ULTIMATE CHARGE COOLER KIT
#26
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What's the cooling are of this huge intercooler? Anyone can add another intercooler and increase cooling.i don't like the fact that it blocks the entire radiator. I'm adding an extra cooler to my car but I would not cover that much. You can run 2 stock intercoolers.
#27
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This might work for a stock unit in colder weather but with higher boost this will not be sufficient at all, also the 3 liter reservoir is not even a gallon of water
#28
You are confusing intercooler with heat exchanger. Big difference. You can't just add another intercooler without serious money for something like the SLR setup.
#29
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2004 E55,1969 300SEL6.3,2011 ML350 BlueTec Diesel,2005 ML400 CDI
The cooling capacity of the intercooler core is going to be directly related to the water temperature running through it. If you have a sufficient heat exchanger in the front to keep the water from warming up then you are not going to heat soak. This setup is simply keeping the water from getting hot. As I have said here before. The required heat exchanger to run full tilt without heat soak is basically another full radiator up front for the intercooling. I talked to Bell intercoolers about this several years ago and the required heat exchanger for around 500hp was about the same size as my radiator.
Also the pump requirements are not as high if the heat exchanger does not have as much back pressure.
Also the pump requirements are not as high if the heat exchanger does not have as much back pressure.
There are tricks, however, to cool ambient below ambient , such as the implementation of sonic venturies, but these reduce the volume of air, so as always, there's no free lunch.
#30
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I ment heatexchangers. Was just looking at intercooler pumps and miswrote
Last edited by Ls1toAMG; 01-06-2016 at 10:28 AM.
#31
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Bell will also tell you that that you must have an intercooler with appropriate BTU rating. The larger capacity heat exchangers already available will cool the coolant to close to ambient. Certainly better than the original mini-heat exchanger, but that's as cold as it will ever get.
There are tricks, however, to cool ambient below ambient , such as the implementation of sonic venturies, but these reduce the volume of air, so as always, there's no free lunch.
There are tricks, however, to cool ambient below ambient , such as the implementation of sonic venturies, but these reduce the volume of air, so as always, there's no free lunch.
#32
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1990 300ce supercharged and intercooled
AgSilver,
I the normal upgrade heat exchangers will keep up with normal daily driving and short bursts but not extended use. That is why a trunk tank is effective. It prolongs the effect of heat soak on the water.
On the btu front you need the same btu removal as to what is added. But you have totally different inputs to the water. So you put 150-250 degree above ambient air through the intercooler. The heat is pulled out by the water. Correct. Now you only have ambient air temp to pull the heat back out so the size of the heat exchanger needs to be able to pull all the heat added back out. Lets say it is 80 degrees outside and you have discharge temps of 150+80=230 degrees input to the water. What ever the btu capacity of the intercooler core you would need 230/80=2.875 times to cool the water down.
You are never going to get down to ambient temps on the water but maybe 15-20 degrees above ambient and around 30-40 degrees above your water temperature. So lets say around 150 degrees after the intercooler on a 80 degree day.
If you are spinning the crap out of the supercharger and have higher discharge temps you are going to have a higher differential to your water temperature. Same with lower ambient air temps and the heat exchanger. The larger the differential the more efficient the exchange of heat will be. So if your discharge temps from the supercharger are a 100 degrees higher then you would need 4.125 the size of a heat exchanger. Same math but 330 degree air/ 80 degree ambient.
I the normal upgrade heat exchangers will keep up with normal daily driving and short bursts but not extended use. That is why a trunk tank is effective. It prolongs the effect of heat soak on the water.
On the btu front you need the same btu removal as to what is added. But you have totally different inputs to the water. So you put 150-250 degree above ambient air through the intercooler. The heat is pulled out by the water. Correct. Now you only have ambient air temp to pull the heat back out so the size of the heat exchanger needs to be able to pull all the heat added back out. Lets say it is 80 degrees outside and you have discharge temps of 150+80=230 degrees input to the water. What ever the btu capacity of the intercooler core you would need 230/80=2.875 times to cool the water down.
You are never going to get down to ambient temps on the water but maybe 15-20 degrees above ambient and around 30-40 degrees above your water temperature. So lets say around 150 degrees after the intercooler on a 80 degree day.
