning hotter. After all, isn't this why it produces more power? I wouldn't be surprised if the reduced cooling capacity, and leaner mixture combined increased the temperature of the head enough to damage it. Do any of you have 20,000 miles on your Hondata gasket?
I am willing to bet that all these mods to reduce intake air temperature will even increase the exhaust gas temperature, since the cooler air will be more dense, leaning out the mixture and burning hotter. After all, isn't this why it produces more power? I wouldn't be surprised if the reduced cooling capacity, and leaner mixture combined increased the temperature of the head enough to damage it. Do any of you have 20,000 miles on your Hondata gasket?
05-20-2002, 04:31 PM
#7
I don't think this is a problem, for several reasons:
1) There's a lot more mass in the head (10+ kg) than the intake manifold (4.4 kg), so a given temp change in the manifold will cause a smaller temp change in the head.
2) The head is also connected to the relatively massive cylinder block (29 kg), giving the two combined a much higher thermal capacity.
3) The temp change in the manifold is not all that large to begin with (10-15 deg C?).
4) Coolant is still flowing, with its temp regulated by the thermostat/thermoswitch.
gernby: Have you ever seen 4 bars on the water temp gauge? Perhaps, to reduce your anxiety, you should consider other cooling mods, such as Mugen/Spoon tstat/tswitch/rad cap. You might also consider drilling out the coolant hole that the Hondata gasket plugs up; this will help coolant circulate as originally designed, and you'll still be able to bypass the throttle body and IAC sensor with a simple hose connection.
1) There's a lot more mass in the head (10+ kg) than the intake manifold (4.4 kg), so a given temp change in the manifold will cause a smaller temp change in the head.
2) The head is also connected to the relatively massive cylinder block (29 kg), giving the two combined a much higher thermal capacity.
3) The temp change in the manifold is not all that large to begin with (10-15 deg C?).
4) Coolant is still flowing, with its temp regulated by the thermostat/thermoswitch.
gernby: Have you ever seen 4 bars on the water temp gauge? Perhaps, to reduce your anxiety, you should consider other cooling mods, such as Mugen/Spoon tstat/tswitch/rad cap. You might also consider drilling out the coolant hole that the Hondata gasket plugs up; this will help coolant circulate as originally designed, and you'll still be able to bypass the throttle body and IAC sensor with a simple hose connection.
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05-20-2002, 05:37 PM
#8
Registered User
Think about the thermal mass in the intake manifold vs. the rest of the cooling system. The manifold is less than 10 lbs of Al, which does not have a high specific heat. The cooling system is about 16 lbs of coolant, which has a pretty high specific heat. In fact, pure water has a specific heat over 4 times as great as Al. That means that every lbs of water has the ability to hold about 4.25 times much heat as a lbs of Al. In other terms, it takes over 4 times as much heat to increase the temperature of a lbs of water a certain amount as it does to effect the same change on Al.
Furthermore, the effectiveness of the intake manifold as a heat sink/radiator is questionable. The intake manifold will never reach a surface temperature of more than about 200-210 F. If it did, the cooling system would have boiled by then. In fact, average temps will probably be much lower. Compare this to the underhood temps which are usually 50-70 degrees above ambient at a stop. Then think about how much surface area the intake manifold has. Now compare that surface area to the radiator - which BTW is exposed to much lower air temperatures than the intake manifold and is exposed to moving air by the fans (or motion of the car).
Finally, consider that even from the factory the intake manifold is somewhat insulated from the head by the gasket, which is a paper composite material. Not the best insulator, but it still has an effect. If Honda truly intended to use the manifold as a heat sink, maybe they would have chosen a more thermally conductive material?
In the grand scheme of things, the intake manifold has the ability to about 1/10th the thermal energy of the cooling system. It has a radiating area no more than 1/10th that of the radiator. And it is exposed to much hotter air, in a non-laminar fashion, at a slower air speed, than the radiator. Oh sure, you're drawing air through it, but that heat just goes into the engine anyways, so its a closed cycle, isn't it? If the intake manifold could account for even 1% of cooling capacity of the engine I'd be dramatically surprised.
Conclusion to this rather long winded post? Don't worry about it.
UL
Furthermore, the effectiveness of the intake manifold as a heat sink/radiator is questionable. The intake manifold will never reach a surface temperature of more than about 200-210 F. If it did, the cooling system would have boiled by then. In fact, average temps will probably be much lower. Compare this to the underhood temps which are usually 50-70 degrees above ambient at a stop. Then think about how much surface area the intake manifold has. Now compare that surface area to the radiator - which BTW is exposed to much lower air temperatures than the intake manifold and is exposed to moving air by the fans (or motion of the car).
Finally, consider that even from the factory the intake manifold is somewhat insulated from the head by the gasket, which is a paper composite material. Not the best insulator, but it still has an effect. If Honda truly intended to use the manifold as a heat sink, maybe they would have chosen a more thermally conductive material?
