By Ray Bohacz:
An HVAC system (Heating, Ventilation and Air-conditioning) in a house or building should easily satisfy any sensible thermostat setting. But what if during a winder’s day you set it to 69F degrees and the room temperature remains at 62F with the heating system running. You then increase the heating value at the thermostat but find a window open. You close the opening and within minutes the room reaches the desired temperature and the thermostat setting reduced.
Similarly, some supercharger installations allow boost to escape to atmosphere instead of being captured in the cylinders: closing the open window increases the power.
Boost leaks can occur during initial installation or over time from vibration or from heating and cooling cycles that relax clamps and loosen fittings.
More importantly, small leaks cumulatively contribute to significant reductions in engine power and are difficult to locate when proper procedures are not employed.
A leak-free installation
Every TorqStorm supercharger installation should begin with an eye to making sure the path from the volute’s discharge opening to the air entry of the engine (either carburetor or throttle body) is not a potential leak site.
Common mistakes made during the installation of the supercharger are not using bead rolled ends on all induction piping, loose or poorly fitting rubber tubing connections on the induction piping, hose clamps that do not create enough pressure or have enough surface area, hose clamp positioning, the lack of Teflon tape on threaded connections, loose-fitting vacuum hoses on the engine, compromised induction path gaskets anywhere on the engine, a failed PCV valve, and throttle shaft bushings.
It needs to be recognized that a TorqStorm supercharger pressurizes the induction system. The same engine without it works under a vacuum, which is any pressure less than atmospheric.
In most applications under full boost, the supercharger will expose the induction system to between 6 to 8 psi of pressure. Now let’s study this concept in greater depth. I will use a fuel-injected engine as an example since it is easier to conceptualize.
In stock form the engine has an induction pipe that connects the incoming air to the throttle body with a clamped rubber hose. Since the engine is naturally aspirated, there is a varying degree of vacuum (low pressure) exposed to the rubber hose connection. Under vacuum, the rubber hose is actually drawn closer to the inlet piping and throttle body connection.
Then you bolt on a TorqStorm supercharger. Instead of a vacuum, there is 8 psi of pressure expanding against the same connections. The pressure pushes against the rubber hose and wants to dislodge it. In simple terms, boost pressure will find a leak where the vacuum will not.
Potential problem areas
The following are prevalent regions where boost can escape, especially at higher engine rpm.
Piping: All inlet piping needs to have a bead rolled lip. If you use an exhaust pipe, it needs to have a bead roll put on the end to hinder the rubber connection from moving and create a tighter fit around it.
Rubber Hose: The hose you use needs to be rigid enough to support the boost level without ballooning and wanting to walk off, even bead-rolled pipe. This must be an extremely tight fit and will be challenging to install. You can use some soapy water or liquid dishwashing detergent as a lubricant. If the rubber hoses are easy to put on, they are too large for the diameter of the inlet piping and will probably leak.
Clamps: I am not going to say that you can’t use hose clamps, but you want one that is wide enough to create compression over a larger area of the rubber hose. Band clamps are excellent but maybe awkward to work with in some installations. A T-bolt clamp, preferably with a spring, is easy to position and provides superior clamping force. Obtain the clamps before beginning the installation. You do not want to be anxious to get the job done and install a marginal clamp. Position the clamps, so they are near the bead roll but not on it.
Threaded connections: Any threaded connection for a sensor or other fitting must be fully tightened. Teflon tape must be employed, or it will leak from around threads.
Vacuum hoses: All vacuum hoses on the engine must not be degraded and fit very snuggly. You need to recognize that there will be pressure under boost and not suction under boost.
Inlet gaskets, carburetor, and throttle body shaft bushings: The gasket under the carburetor or throttle body to the intake manifold and the throttle shaft bushings are common areas where boost can escape. What leads many astray is that there is no leakage under a vacuum, and the engine runs fine. However, the boost will leak where the vacuum does not.
PCV valve: The wrong PCV valve or one that is worn or poorly made is a typical source of a low boost condition. If an OE valve is still available, that is always the best choice. If not, consider using a tunable PCV valve. These cost around $130.00 but are rebuildable, so you will never need another. Also, it can be moved to a different engine in the future. Do an internet search for an adjustable PCV valve; it will bring you to some sources.
Finding the leaks
With all the potential leak sites identified, the question now becomes how do you determine if any are letting boost escape?
I do want to add a caveat. Even if you follow all of the prescribed steps, the induction path should always be checked for any leaks.
The most effective means to confirm the integrity of the supercharger’s forced induction path is with a special machine called a smoke leak detector.
This unit creates a nonhazardous and noncombustible smoke fed into the induction path via air pressure from a compressor. Within a few minutes, any leak will be revealed with a trail of smoke.
Since it is common to have multiple leak sites, this tool is almost essential to get the most from your TorqStorm supercharger investment.
There are all different levels of smoke leak detectors, but a basic design (which is all you will need) begins at around $125.00 and can be used to find leaks in almost anything. It is a worthy addition to your toolbox.
Another method, though much less effective, is to make a soap solution in a spray bottle and, with the engine running, wet each potential leak site and check for bubbles. But this method will often leave many small leaks undetected.
Suppose for some reason, you do not want to invest in a smoke leak detector. In that case, many better auto repair and performance shops have a more powerful professional-grade tool, and you can hire them to smoke your system. A standard charge for this service is around $100.00.
The design of a TorqStorm supercharger is based on an intercooler not being used. If an intercooler is installed, there will be an inherent drop in boost that is reaching the engine and a decrease in airflow.
Therefore, each TorqStorm kit is an application designed for the highest horsepower gain while providing simple and reliable operation on a streetcar.
TorqStorm offers four different pulley diameters (the smaller the pulley, the more boost created) for most applications. However, before you go that route, you need to ensure there are no leaks and that all of the boost is getting into the engine.
I will end as I began… close the window, don’t turn up the thermostat!