SPG CUSTOM EXHAUST
The first new exhaust I got for my car was an old "Group 6" exhaust. It was supposed to be stainless steel and 2.5" from the cat-back.
Right from the beginning I never liked it. I fought with it year after year, trying to keep it from clanking around.
Finally, after 2 years, it rusted through the seems and pretty much fell off.
To replace this system, I wanted a really nice system including a 3" downpipe, hi-flow catalytic converter and good muffler.
A 3" system is really only necessary after the turbo and into the cat. The stock cat is really bad for high performance engines.
It's really restrictive and combined with the small downpipe it's a huge hit in performance.
In order to fit the 3" downpipe, I knew that I had to move the battery somewhere. So, this was my first mission.
I spent one entire weekend moving the battery to trunk.
To read about this click here:
DIY Battery Relocation
Now that the battery was moved I was able install my new custom downpipe. It is built for the garrett turbos and it eliminates the stock internal wastegate.
The wastegate is now a completely separate exhaust path until it joins the main exhaust about 12" past the turbine exit.
This creates faster spool up and prevents boost creep in high boost environments.
Also notice that this downpipe has 2 oxygen sensor bungs. One narrow band and one wide band for custom ECU tuning.
This downpipe was not cheap. I believe I paid $800 for it, which also included a special exhaust coating to keep underhood temperatures down and exhaust gasses hot!
The second part of the exhaust was to include an intermediate downpipe to the cat, high flow cat, and then a nice mandrel bent system the rest of the way.
I bought the mandrel system from John at Saab Savior and then I took the entire system to a custom exhaust shop to put it all together.
The total cost was around $2000, but it should last forever.
The last component is to add a tube header. People say that the tube header adds a lot of top end performance, but takes away the classic C900 burble...
I haven't committed to losing that sound just yet!