Precision Industries Vigilante Torque Converter Install and Test

We all like to go faster, but the path to lower e.t.'s isn't always through engine upgrades. There's performance to be found in the remainder of the drivetrain as well. Adding a higher-rpm stall torque converter to the 4L60-E or 4L65-E automatic transmission behind your GTO's LS1 or LS2 powerplant will improve acceleration, providing that the stall speed is properly matched to the engine output and torque characteristics. Another advantage is the stealth nature of a converter upgrade. No one will know about it except for you. In fact, it will be very difficult to detect-even by the dealer-which is a major plus if your GTO is still under warranty. This can't be said for more obvious underhood mods.

The torque converter, which is a hydrodynamic fluid coupling device, links the engine and transmission and acts as a torque multiplier during the stall and acceleration phases. Providing your GTO with the optimum stall speed will result in the best performance.

As the fluid is pumped through the converter, there are energy losses, however, leading to a coupling efficiency that in the past could never achieve 100 percent. With the advent of the lock-up torque converter, the industry was forever changed. Lock-up converters by nature add a clutch that physically links the pump and turbine, effectively changing the converter into a purely mechanical coupling upon lock-up.

This is a benefit to those installing a higher-stall speed converter when using the overdrive transmission because at highway speed with overdrive, cruise rpm will be lower than stall rpm. There would normally be slippage, which increases heat and reduces reliability, however, the lock-up feature has eliminated the slippage so now you can run a higher-stall speed converter to improve torque multiplication (performance) off the line and still cruise in overdrive at low rpm without worry.

Choosing a converter upgrade is generally determined by matching the converter stall speed to the engine's powerband, vehicle weight and rear gear, among other factors. According to Terry Hendrick, of Precision Industries, "Stall speed is determined by the engine's peak torque and is the rpm at which the converter will hold the engine speed and not allow further increase. Since many times when you rev the engine against the brakes the torque will overcome braking power and the car will start to push through them before stall speed is reached, hobbyists commonly use flash speed to discuss converters; that is the engine rpm at which the car begins to move forward when the gas pedal is depressed on launch.

"The real trick is to produce a torque converter that's strong enough to handle increased stall speed and still lock up efficiently. For owners of late-model F-bodies and GTOs, the factory torque converters stall between 1,500-1,800 rpm, depending on power. In general, for the majority of street applications, our Vigilante series of lock-up converters with a stall speed of between 2,800-3,200 are recommended."

Precision Industries developed the Vigilante line of converters from a clean sheet of paper and they contain state-of-the-art features including a specially designed and heat-treated 4130 alloy machined impeller hub, along with a heat-treated 4142 alloy turbine hub.

Precision Industries was the first aftermarket torque converter manufacturer to design, develop and manufacture multi-disc torque converters. In addition to carrying an industry-leading written unconditional two-year warranty, each converter is eligible for one free stall adjustment within two years of the date of purchase.