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How to Get Boost without Heat Using a Cooler System - Liquid Refreshment
MPG Max dyno test on turbo (non-intercooled) 4.6L 2V mod motor
There is a common saying in the performance community: Once you go boost, you never go back. OK, maybe that is not so common, but it sure should be. Boost is an amazing thing since it is basically a multiplier of the power already present and as we all know, more is better, right?
As great as boost is, there are obviously difficulties associated with force-feeding your Ford. One of the major obstacles is heat. Boost pressure is great since more boost equals more power (yeah, I know I’ll get letters), but more boost also equals more heat. Unfortunately, one of the laws of nature states that heat is a byproduct of pressure, the greater the pressure the greater the associated heat. While boost is good, heat is somewhat less so since heat is both the enemy of performance and the breeding ground for harmful detonation. The question now is how do we get the boost without the heat? Enter Snow Performance Boost Cooler!
The heat associated with boost building is nothing new, nor is the cure. Intercooling has been around almost since the inception of forced induction, but each form of intercooling has it merits. Traditional intercooling, whether air-to-air or air-to-water, employs a cooling medium to lower the charge temperature. Passing the heated charge temperature through (hopefully) ambient air or water lowers the inlet air temp to improve power and reduce the chance of detonation. The charge temps can be lowered even further using a transfer medium that is lower than ambient.
These include ice water for the air-to-water systems and supercool gases like nitrous oxide for air-to-air coolers. The downside to these intercoolers can be the length of the inlet tract and associated drop in boost pressure. While there will be some drop in boost just from cooling, the greater the length and number of bends associated with the of the inlet tract, the greater the boost loss.
Though air-to-air and air-to-water intercoolers are the most common, there is a third form that offers substantial cooling benefits. Liquid cooling, or more specifically water/methanol injection, battles the heat by injecting a water/methanol injection mixture into the inlet tract. The latent heat of vaporization and introduction of the mixture into the combustion chamber dramatically lower both the charge temperature and risk of detonation. This not only lowers the charge temperature but, thanks to increased octane from the presence of alcohol, also allows increased boost and ignition timing, even on pump gas. We all know it is possible to run elevated boost levels on race gas, even without intercooling. The problem with this combination is twofold. First, the lack of charge cooling will reduce power (compared to an intercooled system). The second problem is the cost, as race fuel is at least twice as expensive as pump gas. The liquid cooling offered by the water/methanol cures both problems.
To illustrate the gains offered by the Snow Performance Boost Cooler, we set up a test using a turbocharged 4.6L PI motor. The Two-Valve test motor was simultaneously perfect and inadequate for this turbo test. The Sean Hyland short-block offered forged internals to make it strong enough to withstand the intended power and boost levels, but the stock heads, cams, and intake manifold meant the levels would be lower than we like at any given boost level. Despite the power limitations, we set up the test with a homemade single-turbo system consisting of a 76mm turbo and tubing from CXRacing, a pair of turbo manifolds pirated from an old twin-turbo system from HP Performance, and plenty of exhaust tubing from a local muffler shop.
The two manifolds were connected by a Y-pipe that ended in a T4 turbo flange. The Y-pipe also featured a provision for our 45mm Hyper Gate wastegate from Turbo Smart. The turbo supplied boost through a section of 3-inch tubing to the stock throttle body—simple but effective.
The game plan was to run the turbo in non-intercooled form, then again after a little Liquid Refreshment (read: the Boost Cooler from Snow Performance). It should be noted that the introduction of water and/or methanol can provide cooling and suppress detonation, but only if supplied in the correct amount. The key to a successful water/methanol injection system is dialing in the mixture. The beauty of the MPG Max system was not just that it injected the necessary water/methanol mixture, but that it did so in the desired amount.
Excessive injection will result in a dramatic reduction in power, while insufficient injection may result in engine damage, neither is good (though always err on the power loss side when tuning).
The jetting available through the multiple-nozzle system combined with the programmability of the controller made dialing in the onset and eventual flow rate of the system a snap. Once dialed in, the Boost Cooler not only added power, but allowed us to increase both timing and boost on pump gas.
To start things off, we ran the 4.6L Two-Valve motor in normally aspirated trim. Run with a fresh pan of Lucas synthetic oil and a set of Kooks long-tube headers, the forged but stock PI motor produced 284 hp and 321 lb-ft of torque. Remember, the motor was run on the dyno with no accessories (Meziere electric water pump), long-tube headers, and optimized tune, to say nothing of the open throttle body (no air intake). After adding the single (non-intercooled) turbo system, the power numbers jumped to 396 hp and 428 lb-ft of torque at just under 6 psi of boost.
