Dunrite Converters

BASIC FUNCTIONS OF A TORQUE CONVERTER:

The torque converter takes the place of a conventional clutch and pressure plate used with stick shift transmissions. It is nothing more than a centrifugal pump (impeller) which could be compared to a fan, which drives another fan (turbine) that is connected to the rear wheels. The force that turns the turbine is referred to as torque. This results from the impeller expelling a column of fluid rotating counter clockwise (viewed from the rear of the vehicle) as it enters the turbine runner. It is very similar to a fire hose aimed at a wall that creates a rearward force on the hose. This rearward force from the column of oil rotating from one fan to the other and finding the exact strike point is what creates torque and turns the turbine. Finding the strike point of the rotating oil is achieved by changing the angle of the fins of the impeller. As torque increases, the vehicle begins to accelerate at a higher rate. One of the ways that stall can be raised or lowered, is by changing the angle of the direction of flow entering the turbine runner. Another is by changing the diameter of the converter itself.

DUNRITE POWER PULLERS:

Torque converters used for towing heavy loads are designed differently than those for RV use and are usually used behind big cubic inch engines and/or diesels.
Dunrite "Power Puller"T torque converters tend to be slightly lower stall with tremendous pulling ability and are built stronger inside to withstand higher temperatures and greater input torque.

If a torque converter has a lockup clutch, it generates tremendous heat to the friction clutch during lockup under a hard pull. This is the area that generally fails first. The resulting contamination of burnt friction material and metal particles end up in the transmission causing valves to stick and early trans failure.

Just because the stall is lowered in a torque converter doesn't mean it is producing more torque (twisting force). This has been proven in our facility by comparing test after test using the same vehicle with numerous changes made to the torque converter. (See graphs under torque converters). The torque curve changes dramatically whenever the stall ratio is altered.

When considering a Dunrite "Power Puller" torque converter, one must consider what the maximum combined gross vehicle weight will be, and what engine modifications have been made. Approximate torque, and horsepower is necessary in order to match the engine to the torque converter. This information is necessary to establish the correct stall ratio for the vehicle. Once this is established, the converter is designed to hydraulically reduce the impeller to turbine speed differential as close to one to one as possible without sacrificing power loss before the converter lockup clutch is engaged. By reducing the speed differential between the impeller and the turbine at the time of converter clutch lockup, we reduce glazing and overheating of the friction material which is what causes premature lockup and transmission failure.  Heat is reduced and the durability of the torque converter is extended to match the rest of the power train.

HEAVY DUTY FOR STOCK APPLICATIONS:

When replacing a Torque Converter, price is usually the primary concern. Usually the converters available for common applications, such as Ford AOD's or Chevrolet 400 and 700 series Turbo transmissions, have a large selection of aftermarket components available at a discount price.

However, when selecting a replacement converter for a transmission rebuild, saving $100 to $150 on low tier discount converters can cost a transmission rebuilder $500 to $1000 in comebacks. Even worse, low cost converters not only fail to operate, but can damage the automatic transmission as well.

The solution to premature converter failure and costly comebacks due to shoddy and inferior work is a heavy duty converter built right the first time.

Dunrite Converters, torque converters done right the first time.

RECREATIONAL VEHICLE APPLICATIONS:

With recreational vehicles, the power and load requirements are different than those of conventional cars or trucks. The automatic transmissions and torque converters used in RV applications face greater load and wear that can shorten the life of the drivetrain significantly. When the time comes to repair and replace these components, often the only components available are those intended for conventional car or truck applications.

Taking into consideration the special needs of these applications, extra efforts have to be made when repairing recreational vehicles. The last thing that an automatic transmission mechanic wants to worry about is the quality or durability of the transmission components going into the transmission they are rebuilding. They want components that will work right the first time and they want components that will last.

Dunrite Converters has the answer. Dunrite has developed torque converters for recreational vehicles that are able to withstand the abuse and damage that RV's put on automatic transmissions.