Twin Turbo

The Turbo Technology Inc. Twin Turbo kit for late model Mustangs consists of two Turbonetics Hi-Fi 60-1 turbos, a set of headers, two wastegates, down pipes, intercooler, various nuts, bolts, gaskets and oil lines.

This kit, with some modifications, will be used on the test car. We chose not to get the intercooler, instead designed our own with selection help from Spearco Intercooler's.

Although hard to make out (click on image for large view), the above is the CAD drawing sent to Spearco for the intercooler.

The other picture is a 3D solid model of the Intercooler and Radiator assembly. The intercooler has two inlets, one from each turbo and one outlet. We ordered the intercooler without the top tank, so the exact outlet configuration wont be decided until final engine placement is done.

The other modifications to the Turbo Technology basic kit included: the material used to construct the headers, the type of wastegate, and the addition of a blow off valve. Turbo Technology uses type 304 stainless for the header material. While 304 is OK for most exhaust applications it is not the ideal stainless for turbo applications. The problem with 304 is that it allows carbon precipitation at elevated temperatures, 800 degrees F to 1600 degrees F, right in the range of an exhaust system. Carbon precipitation is the movement of carbon to join with the chromium in the stainless, this causes the stainless to become more susceptible to corrosion and over time become brittle and form cracks in the headers.

For more information on Stainless Steel try these links:

Stainless Steel White Paper by Stainless Plate Products Inc
Detailed properties of Stainless steel from MatWeb
Build your own headers - Stainless products (J-bends etc) for header builders

The ideal header material is type 321 stainless. 321 differs from 304 in that it contains Titanium. 321 is commonly used in aircraft exhaust, welding equipment, and jet engine parts. It costs about double the price of 304 but considering the $1500 or so price tag for a set of custom headers an additional $200-$300 is cheap insurance on the pricey headers.

The standard kit uses Deltagates waste gates. These were replaced with the larger Racegates