The Differences Between Air-to-Air and Air-to-Water Intercoolers

What's the best intercooler, air-to-air or air-to-water? What are the advantages of different types of intercoolers?
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Modern engines are trending towards downsized turbocharger solutions. In order to make power efficiently, air temperatures need to be cool before entering the engine. Turbochargers compress air, and doing so increases the air's temperature, decreasing density. That's where intercoolers come in, which use ambient air to reduce the temperature of the air used for combustion.
There are two main styles of intercoolers, air-to-air and air-to-water. Both are effective, but they each have their own distinct advantages with regards to packaging, efficiency, turbo lag, throttle response, and of course cost. Check out the video to learn more about how these systems work, and perhaps decide which solution might be best for your own projects!
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[@vali69]

"im not in my bed room... Im outside! I did it mom!" Ahh good for u *cries in the corner of his bedroom*

[@oscarmathson3006]

I think is easier to design engine room without air to air piping that takes a lot of space and maybe cheaper.

[@nightowlcoffee1033]

🤣😂

[@StokmanFeilsok]

Hahaha i really laughed at that one

[@wobblysauce]

I am not in my bedroom... but someone elses.

[@AdamAdamHDL]

So the air to water system has an intercooler for your intercooler. Got it

[@nazhif1]

yo dawg...

[@nickf1724]

Adam Adam very good way to put it

[@AdamAdamHDL]

@@nickf1724 I believe in being succinct

[@AnasHart]

+Adam Adam Explains the name bro :D

[@exothermal.sprocket]

Basically using the density of fluid to transfer cooling at the front of the vehicle to cooling at the intake of the engine. Much more thermal density (at whatever temperature) can be achieved in fluid and it also happens to be easy to plumb in small lines. But it's going to be more complex with a pump, two cores, fluid, and plumbing. Be interesting to see the actual NET result of air between the two systems, with all the statistics about core sizes and overall weight, ambient temps and intake temps. Would be quite a science project.

[@soveu8237]

Jason said 36 times "cool" and the video is 280 seconds long That gives about one "cool" per 7.8 second So I can say it is a very *_cool_* video

[@ignasanchezl]

This video is intercooled.

[@nezabytes]

you have way too much time on your hands...

[@snazy7777]

Theres a different sized white board for all occasions

[@letrolldesbois1]

*I did it mom !*. Pure gold right there.

[@tjsrisawat3777]

One can only dream to do the same

[@anderslolle2147]

I was worried about the whiteboard for a second there... But Jason always has one with him 😎

[@kern417]

I have a newer BMW with the B58 engine and air-to-water cooler. I was so excited to get it. It performs great, response is awesome, and less to worry about when upgrading. Then at 1000 miles i noticed the aux coolant tank that supplies the cooler was dry. Come to find out BMW only put a level sensor in the main tank and not the aux tank. So I had no warning that it was dry outside of a forum thread where several people said they found theirs was empty. So I had my first dealer visit 3 months into ownership. Great idea. But it's always going to be a BMW.

[@EngineeringExplained]

Thanks for sharing your experience!

[@Bestwick1983]

The unfortunate reality of the B58/B48 motors is the radiator supplying the cooler is made of a material I can only describe as "tinfoil". This is mounted in front of the engine radiator and ends up like swiss cheese after the first shower of small rocks, leading to leaks in the system (and with no level measurement as you mention). Madness really. Also the efficiency of the water-air system on the B58/B48 is nowhere near as efficient as that of the S55 or S63 motors and tends to heatsoak rather rapidly with back to back pulls in even mild weather.

[@Bestwick1983]

Yes, I'm aware of the sensor in engine cooling circuit, however the circuit cooling the intercooler is completely seperate from the engine cooling circuit, hence the two tanks and the issue when the radiator for the intercooler circuit is compromised.

[@kern417]

For sure. I'm still not sure if it's actually a leak, or if it just wasn't filled properly at the factory. There's a growing thread on the Bimmerpost F30 Forum where people are discussing how they are going about getting it resolved.