If you are spinning the crap out of the supercharger and have higher discharge temps you are going to have a higher differential to your water temperature. Same with lower ambient air temps and the heat exchanger. The larger the differential the more efficient the exchange of heat will be. So if your discharge temps from the supercharger are a 100 degrees higher then you would need 4.125 the size of a heat exchanger. Same math but 330 degree air/ 80 degree ambient.
#33
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mercedes e55 amg estate
Thankyou for your varied comments, I sorted my cooling before I fitted all my tuning parts as I thought the stuff offered on the market seemed rubbish. Apart from a quaife lsd, k&n drop in filters and fabberge middle and rear exhaust work. im still running my catalysts. Im not in to drag racing so filling my car boot full of ice it does not appeal to me its a car not a fridge, as I like track days I like fast driving not just on the straights. Im not a person with **** loads of money but I just tried improving our charge cooler issues, yes the kit retails at £997.50 but I also thought the pound was very strong against the dollar and I understand many people are put off with cost, but ive bought most of my stuff from the USA and the coolers their I was not impressed with cutting bumpers, not having brackets to hang items. Yes as soon as I bolt everything on I will be back on here with the results. But at the present im happy having an additional 84bhp at the engine.
Yes their are any experts on here and good for you but I put my money where my mouth is when taking project on with forge motorsports and trust me they carried out all the import calculations out so this was not thrown together.
The mods im installing will be kleemann headers,fabberge downpipes,fabberge decat x-pipe,82mm throttle body and modified snout, UPD 180mm crank pulley, upd belt wrap kit, upd uprated pulleys, upd 550 injectors,carbon fibre modified air box, carbon intake tubes and carbon engine cover.
Yes their are any experts on here and good for you but I put my money where my mouth is when taking project on with forge motorsports and trust me they carried out all the import calculations out so this was not thrown together.
The mods im installing will be kleemann headers,fabberge downpipes,fabberge decat x-pipe,82mm throttle body and modified snout, UPD 180mm crank pulley, upd belt wrap kit, upd uprated pulleys, upd 550 injectors,carbon fibre modified air box, carbon intake tubes and carbon engine cover.
#34
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As I have said here before. The required heat exchanger to run full tilt without heat soak is basically another full radiator up front for the intercooling. I talked to Bell intercoolers about this several years ago and the required heat exchanger for around 500hp was about the same size as my radiator.
I kind of agree with that. I'm curious where it came from, but here's my angle. As soon as I bought my first S600TT, I was determined to prove that you could use a second engine radiator at the front to cool the IC. Three years ago I did a survey of almost all the radiators and charge coolers on modern European and Japanese cars. Quite obsessive, I was (got an account with Nissens etc). See my sig. I now use a BMW X3 engine radiator for the HE - it was difficult, but it worked, and it's caused zero cooling problems. I did a lot of theoretical and practical research and several things became very apparent:
- Turbo-charging is becoming the norm.
- Intercooling is essential for effective forced induction.
- Boost levels and specific outputs are getting higher.
- Intercoolers are consequently getting bigger.
- Modern factory air-air coolers are now around the same size as the engine radiator.
- Heat exchangers only have to be half the size.
- In liquid coolers, the IC and HE are usually the same volume.
- As a starting point that volume should be roughly the same as the engine capacity
- Make it double that for high compression engines (say 1.5 bar).
- Increasing the boost level DRAMATICALLY increases the heat generated.
- Therefore for a highly-charged 5 litre engine, you need a 10 litre IC and a 10 litre HE
- This is the same size as a fairly large engine radiator!
HOWEVER, fitting my engine radiator HE increased the installed flow more than the bigger pump (Pierburg) did, as the total system resistance was reduced so much. So yes, the pressure requirements are reduced, but not the flow. And you wouldn't fit a smaller pump anyway, would you ;-).
If that was the right approach to cooling in general, then we wouldn't have AC condensers that are universally the same area as the engine radiator. My first thought on seeing the new Forge HE was shame it doesn't go all the way to the top of the radiator. Maybe packaging limitations got in the way. Modern production cars are increasingly moving towards full height HE's. Mercedes didn't used to do it, but they do now. There are a few exceptions, like some BMW's, but new design cars almost always come with a radiator pack configuration like this:
Front: 16mm thick AC condenser (not 14mm)
Centre: 20mm thick liquid cooler or 30mm air cooler
Rear: 30 to 40mm thick engine radiator.
