How Water can Calm the Detonation Blues

Written by Steve Magnante on
The Petersen Publishing Archives – Photography;

War is hell kids, but it’s undeniable that many world-changing technological advances were derived from armed conflict. War-related research brought us the moon landing, jet powered airliners, hemispherical combustion chambers, super glue, synthetic oil, and the cell phones in our pockets.

Way back in WWII, the German Focke-Wulf FW 190 fighter plane needed a horsepower boost to give it an edge during aerial combat against U.S. Air Force P51 Mustangs. The FW190’s 1,677 horsepower, 14-cylinder BMW radial engine was already supercharged so adding a huffer was off the menu. Instead, the so-called MW 50 system was devised. As the name implies, a 50/50 spray of methanol and water was administered for short bursts and output jumped to 1,973. Though the MW 50 units were only used experimentally, the idea took root and has been exploited by horsepower seekers looking for minimal hardware investment ever since.

So what exactly does methanol – water injection do? The core objective is to prevent abnormal combustion. Usually identified with words like detonation, ping, and knock, the audible sounds are caused by a fuel/air mixture that’s started to burn too soon. The resulting “death rattle” is just that. The uneven cylinder pressure hammers the chambers, pistons, rings, ring lands, pins, bearings, and block without mercy. In extreme cases, the vibration can be so extreme as to cause flex plate and header flange bolts to loosen

Beyond its threat to mechanical systems, detonation also kills power. The uneven power pulses, which are clearly visible on a printed dyno curve, disturb intact tract function, ignition system efficiency, and vehicle acceleration. While detonation is a problem with naturally aspirated engines, when you add an exhaust-driven turbo or belt driven supercharger and forcibly cram the air molecules together, even more detonation-making heat is the result. Something must be done.

That something is water-methanol liquid injection, which aims to cool the intake charge before it enters the combustion chambers. Back in the ‘70s when the federal mandate for reduced octane, unleaded fuel first hit, and entire crop of aftermarket water injection kits emerged to help drivers of pre-1971 cars run on the lower-octane gasoline. These cars typically had compression ratios north of the critical 10:1 threshold and rattle-prone iron cylinder heads.

Grab a late seventies copy of Car Craft and you’ll see advertisements for water injection kits from outfits like Spearco and Roto-Master. These early kits generally introduced straight atomized water into the fuel/air charge. Since water doesn’t burn and expand during combustion, the water molecules took up a certain amount of space, so less fuel was present and power wasn’t necessarily enhanced. Rather, these systems simply helped the engine “be all it could be”, to borrow a recruiting phrase from the mighty U.S. Army. However, straight water begins to freeze at 32-deg. F, so makers of those water injection kits told users to add various amounts of windshield washer fluid (which contains alcohol to prevent freezing) to ensure their systems would function in the winter time. As victims of cracked engine blocks can attest, confined water takes up seven percent more volume when it freezes into ice. So following the lead of the Focke-Wulf engineers in 1942, many aftermarket water injection system makers incorporated methanol into the equation. Well whaddaya know, alky is combustible and can add power while the water component curbs detonation; it’s a win – win.

Its’ been over four decades since those first water-methanol injection kits hit the aftermarket, and since the best pump gasoline available is still a mere 91 to 93 octane, detonation remains a problem for naturally aspirated engines with more than 9.9:1 compression. With today’s massive surge toward add-on turbo and supercharger kits, the need for water-methanol injection systems has never been greater.

Lets’ watch as the Buzzell brothers of NextGen Performance install and test a Snow Performance Boost Cooler on a Vortec blown 1965 Mustang 2+2. The entire process took just a few hours but added nearly 41 horsepower and 29 lb/ft of torque while calming all signs of detonation.

