When it comes to picking the right torque converter for your strip/street vehicle or race car, it is vital that you follow the logical process to help pick the right parts. It all starts with finding the performance target.
The key will be the peak torque figure. Once you have found that RPM point, then you need to pick a torque converter that has a stall speed of 300 to 400 RPM higher than that point. Once you start the launch with a car running a trans-brake, your RPM will drop, so your stall speed should be able to compensate for that particular change. You don’t want the RPM to drop below the peak torque figure.
Size does matter, even when it comes to torque converters. The size of the torque converter can also be confusing. The smaller that your converter is, the less fluid needed. Less fluid means that there will be a lot less drag on your converter internals, in turn is what lets it stall at a higher speed. Normally, you will want to actually avoid the smaller converters on your average street car, simply because of the higher stall speeds. But, if you plan on adding things such as a lot of nitrous, running high blower pressure, or are using transbrakes, you will need to have a converter that has been built to handle all of the extra stress. Extra torque that is generated can cause your converter to expand or balloon in diameter.
Torque Converter Guidelines
- 7-inch converter: This is ultra-high performance from 6000-9000 RPM stall speeds.
- 8-inch converter: High performance that has stall speeds from 4000-7000 RPM as made by the engine combination.
- 9-10 inch converters: High performance especially for engines that have power adders like super and turbo charging as well as nitrous injections. Normally for engines that have around 1200 HP and the stall speeds may be customized according the how they are applied.
Whenever you are beginning to order torque converters, it is virtually impossible to give the builder a lot information. When you give the right information, you are enhancing the converter builders and your opportunity for success in getting the right converter. The things that the builder needs to know are:
- What type of racing you are doing and how the vehicle is used (throttle stop racing, street strip, 8th mile or quarter mile, brackets, pro or full tree, heads up, etc.)
- How the car is staged (2 step, foot brake, throttle controller, transmission brake)
- Vehicle weight
- Torque and horsepower characteristics of the engine
- Power adders (nitrous assist, super charged or turbocharged)
- Engine specifications (induction system, camshaft specifications, compression ratio, displacement)
- Tire size
- Shift RPM/Max RP
- Mid plate thickness
- Axle ratio
The one size for all theory doesn’t actually work for torque converters. It doesn’t matter what your friend tells you, or what advice you were given by the speed shop counter dude or on the internet, you should use a converter that is suited for your needs. For help choosing the perfect torque converter for your vehicle, your type of racing, and your driving style call the experts at Roadrunner Torque Converters at 1-800-994-2301