The point is that all these coolers have the same width and height (typically 600x450mm), and are close coupled together, so the air flows through each cooler in sequence. All leaks are suppressed with rubber or foam seals. I don't think there's anything wrong with full-height coolers, and its now very much the norm. They are very rarely any thicker than above. When you need more cooling, you use two coolers (or three on the stock M5).
Nick
Last edited by Welwynnick; 01-07-2016 at 07:27 PM.
#35
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AgSilver,
I the normal upgrade heat exchangers will keep up with normal daily driving and short bursts but not extended use. That is why a trunk tank is effective. It prolongs the effect of heat soak on the water I said that in my original post.
On the btu front you need the same btu removal as to what is added. But you have totally different inputs to the water. So you put 150-250 degree above ambient air through the intercooler. The heat is pulled out by the water. Correct. Now you only have ambient air temp to pull the heat back out so the size of the heat exchanger needs to be able to pull all the heat added back out. Lets say it is 80 degrees outside and you have discharge temps of 150+80=230 degrees input to the water. What ever the btu capacity of the intercooler core you would need 230/80=2.875 times to cool the water down.
You are never going to get down to ambient temps on the water but maybe 15-20 degrees above ambient and around 30-40 degrees above your water temperature. So lets say around 150 degrees after the intercooler on a 80 degree day.
If you are spinning the crap out of the supercharger and have higher discharge temps Latent Heat Of Compression you are going to have a higher differential to your water temperature. Same with lower ambient air temps and the heat exchanger. The larger the differential the more efficient the exchange of heat will be I also stated that in my original post. So if your discharge temps from the supercharger are a 100 degrees higher then you would need 4.125 the size of a heat exchanger Are you not referring to the Intercooler? Same math but 330 degree air/ 80 degree ambient.
I the normal upgrade heat exchangers will keep up with normal daily driving and short bursts but not extended use. That is why a trunk tank is effective. It prolongs the effect of heat soak on the water I said that in my original post.
On the btu front you need the same btu removal as to what is added. But you have totally different inputs to the water. So you put 150-250 degree above ambient air through the intercooler. The heat is pulled out by the water. Correct. Now you only have ambient air temp to pull the heat back out so the size of the heat exchanger needs to be able to pull all the heat added back out. Lets say it is 80 degrees outside and you have discharge temps of 150+80=230 degrees input to the water. What ever the btu capacity of the intercooler core you would need 230/80=2.875 times to cool the water down.
You are never going to get down to ambient temps on the water but maybe 15-20 degrees above ambient and around 30-40 degrees above your water temperature. So lets say around 150 degrees after the intercooler on a 80 degree day.
If you are spinning the crap out of the supercharger and have higher discharge temps Latent Heat Of Compression you are going to have a higher differential to your water temperature. Same with lower ambient air temps and the heat exchanger. The larger the differential the more efficient the exchange of heat will be I also stated that in my original post. So if your discharge temps from the supercharger are a 100 degrees higher then you would need 4.125 the size of a heat exchanger Are you not referring to the Intercooler? Same math but 330 degree air/ 80 degree ambient.
In one of my other lives I operated an industrial refrigeration company and while I'm well into my 8th decade, heat exchange is now a distant memory, but it has not, shall i say, evaporated (heh) entirely.
#36
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I understand what the vets are saying. I will simply put it this way. The intercooler is the problem. That and ambient temps. I don't care if you have 50 Gallons in the trunk it's only going to make as much power as ambient temps plus 10 or so. It has its limits when temps are warm. The only true way to make a big power difference in a car with a large pulley is cooling it. Meth,nitrous or killer chiller. They will kill heat real quick and when heat strikes those systems are not held hostage to the outside temps.
It's a nice complete kit I'm glad someone is making one. But you can go to frozen boost and get heat exchangers/radiators of all sizes and make it yourself.
IMO 300 for any heat exchanger is too much. It's double what you can find them for.
