air/air vs water/air intercooler?

Long story short I damaged the front end of my Skyline autocross car a while back, not at autocross, which smashed the intercooler so I have to get a new one. And a new front end on top of it.

To fit a front mount on it again I will have to cut the bumper and everything and spend $600-$1000 on an intercooler for it. The new bumper I bought has fog lights, active spoiler, and a "grill" all of which requires surgery to remove.

So instead of cutting up a new bumper for this car i'm thinking of going to a water-air setup.

This is mostly a street car that I autocross for fun but I heard that water-air setups are not really good for motorsport. On top of it I live in Las Vegas where it gets really hot. Any input on if this would be a good idea?

Added benefit is i'm considering buying a "kit" like this: http://www.frozenboost.com/liquid-air-intercooler/water-to-air-intercooler-p-1006.html

which is a good deal cheaper than anything i've seen on the other end.

Actually I wouldn't be surprised if a water/air system gives you better results in a places as hot as Vegas than an air/air system provided it's sized right. Mind you, that's a completely non-scientific opinion and I have no data to back it. I'm also not convinced that the people who think air/air is superior have data to back that up either.

That said, where would you be mounting the radiator for that system? Can you do that without cutting the bumper?

Water IC is great when you have little space and/or poor plumbing.

It's also great when you can run ice.

But, as you pointed out, heat sink can be a big problem.

And IF there's a leak in the cooler, you can trash your engine (so you need really good parts).

I would *think that at lower speeds (less air flow) the air/water would be superior. Also with autocross you not only have lower speeds but also sitting in grid between runs would create heat soak. Again, I would think air/water is to your advantage in that scenario.

yeah, what 'water' do you plan to use? If using engine coolant you are basically just shifting the 'air cooling' load from the intercooler to the radiator. Technically then the COLDEST you can expect intake air to be with air-to-water is coolant temp (200 degrees), and ambient air (usually less than 200) with air-to-air. Realize though that intake air temp during boost (the only time you care) will never approach this coldest limit, so this probably is moot.

Some race setups can use a separate water source for the air-to-water IC. (Think drag racers dumping ice into their engines before a run).

Or you can run a separate water system and another air-to-air heat exchanger somewhere else in the system.

Overall, air-to-water is probably more complicated and heavy than air-to-air, but can have packaging advantages of a smaller intercooler or less intake pipe.

Great, seems like consensus is that it's probably a good idea.

That said, where would you be mounting the radiator for that system? Can you do that without cutting the bumper?

One of the options they offer is a 26x7x2 radiator which I believe I can fit without cutting. The main problem I had with FMIC the last time was the pipes more than anything.

The actual intercooler its self I saw someone fit in the area where the oem intake box is, he had the same kit. The difference is he has a R33, so I can't compare the radiator placement, but that area of the engine bay is the same.

Water IC is great when you have little space and/or poor plumbing.

Pretty much my problem lol. The plumbing in this car for intercooler fitment is poor. Most people who do serious mods to these get a aftermarket intake and reroute it.

I would *think that at lower speeds (less air flow) the air/water would be superior. Also with autocross you not only have lower speeds but also sitting in grid between runs would create heat soak. Again, I would think air/water is to your advantage in that scenario.

This makes sense, good explanation.

I'm in a similar situation as you - looking at Air-Water due to packaging. Have you considered methanol injection as an alternative?

Robbie wrote: yeah, what 'water' do you plan to use? If using engine coolant you are basically just shifting the 'air cooling' load from the intercooler to the radiator. Technically then the COLDEST you can expect intake air to be with air-to-water is coolant temp (200 degrees), and ambient air (usually less than 200) with air-to-air. Realize though that intake air temp during boost (the only time you care) will never approach this coldest limit, so this probably is moot. Some race setups can use a separate water source for the air-to-water IC. (Think drag racers dumping ice into their engines before a run). Or you can run a separate water system and another air-to-air heat exchanger somewhere else in the system. Overall, air-to-water is probably more complicated and heavy than air-to-air, but can have packaging advantages of a smaller intercooler or less intake pipe.

