# FMIC vs Air to Water - Pls explain



## blue32bingo (Dec 5, 2008)

I'm curious, what are the pros / cons of an air to air (SM or FM) intercooled setup vs an air to water setup.
It just seems to be the 'new black', HPA has released theirs, it looks like VF is doing the same with their turbo R setup and have been doing the same for years on M3s.
You can easily buy the required components at PAG Parts, so what gives?
Why are the likes of C2, who do their own tuning, sticking with a FMIC setup? 
Obviously there is a lot less piping involved, does this translate to better throttle response?
Is it the cost, ie. $650 vs $450 (water vs air) on PAG Parts for a 750hp capable core.
Is maintenance perhaps a little bit more involved with a water cooled setup?
What say the Vortex Gods - why is air to water not the norm for a turbo VR6 setup?


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## dub_slug (May 12, 2008)

*Re: FMIC vs Air to Water - Pls explain (blue32bingo)*

I was going through this "dilema" the other day with a friend of mine, Air2water intercoolers are awesome but become heat soaked quickly and are great for the track but for a daily or even a mountain cruiser like myself this is probably not a good idea...
Air2water's require more maintance and up keep witht he possibility of the pump or a number of other things failing
Whereas air-air, just hook it up and your ready to rock!
Air2water systems also add weight to the vehicle... the reservoir (if you choose to run one) will consist of a few gallons of water, a gallon is about ~8.5lbs, so an extra 45lbs added just right there, ie... there goes that spare you just pulled to try and cut down times
Overall an air2air is more reliable and still makes great power, just depends on the core you use.


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## benzivr6 (Feb 16, 2001)

*Re: FMIC vs Air to Water - Pls explain (dub_slug)*

It depends on your HP and driving goals your car is used for. applications around 350hp and your on a budget stick with a FMIC cheaper on pockets. looking for 400whp and drive both on the street and track and have some extra change to play with AWIC. I have had both a FMIC and a AWIC and from my personal experience the AWIC when properly setup is VERY good for a high HP DD Street setup. Only downside I personally see is the weight. Alot of texers here are quick to post negative comments on AWIC.( Alot of them don't even have a FMIC either ) which I feel is wrong. I have experience with both and I also have a intercooler temp gauge in my car so I monitor temps both in/out on my AWIC core as well. One thing I would also like to mention is lots of production cars use FMIC/SMIC setup due to cost not because of quality/efficiency. If a AWIC is good enough for a 500+ hp Mercedes benz then why not mine

_Modified by benzivr6 at 11:12 AM 2-22-2009_


_Modified by benzivr6 at 11:13 AM 2-22-2009_


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## vr6_Love (Jun 29, 2006)

-Like said a AWIC is more expensive, theres more maintenance/parts. 
-Air/Air is less expensive and still does the job.

- AWIC you dont have to hack your bumper. So you can keep the stock look.
-Water is 14 times more effective than Air, therefore you can use a smaller core. It also saves on plumbing.
etc.. etc.. 

_Modified by vr6_Love at 8:23 AM 2-22-2009_


_Modified by vr6_Love at 8:24 AM 2-22-2009_


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## leebro61 (Nov 7, 2001)

*Re: (vr6_Love)*


_Quote, originally posted by *vr6_Love* »_
-Water is 14 times more effective than Air, therefore you can use a smaller core. It also saves on plumbing.
etc.. etc.. 


I think you mean '4'


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## slc92 (Feb 9, 2005)

*Re: (leebro61)*

I went round and round with this as well. I chose A/A for the following:
1) Cheaper. I spent ~$250 from the outlet of the turbo to the throttle. Thats core, piping, T-bolts, and all silicone. Add up the total cost of an A/W setup, SRI, couplers, etc. Some have spent upwards of $3k.
2) Less complicated. Nothing to fail(pump), less parts, no wiring, no water lines etc. This is why almost all factory turbo cars come A/A.
3) Water transfers heat better than air sure but what happens during a track day or prolonged street driving when the air hitting the front of the car is colder than the water that has gotten warmer. Drag car/ adding ice and I'm sure A/W has an advantage.
For a street car I think it comes down to fitttment. If you can fit an A/A IC/piping then I don't see the reason for A/W. I was losing A/c for weight anyway so fitting an A/A in a Corrado was pretty easy. Slight trimming of stuff you'll never see and from the outside it looks 100% stock.


