A/A or A/W intercooler for a turbo track car?

[CL65 Captain]

I was wondering which is a better setup for a track car - A/A or A/W?

Assumptions are a stock~ish engine with one of the Prime guys turbo kits running a conservative 380-400 rwhp.

 

[sca037]

In general terms, the less fluids (even water) that pose the possibility of getting on a track, the better :wink:
Cody and others can chime in here, but I suspect at that moderate power level air-to-air should be fine.

Brian

 

[scorp965]

It is going to depend on placement, I don't like the location of most A/A setups, they will heatsoak very quickly if placed adjacent to the exhaust, or on top of the engine, under a lexan hatch. An A/W system gives you greater flexibility, and provides greater heat dissipation potential.

As far as a fluid leakage concern... the coolant being used in an air/water setup is not going to be under high pressure, a simple electronic pump, rubber hoses down the coolant line channel, and barbed fittings with hose clamps are you're set... I check my air/water coolant level regularly, and have very minimal loss.

 

[brandonsan]

Air to water ...hands down.

 

[jorligan]

Brian's post regarding fluid is probably based on his position as a track official at SCCA events. A-A probably gets heat soaked prety easily based on my prior experience but there are definitely some ingenious tuners who are getting airflow so for lower HP:biggrin:, may be just fine.

 

[doc_tai]

lovefab water to air or wil air to air cause I like where they place the cooler

 

[CL65 Captain]

I was looking at the Porsche 997TT and GT2 setup and they are A/A. It seems that if you are not big HP #s, reaching for the last few HP, and with average speeds on the track at 70+ mph that the simplicity of the A/A outweighs the extra HP of A/W. If I end up with 370rwhp instead of 380 or 400, it's still better than the 270 rwhp that I am currently running around the track with.

I have no problem staying with Vettes or GT3s on the track except when they disappear over the horizon on the long straights.

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I guess I am just wondering from an Intake Temp perspective if the low ITs from A/W would be "healthier" for the car when pushing it hard on the track on a regular basis. Car will also have a 3qt Accusump and SOS oil cooler.

 

[Daedalus]

Space and size constraints aside, I'm curious as to why a A/W would enable more horsepower than an A/A. Unless you're using chilled coolant for a short duration, you have most of the same challenges with implementation in either case. You need an A/A heat exchanger somewhere in both cases; an A/W setup just allows more flexibility in where it can go. The downside is that the water in A/W is probably going to be hotter than the air in A/A. It seems an A/A system cuts out the inefficiency of the middle man.

 

[scorp965]

Space and size constraints aside, I'm curious as to why a A/W would enable more horsepower than an A/A. Unless you're using chilled coolant for a short duration, you have most of the same challenges with implementation in either case. You need an A/A heat exchanger somewhere in both cases; an A/W setup just allows more flexibility in where it can go. The downside is that the water in A/W is probably going to be hotter than the air in A/A. It seems an A/A system cuts out the inefficiency of the middle man.

You don't use an A/A anywhere in the system, you have a second 'radiator' dedicated only to the air/water system, which chills the coolant water - this water is then pumped through a smaller radiator, enclosed in a shroud, installed in the engine bay. The hot intake charge is passed through this engine-bay mounted chilled water radiator, cooling the intake charge. The main benefit of A/W is reduction of heat soak; you're pumping the coolant away from the hot engine bay, to a remote location where it can be efficiently cooled; in addition, you're able to maximize placement of the cooling components without the restriction of trying to keep the charge pipes as short as possible; you can stick the cooler in the front of a mid engine car, then just pump the water into an in-line intake charge heat exchanger, such as a bullet unit from lama nova.

Essentially, you reduce design considerations, and can create a system which is capable of more efficient cooling; it's a better system, unless you have a situation where an A/A setup can be simple and efficient, such as on a porsche with a turbo tail, or a front engined car such as a supra. On a mid-engined car, it's very difficult to find a suitable air/air intercooler placement that won't be affected by heatsoak.

 

[NA1MT]

You don't use an A/A anywhere in the system, you have a second 'radiator' dedicated only to the air/water system, which chills the coolant water - this water is then pumped through a smaller radiator, enclosed in a shroud, installed in the engine bay. The hot intake charge is passed through this engine-bay mounted chilled water radiator, cooling the intake charge. The main benefit of A/W is reduction of heat soak; you're pumping the coolant away from the hot engine bay, to a remote location where it can be efficiently cooled; in addition, you're able to maximize placement of the cooling components without the restriction of trying to keep the charge pipes as short as possible; you can stick the cooler in the front of a mid engine car, then just pump the water into an in-line intake charge heat exchanger, such as a bullet unit from lama nova.

Essentially, you reduce design considerations, and can create a system which is capable of more efficient cooling; it's a better system, unless you have a situation where an A/A setup can be simple and efficient, such as on a porsche with a turbo tail, or a front engined car such as a supra. On a mid-engined car, it's very difficult to find a suitable air/air intercooler placement that won't be affected by heatsoak.