The "kit" i'm looking at buying has the coolant segregated from the engine coolant. It is a whole separate system. It seems to be made for drag racing in mind and they even have the "icebox" stuff available there

mikeatrpi wrote: I'm in a similar situation as you - looking at Air-Water due to packaging. Have you considered methanol injection as an alternative?

I was looking at that as a future possibility down the road but haven't done any serious reading into it as an option now.

In my mind I always thought of meth inject as a more "serious" open for a more motorsport focused car where this is more of a street car.

Water has better cooling properties than air so if everything is correct, water to air not only cools better and doesn't heat soak but because it's more effiecient the core can be smaller and thus has a lower pressure drop than a larger air to air unit.

As for meth injection don't write it off as serious only I built my own kit for a daily car (cost about $100 total using 100psi pump, name brand nozzle and some used nitrous solenoids) heck it started in aviation! It's at least worth a read, some use them to replace an intercooler entierly but I wouldn't do that, too much reliance on electronics but it does do wonders for an engine, det resistance and chemical intercooling not to mention steam cleaning the engine

Deja vu.

In this thread 2 years ago, I gave you detailed pictures on a low buck solution that I did in your exact same situation in my Skyline. Seriously, for autoX go with air to air. This setup was cheap and was overkill for every track situation in 90* Atlanta heat.

https://classicmotorsports.com/forum/grm/front-mount-intercooler-fabrication/80667/page1/

Extremely minimal bumper trimming, kept my A/C.

crankwalk wrote: Deja vu. In this thread 2 years ago, I gave you detailed pictures on a low buck solution that I did in your exact same situation in my Skyline. Seriously, for autoX go with air to air. This setup was cheap and was overkill for every track situation in 90* Atlanta heat. https://classicmotorsports.com/forum/grm/front-mount-intercooler-fabrication/80667/page1/ Extremely minimal bumper trimming, kept my A/C.

lol forgot about that thread. I went with air-air then and just modified the bumper. I'll check out your solution again.

The main difference between then and now is I have this bumper now:

which has far less space to work with and I actually "like" it lol

I think the bottom pipe will conflict with the fog light though

Your setup closely mirrors my previous setup.

As for meth injection don't write it off as serious only I built my own kit for a daily car (cost about $100 total using 100psi pump, name brand nozzle and some used nitrous solenoids) heck it started in aviation! It's at least worth a read, some use them to replace an intercooler entierly but I wouldn't do that, too much reliance on electronics but it does do wonders for an engine, det resistance and chemical intercooling not to mention steam cleaning the engine

All of that is without a doubt of interest to me, i'll check that out.

I could have moved that IC core back another 2 inches to mount it. Playing around with that more, you would have room for foglights for sure. The other thing I loved about this top to bottom setup was beside the ease of mounting it in that setup, the pipes were really short and spool up improved.

The wheel wells are a good go to for ic mounting if the front of the car is cluttered. There is tons of air flow potential there. A simple mesh screen will keep rocks from causing trouble. You wouldn't have to worry about the radiator or ac condenser or any other heat sync system causing heat soak either.The water to air or the air to air will benifit there too.

The plus side of the water to air is you could have multiple small radiators with/without addition to the ice tank.( They could go anywhere there is good air flow not just the front of the car) You can use a factory bosch pump from a svt mustang or a dozen other donors.

My supercharged Focus is air/water intercooled. The system is completely separate from the engine cooling system. The radiator is mounted in front of the car radiator, the water pump is on the left fender, the coolant tank is on the right fender. The actual intercooler is a radiator-like plate sandwiched between the supercharger and the intake manifold.

I have seen similar setups on turboed cars with the only difference being that the intercooler looks like a bullet muffler and is mounted in the intake piping between the turbo and the intake.

alfadriver wrote: Water IC is great when you have little space and/or poor plumbing. It's also great when you can run ice. But, as you pointed out, heat sink can be a big problem. And IF there's a leak in the cooler, you can trash your engine (so you need really good parts).