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## benzivr6 (Feb 16, 2001)

*Re: (slc92)*


_Quote, originally posted by *slc92* »_I went round and round with this as well. I chose A/A for the following:
1) Cheaper. I spent ~$250 from the outlet of the turbo to the throttle. Thats core, piping, T-bolts, and all silicone. Add up the total cost of an A/W setup, SRI, couplers, etc. Some have spent upwards of $3k.
2) Less complicated. Nothing to fail(pump), less parts, no wiring, no water lines etc. This is why almost all factory turbo cars come A/A.
3) Water transfers heat better than air sure but what happens during a track day or prolonged street driving when the air hitting the front of the car is colder than the water that has gotten warmer. Drag car/ adding ice and I'm sure A/W has an advantage.
For a street car I think it comes down to fitttment. If you can fit an A/A IC/piping then I don't see the reason for A/W. I was losing A/c for weight anyway so fitting an A/A in a Corrado was pretty easy. Slight trimming of stuff you'll never see and from the outside it looks 100% stock. 

On your theories 2 & 3 I disagree bro.
I can name more than 10+ FACTORY production cars off the top of my head that car with AWIC and the reason why the manufacture went with that type of setup was not due to failing parts it was due to cost
Ford Mustang
Ford Lighting
Toyota MR2
Mercedes benz 55 & 65 cars
Toyota Celica GT-Four
Bugatti Veyron ( BTW world's fastest car )= Prolonged speed
Shelby GT500
Ariel Atom
GMC Typhoon & Syclone
GM Saturn ion redline
Subaru Liberty RS
Lotus Esprit
I have read your threads and VERY impressed with accomplishments bro and Hopefully I will have the pleasure to meet up with you someday but I can GUARANTEE that my AWIC setup is more efficient than your FMIC for track day or prolonged street driving. Reason why? it's all goes on how it setup.


_Modified by benzivr6 at 12:45 PM 2-22-2009_


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## benzivr6 (Feb 16, 2001)

*Re: (leebro61)*

In Leebro's defense Air has a specific heat value of 1.01 (at a constant pressure), while the figure for water is 4.18.


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## slc92 (Feb 9, 2005)

*Re: (benzivr6)*

Come on man, this isn't an argument. If you went A/A don't get your panties in a knot http://****************.com/smile/emgift.gif 
That's a nice list but almost ALL of those cars are "special" models or platforms that added FI to a special edition. What form of IC do the vast majority of manufacturers chose? A/A. Why? Cost and simplicity. Think Subaru, VW, Volvo, etc.
I'm not a rich guy so I take the cheapest path to reliable power. If you don't mind some trimming that's A/A on these cars. I'm not familiar w/ your setup but my pipe out of the IC stays cool, always, so I'm not sure what A/W would do w/out ice in the resevoir.
Go to Spring SNG. Run 10psi like me and show me the A/W is more efficient.


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## benzivr6 (Feb 16, 2001)

*Re: (slc92)*

Bro Im not trying to argue with you. Im all about saving a dollar and really going by real world accomplishments and not engineering theories ( See my sig ) Like said I respect your accomplishments bro but as far as drag racing goes that's another topic I will not get into it with you because you prolly have more track time under your belt than me. The topic was what's more efficient between the AWIC and the FMIC. I feel when properly SETUP the AWIC wins. BTW most factory produced F/I models cars usually are special model cars to begin with.


_Modified by benzivr6 at 1:28 PM 2-22-2009_


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## vr6_Love (Jun 29, 2006)

*Re: (benzivr6)*


_Quote, originally posted by *benzivr6* »_ BTW most factory produced F/I models cars usually are special model cars to begin with.
_Modified by benzivr6 at 1:28 PM 2-22-2009_

uhh.. im not 2 sure on that. What do you mean by "special models" ? Cuz i mean all the 1.8T's, 2.0T's, TDI's etc are all F/I but not "special".
leebro.. i read that it was 14 times but i guess it was wrong. http://****************.com/smile/emthup.gif







stupid Jeff Hartman









_Modified by vr6_Love at 10:43 AM 2-22-2009_


_Modified by vr6_Love at 10:44 AM 2-22-2009_


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## benzivr6 (Feb 16, 2001)

*Re: (vr6_Love)*



vr6_Love said:


> uhh.. im not 2 sure on that. What do you mean by "special models" ? Cuz i mean all the 1.8T's, 2.0T's, TDI's etc are all F/I but not "special".
> I stand corrected I should have mentioned cars other than VAG group.