There is no truly "efficient" way to use either in an NSX....sure the w/a will work and is more concealable but cmon' you are trying to cool 180 degree intake temps with 130 degree water. Any a/a setup I've seen to date is pretty rude looking on top of all that i/m/o. The best way to cool these cars is simply by spraying meth. After I do a dyno pull my charge pipe actually frosts over.

 

[Skatethesea]

From what i understand, the FMIC a/a is a great thing for track conditions. But the AC a/w is your best bet for heavy traffic conditions. If you go with the A/W combo, well actually either combo, go with a 1.3 rad cap, new thermostat and maybe a better radiator and you will be fine. I drive from Tampa to Norfolk all the time and have a VTSC w/ AC and didnt have a single problem in heavy traffic.

 

[stuntman]

There is no truly "efficient" way to use either in an NSX....sure the w/a will work and is more concealable but cmon' you are trying to cool 180 degree intake temps with 130 degree water. Any a/a setup I've seen to date is pretty rude looking on top of all that i/m/o. The best way to cool these cars is simply by spraying meth. After I do a dyno pull my charge pipe actually frosts over.

JW: Are you forced induction?

Self-contained (not connected to radiator) AITs are often higher than 180*F (maybe ad another 100*F), and the cooled water temps can be below 140*F, 130, 100 under sustained use depending on configuration, ambient temps, etc... Some superchargers would die to see 180*F (and some do)

 

[NA1MT]

JW: Are you forced induction?

Self-contained (not connected to radiator) AITs are often higher than 180*F (maybe ad another 100*F), and the cooled water temps can be below 140*F, 130, 100 under sustained use depending on configuration, ambient temps, etc... Some superchargers would die to see 180*F (and some do)

If I wasn't forced induction why would I post up my experience with my charge pipe into my throttle body frosting over after a dyno pull. My AIT with the Novi2000 ranged from 130 to 190 degrees depending on ambient temp with an a/w.

 

[brandonsan]

There is no truly "efficient" way to use either in an NSX....sure the w/a will work and is more concealable but cmon' you are trying to cool 180 degree intake temps with 130 degree water. Any a/a setup I've seen to date is pretty rude looking on top of all that i/m/o. The best way to cool these cars is simply by spraying meth. After I do a dyno pull my charge pipe actually frosts over.

I had air to water on my Lovefab system and it never ran hot. I was amazed at how efficient it was. After selling the kit to my freind I tested the car and boosted it for long periods (beat the crap out of the car) without ever seeing high IATs. After driving the car hard I could put my hand directly on the aluminum reservior for the AWIC or the AWIC itself and it wouldn't even come close to burning me (just above luke warm).

 

[WOODY]

I am with Brandonson, My A/W never gets very hot. I did over a dozen highway pulls with Cody on the computer and I don't think we saw >125 on the on the IAT's

"Self-contained (not connected to radiator) AITs are often higher than 180*F (maybe ad another 100*F), and the cooled water temps can be below 140*F, 130, 100 under sustained use depending on configuration, ambient temps, etc... Some superchargers would die to see 180*F (and some do)"

Where is this from? Why would a radiator cooled, self contained intercooler run that high? If the combustion engine can maintain temps +/- 180 with a radiator, a closed system cooling compressed air certainly can maintain temps well below that.

 

[stuntman]

To reword it:

Charge temps are easily over 180*F on turbo and S/C applications. Many self-contained (separate from radiator) A/W systems can effectively cool the charge temp to result in 100-140*F sustained AIT without methanol.

If your radiator water temps are 180-220*F, at best you can only cool your charge temps to this level, which is why many people run self-contained/separate A/W systems.

"Some superchargers would die to see 180*F" -means that the AIT's of some superchargers can be well above that since the charge temps are not cooled atall.

Hope that helps.

 

[WOODY]

Gotcha, Obviously I was thinking intercooled charge temps.

 

[sstarkey]

Realtime Racing used water to air in the race NSX. Peter Cunningham said that water gave much more consistent air inlet temperatures.

 

[camber_combover]

no turbo here but fyi, I use a Bell liquid/air core housed in a custom intake which works great for my CTSC hi-boost setup.

My engineer produced a stock height custom intake which conceals well and adds great performance to my older whipple blower. there is a low pressure water pump mounted in the spare tire area which moves coolant from a smaller radiator mounted in front of my car's radiator back to the rear of the car via hoses, through the intake core then back to the front radiator to start the cycle over again.

liquid/air systems have the potential to spring leaks in both the routing hoses as well as the intake core itself which if it happens dumps a nice, huge cloud of steam onto unsuspecting cars behind you on the track. If it happens, tell everyone around who sees it that you hit the knight rider style "cloaking" button by mistake.

best of luck with the one you decide to go with in the end.