Set it up similar to the supercharged Ion Redline & Cobalt SS......the w2a setup in them ran off an electric water pump and was completely separate from the engine's coolant supply. It worked relatively well, but that was with a positive displacement s/c.

I just can't see how jamming all that stuff into an engine bay is easier or packages better than a front mount air/air

Jumper K. Balls wrote: I just can't see how jamming all that stuff into an engine bay is easier or packages better than a front mount air/air

Water lines are much smaller than the air pipes. So you can just put the intercooler bit in-line with the piping and keep the charge piping short and sweet, without having to get it up front. And it's easy enough to run the smaller, more flexible water lines up front (and the water radiator is thinner than an air/air core, so easier to mount).

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.) At best, the water may act as a heat sink when cold until it warms up. Then the opposite effect takes place, and it will store more heat within the system compared to an air/air set up. Air/water setups are to overcome packaging problems, or for short duration like drag racing. I'd much rather have an air/air set up for daily driving in Las Vegas.

I'm suprised to hear that it's difficult to fit the I/C and piping on a Skyline. You would think that there would be a number of options. What about a large side mount, like a Supra?

Air to air and water to air are not equal. Keep reading. If what you say is true (still cooled by air regardless) why are there ZERO air cooled cars anymore? Oh that's right, because water cools better than air. It's science.

Air/water will generally be more effective not because it can transfer more heat overall, but because it can store some amount of heat, so intake temps will climb less over the course of a WOT blast (the water temp will climb as you exceed the ability of the system to get rid of heat, but this reduces the IAT climb compared to air/air where there's no intermediate heat storage).

chiodos wrote: Air to air and water to air are not equal. Keep reading. If what you say is true (still cooled by air regardless) why are there ZERO air cooled cars anymore? Oh that's right, because water cools better than air. It's science.

Apples meet oranges.

Boost_Crazy wrote: I'm suprised to hear that it's difficult to fit the I/C and piping on a Skyline. You would think that there would be a number of options. What about a large side mount, like a Supra?

It's not hard though. I had no issues with it at all and made 320 hp with zero heat soak on the same car in 90 degree temp. If he wants to keep his foglights, he is better with a air to air fmic than a large side mount (that sits behind his foglight and wont cool for E36 M3). Honestly, if you are stock turbo and relatively stock boost levels, running the stock rb20 smic would probably be plenty for autocross. Track days on a road course with long boost pulls would require additional intercooling at that point. I never ran in to knock issues 2nd gear in a parking lot.

In reply to chiodos:

Air to air and water to air are not equal. Keep reading. If what you say is true (still cooled by air regardless) why are there ZERO air cooled cars anymore? Oh that's right, because water cools better than air. It's science.

You are joking right? You do realize that that once the water is up to temp, it's not cooling anything, right? The water is just a medium to transfer the heat from one place (the engine block in your example) to the radiator, which is cooled by the air. It's a closed system. If you were driving in a lake (or had a motor boat, which would make more sense) and had an unlimited supply of water, then the water would be doing the cooling. You could cool an engine by air, but building one that incorporated enough heat exchangers and airflow would be difficult, and quite large. So we use water to move the heat to the remote mounted radiator. This is the exact same concept as an air/water intercooler. But since it's not nearly as difficult to get the heat from the air charge out to the front of the car as it is to get the heat generated by then engine itself, you usually don't need to use water to get it there. Air/Water I/C's are not bad, and they do have benefits over Air/Air, but ultimate cooling capacity is not one of them.

What about e85 and no intercooler? I've heard some VERY good things, between the cooling capacity of the fuel and the detonation resistance...

Air-to-air gives good cooling and is usually the cheapest (or at least the best bang-for-buck).

Air-to-water sharing the existing radiator usually doesn't cool as well as air-to-air because the intercooler now has to share heat-shedding capacity with the engine. And there's the increased risk of failure now shared between the two systems.

Air-to-water with a dedicated radiator gives the best cooling and least pressure drop without any reliability downsides, but it's the heaviest and most expensive setup.

So I'd recommend trying to jam another air-to-air IC where the broken one was, and if you can't, try to fit an air-to-water IC with a dedicated radiator.