Buzz Words

Our Performance Industry has hundreds of insider sayings and 'slang' that is part of their every day lives. Here's your chance to read and post terms and their definitions that you use every day. If you would like to see a term or saying that you happen to use, just fill out the form below and after reviewed, your term will be post to MotionParts.com

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• Q: What is "Bump Steer"
  A: Bump Steer - is when your wheels steer themselves without input from the steering wheel. The undesirable steering is caused by bumps in the track interacting with improper length or angle of your suspension and steering linkages.
• Q: What are "Left Hand Turn" cars?
  A: Left Hand Turn Cars - This is a term that refers to any race car that only turns left during the race. Typically This term refers to circle track cars.
• Q: What is cam timing?
  A: Cam Timing - refers to the relationship between the cam shaft and the remainder of the valve train. Specially it refers to the exact point when the cam shaft opens and closes bothThe exhaust and intake valves.
• Q: What is "Bench Racing"?
  A: Bench Racing - refers to a group of enthusiasts that are just sitting around discussing their favorite racing sport. Telling stories, comparing notes and just exchanging thoughts about their interests.
• Q: What is "Butt Gap"?
  A: Butt Gap - refers to the distance between the ends of the ring after installation. This distance can vary by engine combination. The distance can be determined by actually using a ring gapping tool.
• Q: What is "Wheel Back Spacing"?
  A: Wheel Back Spacing - is the measurement between the back side if the wheel and the outer edge of the rim. The distance is measured from the mounting surface of the wheel and the other edge of the rim
• Q: What is "Advance Curve"?
  A: Advance Curve - is related to the ignition and the advance curve that is built into the ignition. This curve is controlled by weights and springs within the actual ignition. The engine requires different degrees of ignition spark at different rpm’s. The advance curve is a critical segment of efficiently burning fuel as it passes thru the combustion chamber.
• Q: What is "Rocker Arm Ratio"?
  A: Rocker Arm Ratio - refers to the relationship between the push rod cup and the roller tip that actually depresses the valve stem. Positioning the rocker trunion in different locations can vary the amount of valve opening as the cam shaft rotates. Typically ratios are 1.5 – 1.6 in SBC and 1.7 in BBC. SBF’s use 1.6.
• Q: What is ignition "HEI"?
  A: HEI - stands for High Energy Ignition – Typically these ignitions are manufactured with control modules and coils build directly into the housing and caps. Always make sure that you select an ignition that is matched to your engine needs. Consider vehicle usage, compression, camshaft, transmission type, intake and rear end gear ratio. Performance vehicles are like a musical band, if one instrument is out of tune or not correctly matched, the entire song will not sound good. Think thru your project and match the parts accordingly.
• Q: What is "Primary Tube"
  A: Primary Tube - refers to the tube that connects to the exhaust flange on your performance headers and terminates at the collector. This portion of the header is critical to the performance of the header because it plays a big part in controlling exhaust back pressure in the cylinder head combustion chamber. Typically street / strip engines will require a smaller primary tube. This causes an increase in back pressure which increases the burn rate in the combustion chamber, which equals ‘More Power’
• Q: What is "Color/Soap Sanding"
  A: Color / Soap - refers to one of the final steps in preparing a new paint job for polishing. Typically the detailer or painter will start with a soapie solution of water and Ivory soap and 800 wet and dry sand paper and then begin the slow process of sanding the new paint. The process is comprised of straight line sanding that will flatten the paint and eliminate ‘Orange Peel & Fish Eyes’. It’s the sanding process that sets the stage for the quality of the final paint product. Remember, never sand in circles, always straight line.
• Q: What is "Torque Converter Stall Speed"
  A: Torque Converter Stall Speed - refers to the amount of slippage that is built into the transmission torque converter. If you can imagine the torque converter as the clutch and flywheel assembly in a manual transmission vehicle, then it might be easier to understand the value and application of the torque converter in your vehicle. The torque converter is the mechanical connection between the engine and the transmission as is the clutch and flywheel. Stall Speed refers to the RPM level that the converter is set at before it will actually hook up and begin moving the vehicle. The reason for stall speed is to allow the engine to RPM up to a level where it’s beginning to make real power. It’s like slipping a clutch in a manual transmission set up and then side stepping the clutch pedal. Stall speed is determined by the internal angle of the fins that actually move the transmission fluid. The higher the stall speed, the faster the fluid moves inside the transmission, which increases the heat level and increases the need for transmission oil coolers. Remember it’s really heat that kills the transmission. Always use a good cooler!