Air/Water Intercooler System Installation

Since I enjoy tinkering and experimenting, I decided to try and put together a custom air/water intercooler system.  I knew this wasn't the easiest approach, but it seemed like it would be the most fun.  I did some research and started designing the system.  I ended up using a standard Spearco air water intercooler core because of it's small size and reasonable price (part & price list to follow).  I had them weld up a 2-252 intercooler core with the charge air manifolds both pointing in the same direction.  Before I ordered the 2-252, I made a cardboard mock up to make sure that it would fit under the hood.  Didn't want to have a custom 2-252 made and later find out that it wouldn't fit.  Turns out that it fit nicely (although tight) without having to move any of my existing components.  I did need to rotate the turbo compressor housing outward (toward fender) and drill & tap new mounting holes for the waste gage actuator.  I used Spearco's 90deg elbow that bolts directly to the stock 2 bolt flange turbocharger.

Spearco 2-252 Air/Water Intercooler Core

Besides the 2-252 air-water intercooler core, I needed to select some heat exchangers that would cool the "hot" water coming from the intercooler core. I decided that I would mount the coolers up front in the lower bumper cover openings where they would get plenty of fresh air.  I checked into some low cost heater cores (~ $15 each), but decided against them because they appeared to be of an inefficient design.  In addition, they seemed too fragile to be able to handle road debris and rocks that may be kicked up near the ground.  I ended up going with high efficiency engine oil coolers that had a sturdy aluminum honeycomb design that could handle some occasional road debris.  Two of these coolers fit almost perfectly in the lower bumper cover openings (see photo below).  I needed to trim the bumper cover a little, but they ended up fitting real nice.  To help ram more air through the coolers, I got some industrial belting material and made an air dam along the bottom of the bumper cover.

Front coolers and extra air dam

To circulate the intercooler cooling water, I chose a Jabsco marine bilge pump (Water Puppy model).  This pump is rated at 6GPM and seemed to be very well built.  It is a centrifugal type pump with bronze housing and a heavy duty rubber impeller.  I mounted this pump directly underneath the stock air box in the fender well.  It was necessary to wire a relay to provide power to the intercooler pump when the ignition was on.  One downside of this type of pump is the noise.  It hums noticeably most of the time, except at higher speeds when wind noise drowns the hum out.  A high output diaphragm type pump should also work well and would make less noise.  Personally, I've gotten used to the hum of the centrifugal pump and it doesn't bother me so much.

For filling, water expansion, and additional water capacity, I added an intercooler coolant reservoir.  I searched the junkyard and ended up getting a small tank off of a late 80's style Pontiac LeMans.  Unless most tanks which were simply for radiator overflow, this tank was designed to handle pressure and had a pressure cap that came with it.  I ended up mounting this up behind the driver's side headlight.  The pump, Spearco 2-252 intercooler core, as well as engine oil coolers came with 1/2" NPT threads.  I got some 1/2" hose barb fittings and screwed them into the IC core, pump head, and coolers.  I then connected it all together using 1/2" hose.  Later, to help the pump out, I re-routed some hoses and replaced the 1/2" suction hose with a 5/8" line that ran from the expansion tank to the pump inlet.  It is a proven fact that pumps work best with the least amount of restriction on the suction side.  It is better to relocate necessary restrictions (heat exchangers, intercooler core, etc...) to the pressure side, as this will not adversely affect overall flow as much.

I did some temperature testing using a digital voltmeter with a thin wire thermocouple.  First, I installed the wire thermocouple between the silicone coupler and turbocharger outlet.  This reading (BEFORE IC) gave the temperature of the heated, compressed air coming out of the turbocharger.  I took about 10 readings at highway speeds with the voltmeter set to capture the maximum temperature.  It was a typically warm day in Florida with ambient temperature hovering around 85F.  After these readings, I placed the thermocouple between the silicone coupler and IC outlet (AFTER IC) to get the intercooled charge air temp.  In both cases, I was careful to make sure that the wire thermocouple was bent so that it was in the air stream and not touching the sides of the air passage.  I took 10 readings this way also - below is the data that I gathered.