[@darkened13]

Bestwick1983 s55/s63 have duel heat exchangers compared to one on the b58/48.

[@abel8658]

You got a like from me purely for the "I did it Mom" statement.

[@Killatunga]

That is some beautiful scenery in the background

[@quillaja]

Lolo Pass Rd, Oregon.

[@3500camarz]

This dude is amazing! He really knows how to simplify anything that’s automotive. I was trying to understand why a air to water intercooler uses a heat exchanger (I was confused thinking the heat exchanger was for the air also) then his video helped me understand the heat exchanger is for the coolant. Excellent video!

[@EngineeringExplained]

Happy to help, glad you enjoyed the video!

[@johnclary729]

Also in performance applications you can run the coolant through a reservoir filled with ice after the radiator to get intake temperatures below ambient after compression, and make the ice last longer than just using the reservoir.

[@rx8cosmo]

It's good to see you remake old videos!! It was needed to be honest! You are much more experienced now regarding KZbin.

[@yaberwoocky]

i had this car for a few days to try, and i have to say i absolutely loved every minute of is

[@CaptCommandoXII]

I'm totally new to BMW engines & they've introduced me to the concept of air-to-water intercooling. I watched a video of Mat Armstrong BMW M5 rebuild & was fascinated by that engine. Up to now I've only known air-to-air intercooling. This video really broke it down for me & now I'm obsessed. Thanks so much for the info 👍🏽

[@Linuxian]

I was literally hoping to find a video from you while googling the differences and how air to water ICs work. Thank You for all the work you put into these videos!.

[@Linuxian]

Do you have any data comparing the rate of energy transfer of the two designs? Which one is better at cooling intake air. Let’s say I was running 25psi if boost, which system would be better? What prevents the airy to water system from heat soaking like the air to air systems do?

[@thomasphilyaw8593]

As usual short and to the point packed with relevant information. Awesome all the way around!!!

[@BBradCO]

The vids just keep getting better! I was almost worried about a lack of diagrams lol. Great explanation as always!

[@dangleason9023]

"I did it mom!" Classic.

[@ER2313_]

So, more that can break down. Great!

[@konradboltz4504]

Er1323 The B58 actually is a really good engine … so far no Big Problems

[@Conservator.]

Er1323 If that was a criterion then we’d all still drive T-Fords. Modern cars are way more complicated then the ones from 30 years ago yet the service intervals have gone up to 20miles/30km.

[@achmadfajar6845]

But we can't deny that eventough modern automobiles is complex in design and tech, it also more easy and pleasant to use

[@404nobrakes]

@@Conservator. criterion. Criterium is a bicycle race.

[@Conservator.]

Saurabh Kulkarni Thank you 🙏! Corrected

[@JaZoN_XD]

Yo dawg, I heard you liked cooling stuff, so I used an intercooler to cool your intercooler so you can cool your intercooler while you cool your air

[@accordinglyryan]

An inherently complicated system on top of it being a BMW? Ohh man that thing's gonna be good friends with the dealership service department.

[@MaikEletrica]

Nice explanation, thanks!

[@lkinchen101]

Very very helpful, thank you.. love the show

[@TheAdventureAuto]

Interesting info. I came here because the new Mazda3 turbo was just announced to have a water to air system. Thanks!

[@RS-nq8xk]

Intercooler on top of the engine. Is that the Subaru Impreza WRX kind of placement?

[@nickf1724]

no, the wrx uses ambient air to cool the top mount intercooler, but it does not have a second air to water ntercooler in the front of the engine, it is just one air to air intercooler located on top of the engine, also it uses a hood scoop to take in that air which the bmw just uses the air coming through the grille

[@RS-nq8xk]

I mean the air to air intercooler

[@spamcan9208]

Yes, that's the car I thought of too when he mentioned that location.