That being said you kit will perform well with your 180 pulley. But it will be in the same ballpark as the other kits people are running. There is no way a guy with a trunk kit he ect is going to pick up 40-80 by switching to your kit. They will be close IMO
It's a nice complete kit I'm glad someone is making one. But you can go to frozen boost and get heat exchangers/radiators of all sizes and make it yourself.
IMO 300 for any heat exchanger is too much. It's double what you can find them for.
That being said you kit will perform well with your 180 pulley. But it will be in the same ballpark as the other kits people are running. There is no way a guy with a trunk kit he ect is going to pick up 40-80 by switching to your kit. They will be close IMO
#37
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This looks like a beautiful kit. While I'd love to scratch off my old text books and join the science discussion I'll stay more practical. Google MBH Monster Heat Exchanger. Something very similar to this has already been done with marginal success. Intercooler. Intercooler. Inter cooler. It doesn't flow and it doesn't have the capacity to cool a highly boosted 55k. I wish it was simple as adding a huge HE up front but if that was the case we wouldn't have had to wait 13 years for them to show up. But again it is beautiful and price no object the best option out there for a HE.
#38
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1990 300ce supercharged and intercooled
Of course larger intercoolers will be more efficient. They would flow more air and cool better. My point was and is that everyone simply states that the E55 intercooler can not cool the air. And that is not true or things like trunk tanks, with or without ice and killer chillers, which just cool the water, do work. These methods and a larger intercooler would be better.
Heat soak is an issue of the water not the intercooler core. The one run and you are done is a water heat soak issue. And a larger intercooler will heat soak as well but yes it will still be marginally better at the exchange at those higher water temps. The larger intercoolers will also exchange the heat faster into the water. Thus having a higher demand for the water to be cooled down. Because otherwise it would just heat the water up faster and to a higher degree because the btu exchange rate would be better.
I would just spend more money and time focusing on the water temperature until I had water that stayed cool. As you said maximizing the TD. If you are drag racing only then you should forgo the heat exchanger completely and just have a trunk tank with ice. Now if you have ice cold water running through the system and your iat are high then the i/c core is not sufficient.
Heat soak is an issue of the water not the intercooler core. The one run and you are done is a water heat soak issue. And a larger intercooler will heat soak as well but yes it will still be marginally better at the exchange at those higher water temps. The larger intercoolers will also exchange the heat faster into the water. Thus having a higher demand for the water to be cooled down. Because otherwise it would just heat the water up faster and to a higher degree because the btu exchange rate would be better.
I would just spend more money and time focusing on the water temperature until I had water that stayed cool. As you said maximizing the TD. If you are drag racing only then you should forgo the heat exchanger completely and just have a trunk tank with ice. Now if you have ice cold water running through the system and your iat are high then the i/c core is not sufficient.
#39
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I'm going to try and answer my own question. The W211 AC condenser measures 630 x 441mm, so ignoring parallax for a moment and scaling from the pictures above, I estimate the HE core measures about 21 x 13" or 273 sq in. Assuming the core is 1.25" thick (full size HE's usually are) that makes the volume 5592cc. That's much better than stock, but hardly over-large.
The MBH Monster HE for the CLS measures about 21 x 14" = 292 sq in, and they only measured 10-12 bhp increase. That seems to be typical for HE-only upgrades. It's hard to see where 80 bhp comes from.
https://mbworld.org/forums/w219/3625...ease-dyno.html
The HE should really be a similar volume to the IC. Does anyone know what the dimensions of the IC are?
Thanks, Nick
The MBH Monster HE for the CLS measures about 21 x 14" = 292 sq in, and they only measured 10-12 bhp increase. That seems to be typical for HE-only upgrades. It's hard to see where 80 bhp comes from.
https://mbworld.org/forums/w219/3625...ease-dyno.html
The HE should really be a similar volume to the IC. Does anyone know what the dimensions of the IC are?
Thanks, Nick
#40
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This looks like a beautiful kit. While I'd love to scratch off my old text books and join the science discussion I'll stay more practical. Google MBH Monster Heat Exchanger. Something very similar to this has already been done with marginal success. Intercooler. Intercooler. Inter cooler. It doesn't flow and it doesn't have the capacity to cool a highly boosted 55k. I wish it was simple as adding a huge HE up front but if that was the case we wouldn't have had to wait 13 years for them to show up. But again it is beautiful and price no object the best option out there for a HE.