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## xblueinsanityx (Nov 20, 2005)

the main benifit to air-water is that you maintain a more constant cooling effect i have almost the same temps sitting at a stop light as i do going down the highway but for most people a good air to air is the best bang for the buck


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## steven12345 (Jul 18, 2006)

did you look into a water/meth set up?


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## slc92 (Feb 9, 2005)

*Re: (benzivr6)*

^^
It's cool http://****************.com/smile/emthup.gif The companies that turbo their regular models are what Subaru, VW, Volvo, and I'm sure there are a few more. None of them use A/W to my knowledge. 
Doesn't really matter. They both work. Cost vs. benefit and A/W made no sense performance wise. I'll go as fast as I need to go without it. I buy the "I'm keeping A/C or don't want to trim anything" arguments for A/W. Just not the performance ones for a street car. Just my opinion when $$ is a factor. For most of us when isn't it








I'm with you on the real world stuff. Bling SP SRI and AWIC setup looks great on a show car and Vortex bragging rights. I'm sure they are quality products as well. However, you can spend 1/10th of that on an IC setup and make as much power as you'll ever put down on the street or legally use @ the track w/out a bar/cage. No one is right or wrong but I have $2700 in my pocket left over to use for slicks, axles, clutch, more boost, etc.
Any details on your setup? I'm not familiar with it. Feel free to IM to keep the thread on track http://****************.com/smile/emthup.gif


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## jhayesvw (Oct 3, 2001)

*Re: (slc92)*

Air to Air, if done properly is more efficient than air to water.
http://www.bellintercoolers.co...FAQ_5
read up.
bell intercooler (corky bell) isnt a fly by night POS operation.
they sell both setups.
they feel that a properly sized air to air, is better for the street and road course.
for drag racing, the air/water is definitely better.


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## leebro61 (Nov 7, 2001)

*Re: (jhayesvw)*


_Quote, originally posted by *jhayesvw* »_Air to Air, if done properly is more efficient than air to water.
http://www.bellintercoolers.co...FAQ_5
read up.
bell intercooler (corky bell) isnt a fly by night POS operation.
they sell both setups.
they feel that a properly sized air to air, is better for the street and road course.
for drag racing, the air/water is definitely better.


You do realize that his definition of efficiency is entirely arbitrary? If you read through, he defines efficiency as deltaT_intercooler/deltaT_turbo. Anybody else in the world will define a heat exchanger efficiency as Thot_inlet - Thot_outlet / Thot_inlet - Tcold_inlet. More commonly, the effectiveness of a heat exchanger is used in place of "efficiency". Efficiency is an over used engineering buzz word, where people often throw it out with semi meaningless definitions.

_Quote, originally posted by *Bell* »__What ranges of efficiency can be expected from an intercooler?_
A typical air-to-air intercooler for a street application achieves between 60% and 70% efficiency, an excellent/optimum design for road racing can approach close to 90% efficiency, but requires an adequate "budget!”
Typically, a liquid-to-air intercooler achieves higher efficiencies than an air-to-air intercooler, starting at 75% efficiency and reaching peaks of 95% efficiency. Another advantage is the optional use of ice as a coolant, which is the only way to reduce the charge-air temperature below the ambient air temperature.


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## slc92 (Feb 9, 2005)

