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Author Topic:   Intercooling

jimh posted 06-22-2005 12:17 AM ET (US)
It just occurred to me that in a marine environment, the efficiency of an intercooler must be greater than in automotive applications.
To review, an intercooler is a device which tries to lower the temperature of the intake air in an engine, usually after it has been raised by passing through a supercharger or turbocharger. In a marine engine, there is an unlimited supply of relatively cold water to provide the cooling for the intercooler. In contrast, in automotive applications there is only the ambient air as a source of cooling. You would assume that the engine and its cooling water would be much hotter than the air temperature, and would not be useful for cooling.
This must make a marine intercooler much more effective. In this light, it seem that the Verado engine is taking advantage of a unique situation with the marine engine and its unlimited supply of cold water.
jeffs22outrage posted 06-22-2005 09:18 AM ET (US)
Jim,
Unfortunately boats do not get the amount to fresh air FLOW that cars get. Though the ambient air might be cooler on the water few boats get to speeds that would make the intercooler efficient When I would be driving in heavy traffic (speeds of 20 - 30) with my Subaru the intercooler would begin suffer heat soak. This is where the intercooler is not getting enough air flow through it and thus the intercooler begins to soak up the heat of the engine compartment.
I will bet you will see marine engines that have forced induction run an heat exchanger unit like the Ford lightning trucks and mustangs did. This unit used cold water pumped through a radiator like set up to cool the charged air. With sea water being cooler than the air and all around, I would think this would be the way to go on the water.
erik selis posted 06-22-2005 09:27 AM ET (US)
I think the intercooler would have more effect on a diesel engine. Many diesel inboard engines use turbo chargers and intercoolers.
Erik
WhalerMark posted 06-22-2005 10:07 AM ET (US)
This is interesting actually, on my car the intercooler has a water spray to cool it which is activated by a button on the dash. Not an aftermarket device, it came this way from the factory. On the Verado, I have to wonder though, the effect of the cool water on the hot intercooler causing expansion and cracking. I'm sure that they've considered that.
jeffs22outrage posted 06-22-2005 10:12 AM ET (US)
Mark what kind of car do you have? I only have known Subaru STi's to have an intercooler sprayer stock. Also Mitsubishi EVO's, Dodge Neon SRT 4, and turbo Porsches having it as a option.
WhalerMark posted 06-22-2005 11:24 AM ET (US)
Hey Jeff, you really know your cars... yes it's a blue Subaru wrx sti and it's a lot fun. I rarely drive it though and it has only 1200 miles.
jeffs22outrage posted 06-22-2005 11:53 AM ET (US)
Mark your are so lucky! I sold my modified wrx wagon to get my whaler. I REALLY miss that car. The one thing I dreamed of more than owning a subaru WRX as a kid was owning a whaler. I love the STi man what a great car. I hope you have the gold wheels ; ). If you ever want to get rid of the car in a year or two email me at jrohlfing@gmail.com ...I AM NOT KIDDING. Well cared for used STi's are though to come by.
Here is my old wagon
http://photobucket.com/albums/v427/jeff_rohlfing/WRX/
OK sorry Jim, Subaru owners are JUST LIKE Whaler Owners...Crazy about thier obessions and love to talk about them.
LHG posted 06-22-2005 12:02 PM ET (US)
From what I have read on the Verado intercooler, Jim is correct. The water cooled intercooler gives it almost unlimited cooling capabililty.
Evidently even the 275 Verado is bleeding off a lot of unneeded boost from the supercharger. There is more potential in the system. The word from the performance crowd is that the engine can put out a lot more than 275HP by re-mapping the fuel, changing the computer and turning up the boost. I have heard rumors up to 500 HP with HD internals! Supposedly a 340 HP version is due shortly for the performance/racing market. As most know, when a new engine/block comes out, the earlier models are always in lower HP version, and right now, nobody else has anything more powerful than the recreational 275, including the supposedly 300HP HPDI (when it runs). This is where the Verados are now. Once the new 1.7 liter 4 cylinder models get broken in, I'm hoping to see a 200 HP version, easy to accomplish I would think
where2 posted 06-22-2005 12:54 PM ET (US)
The Verado uses an air-to-water intercooler, as opposed to the air-to-air versions used in most automotive applications. Thus Jim and LHG are right that you've got a HUGE supply of relatively cool cooling water to cool your charged air once you've pressurized it.
I can only dream of having such a plentiful source of cooling for the air leaving the supercharger on my Volkswagen...