                                                          BEFORE IC                                     AFTER IC

With this temperature drop and given the ambient temperature, IC system efficiency is around 67%.  Dropping charge air temperature nearly 150 F is a definite improvement over NO intercooler - though there is room for improvement.  I would like to get efficiency in the 80% range, and I am currently working on adding an additional heat exchanger up front.  This should boost the overall system efficiency by further cooling the IC water nearer to outside ambient temperature.  In addition, I also plan to add some Redline Water Wetter heat transfer agent in the hopes that this will help efficiency a bit.  This has been a fun project, and I am glad that I chose to go this route.  Below is a list of the parts I used in my Air/Water Intercooler system, their source, and price.
 
 

       COMPONENT                                           SOURCE                                                      PRICE

SPEARCO 2-252 IC CORE	SPEARCO	$385
SPEARCO 2-1230 ELBOW	SPEARCO	$46
SILICONE COUPLERS (QTY 3)	SPEARCO	$36
JABSCO 6360-1001 BILGE PUMP (SEE ADDENDUM BELOW)	E&B MARINE	$89
MISC FITTINGS	HARDWARE STORE	APPROX $10
EXPANSION TANK	JUNKYARD	$5
1/2" & 5/8" HOSE	AUTO PARTS STORE	APPROX $20
ENGINE OIL COOLERS (QTY 2) P/N38NF1482N	JC WHITNEY	$92
AIR DAM	INDUSTRIAL BELT COMPANY	APPROX $10

PUMP RECOMMENDATION ADDENDUM

After some bad experiences with the Jabsco 6360-1001 Bilge Pump (Water Puppy), I now recommend a different type of pump.  On two occasions, the Water Puppy threw an impeller blade which got lodged in the pump output.  I realized something was wrong when the pump became very noisy and the output was reduced.  In my experience, the continual rubbing of the flexible impeller in the pump housing is not a good choice for a daily driven car.  One advantage of the Water Puppy is that it is a positive displacement/self priming pump and has a good ability to draw water into the pump head.  The self priming feature makes the mounting location less critical for this pump.  In my opinion, the Water Puppy would be a good choice for a race car that was not driven daily.  This pump has a decent flow rate of around 7GPM at open flow.

Thanks to Depco Pump Company, I was able to get a different pump from Jabsco at no cost, even though I didn't originally purchase the pump through Depco and it was past the 1 year warranty period.  Depco recommended the Jabsco Centri-Puppy for my air/water IC system.  This pump is a centrifugal type with a bronze impeller.  It is a slightly bigger & heavier pump, but it has a lower current draw and a much higher flow rate.  Open flow on this new pump is around 20 GPM (however this is significantly reduced with back pressure).  A nice advantage of this pump is it's quietness.  The Water Puppy continually buzzed and was very loud.  The Centri-Puppy is so quiet that it is not even noticeable with the engine running.  Even with the engine off, the gentle hum of the pump motor is very quiet.  This pump is NOT a self priming type, so it is very important to mount it so that water is drawn into the suction side by gravity.  In my case, I mounted it down below the intercooler reservoir - underneath and behind the driver's side headlight.  I received the Centri-Puppy pump with lip seal (Jabsco # 18510-0000).  This pump normally costs around $120 (no cost to me).  There is an extended life model with a face seal (Jabsco # 18510-0020) that costs around $190.  So far, I have been very pleased with this new pump.
 