[@spamcan9208]

@@nickf1724 he's referring to location placement

[@Petrospect]

RX-7 Turbo IIs have that placement

[@JohnmillerPowerlifting]

thanks well explained like always

[@richardm14]

Another quality, short and informative vid thank you!

[@EngineeringExplained]

thanks for watching!

[@exothermal.sprocket]

For all the added complexity of air-to-liquid intercooling, they may as well just run plumbing to the trunk for an ice-tank and really get that air cooled off. Just run air-to-air with a front-mount water spray device to get temporary power increases by evaporative cooling of the external core surfaces.

[@nickit22]

Keeping that much water is not convenient. This system you don't need to refill or keep adding like yours would.

[@IainWandersButIsNotLost]

Great stuff Jason. I have not seen a better explanation of the differences. For me, I'd take the simplicity of the air-to-air intercooler. Coolant and cooling system failures can quickly lead to catastrophic consequences which I assume would be less so in terms of an intercooler, but still the potential for more coolant leaks alone is enough for me to avoid the system.

[@yolo_burrito]

It’s not really heat cycling like engine coolant so the systems are pretty robust. Not to say it’s not a concern but systems like this have been around a while with little issues. Also the intercooler leak would have to be catastrophic to cause engine damage. A pin hole leak ingested into the intake wouldn’t be likely to affect the engine.

[@Blafard666]

No, I have no questions, because that was very clear explanations, thank you.

[@abrarulhaqkhan1775]

I am also a student in Auto field but . Follow your videos to improve our knowledge

[@abdulazizal-zadjali8574]

Keep white board wherever you are with u so we can catch up🍅what you explaining❤️

[@nomadadventures1422]

your videos are always great!!! thanks

[@phildem414]

Good explanation, but there is also another advantage : the thermal inertia of water. In fact when the power needs are intermitent, not an oval track for exemple, you can aford a smaler pair of exchangers because the water can still be cooled when off-boost. A notable example is the second turbo version of the Lotus Esprit.

[@bradsailer7739]

Thank you for teaching me

[@KVW22]

"Just because Im outside doesnt mean i forgot my white board" 😂😂 i love you man

[@jiakabery3550]

Look at that NW view! FANTASTIC. Much like your videos. 😉

[@EngineeringExplained]

Best place ever! ☺️

[@jiakabery3550]

@@EngineeringExplainedI've lived in Portland area since 81. I don't think I could ever live anywhere but the 4 NW states. Also...saw your CL post selling your Integra parts. For a second I thought I was in the twilight zone. Then realized it was real and I was under the influence of Cannabis. LOL. Hope you have a fantastic day and thanks for the great content.

[@suserman7775]

I love numbers too. Some numbers that would be nice are expected additional cost and what kind of lag reduction or power boost would be typical.

[@bholm369]

The cool thing about air to water is that you can get an aftermarket setup to drop the coolant temps using the ac system. Puts more strain on the ac but temps are below ambient.

[@nooranik21]

Great engineering, better explanation.

[@alejandrobarela2111]

Kudos for all your videos. Easy way to explain. Btw Something I am wondering about this. How come automakers haven’t used the air conditioning system for this. Instead of using the (in case of the water inter cooler) outside cooler use the a/c compressor to cool down the inner coil. And should be colder at all time. My two cents.

[@rudolphna54]

While it would improve volumetric efficiency at high temps, the AC compressor uses far more energy to drive than a small electric circulatory pump. That would render it pointless since the whole point of air-water intercoolers is power and efficiency.

[@cxbra]

In a performance setup, I would like a air-air intercooler with a nitrous sprayer that sprays onto the air to air intercooler core. NOT for power, but mainly to spray after a high speed run or only when the air intake hit a certain high temp. To do this, the intercooler would need an electronic "thermostat" using heat sensors that go to a nitrous spray "ecu". For example say air intake temps get to 300 degrees (hypothetical number) at the end of a 1/4 run on say, a Evo 8 running a g35 turbo. I wouldnt spray during the run (reduced a.i.t's can actually inadvertently raise boost pressure due to air density).. I would spray after the run to reduce air intake temps to say 180 degrees. Then spray once more right before the run to cool the intake to say 70 degrees right before the launch of the next run.

