FTI Performance Torque Converters & Transmissions

FTI Performance Torque Converters & Transmissions

FTI Performance is one of the most respected names in high-performance automatic transmission and torque converter engineering, building its reputation on drag strips and road courses where the mechanical demands on automatic transmissions exceed what factory and generic aftermarket components can reliably handle. Founded on the principle of delivering race-proven driveline components with exceptional customer service, FTI has earned the trust of professional drag racers, Pro-Mod competitors, and street performance builders who need converters and transmissions engineered for specific power levels and vehicle applications rather than generic one-size-fits-all solutions. In 2019 FTI was acquired by NHRA Funny Car driver Paul Lee, bringing fresh investment into the brand's engineering and manufacturing capacity while maintaining the founder's commitment to quality and technical support. FTI's product range covers everything from mild street performance converters for 400 to 600 horsepower builds to full competition transmissions and converters for vehicles producing over 5000 horsepower.

Popular Upgrades

FTI's most popular products include custom-stall torque converters for 4L60E, 4L80E, TH400, 700R4, 4R70W, 6L80E, and 8L90E automatic transmissions that are calibrated to the specific engine's torque curve and target stall speed rather than a generic catalog unit, complete rebuild transmissions for 4L80E and TH400 applications in street-strip and drag race configurations, and performance valve bodies and shift kits for GM and Ford automatic transmissions that improve shift firmness, reduce shift time, and increase line pressure for better clutch pack longevity under high torque loads. Lock-up converter clutch upgrades for overdrive transmissions improve highway fuel economy while retaining the higher stall speed needed for performance launches.

Performance and Handling

A correctly matched FTI torque converter stall speed is one of the most impactful single transmission upgrades available for a modified automatic vehicle, because a converter that stalls too low forces the engine to launch below its peak torque rpm while a converter stalled too high wastes parasitic slippage in normal driving and at cruising rpm. FTI's custom converter program allows builders to specify their engine's peak torque rpm, camshaft profile, power adder type, vehicle weight, and tire combination so the converter is built to the exact stall speed that maximizes launch performance without sacrificing converter lockup efficiency at highway speed. Transmission upgrades including upgraded clutch packs, shift kits, and hardened sun shells convert a stock automatic transmission from the weakest link in a performance drivetrain into a reliable power transfer unit capable of handling consistent 1.3-second 60-foot launches.

What stall speed do I need for my converter?

Stall speed selection depends primarily on the engine's peak torque rpm, with naturally aspirated V8 builds typically needing a converter stalled 300 to 600 rpm above the peak torque point to allow the engine to reach its torque plateau before the converter begins lockup. Supercharged and turbocharged builds with high torque output at lower rpm often benefit from lower stall speeds in the 2000 to 2800 rpm range to prevent excessive slip under boost, while high-revving naturally aspirated and nitrous builds may benefit from stall speeds of 3000 rpm or higher. FTI's technical team provides free converter recommendations based on the engine specifications and intended use, making the custom ordering process accessible even for first-time converter buyers.

Is a 4L80E stronger than a 4L60E?

Yes, the GM 4L80E is a significantly stronger automatic transmission than the 4L60E, using a larger case, a three-shaft gearset versus the 4L60E's two-shaft design, and a rated factory torque capacity approximately twice that of the 4L60E's 360 ft-lb limit. The 4L80E is the preferred swap choice for Hellcat, LS, and big block builds above 550 horsepower where the 4L60E's case, clutch packs, and output shaft are undersized for the application. FTI builds performance 4L80E transmissions from a fully reconditioned core using upgraded clutch packs, hardened sun shells, and billet intermediate shafts that handle consistent high-horsepower duty without the valve body failures that affect factory units used at elevated power levels.

Why These Parts Fit Right

FTI converters and transmissions are built to order based on the customer's specific vehicle, engine, and power level specifications, ensuring the converter stall, clutch pack count, and valve body calibration are matched to the application rather than approximated from a catalog. Transmission product pages include supported vehicle platforms, power ratings, and installation hardware requirements. Fast shipping and FTI's technical support team are available for any converter or transmission specification question.

Support your driveline upgrade with performance exhaust from our exhaust collection, improve suspension dynamics with parts from our suspension catalog, and maximize engine output with our air intake systems collection.