Ensuring maximum repeatability was a FAST XFI/XIM management system controlling a set of 36-lb/hr injectors. After a few runs to nail down the onset and flow rate of the Boost Cooler, we were rewarded with a jump in power to 416 hp and 441 lb-ft of torque with no change in boost or timing. Run on 91-octane pump gas, we limited total timing to a safe 17 degrees under boost. Even at just 6 psi, the Boost Cooler dropped the charge temps by 46 degrees and added 20 hp.
Satisfied with the gains and cooling offered by the Boost Cooler, we decided it was safe to advance the ignition timing. With no changes in boost (still on the wastegate spring near 6 psi), we increased the ignition timing from a 17 degrees to 22 degrees with positive results. The timing change raised the power peaks from 416 hp and 441 lb-ft of torque to 433 hp and 459 lb-ft of torque. The 5 extra degrees of timing offered power gains through the entire rev range.
With the methanol-injected PI motor now optimized at 6 psi, it was time to crank up the boost. Jumping up to 8.9 psi allowed the us to exceed 500 hp with peaks of 502 hp and 529 lb-ft of torque. Stepping up to a peak of 13.7 psi required introduction of the secondary injection nozzle for the first time, but once tuned, the combination produced 594 hp and 637 lb-ft of torque. The final test of the day involved no more boost, but a different turbo. After installation of the GT45-style turbo, power jumped to 643 hp and 671 lb-ft of torque at the same boost level. Running near 1 bar of non-intercooled boost is not something we’d try on pump gas without the safety (and performance) offered by the MPG Max Boost Cooler system from Snow Performance. With our test completed, it was time for a little Liquid Refreshment of our own.
01. The LCD screen displayed boost pressure (eliminating the need for a separate boost gauge), injector duty cycle, and injection percentage. These parameters were important because injection of the dual-stage water/methanol can be based on both map pressure and injector duty cycle.
02. The difference in the supplied injector nozzles was obvious in this photo. The nozzle sizing can be combined with the adjustability offered by the controller to fine-tune the system to the injection/cooling requirements of the motor.
03. This Stage 3 MPG Max system offered dual-stage injection, meaning two separate nozzles were employed. The flow control solenoid eliminated flow to the secondary nozzle until the motor reached the prescribed boost/injector duty cycle.
04. For this dyno session, we opted to feed the MPG Max system with a gallon of ready-to-run Boost Juice.
05. Testing this turbo motor also gave us the opportunity to try out the new dual-oxygen sensor system from FAST. The dual system allows you to read both banks of the V-8 to compare air/fuel differences side to side.
06. Though sporting a forged rotating assembly, the mild 4.6L 2V was saddled with stock PI heads, cams, and intake, meaning the normally aspirated power output was somewhat less than overwhelming. The basically stock PI motor produced just 284 hp and 321 lb-ft of torque.
07. The turbo kit was a conglomeration of parts we had at our disposal, including turbo manifolds from an old twin-turbo kit from HP Performance combined with custom exhaust tubing. Basically we joined the two sides of the exhaust into a common turbo flange and mounted a single 76mm turbo from CX Racing.
08. Engine control and a set of 36-lb/hr injectors came from FAST. The XFI/XIM management system was used to dial in the air/fuel and timing-even more critical on a turbo motor with no intercooler.
09. Prior to running, the well-worn mod motor was freshened up with a pan full of Lucas 5W-30 synthetic oil.
10. Boost control came from this 45mm Hypergate from Turbo Smart. Like timing and air/fuel, boost control was critical on this non-intercooled turbo motor.
11. Simple but effective, the discharge side directed the boost right from the turbo to the stock throttle body. Run at 6 psi, the turbo motor produced 396 hp and 428 lb-ft of torque. After dialing in the Snow MPG Max system, the peak numbers jumped to 416 hp and 441 lb-ft of torque with no change in boost or timing. With plenty of cooling, we then increased ignition timing from 17 to 22 degrees and were rewarded with peak numbers of 433 hp and 459 lb-ft of torque.
12. With the safety of our Snow Performance water/methanol injection we were able to raise the boost pressure up to 8.9 psi, where the turbo mod motor produced 502 hp and 529 lb-ft of torque. Stepping up to 13.7 psi resulted in 594 hp and 637 lb-ft of torque. We eventually tried this more efficient (larger) GT45-style turbo, which brought the power peaks up to 643 hp and 671 lb-ft of torque.