[@AgsCgs]

very good explanatory video

[@nicksauer6749]

Jason. I think you missed an important point about the duty cycle of the engine. High power road cars will require inter-cooling for short periods of time. In between those bursts of power, air coming off of the turbo will be cooler and help to cool both systems. Indirect water systems will heat up more slowly under power and cool more slowly when power is reduced. You can even use this approach to provide unvented inter-cooling. Essentially that would be a water intercooler without an external pump or radiator, but that would take longer to recover after a full power event. Love the channel.

[@pebblez_]

Thx info

[@Yathuprem]

Can u do a review of the cars u used for each engineering explained video. Like the old days. Give us its engineering feats. Like the Type R one.

[@Tsukiko.97]

I am now off to binge watch your videos!

[@prodj.mixapeofficial6431]

EE channel is awesome. wow.

[@JTuesday]

As always, great explanation, but it was simple (you already got a video of intercoolers). Cloud you go more in depth between this two systems? I am about to make my STi water to air intercooler and there are things I don't know yet like: how fins (bars/plates or tubing) affect the water flow? How much is enough in terms of speed of the water flow in order to allow enough heat transfer? What is a good disign to avoid turbulence and not to get water stocked inside the system that affects heat transfer (like the effect inside the back box of a pickup truck)? Make sense what I'm asking?

[@StrikeFreedom1920]

Almost at 2 mil subs! =)

[@SupraSav]

That devious smirk, when he says " And don't think I forgot my whiteboard" !

[@WC3fanatic997]

Thank god you remembered the white board. I was worried this would be a bunch of stuff I would only begin to understand otherwise.

[@erikschutzman2402]

Can you make a video on the engine-mounted encapsulation system BMW uses on the b58 engine?

[@BirdiesGoCherp]

What is this *outside* you speak of? Hooray for the B58 engine!

[@SJC1995]

I have a 21 supra with the same motor. It seems complicated but it actually simple. Your turbo air only travels about 3 feet total to get to the cylinders. In a FM intercooler it has to travel atleast double that. The charge pipe runs straight from the the turbos cold side outlet to the intake manifold. Pretty cool stuff. If you want to see the brilliant engineering behind the motor check out Stephen papadakis b58 tear down.

[@ducfandan1117]

“I did it Mom!” + portable whiteboard = great video 😂👍

[@DzastinasLTL]

I wonder what actions are taken to avoid hydrolock in case of a leak?

[@Derkenblosh2]

baaahaha, cause BMW cares about this? I have an EGR cooler on my M57, and I worry about this all the time (1st gens were known to fail in the EU, hydro-locking). also, (most) people who buy expensive BMW's don't care, because they are just gonna off them the 1st sign of any inconvenience/maintenance

[@EngineeringExplained]

Prevent leaks through solid design!

[@SoYFooD2]

then dont buy BMW

[@SD-tj5dh]

@@EngineeringExplained they haven't had a solid design in at least 20 years 🤣

[@DzastinasLTL]

@@EngineeringExplained If it's as solid as the wastegate rattle on my N54 then is all good! 😂

[@adelsaeed4696]

Hey EE, can you please make a video about Wavy brakes and their pros and cons?

[@Anonymoose0913]

I did it mom!!! I just shot coffee out my nose.

[@gogutzy]

nice video, but a good question would be - is the extra complexity worth that volume reduction?

[@nobenznofun9139]

Hey good video! Just to clear something up for me: the coolant in the water cooled intercooler is not the same coolant cooling the engine, right?

[@BMWI-gk9wh]

I got the 335i n55 love it

[@edel.m1138]

Could you please make an episode about water cooling turbo chargers in bmw and amg m-benz 63/v8 4.0l advantages... thanks the best and the only real engineering auto channel.