In the grand scheme of things, the intake manifold has the ability to about 1/10th the thermal energy of the cooling system. It has a radiating area no more than 1/10th that of the radiator. And it is exposed to much hotter air, in a non-laminar fashion, at a slower air speed, than the radiator. Oh sure, you're drawing air through it, but that heat just goes into the engine anyways, so its a closed cycle, isn't it? If the intake manifold could account for even 1% of cooling capacity of the engine I'd be dramatically surprised.
Conclusion to this rather long winded post? Don't worry about it.
UL
05-20-2002, 07:18 PM
#9
Former Sponsor
Thread Starter
I aggree with much of what you are all saying, but I disagree about the heat sink potential of the intake. The coolant is a good conductor of heat, but it only transfers heat to the radiator, which is the heat sink. High performance radiators are generally aluminum (I think) because aluminum makes a great heat sink. The intake is also very course, which creates a lot of surface area and turbulance in the air that flows over it. The OEM gasket is also a good heat conductor since it is steel (not paper).
What I am convinced of is that there are way too many variables in the whole system. I see many reasons why it is AND isn't a problem. I think that this can only be settled with imperical data. I don't know how that can be attained without waiting to see if all the Hondata equipped engines fail after 10,000 miles, but I would really like to know if any of you guys have checked your spark plugs. I wish I had examined my spark plugs before the spacer. If I remember correctly, a plug with the proper heat range will have some carbon build up on the base of the electrode's insulator, and the tip will be white. If the plug is too cold, then carbon will build up on the end. If the plug is too hot, doesn't it turn pink?
My plugs are pink, so I think I need to go to a colder plug. However, before I do this, I want to see if the problem is caused by my head getting too hot. If there are a few of you with and without the Hondata gasket that will check your spark plugs and report back, please do so. If it is the Hondata gasket that is causing this problem, then going to a colder plug would just mask the high head temperatures, and could eventually lead to a head failure. Another helpful bit of info would be for someone to use a pyrometer to take some temperature measurements of a stock and modified head immediately following a long, hard drive. I would do this, but I don't have a pyrometer.
The Hondata gasket is my favorite mod, so I really don't want my theory to be correct. However, I really don't want to be reporting back here in a year that I cooked my head.
What I am convinced of is that there are way too many variables in the whole system. I see many reasons why it is AND isn't a problem. I think that this can only be settled with imperical data. I don't know how that can be attained without waiting to see if all the Hondata equipped engines fail after 10,000 miles, but I would really like to know if any of you guys have checked your spark plugs. I wish I had examined my spark plugs before the spacer. If I remember correctly, a plug with the proper heat range will have some carbon build up on the base of the electrode's insulator, and the tip will be white. If the plug is too cold, then carbon will build up on the end. If the plug is too hot, doesn't it turn pink?
My plugs are pink, so I think I need to go to a colder plug. However, before I do this, I want to see if the problem is caused by my head getting too hot. If there are a few of you with and without the Hondata gasket that will check your spark plugs and report back, please do so. If it is the Hondata gasket that is causing this problem, then going to a colder plug would just mask the high head temperatures, and could eventually lead to a head failure. Another helpful bit of info would be for someone to use a pyrometer to take some temperature measurements of a stock and modified head immediately following a long, hard drive. I would do this, but I don't have a pyrometer.
The Hondata gasket is my favorite mod, so I really don't want my theory to be correct. However, I really don't want to be reporting back here in a year that I cooked my head.
05-20-2002, 07:56 PM
#10
Registered User
Disagree about "potential", but if you look at first order cooling effects, you can model the situation quite effectively for our purposes. And the math says the intake manifold really doesn't matter.
Before I try to explain further, let's talk about spark plugs. Trying to read plug color with modern, unleaded gasolines is virtually pointless. Outside of the electrode being covered in soot, or cooked bone white, you really can't tell much. A reddish, or orangish color is often the long term effect of exposure to unleaded gasolines. It really doesn't tell you much about plug temperature. You might see some discoloration of the insulator, but most of that is just adhesive/sealant. If the whole thing is discolored, you might have a problem, but that's really about combustion/plug temps - it has little to do with coolant. Why you say? The combustion chamber gasses will reach peak temps in the range of a couple thousand degrees fahrenheit. The plug tip may even reach even hotter temps momentarily thanks to the hot plasma of the spark itself. Most of the heat from the plug (over 50%) is conducted back to the plug seat and into the cylinder head where it is dissipated by the cooling system. Now, if you're cooling system is running 10 F too hot, what does that mean for spark plug temps? Very little since the other critical variables for thermal transfer are unchanged. The transfer area, the material, the distance over which heat must travel, etc. are all the same. All that has changed is the differential between plug head and cylinder head. Given the differential during normal operation, a 10 F change in coolant temp isn't going to affect the plug temps noticeably - certainly not enough to require a colder plug.
