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Dez Racing's Air-To-Water Intercooler Install - Chillin' Like A Villain
Dez Racing's Air-To-Water Intercooler Makes Its Way From The Track To The Street.
They say racing provides a trickle-down effect of technology from the racetrack to the street. Advancements made in the harsh racing enviroment help push product development, and that holds true from the Big Three automakers down to your local Mustang shop.
We hooked up with Mike "Dez" Dezotel of Dez Racing (Seekonk, Massachusetts) at an NMCA street-legal drag race last year and saw an interesting intake manifold on his record-holding Street Race class car. The intake manifold caused quite a controversy in the class as Dez pushed the rule book to its limits. What he didn't realize was that while he sought a solution to class restrictions, he actually opened up an avenue that would benefit serious street/strip Mustangs equipped with a supercharger or turbocharger.
Street Race class rules require the intercooler to be mounted forward of the firewall. Most forced-induction class entries utilize a front-mounted air-to-air intercooler, and that worked well for most of the competitors. "Mounting the cooler in the front of the car made my Mustang too nose heavy," says Dez, the '05 Street Race champion. "That made the car unpredictable. I figured-why not run the aftercooler and upper manifold as one piece? We were trying to get rid of nose weight."
This wild-looking intake was one of the key components to keeping his ride in front of the competition in 2006. Needless to say, the intake worked flawlessly-that meant it was banned due to severe racer uprisings. Dez complied with the NMCA tech officials' request to remove the intake for the remainder of the season. He wasn't mad or regretful about it. "I was somewhat disappointed," he says, "but I was happy to have built the intake, which ultimately benefited my customers."
There are two types of intercoolers: air-to-air and air-to-water intercoolers (sometimes called aftercoolers). The air-to-air intercoolers are usually front-mounted because they rely on the air rushing over the fins to drop the temp of the pressurized air inside the unit. An air-to-water intercooler is an air-to-air unit that has been enclosed and has ice water pumping through it to cool off the air inside the intercooler.
Dez looked to an air-to-water intercooler due to the more efficient cooling capabilities in his 800-plus rear-wheel horsepower combination. Normally, when people think of an air-to-water intercooler, it is either in mild street or wild racing applications. The mild street version is found in some centrifugal supercharger kits as well as positive-displacement superchargers like those on the '03-'04 Cobra and '07 Shelby. The hard-core air-to-water intercoolers usually sit in the passenger seat of the Pro 5.0 and Outlaw cars on the racing circuit. Their huge box size and weight dictate the placement inside the cockpit because it is the only place it fits. Dez set out to build something in the middle of those applications that fit the Street Race rules and was efficient enough to run in a serious street/strip Mustang.
Dez utilizes a TFS lower manifold due to its efficient runner design for the 356ci-supercharged engine. It would be the basis for a fabricated upper intake manifold that includes an intercooler core. Dez Racing is a full-on speed shop, but the fabrication of an aluminum upper intake was too big of a task to handle itself. The staff called in Dennis MacPherson of DMC Racing for help. DMC is the fabrication shop responsible for the chassis work on Dez's Mustang.
Past experience pushed these guys to run the Spearco pass-through intercooler because of its efficiency. The water enters on the left side of the intake, flows across the fins, and exits on the right side. Many designs route the water over the fins and then recirculate it to the same side of the manifold. By the time the water turns around and heads back, it has been heated and negates some of the cooling effect.
MacPherson started with a Reichard Racing billet lower base that connects to a TFS "R" lower. He then laid the Spearco core in place and built a hat on top and a funnel piece on the bottom. Reichard Racing is credited with the billet pieces used to enclose the aftercooler core. MacPherson also added a variety of vacuum ports and sensor locations to the unit. A custom throttle cable bracket was also welded in place.
The sheetmetal hat can be configured for a variety of throttle-body positions, including the side entry that is common on almost all small-block Ford EFI manifolds. Dez chose to run a forward-facing throttle body for this application due to aesthetics. "If a guy runs a turbocharger in front of the engine, then the forward-facing throttle body would make it easy to run an inlet pipe," he says.
Installation is fairly easy and requires mounting a fuel cell in the rear of the car to hold water, ice, and a water pump to push water through the system. Feed and return lines also need to be run to the front of the car and can be purchased at Home Depot. Dez recommended the large 1-1/4-inch rubber hose to properly supply cold water to the cooler. Some enthusiasts run a bilge pump obtained from the local plumber-supply company, but Dez suggested spending a bit more money and going with a Meziere water pump. It pumps 55 gph, and Dez has seen the inlet temperature drop by about 30 degrees just by switching to the high-volume water pump and big lines.
