Not sure yet, I've already got two air to air intercooled cars, figure I should make the next one with water. Oh fun fact just heard that the new bmw m4 gts, the fastest production bmw ever uses a water intercooler. What are those German retards thinking? Don't they know a big ass front mount is the only intercooler that works? Lol
The nice thing about BMW flooding the market with water intercooled turbo engines is that very very nice Behr intercoolers are cheap on eBay. Pick up one of the intercoolers from their twin turbo V8 for way less than some Chinese crap-core unit.
In reply to chiodos:
I saw that it will also have a water injection system, I don't think that's ever been on a production car.
Especially with the water injection added in, that makes me think they're doing their best to tailor the system to produce as repeatable and consistent a result as possible every time you go WOT (regardless of what state you were in before).
Considering they're running a good bit of boost through those motors, it probably doesn't take much to get into knock retard (or IAT induced spark retard) on pump gas...
Boost_Crazy wrote: In reply to chiodos: I saw that it will also have a water injection system, I don't think that's ever been on a production car.
Haha! A 1962 Oldsmobile used methanol injection on its turbo engine. A carryover from WW2 fighter planes. Nothing new about that.
chiodos wrote: Not sure yet, I've already got two air to air intercooled cars, figure I should make the next one with water. Oh fun fact just heard that the new bmw m4 gts, the fastest production bmw ever uses a water intercooler. What are those German retards thinking? Don't they know a big ass front mount is the only intercooler that works? Lol
It comes to application. One is not inherently better than the other. I used air to air intercooling in the OP's exact same car and with a larger turbo on 90 degree days and it worked great. Conversely, I used liquid to air intercooling on my 911 turbo with no spolier because IT MADE SENSE in that car. Not because BMW is using it now so it must be better. Hell, Toyota and Subaru have gone back and forth from air to liquid and then air again. They aren't "retards" either.
In reply to rslifkin:
Non gts m4 and m3 still have liquid intercoolers without water injection and are still fine making 400sometbing hp. That said direct injection makes a hell of a difference over port injection in terms of knock limit and such. Crankwalk, I only use those terms to mess with boostcrazy who thinks its air to air or death. I did forget about the jetfire! What did they call the liquid, turbo rocket fluid or something? Haha
AKA poison windshield washer fluid.
When commenting on what the OEM's do, one must always remember that they have to compromise too, on packaging, ease of assembly, cost and so on. So to say "BMW does it so it must be better", is a fallacy, as OEM's do it both ways for different reasons.
One point that I haven't seen brought up yet, but I haven't looked thoroughly, is efficiency losses through the heat exchangers. Every time you transfer heat from one medium to another, there is a loss (i.e. some heat remains). By utilizing two such exchangers instead of one, an air/water intercooler is at a disadvantage in this regards. For example, if each stage in an air/water system is 90% efficient, you get 0.9 x 0.9 = 0.81, or 81% efficiency. The water pump's adding energy to the water too, some of which will be in the form of heat (probably negligible though).
NOTE: I am NOT claiming that one's better than another, just pointing out something.
In reply to chiodos:
I only use those terms to mess with boostcrazy who thinks its air to air or death.
I never said that anything close to that. I said both have pulses and minuses, and are more or less equal if designed to the same standard. I even said that air/water is a better choice in some applications. What I have said, over and over... and over, is that air/water is not water cooled.
In reply to crankwalk:
That Oldsmobile is cool! I've got a lot of interest in water/ methanol injection, I'll likely be adding it to my Galant VR4 soon.
Boost_Crazy wrote: Air to water intercoolers are still cooled by the air, and therefore cannot be more efficient or cool better everthing else being equal (i.e., not including ice chests.)
Still can't get over this gem, first thing you said in here lol. Such an exreme generalization
RX8driver wrote: One point that I haven't seen brought up yet, but I haven't looked thoroughly, is efficiency losses through the heat exchangers. Every time you transfer heat from one medium to another, there is a loss (i.e. some heat remains). By utilizing two such exchangers instead of one, an air/water intercooler is at a disadvantage in this regards. For example, if each stage in an air/water system is 90% efficient, you get 0.9 x 0.9 = 0.81, or 81% efficiency. The water pump's adding energy to the water too, some of which will be in the form of heat (probably negligible though).
I did bring it up. In practice, the efficiency from being able to get more cooling surface area to the airflow makes up for the inefficiency of changing medium twice instead of once.
In reply to chiodos:
What do you disagree with? It's basic physics, not an opinion. You want to jump straight into a deep analysis full of complex variables, without showing a grasp for the basic concept. The efficiency of an I/C is measured by how well it removes heat. Fact. In both an air/water and air/air system, air flow through the heat exchanger is the primary methology of how the heat is removed. Fact. In two comparably designed systems, the same amount of heat will be removed. Fact. While there are a lot of other attributes to each system, and they have different performance characteristics, it is physically impossible for the air/water to remove more heat "because of the water."
At first, I thought that you were like the guy at the party that "knows" everything, spouting out misinformation while everyone else rolls their eyes, oblivious all the while. Then I caught a brief glimpse that you might actually want to learn something. Then I thought you were trolling. You may still be, bravo if so.