Now, back to the thermals. You're right, the S2000 intake mani gasket is metal - steel in fact, which is not a particularly good thermal transfer material, but I won't dwell on that. Let's talk instead about surface area and turbulence/air flow. #1 - how much surface area does the intake manifold have? Well, for the one I have sitting in front of me, it's about 13"x4"x2.5" for the main plenum. Each runner is about 8" long by 2" in diameter. And there's a little more area available on the flange itself. Shall we call it 250 sq in? Or how about 300 sq in if we're generous?
Now, compare that to the radiator. The radiator is what, about 24"x12" of actual fin area? I think its quite a bit bigger, but I don't have one sitting in front of me. At first glance, that's only about 300 sq in. But, we forgot about the fins. Call the fins 1/2" deep (again, pessimistic, might be closer to 3/4"). And how many per sq in? The Honda radiator I _do_ have in front of me shows about 16 fins per linear inch. And each fin has two sides. So that makes a total surface area of 16 sq inches for every sq inch of frontal surface area on the front of the rad. That means that the radiator has a total available cooling area of 4800 sq inches. About 16 times that of the intake manifold. Furthermore, the radiator has far more area exposed to the coolant than the intake manifold does, which means more heat can be transferred that way.
Then, move on to actual air flow. We've already noted that the radiator will see far cooler airflow, which means thermal transfer will be higher there than with heat conducted through the intake manifold. Additionally, it will see a lot more airflow. I can't begin to guess how much, but it has to be quite a bit. And any air which reaches the intake manifold will have already picked up heat from the radiator (hence the temp differential argument).
So, again, if the intake manifold accounted for even 1% of the total engine cooling, I'd be surprised. And even if it did, coolant temps would go up a whopping 1-2 F if you totally insulated the intake manifold and the radiator wasn't able to transfer the additional heat.
UL
Before I try to explain further, let's talk about spark plugs. Trying to read plug color with modern, unleaded gasolines is virtually pointless. Outside of the electrode being covered in soot, or cooked bone white, you really can't tell much. A reddish, or orangish color is often the long term effect of exposure to unleaded gasolines. It really doesn't tell you much about plug temperature. You might see some discoloration of the insulator, but most of that is just adhesive/sealant. If the whole thing is discolored, you might have a problem, but that's really about combustion/plug temps - it has little to do with coolant. Why you say? The combustion chamber gasses will reach peak temps in the range of a couple thousand degrees fahrenheit. The plug tip may even reach even hotter temps momentarily thanks to the hot plasma of the spark itself. Most of the heat from the plug (over 50%) is conducted back to the plug seat and into the cylinder head where it is dissipated by the cooling system. Now, if you're cooling system is running 10 F too hot, what does that mean for spark plug temps? Very little since the other critical variables for thermal transfer are unchanged. The transfer area, the material, the distance over which heat must travel, etc. are all the same. All that has changed is the differential between plug head and cylinder head. Given the differential during normal operation, a 10 F change in coolant temp isn't going to affect the plug temps noticeably - certainly not enough to require a colder plug.
Now, back to the thermals. You're right, the S2000 intake mani gasket is metal - steel in fact, which is not a particularly good thermal transfer material, but I won't dwell on that. Let's talk instead about surface area and turbulence/air flow. #1 - how much surface area does the intake manifold have? Well, for the one I have sitting in front of me, it's about 13"x4"x2.5" for the main plenum. Each runner is about 8" long by 2" in diameter. And there's a little more area available on the flange itself. Shall we call it 250 sq in? Or how about 300 sq in if we're generous?
Now, compare that to the radiator. The radiator is what, about 24"x12" of actual fin area? I think its quite a bit bigger, but I don't have one sitting in front of me. At first glance, that's only about 300 sq in. But, we forgot about the fins. Call the fins 1/2" deep (again, pessimistic, might be closer to 3/4"). And how many per sq in? The Honda radiator I _do_ have in front of me shows about 16 fins per linear inch. And each fin has two sides. So that makes a total surface area of 16 sq inches for every sq inch of frontal surface area on the front of the rad. That means that the radiator has a total available cooling area of 4800 sq inches. About 16 times that of the intake manifold. Furthermore, the radiator has far more area exposed to the coolant than the intake manifold does, which means more heat can be transferred that way.
Then, move on to actual air flow. We've already noted that the radiator will see far cooler airflow, which means thermal transfer will be higher there than with heat conducted through the intake manifold. Additionally, it will see a lot more airflow. I can't begin to guess how much, but it has to be quite a bit. And any air which reaches the intake manifold will have already picked up heat from the radiator (hence the temp differential argument).
So, again, if the intake manifold accounted for even 1% of the total engine cooling, I'd be surprised. And even if it did, coolant temps would go up a whopping 1-2 F if you totally insulated the intake manifold and the radiator wasn't able to transfer the additional heat.
UL