RocketMan posted 06-22-2005 02:00 PM ET (US)
The Verado water-to-air intercooler cutaway that I saw made me think that it will be challenged by the usual manufacturing quality, corrosion, contaminant, and ingestion items.
Teak Oil posted 06-22-2005 08:55 PM ET (US)
What happens in 5-6 years when these intercoolers start developing small leaks? Water ingestion is bad
jimh posted 06-23-2005 08:56 AM ET (US)
I do not think you can disqualify the intercooler because it may have problems from raw water being circulated through it. Raw water cooling has been used for cooling outboard motors for decades.
If the raw water is suitable for cooling the engine, why is it suddenly unsuitable for cooling the intercooler?
where2 posted 06-23-2005 12:57 PM ET (US)
My main concern is the welds between the various plates in the intercooler. Everything used in salt water is subject to corrosion, and the least noble metal is the first to go... The intercooler looks nothing like the heads or other cooling parts of an ordinary modern outboard engine.
Raw water was suitable for cooling an OMC Turbojet, and then came the concept that maybe a strainer inline in the cooling system would be a good idea...
TeakOil's point is well taken that owners will want to be ahead of the curve on replacing the intercooler, rather than behind the curve, since salt water ingestion would NOT be good for an engine...
RocketMan posted 06-23-2005 05:15 PM ET (US)
There is a picture of a Verado intercooler (a water - air heat exchanger) in the cetacea on p.80. It is an interesting component and an icon of Mercury's engineering strategy for the Verado engine.
Heat exchanger performance is typically degraded by corrosion and/or leakage. For a water-to-air heat-exchanger an obvious concern would be with salt ater and assumed salt build-up in the heat exchanger passages over time.
Salt build-up could lead to reduced heat exchanger efficiency and eventually blockage. It could debit housing/tubing material properties or weld/braze joint intergrity resulting in leakage. If waterpressure is higher than air pressure the result is engine salt water ingestion. There is some additional risk due to failure modes from any other components/demands required by the intercooling system.
Of course, Mercury knows all this and more and no doubt has painstaking attempted to design-out any problems ahead of time. But these inherent effects can only be engineered-out to some degree, they cannot be entirely eliminated. Variation in the environment, including biological, as well as manufacturing, material, and coating processes will play a role.
Hopefully for all of us boaters Mercury has done their homework and the Verado will prove a winner in the long run, but like the ETEC, time will tell.

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Author	Topic: Intercooling
jimh	posted 06-22-2005 12:17 AM ET (US) It just occurred to me that in a marine environment, the efficiency of an intercooler must be greater than in automotive applications. To review, an intercooler is a device which tries to lower the temperature of the intake air in an engine, usually after it has been raised by passing through a supercharger or turbocharger. In a marine engine, there is an unlimited supply of relatively cold water to provide the cooling for the intercooler. In contrast, in automotive applications there is only the ambient air as a source of cooling. You would assume that the engine and its cooling water would be much hotter than the air temperature, and would not be useful for cooling. This must make a marine intercooler much more effective. In this light, it seem that the Verado engine is taking advantage of a unique situation with the marine engine and its unlimited supply of cold water.
jeffs22outrage	posted 06-22-2005 09:18 AM ET (US) Jim, Unfortunately boats do not get the amount to fresh air FLOW that cars get. Though the ambient air might be cooler on the water few boats get to speeds that would make the intercooler efficient When I would be driving in heavy traffic (speeds of 20 - 30) with my Subaru the intercooler would begin suffer heat soak. This is where the intercooler is not getting enough air flow through it and thus the intercooler begins to soak up the heat of the engine compartment. I will bet you will see marine engines that have forced induction run an heat exchanger unit like the Ford lightning trucks and mustangs did. This unit used cold water pumped through a radiator like set up to cool the charged air. With sea water being cooler than the air and all around, I would think this would be the way to go on the water.
erik selis	posted 06-22-2005 09:27 AM ET (US) I think the intercooler would have more effect on a diesel engine. Many diesel inboard engines use turbo chargers and intercoolers. Erik
WhalerMark	posted 06-22-2005 10:07 AM ET (US) This is interesting actually, on my car the intercooler has a water spray to cool it which is activated by a button on the dash. Not an aftermarket device, it came this way from the factory. On the Verado, I have to wonder though, the effect of the cool water on the hot intercooler causing expansion and cracking. I'm sure that they've considered that.
jeffs22outrage	posted 06-22-2005 10:12 AM ET (US) Mark what kind of car do you have? I only have known Subaru STi's to have an intercooler sprayer stock. Also Mitsubishi EVO's, Dodge Neon SRT 4, and turbo Porsches having it as a option.
