Down Pipe (James – 03)

We have covered part of building the down pipe from the back of the turbo housing, but this post should cover the subject in more detail.

Because we have rotated the turbine housing 180°, we can no longer use the factory down pipe that came with the turbo, nor can we use any of the common aftermarket down pipes that are available for the SR engine.

So we have to build our own. Using the Focussport stainless flange shown above, we can now start to thread the 2.5″ exhaust out from the turbo, around the steering shaft, and down to the exhaust holes in the X-member in the frame.

The exhaust leaves the turbo housing in 2-¼” hole, so a transition needs to be used to upsize the pipe to 2-½”. Burns Stainless makes such a transition, and it was put in the lathe to make it fit for our application.

Here you can see how the size flares up from 2-¼” to 2-½” where is it is joined by the mandrel bend making its bend down.

Now, we need to wrap around the steering shaft with a few cuts of mandrel pipe like this:

If we pull the steering shaft out of the way, it gives a better view how we wrap the pipe around the shaft, and this shot shows the V-band flange and how is sits really nicely in the relief of the engine block, out of the way of everything, but still easily accessible through the inner fender:

Here are a couple shots from down below that show how the exhaust threads around the steering shaft and then makes the transition to the flex pipe in the x-member. (The frame rail will be cleaned up once we pull the engine back out of the car again!)

And here is a shot of the entire down pipe assembly outside of the car:

Scratch that off the list!