Of course larger intercoolers will be more efficient. They would flow more air and cool better. My point was and is that everyone simply states that the E55 intercooler can not cool the air. And that is not true or things like trunk tanks, with or without ice and killer chillers, which just cool the water, do work. These methods and a larger intercooler would be better.
Heat soak is an issue of the water not the intercooler core. The one run and you are done is a water heat soak issue. And a larger intercooler will heat soak as well but yes it will still be marginally better at the exchange at those higher water temps. The larger intercoolers will also exchange the heat faster into the water. Thus having a higher demand for the water to be cooled down. Because otherwise it would just heat the water up faster and to a higher degree because the btu exchange rate would be better.
I would just spend more money and time focusing on the water temperature until I had water that stayed cool. As you said maximizing the TD. If you are drag racing only then you should forgo the heat exchanger completely and just have a trunk tank with ice. Now if you have ice cold water running through the system and your iat are high then the i/c core is not sufficient.
Heat soak is an issue of the water not the intercooler core. The one run and you are done is a water heat soak issue. And a larger intercooler will heat soak as well but yes it will still be marginally better at the exchange at those higher water temps. The larger intercoolers will also exchange the heat faster into the water. Thus having a higher demand for the water to be cooled down. Because otherwise it would just heat the water up faster and to a higher degree because the btu exchange rate would be better.
I would just spend more money and time focusing on the water temperature until I had water that stayed cool. As you said maximizing the TD. If you are drag racing only then you should forgo the heat exchanger completely and just have a trunk tank with ice. Now if you have ice cold water running through the system and your iat are high then the i/c core is not sufficient.
I'm going to try and answer my own question. The W211 AC condenser measures 630 x 441mm, so ignoring parallax for a moment and scaling from the pictures above, I estimate the HE core measures about 21 x 13" or 273 sq in. Assuming the core is 1.25" thick (full size HE's usually are) that makes the volume 5592cc. That's much better than stock, but hardly over-large.
The MBH Monster HE for the CLS measures about 21 x 14" = 292 sq in, and they only measured 10-12 bhp increase. That seems to be typical for HE-only upgrades. It's hard to see where 80 bhp comes from.
https://mbworld.org/forums/w219/3625...ease-dyno.html
The HE should really be a similar volume to the IC. Does anyone know what the dimensions of the IC are?
Thanks, Nick
The MBH Monster HE for the CLS measures about 21 x 14" = 292 sq in, and they only measured 10-12 bhp increase. That seems to be typical for HE-only upgrades. It's hard to see where 80 bhp comes from.
https://mbworld.org/forums/w219/3625...ease-dyno.html
The HE should really be a similar volume to the IC. Does anyone know what the dimensions of the IC are?
Thanks, Nick
#42
MBWorld Fanatic!
Agsilver is 100% correct
That tiny intercooler under the blower is not efficient. Maybe with stock boost with a bigger heat exchanger and a reservoir like this one it can keep up but once it's in 80* weather it's over. A buddy even changed the core in the stock intercooler and didn't get much better.
This kit will not help more than doing a bigger heat exchanger and rear tank which btw will be much cheaper.
That tiny intercooler under the blower is not efficient. Maybe with stock boost with a bigger heat exchanger and a reservoir like this one it can keep up but once it's in 80* weather it's over. A buddy even changed the core in the stock intercooler and didn't get much better.
This kit will not help more than doing a bigger heat exchanger and rear tank which btw will be much cheaper.
#43
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Is not a picture worth a thousand words.
PS: Hulk . . . back in PBG from Germany in about 10 days. Have a few shows for the W109.
Last edited by AgSilver; 01-08-2016 at 06:58 AM.
#45
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1990 300ce supercharged and intercooled
You can say it is fact all you want but without the data of in/out water temps and in/out air temps you can not know the thermal exchange rate of the cooler. If you had a limitless supply of ambient water and kept increasing the supercharger discharge temperature you could find this data out with sensors on both sides.
Again I am not arguing that larger intercoolers like the SLR would not be beneficial but rather not practical vs investing in cooling the water down to increase the systems efficiency.