NextGen’s Josh Buzzell says the Snow Performance Boost Cooler is just as effective as an intercooler – but without the plumbing hassles. What’s more, while forward vehicle movement is needed to push air through the aluminum core, water-meth’s full benefits are available while standing still, like on the starting line or chassis dyno. The Stage 2 kit used here will support 250 to 550 horsepower applications with boost levels no higher than 20 psi, which is still a bunch.
Car owner Jamie Fournier built this raw but solid ’65 2+2 to be a fun, worry-free daily driver. A disc brake conversion system from Mustang Steve employs 2003 Mustang Cobra front discs and Explorer rear discs mated to the 9 incher’s axle tubes. The 2001 Explorer-sourced 302 has the good GT40P heads, a Ford Racing E-303 hydraulic roller cam, Trick Flow valve springs, stock intake manifold and Holley HP EFI with LS1 style coil-on-plug ignition. The Vortec SC1 delivers 6 psi boost, routed through a T5 stick shift.
The Stage 2 Boost Cooler kit (PN 20010) includes everything needed for installation, including a 300 psi electric pump, 3-quart fluid reservoir, two spray nozzles, thread sealant, check valve, ¼-inch nylon feed tubing with easy to use compression couplers, mounting hardware, and complete instructions. Not shown here – but included – is the critical control box.
The VC20 control box connects to a boost source via a supplied rubber hose. It has an internal MAP (manifold absolute pressure) sensor. The twin rotary dials regulate electrical current flow to the pump to ramp up fluid delivery rate and duration. The Start dial is set to 1/3 to ½ of the total boost. Typical start points are between 3 and 10 psi. The Full dial is set to the maximum boost level. This Vortec SC1 blown Mustang was set at 3 and 6. There are no micro switches or hokey “go baby go” buttons to press. It all happens automatically.
To position the reservoir and pump under hood, Eric Buzzell makes paper drill guide templates of each component’s footprint to locate fastener holes. For enhanced accuracy in transferring hole locations by pen, the inner ink cartridge is removed before marking.
To help isolate vibrations from the electric pump drive motor, Snow Performance uses rubber bushings on the feet of the mount. The pump must be mounted at or below the lowest part of the fluid reservoir to assure automatic and instant priming. Take time and seek out the optimal location for each component under your hood.
The electric pump finds a nice home ahead of the driver-side spring tower. Eric uses a Unibit to cut four 9/32-inch holes. The reservoir fits well behind the radiator wall on the passenger-side of the engine bay. The 90-degree pneumatic drill motor is great for tight spaces like this.
Though the kit includes self-tapping screws to mount the pump, the guys switched to Marson’s Ribbed Klik-Nuts rivet nuts for a more finished result and easier serviceability. The Marson system employs a rivet gun-like tool that permanently expands the female rivet nuts in place. Then, 10-32 machine screws hold the pump in position. The fluid reservoir is secured via the same system.
The feed pump and controller nestle between the 302 and driver-side fender wall with the rotary switches facing up for easy access.
The 3-quart reservoir mounts next to the radiator on the passenger side and comes with a low-level LED warning lamp. Though Snow Performance sells its proprietary Boost Juice with a 51/49-percent methanol/water mix for maximum benefits, ordinary blue windshield washer fluid is an acceptable substitute. Snow says the blue stuff is usually 30 to 40 percent alky but spiking it with Gold Eagle brand “Heet” gas line antifreeze (36 ounces per gallon) brings it closer to 50/50.
The spray nozzle holder must be mounted six inches ahead of the throttle body. Before drilling an 11/32 hole and cutting 1/8-27 (National) pipe threads to secure the nozzle holder, remove the air tube to prevent debris from entering the manifold. In rare instances, if the nozzle is located below the lowest point of the fluid reservoir, unwanted siphoning can occur. For this, Snow offers a flow control solenoid (PN 40060).
Several spray nozzle tips are available with flow ratings of 60, 100, 175, 225, 375 and 625 milliliters per minute. For this 1hp-per-cu.in. 302, we used the 175 ml/min unit. Only active when under boost (as determined by the Start and Full dial settings), a typical 250 to 550 horsepower engine will drain the 96 ounce jug with each 15 gallon tank of gas.
With everything in place, the Snow Performance Boost Cooler pretty much hides in plain sight.
Dave Brady at ESP in Sterling, MA (in car) operates one of the few all-wheel-drive dynos in Massachusetts, which attracts tuning business from Jeep Wrangler SRT8, Subaru WRX, and high-end Porsche owners. Without the Boost Cooler activated, our 2+2’s rear wheels delivered a respectable 322.7 horsepower at 5,852 rpm and 323.5 lb/ft at 4,656 rpm. That’s with 92 octane unleaded premium in the tank. NextGen’s Eric Buzzell looks on.

