Description

Exhaust System

OPERATION
For detailed information on the HO2S (heated oxygen sensor)'s, refer to Electronic Engine Controls For additional information, refer to Electronic Engine Controls Locations,

DESCRIPTION
The exhaust system comprises three separate sections; a front section including a 0.8 liter ceramic pre-catalyst, a center section incorporating a 1.50 liter ceramic catalyst and a rear section comprising a rear pipe and silencer assembly.
The front section has an inlet flange which mates with the turbocharger outlet. The flange is sealed to the turbocharger with a gasket and secured with three bolts which screw into the turbocharger housing. An elbow from the flange is connected to a flexible coupling. The elbow contains a threaded boss for the installation of the front (upstream) HO2S (heated oxygen sensor). A bracket welded to the elbow allows for the attachment of a second bracket which secures the front section to the Power Transfer Unit (PTU). The flexible coupling is connected to the pre-catalyst which in turn is connected by a curved pipe to a flange which mates with the center section and the main catalyst. The curved pipe contains a threaded boss for the installation of the rear (downstream) HO2S (heated oxygen sensor). A hanger bar with two rubber mountings is connected to a common bracket, which in turn bolts to the rear of the front sub-frame to
support the system.
The center section has a flange which connects to the front section flange and is sealed with a metal gasket and secured with three studs and nuts. The flange is connected to the main catalyst. From the catalyst a short section of pipe connects to the rear section.
The rear section has a long pipe which is secured to the center section with a clamp. A hanger bar, mounting rubber and bracket secure the forward end of the pipe to the vehicle body. The pipe is routed in a central position under the vehicle, with a slight deviation around the rear differential, where it joins with the rear silencer. The rear silencer is supported by three rubber mountings; two are welded to the rear subframe and the third is attached to a bracket bolted to the vehicle body. The 28 liter rear silencer has an outlet pipe at each end. Each pipe is fitted with a stainless steel finisher.