And the SLR will heat soak as well. The simple laws of thermal dynamics do dictate heat in heat out. And if you look at the size of the heat exchanger vs the size of the intercoolers and say assume that they have the same transfer rate of heat the temp difference in vs out is going to heat the water up. Again, say 150 above ambient discharger temps. So on a 80 degree day you have a air at say around 1100cfm {cfm for around 600hp} at 230 degree into the water and say at 100mph to get close to that same cfm in the area of the heat exchanger at 80 degree air across the heat exchanger. But without any data either way we can all say whatever we want and state it as fact.
To the best of my knowledge and you may correct me, thermal exchange does not have a choke point like fluid dynamics. There is simply not a point at which no more heat can be removed. The exchange simply gets worse and worse. Point of diminishing returns etc.
Again I am not arguing that larger intercoolers like the SLR would not be beneficial but rather not practical vs investing in cooling the water down to increase the systems efficiency.
And the SLR will heat soak as well. The simple laws of thermal dynamics do dictate heat in heat out. And if you look at the size of the heat exchanger vs the size of the intercoolers and say assume that they have the same transfer rate of heat the temp difference in vs out is going to heat the water up. Again, say 150 above ambient discharger temps. So on a 80 degree day you have a air at say around 1100cfm {cfm for around 600hp} at 230 degree into the water and say at 100mph to get close to that same cfm in the area of the heat exchanger at 80 degree air across the heat exchanger. But without any data either way we can all say whatever we want and state it as fact.
To the best of my knowledge and you may correct me, thermal exchange does not have a choke point like fluid dynamics. There is simply not a point at which no more heat can be removed. The exchange simply gets worse and worse. Point of diminishing returns etc.
#47
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There seem to be a lot of hand-waving arguments, but also several attempts to make discussion of intercooler systems analytical and scientific.
Thermal analysis is usually performed (in my experience) by considering power flow and thermal resistances. The cooling system is designed by considering the stack of components, materials, interfaces etc within the system, and adding up the thermal resistance of each one. Thermal resistance is temperature rise divided by power flow. The thermal stack has the heat source at the top, and that heat flows down through each layer to the sink at the bottom. That flow of heat is power - not temperature or energy or whatever - and that power flows through each layer down to the bottom. Where the resistance of a layer is high, there will be a high temperature difference across that layer. High temperature gradients are associated with thermal insulators. A low resistance will give a low temperature difference. The temperature of the source will be the temperature of the sink plus the sum of all the temperature differences. Its rather analogous to electrical resistance in electronics, for example, where you flow a current through some resistors and add up the voltages generated. It facilitates the analysis of a system.
In the case of an air to air cooling system, its simple, as there's only one component. It's the intercooler, and that will have a thermal resistance for a given ambient airflow. Its an intrinsic quality rather than an extrinsic quality, and doesn't depend on any temperatures. The flow of heat is proportional to the difference in temperature between the source and the sink. The bigger the intercooler, the lower the thermal resistance, and the lower the charge temperature.
In a charge cooler, there are two components - the intercooler and the heat exchanger. Each one of them will have their own thermal resistance, and they have to be added together. To have a low total thermal resistance, both have to be low. In other words, both the IC and the HE have to be large (and have lots of fins etc). However, making just one component larger will make its thermal resistance lower and hence decrease the total resistance. This will always be the case.
However, if one of those components is small, then its thermal resistance will be high, and it will be responsible for a large temperature drop within the cooling system. It will be the dominant element in the system, and will presumably have the LARGEST temperature drop. It will obviously be the bottleneck. Notwithstanding that, the other component will still have a finite resistance and a finite temp drop. Improving that component will still reduce that small temp drop. The end result will be less total thermal resistance, and improved cooling - more thermal power will be extracted from the charge air, which will be cooled to a lower temperature.
Therefore a large HE will tend to reduce the IAT, regardless of the IC. However, if the IC is small and is the bottleneck to the system, then the benefits of a large HE will be small. The qualification to this is where the HE is made so large that its too thick, and presents a substantially increased resistance to the ambient air flow. If that happens, the thermal resistance will increase. That's why engine radiators are hardly ever more than 40mm thick, for example.