[@SD-tj5dh]

I've always wondered if you fed the air intake behind the intercooler. The air would pass quicker through the intercooler creating greater cooling, but it doesn't get much hotter than ambient air at the intake because of the speed it passes through the intercooler to get into the air intake. Thoughts?

[@TechSurreal]

Please make a video about hybrid system of Koenigsegg Regera which is 800 volt instead of traditional 400v.

[@Kittievr]

Love the Intro

[@macro820]

Our Jetta also had the water to air intercooler in the intake manifold. Weird watching the turbo outlet going straight over the engine and back into the intake

[@timacofe]

Another disadvantage is that manufacturers use the same coolant as the engine. And not a different circuit. So in long travels the limit tends to 90° instead of ambiente temperature. Unfortunately that means a lot less efficient to cool down compressed intake air.

[@KropfkraenklerNo1]

they don't. there's a second cooling circuit for the intercooler. B38/48/58 engines are designed for intake temperatures of 50 °C at rated power.

[@timacofe]

@@KropfkraenklerNo1 you are probably right. That should be right. But I neve saw that second intercooler under the hood of my car....

[@sergiogiacomosammartano7623]

Ahahah! I was wondering... what will he explain without his whiteboard??? And there it is!! :D

[@jeangerber4519]

It is a very good explanation as usual from you great job on that. But really? is it really as good as it is complicated?. So basically between the amg hot v air to water and the bmw air to water which one is best and more practical??

[@NorthernRiderOffroad]

My rzr turbo had the air to water set up. Same thing, intercooler in the intake manifold.

[@JDMred]

Dear jason, can you explain if there would be any power gain if you cool your intake temperature down with your A/C (place an heat exchanger before the intake) it is clear that you take a lot of power from the engine via the V-Belt, but would it help if you „store“ the refrigerant liquid, and when you kick down, the Compressor disconnect‘s from the engine and you use the previous cooled down refrigerant to coll down the intake temperature to have a few seconds more power? Im an automobile engineer myself but never calculate trough this scenario. BR Dražen from Austria

[@MrSlash00r]

Seems like you'd have a lot of heat soak in the B58 intake once the engine was up to temperature, effectively reducing the advantage of the shorter distance the air travels from the turbo to the engine. I guess additional power wasn't as big of a concern as reduced lag and improved drive-ability. With less lag to worry about now BMW drivers can concentrate even more on not using their turn signals.

[@AndyMechinc]

You the best man

[@naufalkusumah2192]

Isn't the water to air intercooler more efficient cuz the water can absorb and dissipate more heat from the charged air than air to air intercooler?

[@kern417]

Yes that's why you can have a smaller air-to-water cooler do the same work that would typically need a larger air-to-air cooler. Also less pressure drop as pressurized air runs over it.

[@timothyfeist7364]

I was thinking it worked like the A/C system. With a compressor and evaporator valve.

[@swayingGrass]

The heat exchanger for the intake air is, but it's less efficient overall.

[@MarcMonson]

you're not going to get the air colder than the water? especially if its in the same circuit as engine coolant?

[@kern417]

It's basically just another radiator system. The same reason why cars are water cooled now instead of how they used to be air-cooled. You run fluid through the heat source and then route it to a radiator to cool off the fluid.

[@SamiKhan-hn3uk]

Can you do a video on Top mounted intercooler vs Front mounted intercooler

[@jeanpelletier7780]

Thanks for video, I have 2 questions: 1- Did the restriction of an A-W vs A-A intercooler is lower (I want to reduce the restriction on my TDI to increase the fuel efficeincy in the same time). 2- If I use a bigger A-W intercooler is better or it have some drawback?. Thanks for the answer.

[@Russianmafia10]

Can you make a video on rear mounted turbos?

[@jameshaulenbeek5931]

Does anyone know what "coolant" is used in this setup? I know a few people that have done aftermarket a2w coolers who run only distilled water (and ice if it's a track day), but I was curious if BMW added a corrosion inhibitor, or used some other fluid entirely.