ADDITIONAL COOLER AIR-WATER INTERCOOLER SYSTEM

As I looked at my air/water intercooler system efficiency, I was not thrilled with my old set up.  I knew that I probably needed an additional front mounted cooler to help further cool the heated water coming out of my Spearco 2-252 air-water intercooler core.  My original design used 2 high efficiency oil coolers which were about 11" wide X 6" tall X 3/4" thick.  This worked fine, but was not enough cooler area in my opinion.  Recently, I was browsing through some catalogs at AutoZone and found a suitable cooler to supplement my existing IC system.  It is a large heater core found on '75-'88 Ford Light Trucks.  It's dimensions are very unusual as far as heater cores go, but ideal for what I needed...21" long X 3" tall X 2" thick.  Cost of this core was only around $50 from AutoZone.  It fit very nicely in front of the radiator with a direct blast of incoming air (see photo below).  I bent 2 steel brackets, soldered them to the heater core, and attached them to the support rail that crosses in front of the radiator.

Additional cooler for air/water intercooler system

The two "crooked white teeth" you see are 5/8" nylon hose barbs.  The photo was taken before I finished running new 5/8" line through out my system.  Previously, I had 1/2" line but wanted to increase water flow by bumping up the line size.  I replaced all 1/2" fittings with 5/8" and ran new heater hose to match.  I have not had time to do any intercooler efficiency testing lately, but seat of the pants tells me that the engine is definitely happier.  The engine pulls harder and more consistently.   Detonation seems to be reduced/eliminated running with 18psi boost.  I am happy with the results.

Hopefully I will get the chance to run some charge air temperature tests soon - as well as some G-Tech peak horsepower runs to get some actual data to supplement my "seat of the pants" results.

ICE WATER SETUP FOR AIR/WATER IC SYSTEM

I thought it would be fun to experiment with running ice water through my Spearco 2-252 Air Water intercooler.  I picked up a used 10 gallon Igloo industrial drink cooler for $5, a submersible marine bilge pump from Wal-Mart for around $20, some 1/2" hose, a cigarette lighter cord and fuse holder, and off I went.

I can now quickly convert my normal air/water intercooler system to run with the ice water.  It takes about 15 minutes to do the swap.  First, I pull the fuse on my existing intercooler water pump.  I remove the normal intercooler water lines and plug them.  Then, I put the igloo cooler in the passenger seat and secure it with the seatbelt.  I run the ice water lines out the window and through the corner of the cowl (I removed the cowl end piece to permit this).  Hook up the ice water lines to the Spearco 2-252 intercooler core, fill the igloo with about a gallon of water and some ice.... and I'm ready to roll.  In the photo below, you can see the setup and the routing of the ice water lines.

Igloo drink cooler sitting in passenger seat
 

The submersible bilge pump (shown in photo below) was inexpensive and works well for short term use.  I simply power it up by plugging it into my cigarette lighter plug.  I added a fuse to protect the pump in case of electrical overload.  It's a very simple setup.

Submersible bilge pump mounted at the bottom of cooler
 

The photo below shows what the engine compartment looks like with the ice water lines hooked up and the normal water lines disconnected and plugged on the intercooler.

Temporary water lines from Igloo cooler to the Spearco 2-252 Intercooler

While running with the ice water, I was able to turn up the boost 3psi more without detonation problems.  This resulted in an increase of 40HP to the rear wheels!  It was a significant improvement in peak power.  I have found that each bag of ice will last about 10 minutes of hard running while doing G-Tech tests.  So, with 4 bags (what I normally use), I can go for about 40 minutes of frequent, back to back G-Tech runs.  I turn the pump off while adjusting boost, timing, or fuel pressure between runs.  It looks like the 10 gallon cooler could hold up to 6 bags of ice -  which should last for about an hour of back to back runs.  In other words, filling up the cooler with 6 bags of ice should last through a busy night at the drags, since typically you are just sitting around and waiting.  During those times, you simply shut off the bilge pump and turn it back on shortly before making another run.

Obviously the ice water intercooler setup is not practical for everyday driving.  It only makes sense for racing or other short term events.  However, it does work well and is a very inexpensive way to get an air/water intercooler system to significantly cool down the charge air temps.  In this way, it is possible to get charge air temps well below ambient air temperatures.  Cooler Temps = Denser Charge Air = More Oxygen = More Power!  Yet another benefit of an Air/Water Intercooler system.

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