Having said all that, I don't really think charge cooling lends itself to thermal analysis. There are too many variables to isolate just a single parameter like the thermal resistance of one of the heat exchangers. The ambient air temperature varies, the ambient air flow varies, the charge air flow varies, the charge air temperature varies, and the coolant temperature varies. On my car, the coolant flow varies as well. All of this makes it almost impossible to perform any specific analysis that enables us to compare components or systems.
The guys that go to town on water cooling of gaming PC's take a scientific approach to a similar situation, and they're obsessively analytical (and very well educated) about it, and make car folks look very ignorant. Although their objectives are similar (on a smaller scale) they have far fewer variables. The heat source is usually constant, and ambient air flow is usually achieved with fans only, and is also considered as a constant. Even then, analysis is tortuous, and thermal resistance has to be considered as a family of characteristics, rather than a single, constant, value.
So I think that for automotive charge coolers, you have to adopt the mantra: "bigger is better" and do what you can to understand it. I think you need an empirical rather than analytical approach.
Best regards, Nick
Thermal analysis is usually performed (in my experience) by considering power flow and thermal resistances. The cooling system is designed by considering the stack of components, materials, interfaces etc within the system, and adding up the thermal resistance of each one. Thermal resistance is temperature rise divided by power flow. The thermal stack has the heat source at the top, and that heat flows down through each layer to the sink at the bottom. That flow of heat is power - not temperature or energy or whatever - and that power flows through each layer down to the bottom. Where the resistance of a layer is high, there will be a high temperature difference across that layer. High temperature gradients are associated with thermal insulators. A low resistance will give a low temperature difference. The temperature of the source will be the temperature of the sink plus the sum of all the temperature differences. Its rather analogous to electrical resistance in electronics, for example, where you flow a current through some resistors and add up the voltages generated. It facilitates the analysis of a system.
In the case of an air to air cooling system, its simple, as there's only one component. It's the intercooler, and that will have a thermal resistance for a given ambient airflow. Its an intrinsic quality rather than an extrinsic quality, and doesn't depend on any temperatures. The flow of heat is proportional to the difference in temperature between the source and the sink. The bigger the intercooler, the lower the thermal resistance, and the lower the charge temperature.
In a charge cooler, there are two components - the intercooler and the heat exchanger. Each one of them will have their own thermal resistance, and they have to be added together. To have a low total thermal resistance, both have to be low. In other words, both the IC and the HE have to be large (and have lots of fins etc). However, making just one component larger will make its thermal resistance lower and hence decrease the total resistance. This will always be the case.
However, if one of those components is small, then its thermal resistance will be high, and it will be responsible for a large temperature drop within the cooling system. It will be the dominant element in the system, and will presumably have the LARGEST temperature drop. It will obviously be the bottleneck. Notwithstanding that, the other component will still have a finite resistance and a finite temp drop. Improving that component will still reduce that small temp drop. The end result will be less total thermal resistance, and improved cooling - more thermal power will be extracted from the charge air, which will be cooled to a lower temperature.
Therefore a large HE will tend to reduce the IAT, regardless of the IC. However, if the IC is small and is the bottleneck to the system, then the benefits of a large HE will be small. The qualification to this is where the HE is made so large that its too thick, and presents a substantially increased resistance to the ambient air flow. If that happens, the thermal resistance will increase. That's why engine radiators are hardly ever more than 40mm thick, for example.
Having said all that, I don't really think charge cooling lends itself to thermal analysis. There are too many variables to isolate just a single parameter like the thermal resistance of one of the heat exchangers. The ambient air temperature varies, the ambient air flow varies, the charge air flow varies, the charge air temperature varies, and the coolant temperature varies. On my car, the coolant flow varies as well. All of this makes it almost impossible to perform any specific analysis that enables us to compare components or systems.
The guys that go to town on water cooling of gaming PC's take a scientific approach to a similar situation, and they're obsessively analytical (and very well educated) about it, and make car folks look very ignorant. Although their objectives are similar (on a smaller scale) they have far fewer variables. The heat source is usually constant, and ambient air flow is usually achieved with fans only, and is also considered as a constant. Even then, analysis is tortuous, and thermal resistance has to be considered as a family of characteristics, rather than a single, constant, value.