Our test vehicle was already equipped with an in-car aftercooler, which was discarded since we were testing this intake manifold/aftercooler setup. That meant the rear tank and lines were already installed. Our testing procedure consisted of a baseline with the F1R blower pushing 22 psi into a Reichard Racing box intake manifold on top of a TFS lower intake. Dez set the timing at 16 degrees and let it rip on the Dynojet chassis dyno. The '86 GT spun the drums to 687 rwhp and 545 rwtq at 7,100 rpm. The Anderson Ford Motorsport PMS engine-management system recorded an inlet air temperature sensor reading of 180 degrees towards the top of the dyno pull.
An hour later, the Dez Racing upper intake manifold was bolted into place-keep in mind the water tank in the rear of the car and water lines were already plumbed. Our first set of pulls was done to dial in the air/fuel ratio, and we ran the same 16 degrees of ignition timing. You might be surprised to learn the results were not as expected; Dez had to pull an enormous amount of fuel from the injector duty cycle to get the car to even run properly. Output was only 594 rwhp and 508 rwtq. Why the big drop off in horsepower? The air was too cold, and the engine would barely run with just 16 degrees of timing. Despite a valiant effort in tuning-which concluded with an enormous drop in fuel delivery-the air/fuel ratio was still off the chart and overly rich. The car sounded really lazy during the pulls. Simply put, the engine was too inefficient with the low ignition timing and super-cold air-inlet temperature. The cylinders were not hot enough to burn properly.
All the problems went away when Dez added more timing. He plugged in 23 degrees, 7 degrees greater than the baseline of 16. Inlet-air temperature held steady at 82 degrees, and the pull generated 797 rwhp and 613 rwtq. The air/fuel ratio continued to be extremely rich and off the Dynojet A/F chart. Despite that condition, the car picked up 110 rwhp and 68 rwtq. Dez tried to trim more fuel from the program, but we determined that more timing was needed to help put more heat back into the cylinders.
The increase in power came from the upped ignition timing. The cooler air charge temps opened up a pathway for us to increase it. Some people think the power is from the cold air, but it only enables us to turn up the engine. More ignition timing adds heat back into the cylinder, and that is what creates the power. "Lower intake-air charge wards off detonation/pre-ignition, which in turn lets you advance the timing," Dez says. "The denser air coming into the engine from the intercooler allows you to make more power, and once you add the timing, you will have huge power gains."
Another note to mention about this test is that we used less fuel with the aftercooler in place. That is because the non-intercooled application relies on the extra fuel to cool the combustion chamber. Starting with cooler air meant we already had a cool enough charge, and we just needed to spark the air/fuel mixture-more ignition timing.
Dez knew we could safely add more timing, and he elevated it by 2 more degrees, bringing the total to 25. Horsepower increased to 824 rwhp and torque was 626 ft-lb at the rear tires. Just 2 degrees of timing was worth 27 rwhp and 13 rwtq. The increase of 9 degrees of timing from our baseline of 16 provided a 137-rwhp and 81-rwtq increase. "What do you say about that increase?" asks Dez. "The cooler air charge is safer for the engine, and we could have added more boost with the lower temps and made even more power."
The sheetmetal upper intake looks wild, and that is probably what got most of the Street Race competitors jazzed up. It might be illegal for the class, but Dez says this intake is right at home for a variety of applications. He recommends this piece for forced-induction engines running more than 14 psi of boost, and in some cases it's a viable option for cars to run pump gas with high boost numbers. It works great with ProCharger D1SC and F1R blowers as well as Vortech YSi-Trim, T-Trim, and J-Trim units. For the turbocharged crowd, Dez says the ease of mounting and small amount of inlet piping needed help keep the cost down. The air-to-water intercooler is capable of chilling out boost from anything up to 76mm turbochargers, and pos-sibly some larger units, but he has yet to test them out. The cost of the intake is a tricky question because it depends on the application and other parameters. Our suggestion is to call Dez Racing and inquire, as the cost is determined on a case-by-case basis.
Unlocking more power from your supercharged/ turbocharged 5.0L is the answer to blowing past the unnaturally aspirated mod motors and Brand-X racers that are so frequent at the track these days.