WhalerMark	posted 06-22-2005 11:24 AM ET (US) Hey Jeff, you really know your cars... yes it's a blue Subaru wrx sti and it's a lot fun. I rarely drive it though and it has only 1200 miles.
jeffs22outrage	posted 06-22-2005 11:53 AM ET (US) Mark your are so lucky! I sold my modified wrx wagon to get my whaler. I REALLY miss that car. The one thing I dreamed of more than owning a subaru WRX as a kid was owning a whaler. I love the STi man what a great car. I hope you have the gold wheels ; ). If you ever want to get rid of the car in a year or two email me at jrohlfing@gmail.com ...I AM NOT KIDDING. Well cared for used STi's are though to come by. Here is my old wagon http://photobucket.com/albums/v427/jeff_rohlfing/WRX/ OK sorry Jim, Subaru owners are JUST LIKE Whaler Owners...Crazy about thier obessions and love to talk about them.
LHG	posted 06-22-2005 12:02 PM ET (US) From what I have read on the Verado intercooler, Jim is correct. The water cooled intercooler gives it almost unlimited cooling capabililty. Evidently even the 275 Verado is bleeding off a lot of unneeded boost from the supercharger. There is more potential in the system. The word from the performance crowd is that the engine can put out a lot more than 275HP by re-mapping the fuel, changing the computer and turning up the boost. I have heard rumors up to 500 HP with HD internals! Supposedly a 340 HP version is due shortly for the performance/racing market. As most know, when a new engine/block comes out, the earlier models are always in lower HP version, and right now, nobody else has anything more powerful than the recreational 275, including the supposedly 300HP HPDI (when it runs). This is where the Verados are now. Once the new 1.7 liter 4 cylinder models get broken in, I'm hoping to see a 200 HP version, easy to accomplish I would think
where2	posted 06-22-2005 12:54 PM ET (US) The Verado uses an air-to-water intercooler, as opposed to the air-to-air versions used in most automotive applications. Thus Jim and LHG are right that you've got a HUGE supply of relatively cool cooling water to cool your charged air once you've pressurized it. I can only dream of having such a plentiful source of cooling for the air leaving the supercharger on my Volkswagen...
RocketMan	posted 06-22-2005 02:00 PM ET (US) The Verado water-to-air intercooler cutaway that I saw made me think that it will be challenged by the usual manufacturing quality, corrosion, contaminant, and ingestion items.
Teak Oil	posted 06-22-2005 08:55 PM ET (US) What happens in 5-6 years when these intercoolers start developing small leaks? Water ingestion is bad
jimh	posted 06-23-2005 08:56 AM ET (US) I do not think you can disqualify the intercooler because it may have problems from raw water being circulated through it. Raw water cooling has been used for cooling outboard motors for decades. If the raw water is suitable for cooling the engine, why is it suddenly unsuitable for cooling the intercooler?
where2	posted 06-23-2005 12:57 PM ET (US) My main concern is the welds between the various plates in the intercooler. Everything used in salt water is subject to corrosion, and the least noble metal is the first to go... The intercooler looks nothing like the heads or other cooling parts of an ordinary modern outboard engine. Raw water was suitable for cooling an OMC Turbojet, and then came the concept that maybe a strainer inline in the cooling system would be a good idea... TeakOil's point is well taken that owners will want to be ahead of the curve on replacing the intercooler, rather than behind the curve, since salt water ingestion would NOT be good for an engine...
RocketMan	posted 06-23-2005 05:15 PM ET (US) There is a picture of a Verado intercooler (a water - air heat exchanger) in the cetacea on p.80. It is an interesting component and an icon of Mercury's engineering strategy for the Verado engine. Heat exchanger performance is typically degraded by corrosion and/or leakage. For a water-to-air heat-exchanger an obvious concern would be with salt ater and assumed salt build-up in the heat exchanger passages over time. Salt build-up could lead to reduced heat exchanger efficiency and eventually blockage. It could debit housing/tubing material properties or weld/braze joint intergrity resulting in leakage. If waterpressure is higher than air pressure the result is engine salt water ingestion. There is some additional risk due to failure modes from any other components/demands required by the intercooling system. Of course, Mercury knows all this and more and no doubt has painstaking attempted to design-out any problems ahead of time. But these inherent effects can only be engineered-out to some degree, they cannot be entirely eliminated. Variation in the environment, including biological, as well as manufacturing, material, and coating processes will play a role. Hopefully for all of us boaters Mercury has done their homework and the Verado will prove a winner in the long run, but like the ETEC, time will tell.