*Re: (leebro61)*

^ I'm not sure how it's entirely arbitrary but if you say so.
From Bell intercolers:
There is an overwhelming quantity of ambient air available to cool an air-to-air core relative to the charge air thru the inside of the intercooler (The *iced down water *intercooler is the only exception to this argument.). At just 60 mph, with a 300 bhp engine at full tilt, the ambient air available to cool the intercooler is about ten times the amount of charge air needed to make the 300 hp. Whereas the water intercooler largely stores the heat in the water until off throttle allows a reverse exchange. Some heat is expelled from a front water cooler, but the temperature difference between the water and ambient air is not large enough to drive out much heat. Another way to view the situation is that ultimately the heat removed from the air charge must go into the atmosphere regardless of whether it's from an air intercooler or a water based intercooler. The problem with the water intercooler is that the heat has more barriers to cross to reach the atmosphere than the air intercooler. Like it or not, each barrier represents a resistance to the transfer of heat. The net result; more barriers, less heat transfer.
Street use: The air-to-air intercooler will prove superior in efficiency when sized properly. 
Drag racing: The short spurt of power allows the *iced water *to cool the charge air to below ambient temperature. 
Endurance racing: The air-to-air intercooler is clearly superior due to the shorter route of getting the heat out of the air charge and into the atmosphere. Endurance racing would preclude the use of ice water, thus negating the singular advantage of the water intercooler. Further, the air-to-air intercooler is (virtually, see comments below) maintenance free. 
Looks like from a company that sells both they are saying that an A/W really only makes sense if you can't fit an A/A or it's a drag car and you plan to use ice or coolant.


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## leebro61 (Nov 7, 2001)

*Re: (slc92)*

It's arbitrary because efficiency is always defined in terms of output/input. Sometimes efficiency is defined by actual/ideal, but this convention is always marked by a modifier such as isentropic efficiency. Anyway, if each company/manufacturer uses a made up standard of performance it makes comparing competing products difficult. For example, with this definition... you could theoretically put on a more efficient turbocharger, reducing your intercooler inlet temperature and changing your intercooler efficiency. Does that make any sense?


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## slc92 (Feb 9, 2005)

*Re: (leebro61)*

Yes it does, but so does Bell's definition in my opinion.








I know something else that makes sense. 400-600whp cars that run ~$100 CXracing(ebay) A/A intercoolers. Guess they are efficient enough huh? Make sense? I didn't even need an engineering degree to figure that out http://****************.com/smile/emthup.gif 
505whp integra and a 9 sec. DSM both running CXracing A/A IC's. Check it out on page 2.
http://forums.vwvortex.com/zer...age=1


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## jhayesvw (Oct 3, 2001)

*Re: (slc92)*

i understand lee's side (or i think i do).
however, i do stand by my OPINION that a properly sized air to air is very efficient, has almost no maintainance, and is reliable as anything out there.
a very well thought out air/water MAY be more efficient, but also adds weight and complexity. it also lends to more parts failing. there is no way to dispute that IMO.
either way, you cant go wrong with either setup if done properly for our cars. http://****************.com/smile/emthup.gif


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## leebro61 (Nov 7, 2001)

*Re: (jhayesvw)*


_Quote, originally posted by *jhayesvw* »_i understand lee's side (or i think i do).
however, i do stand by my OPINION that a properly sized air to air is very efficient, has almost no maintainance, and is reliable as anything out there.
a very well thought out air/water MAY be more efficient, but also adds weight and complexity. it also lends to more parts failing. there is no way to dispute that IMO.
either way, you cant go wrong with either setup if done properly for our cars. http://****************.com/smile/emthup.gif 

. http://****************.com/smile/emthup.gif 


_Modified by leebro61 at 9:08 PM 2-22-2009_


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## slc92 (Feb 9, 2005)

*Re: (leebro61)*


_Quote, originally posted by *leebro61* »_
Everything you said makes complete sense. It's refreshing to see somebody take an objective point of view about this. http://****************.com/smile/emthup.gif 

I think it's also refreshing that some of us on Vortex don't "follow the herd". These wheels are cooler, you need this $3k intake mani and A/W setup to make power, it's better b/c it's more expensive, Rotas are too rice,etc., etc.
I like budget builds. That's my thing. Some guys spend $10-$15k on standalone, an SP SRI/AW setup, GT turbo, built motor, forged pistons, etc. to make 400whp and that's cool







Others spend $4k on a T series turbo, stock mani, some headstuds/spacer, ebay IC and piping, and a chip and make 400whp. Who's right? Both. Do what makes you happy and your budget allows. Objective








For 400whp I'll build the second car and spend the $6-$11k on something else. Subjective http://****************.com/smile/emthup.gif


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## leebro61 (Nov 7, 2001)

*Re: (slc92)*

Nothing wrong with that either. It just so happens that I fit into neither of those descriptions. I build things myself for the cost of materials (or less). Yeah, I could just spend the $ and get the power I'm looking for, but I really enjoy designing, spec'ing out, machining, and then building custom components... even if it causes headaches and takes 10x as long.


