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Torque Converters

The articles below have been reprinted by permission from Precision Industries.

Over the past year a number of torque converter rebuilders as well as some "Johnny come lately" start up converter rebuilders have entered the high performance street car torque converter market. Both the existing and newbie companies have tried to get in this segment of the market before only to fail due to the drastic differences between racecar torque converters and high performance street torque converters.

Precision Industries has specialized in this market for more than 10 years. Now we are seeing all of these so called expert torque converter builders reappear with there low prices and short warranties. One of the key signs of quality is the length of a products warranty. A warranty shorter than 2 years for a torque converter is a joke! Would you buy a car with a 90 day warranty? The answer is a simple "NO"! The high performance streetcar has more demanding requirements than any race converter. It has to perform in all kinds of weather, temperatures and uses.

1. A typical race torque converter will never see 1000 miles in a lifetime of use while a high performance street torque converter will probably see 100,000 miles in a lifetime of use.

2. A race torque converter will be heated up and cooled less than 1000 times while a high performance street torque converter will see many 1000's of heat and cool cycles in the lifetime of usage.

3. A race torque converter does not use a lockup clutch but a lockup clutch is one of the most important units in a high performance street torque converter. The typical race torque converter needs to be freshened up every year while a high performance street converter never gets freshened up unless the customer wants to make a stall change or has a transmission failure.

4. A race torque converter operates in an rpm range of 4000 - 8000 rpm with very poor low and mid range capabilities. A high performance street torque converter needs to operate in rpm ranges from 1500 - 6000 rpm with high efficiency and torque multiplication.

5. A race torque converter is only used under full throttle conditions while a high performance street torque converter is used to race, drive short distances, drive long distances, etc. plus be dependable.

Most racecars get transported to the track while most high performance streetcars get driven to the track. These are just a few of the reasons why quality is so critical when designing and building a high performance street torque converter.

Most companies jumping into the street torque converter market are still using 1960's technology. Just because a company has been building race torque converters for 50 years does not mean it can build a high performance street torque converter. Most race torque converters are still being manufactured using ancient technology. By ancient technology I mean stock front covers with welded on rings and pilots, spacer plates to get the impeller hub in the right location, rebroached stock turbine hubs that end up with inferior thin walls, handmade stators with incorrect vane geometry, after thought brazing of turbine vanes that cause imbalance and disturb oil flow, 4 and 6 cylinder low capacity lockup clutches and OEM type friction material.

New technology includes steel billet front covers, high capacity clutches designed for V8 engines, friction material that will handle the rigors of pulse width modulation, impeller hub mountings designed for the application, thick walled turbine hubs designed for the application and turbines with 31 specially designed furnace brazed braces to prevent failure and not disturb oil flow.

These new technologies are an absolute necessity for high performance street torque converters to be dependable and to last. The billet front cover was designed to allow for exact concentricity, perpendicularity between pilot, mounting pads and bolt circle virtually impossible using a stock 245 torque converter cover due to all of the distortion of adding a mounting ring and pilot. The billet cover is also designed to allow for more clutch friction contact area something that is impossible with a stock type front cover.

A stock 12" torque converter that originally came in the car has 19.7921" of contact area, a stock 245 mm torque converter cover has 16.4867" of contact area and our steel billet cover and special clutch has 37.1101" of contact area. For a 245 mm torque converter clutch to hold a modified V8 it will need to have 40 percent more area of contact than a 12" torque converter. Yes, the 245 mm clutch will hold for a short period of time but not for very long. This might be one of the reasons for the short warranty our competitors offer.

If these 245 mm OEM stock torque converter parts are so good why doesn't GM use these parts in a stock low horse powered LS1? The other part of this scenario I hear all the time is "The warranty is only 90 days but I will take care of you for a year". This is another comical statement because the person making this statement is probably not the owner and may not even be working there next month.

REMEMBER!!!! All company polices are in writing, if you do not read "1 YEAR WARRANTY" then you do not have a 1 year warranty. Precision Industries is so confident in the QUALITY of our product that we offer a "2 YEAR UNCONDITIONAL WARRANTY" in writing.

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