[@caddy_v3277]

hey just a random video idea, was wondering about this. So lets say on a Dino 2 identical engines both turbocharged. My thought is both are making the "same" amount of boost pressure. But the turbos themselves are 2 different sizes ie a 1" inlet and a 2.5 inlet with similar exhaust turbine sizes. Would they make the same overall power or would the larger one have more cfm and thus more airflow. thanks and love your channel.

[@petaren]

Would it make any sense to use an AC style system to cool the intake air to sub-ambient temperatures?

[@Tacoexplorer]

I believe air to water is more efficient at removing heat when ambient temps are high. I have an BMW M2 s55 engine with air to water intercooler and I never had any heat soak issues when pushing hard in high ambient temps. When an N55 M2 is pushed in high ambient temps you get heat soak issues due to the air to air intercooler. Plus the M2 air to water inter poker sits ontop of the engine and is not integrated into the manifold. Bmw did this because it reduces more heat than typical air to air system.

[@liquidsk8s]

You mentioned the air to air would cool to ambient while air to water would be higher. In practice, this is not the case. Air to air is typically 30+ degrees over ambient while air to water is only slightly above ambient as it has 2 heat exchangers plus the intercooler.

[@macca181818]

What about the thermal mass effects for low speed movements?

[@RichardFanders]

I think water transfers heat 25 times faster than air. My Ea211 VAG engine has a water cooled intercooler. I've done 127,000 miles in it in 4.5 years, it's still a pleasure despite having a second car that's a lot faster. Thumbs up for this system.

[@crankstonshnord6591]

To beat the inefficiencies, run a couple thermoelectric coolers on your coolent pipes post-intercooler. This way your coolent can actually be cooler than ambient

[@dr_jaymz]

I think under harsh acceleration the water can soak much more heat before the coolant heats much. So for short pokes on three throttle it probably works better than air.

[@ElySky95]

I was expecting you would explain core sizes vs flow restrictions and efficiency compared to a regular intercooler.

[@deepakr3706]

your explanation is quite good but you r not showing the parts separately if u show it that's much more better any way I like it👍

[@henrylima6974]

Im trying to do a water to air system (no ice), but Im afraid the performance will not be better than an air to air. What do you suggest? Wich system can get me more whp? Wich system will suffer less from heat soak?

[@Jare2110]

Can you make a video about TMIC vs FMIC?

[@iDONTletUnuke]

Who here thoght n55 vs b58 when they saw this before even playing this?

[@aarons345]

Jason, are you able to expand some on air-to-water system specifically the coolant side. Is it a separate coolant system from the engine coolant so it’s not ~190F when the engine is at operating system? If I am not mistaken, some also have “ice” tanks or there are at least aftermarket ones that can be purchased like the E55 AMG etc... Thanks!

[@EngineeringExplained]

Yes, separate cooling system from the engine coolant.

[@sylak2112]

I would have thought that thought air to liquid was more efficient. didn't thought about exchanging air twice. Very interesting.

[@fjanahi]

i usually hear manual gearbox are better for towing, is it because of the torque converter? we can have a video on the subject ;)

[@shngsam8777]

with additional weight, less efficiency, and also possibility of so many things that can go wrong, pump stop working, leaking outside, leaking in the manifold and coolant sucked in by engine, etc

[@manikdj123]

That’s pretty cool.

[@Curtis_Plays_yt]

Hi my name is Brett Mcintosh I'd like to see a video with an answer to the age old Subaru argument about wether or not lightweight pulley' s cause engine damage and also how a Subaru is really balanced and wether the oem crank pulley acts as a balance or simply a pulley. Will lightweight pulleys cause spun bearings??

[@Curtis_Plays_yt]

Please 😭😢

[@chriskelvin248]

Are there other readily-available liquid cooling mediums or straight up refrigerants that can cool off the air even better and more quickly than water?

[@kraken509]

How feasible to use a compressor and freon and run that through the intercooler vs cooling water with ambient air?