With the Boost Cooler activated, the increased octane value and cooler, denser intake charge took the 302 from 322.7 hp and 323.5 lb/ft to 363.4 hp and 352 lb/ft of torque. That’s an extra 40.7 horsepower and 28.5 lb/ft for under five hundred bucks. Better yet, the system stands ready to support further increases in output as mechanical upgrades are made to other areas of the engine and / or more aggressive boost and ignition timing thresholds are explored.
Snow’s Boost Juice retails for under ten bucks a gallon, and at 51 percent alcohol is more potent than washer fluid.

Turbo Rocket Fluid: Don’t Leave Home Without It

Way back in 1962 and ’63, the compact Oldsmobile F85 Jetfire added an AiResearch exhaust-driven turbocharger to its 215 cube, aluminum block V8. The turbo was mounted to pull air through a sidedraft 1-barrel carburetor. With Chevrolet’s same-year Corvair Monza turbo, these were America’s first mass-produced, post-war turbo cars.

To solve the persistent turbo lag issue, Olds engineers equipped the little 215 with a sky high 10.25:1 compression ratio. It increased low speed cylinder pressure until the turbo’s 5-psi boost came on strong at 2,200 rpm.

To tame low-rpm / high-load detonation tendencies, Olds resorted to – you guessed it – water-methanol injection. A 50/50 mix of distilled water and methanol, Olds dealers sold the fluid in specially marked metal cans and rigged a sensor to bypass the turbo if the underhood reservoir was empty.

Though a brave effort, the system was hampered by overly conservative tuning to protect against careless users. Under boost, the Jetfire’s Turbo-Rocket 215 delivered 215 horsepower at 4600 rpm and a stout 300 lb/ft at 3200 rpm. For comparison, Corvair’s 164-inch flat six turbo made 150 hp and 210 lb/ft.

Though a 3-speed manual was standard in the 1962 Jetfire (a four-speed became optional in ’63), most got a sloppy three-speed Hydramatic and mild 3.36:1 gears out back. The September 1962 issue of Motor Trend magazine tested an automatic turbo car and recorded 0-60 in 10.2 seconds, only 2.5 seconds quicker than the non-turbo 215 V8 with its single 2 barrel and 155 horsepower rating. The turbo’ed Jetfire cranked the quarter mile in a pretty mild 18.7 seconds and 80 mph.

Sold only in the Jetfire two-door hardtop (a specific model with style code 3147), the complex turbo V8 forced the sticker price over $3,700, only $300 less than a stripped Corvette. Production reached 3,765 in 1962 and 5,842 in 1963 before the idea was dropped. But as a pioneering mini muscle car, the Jetfire deserves recognition.

Part of GM’s ground breaking senior compact lineup which included the Buick Special and Pontiac Tempest, the Jetfire shares its basic platform with the rear-engine Chevy Corvair. Creative cut-and-paste chassis, suspension and driveline design enabled these front engine spin-offs.
Turbocharging brought the all-aluminum 215 V8 to one horse per cubic inch. Olds and Buick shared the 215 short block but with different heads. Only Oldsmobile’s Jetfire 215 got the turbo.
This factory schematic depicts the complex Turbo Rocket Fluid delivery system. GM was innovating madly with this family of cars. Beyond the Corvair’s exotic air cooled flat six, other wildness included Pontiac’s half-a-V8 Trophy “slant four” and Buick’s odd-fire V6. In 1978 Buick added a turbo to the revived V6 and made more history.
Every Jetfire came with this handy turbo boost indicator. The “fluid injection” marking reminded owners to keep the reservoir filled with Turbo Rocket Fluid.