So I think that for automotive charge coolers, you have to adopt the mantra: "bigger is better" and do what you can to understand it. I think you need an empirical rather than analytical approach.
Best regards, Nick
Last edited by Welwynnick; 01-08-2016 at 07:06 PM.
#48
MBWorld Fanatic!
I come back to my original question on the V8 intercooler though. How big is it?
If its too small, then its too small. But if its too small, how do you KNOW its too small, and then what can you do about it? How many BTU's does it have? sic How many does it need? Yes, the SLR cost-no-object supercar has bigger coolers, but they cost $11,000 even if you can find one. Has anybody ever fitted them to an E55? I saw a picture of an SLK that had SLR coolers, and they stuck out of the hood. I think its rather academic.
My automotive poison is the V12TT, and the original implementation of that intercooler was TERRIBLE for all sorts of reasons. However, it did have some good IC's, and rather like a few BMWs like the 760i and 550i, they're not too closely coupled to the inlet manifold, they're quite a good size to start with, and they can be upgraded. There are also some obscure subtleties to their design that most people don't realise, and which many V8 IC implementations can't take advantage of.
Equally, there are some awful design calamities like multiple air locks that the V8 system doesn't suffer from.
Nick
Edit: here's some good reading that I just stumbled across again. This is the best effort to get analytical about charge cooling that I've seen yet. Well worth a read:
http://www.mez.co.uk/turbo8-new.html
If its too small, then its too small. But if its too small, how do you KNOW its too small, and then what can you do about it? How many BTU's does it have? sic How many does it need? Yes, the SLR cost-no-object supercar has bigger coolers, but they cost $11,000 even if you can find one. Has anybody ever fitted them to an E55? I saw a picture of an SLK that had SLR coolers, and they stuck out of the hood. I think its rather academic.
My automotive poison is the V12TT, and the original implementation of that intercooler was TERRIBLE for all sorts of reasons. However, it did have some good IC's, and rather like a few BMWs like the 760i and 550i, they're not too closely coupled to the inlet manifold, they're quite a good size to start with, and they can be upgraded. There are also some obscure subtleties to their design that most people don't realise, and which many V8 IC implementations can't take advantage of.
Equally, there are some awful design calamities like multiple air locks that the V8 system doesn't suffer from.
Nick
Edit: here's some good reading that I just stumbled across again. This is the best effort to get analytical about charge cooling that I've seen yet. Well worth a read:
http://www.mez.co.uk/turbo8-new.html
Last edited by Welwynnick; 01-09-2016 at 06:08 AM.
#49
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1990 300ce supercharged and intercooled
Welwynnick,
Your point of the thermal resistance is on point. The simple question is what is the transfer rate of the heat to the water in the i/c core. If you have rising air temps with a constant water input temp then the core is not doing the job. If the front heat exchanger is adequate to keep the water at near ambient temperatures you should not see a continous rise in iat at full load. Or a very marginal one. So say you start a pull and a moment later you are running 30-40 degrees above ambient iat. They should stay close to that no matter how long you are at full load. If your water is heating up the iat will go up as well.
Same goes for using a large trunk tank with ice. If the water stays at say around 35F and your iat at full load are 30-40 degrees above that and stay there until the ice melts and water temps go up then the core is doing the job. Obviously if money was no object and fitting it in the car was no problem all of it would be upgraded for maximum efficiency but I would bet that there are more gains in flow restriction than temperatures on the stock core.
Your point of the thermal resistance is on point. The simple question is what is the transfer rate of the heat to the water in the i/c core. If you have rising air temps with a constant water input temp then the core is not doing the job. If the front heat exchanger is adequate to keep the water at near ambient temperatures you should not see a continous rise in iat at full load. Or a very marginal one. So say you start a pull and a moment later you are running 30-40 degrees above ambient iat. They should stay close to that no matter how long you are at full load. If your water is heating up the iat will go up as well.
Same goes for using a large trunk tank with ice. If the water stays at say around 35F and your iat at full load are 30-40 degrees above that and stay there until the ice melts and water temps go up then the core is doing the job. Obviously if money was no object and fitting it in the car was no problem all of it would be upgraded for maximum efficiency but I would bet that there are more gains in flow restriction than temperatures on the stock core.
#50
Senior Member