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## slc92 (Feb 9, 2005)

*Re: (leebro61)*

^^
Whatever turns you on man







It's not wrong if someone loves what they spent the time and money on.
I just play devil's advocate to the Vortex theme of "It's better if it's more expensive and I'll dig up some theory to prove it". I can't argue someone's subjectivity regarding their nice new $1300 manifold. If they like it then it's $$ well spent. However, you can argue cost vs. HP/ET. Dynos and timeslips prove that, not pricetags or # of views in a thread.


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## xblueinsanityx (Nov 20, 2005)

you can build a good air to water setup for well under 1,000 dollars and for allot of peoples setup it works awesome and others air to air works better both can be built to work extremely well! there are too many different things to argue about i personally love having a nice air to water setup. its complicated but it works awesome in my situation and i wouldent trade it for the best air to air. i like not having a big bug catcher on the front of my car haha


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## blue32bingo (Dec 5, 2008)

*Re: (xblueinsanityx)*

Thanks for the info! http://****************.com/smile/emthup.gif


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## vr6_Love (Jun 29, 2006)

so pretty much it comes down to you could have either/or.. as long as the system is designed properly.


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## xblueinsanityx (Nov 20, 2005)

exactly! both work great when built correctly and both suck! when designed poorly


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## water&air (Aug 1, 2002)

*Re: (xblueinsanityx)*

i went with a awic due to space constraints, i have an 01 beetle and to fit the right sized fmic i would have had to butcher my front end.
my awic didn't cost near $1,000 either.
both work great when sized right. 
the other benefit to waic is the lack of pressure drop (.01-.05 on most setups) as opposed to and average 2-3 psi drop on fmic's due to the length of piping. i have 23 inches of piping and a few couplers with my awic setup.


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## 05JettaGLXVR6 (Jan 25, 2006)

*Re: (water&air)*

I think its all about what you feel justified. My Air to Air setup is good for the street and the track. I drive mostly on the street. I can't see spending money on all these pumps and lines when my setup works fine for what i do. With my AC removed i fit a 24x12x3 behind my euro bumper. my $.02. 


_Modified by 05JettaGLXVR6 at 3:42 PM 2-23-2009_


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## water&air (Aug 1, 2002)

*Re: (05JettaGLXVR6)*

but i like ac. lol


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## 05JettaGLXVR6 (Jan 25, 2006)

*Re: (water&air)*


_Quote, originally posted by *water&air* »_but i like ac. lol

My DD has it. Thank god. Plus my VR's was broken when i got it. So i wasn't about to try and fix it.


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## water&air (Aug 1, 2002)

*Re: (05JettaGLXVR6)*

even with out my condensor (on a new beetle) i would have has to butcher the front end, loose my grill and fogs and just look ghetto.
i think i spent about 600 total on my awic, which wasn't to bad.
best part about having ac in a street/drag car is you don't cook yourself while staging. lol


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## KubotaPowered (Jan 27, 2005)

*FV-QR*

FWIW I use an air-to-air and made a ton of power with almost back to back runs that were very close in power.


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## xblueinsanityx (Nov 20, 2005)

*Re: FV-QR (KubotaPowered)*


_Quote, originally posted by *KubotaPowered* »_FWIW I use an air-to-air and made a ton of power with almost back to back runs that were very close in power. 

you have a bunch of space for a nice air to air too! if your in a raddo like me you have no space up there without cutting everything. my last 3 dyno runs where within 5hp and i will say i spent under 400 on my air to water setup but it does take allot more work to install and run lines and hoses and all that crap! oh and your making some nice number kubota


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## KubotaPowered (Jan 27, 2005)

*Re: FV-QR (xblueinsanityx)*

I will add that only the lower 2 inches of the core is exposed to air as well and the cold side end tank is the same temp as ambient


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## slc92 (Feb 9, 2005)

*Re: FV-QR (KubotaPowered)*


_Quote, originally posted by *KubotaPowered* »_I will add that only the lower 2 inches of the core is exposed to air as well and the cold side end tank is the same temp as ambient

Good to know.
I plan on making more power eventually and I don't want to run an aftermarket bumper on my Corrado and will never cut up the stock one.
Only about the lower 3" of my IC get's direct airflow via the lower grill opening. 10 psi and it's working great. I'm just wondering how much boost I'll be able to run w/ a 27x8x2.5 core and limited airflow.


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