You stated early on that "It's Science." Watching a couple episodes of Myth Busters doesn't make you a scientist. If you understood what you were saying, you would know that science is about coming up with a theory and trying to disprove it. You do the opposite. You reject every shred of evidence that doesn't support your predetermined conclusion, and cling to every scrap that might support it no matter how irrelevant. That is NOT science. I realized the mistake that I made. I didn't just roll my eyes.
Boost_Crazy wrote: In reply to crankwalk: That Oldsmobile is cool! I've got a lot of interest in water/ methanol injection, I'll likely be adding it to my Galant VR4 soon.
That being said, I am Crankwalk over at galantvr4.org (formerly 1439/2000 for many years and I built the white and carbon GVR4 you probably have seen over there). I ran 400 + hp in 90* GA heat with a giant air to air cooler and never ran in to issues with knock on 93 octane and no methanol. You probably don't need it unless your fuel suck.s
In reply to crankwalk:
My fuel does suck, 91 is the best I can get, and that is suspect sometimes. E85 is not readily available. I'd like to get to 400hp on pump gas, but I think I'm still a ways off.
Boost_Crazy wrote: The efficiency of an I/C is measured by how well it removes heat. Fact. In both an air/water and air/air system, air flow through the heat exchanger is the primary methology of how the heat is removed. Fact. In two comparably designed systems, the same amount of heat will be removed. Fact.
Overlooked: You can build a much larger (comparably speaking) water system into the same nose space as an air system. Nose space is always at a premium.
The only time I've seen it NOT a premium, in a passenger car, is the Buick GNs, where you can fit a maybe 19" by 26" by 4.5" core in between the core support and bumper. But this is more thanks to General Motors' horrible space efficiency in the 1970s when the G body was hatched.
Even then, since GNs generally run in 8 to 10 second bursts, an IC that big mostly does act as a heat storage device like brakes, instead of a real time cooler. Those intercoolers have a LOT of aluminum mass...
Don't gigantic air to air intercoolers have massive pressure drops? Or are those just with the poorly designed/poorly plumbed ones?
Appleseed wrote: Don't gigantic air to air intercoolers have massive pressure drops? Or are those just with the poorly designed/poorly plumbed ones?
Even if it's well designed and doesn't have much pressure drop, by the time you have that much piping and a core that huge, you've got a lot of air in there to pressurize, so it adds lag to the system.
Appleseed wrote: Don't gigantic air to air intercoolers have massive pressure drops? Or are those just with the poorly designed/poorly plumbed ones?
Solid "it depends". A core that has few, long tubes will have a lot of pressure drop. A core that has many short tubes will have a lot less pressure drop.
Of course, most OE intercoolers are of the few/long variety for space reasons. Having long end tanks that also direct the flow roughly evenly is pretty durn difficult to package.
This is the IC that I was talking about, incidentally, shown with bumper/grille gone for clarity:
You get to keep functional A/C with these things! And if you spray 'em black, they are practically invisible.
On the OE side, my Volvo has the largest OE intercooler I've ever seen. It is physically larger than the coolant radiator, which is sandwiched between the intercooler and the radiator fan - the fan bolts to the IC, not the radiator. All for 160hp. I put together an air/water package for a 750hp supercharged engine with a heat exchanger HALF of its size. It could keep discharge temps near ambient. Before the IC installation, air change temps were near 200F just driving in light traffic, no boost. (Superchargers kinda suck sometimes)
Overlooked: You can build a much larger (comparably speaking) water system into the same nose space as an air system. Nose space is always at a premium. The only time I've seen it NOT a premium, in a passenger car, is the Buick GNs, where you can fit a maybe 19" by 26" by 4.5" core in between the core support and bumper. But this is more thanks to General Motors' horrible space efficiency in the 1970s when the G body was hatched. Even then, since GNs generally run in 8 to 10 second bursts, an IC that big mostly does act as a heat storage device like brakes, instead of a real time cooler. Those intercoolers have a LOT of aluminum mass...
Not overlooked, and I completely agree. You could look at every car/application combo and have different "best" intercoolers for each combo. I'm not championing air/air set ups, just trying to keep the comparison accurate. There are many reasons why air/water are better choices in many applications, as you have demonstrated. The same could be said for air/air.
One thing that I think it's easy to get too wrapped up in is the ultimate cooling capacity. It gets exponentially harder to capture "lost" efficiency. An intercooler that is 25% bigger doesn't cool 25% more. Rather, you will get 25% of what you didn't get the first time. So if your I/C is 70% efficient, increasing the size by 25% will get you 25% of the 30 you missed, and bring you up to 78%. Of course, there will be more internal restriction with the bigger I/C, so the net gain is even smaller. At some point, you need to worry about flow more than absolute cooling. Which sometimes is a strong point of air/water, usually infrequent, short duration.
Interesting thread. Back in the mid 90's Volvo had to revise the air to air intercooler piping on the high pressure turbos to bump temperatures up because the intake air was 'freezing' the throttle butterfly (thermally motivated tolerance binding?) in low ambiant temps. The revised much longer with more curves routing changed the direction of air flow though the rather tall inter-cooler from top down bottom up. I fully understand why OEMs are gating operating parameters everywhere they can and looking for every molecule of packaging space and going with water to air makes total sence. It makes sense to have a warm temp for hwy gas mileage too.
when I get around to getting my saab back together.. I have an intercooler from a 745 to replace it's small stock sidemount. Was a -lot- cheaper on ebay than any of the questionable big tube intercoolers.. not as shiny, but cheaper and probably a lot better
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