Sonnax turbine stiffener plate GM-WS-39 is used to create a stronger turbine in GM TH400, Allison AT 540/545, BW 310mm LU (A618) and BW 310mm NLU converters. The design incorporates a contour and reduced outside diameter for optimum fit to the turbine.
The Sonnax plate can be welded as-is to the turbine in GM TH400 and BW 310mm NLU converters, but in Allison AT 540/545 and BW 310mm LU (A618) converters, GM-WS-39 must first be modified.
To weld GM-WS-39 to the turbine, a stock TH350 transmission forward clutch piston may be used as tooling to hold it in place for tacking and welding. Tack welding four to six segments on both the inside and outside diameters of the stiffener plate should be adequate, however some may elect to weld completely around both diameters for maximum strength.

Contour designed for optimum fit to turbine
Enhances strength of turbine
Weld-in-place

More From This Category

Cast Piston

Cast Piston

$100.64

KB Piston, 4 in. Bore, For Ford 302 Rod 5.090 Hollow Dome -14.7cc 2V, .060 Oversized, w/ Rings, Each

KB Piston, 4 in. Bore, For Ford 302 Rod 5.090 Hollow Dome -14.7cc 2V, .060 Oversized, w/ Rings, Each

$1,150.95

Motive Gear Differential Bearing Kit, Koyo, For AM GENERAL HUMMER 1992–2001, Kit

Motive Gear Differential Bearing Kit, Koyo, For AM GENERAL HUMMER 1992–2001, Kit

$256.79

Motive Gear Nv4500 M/S Chev P-Series (Bolt, Each

Motive Gear Nv4500 M/S Chev P-Series (Bolt, Each

$404.23

TURBOSMART Boost Reference Adapter, For VW Golf GTI Mk5/6, Black, Each

TURBOSMART Boost Reference Adapter, For VW Golf GTI Mk5/6, Black, Each

$61.67

Wilwood Caliper, AERO4-DS, Radial, 0.81 in. Rotor Width, 15.00 in. Rotor Dia, 1.12/1.12 in. Bore, Universal, Alum, Black, Each

Wilwood Caliper, AERO4-DS, Radial, 0.81 in. Rotor Width, 15.00 in. Rotor Dia, 1.12/1.12 in. Bore, Universal, Alum, Black, Each

$871.85