MK1.5 4" aluminum exhaust - CyKlops Custom Creations

The exhaust has also seen several versions. It began with an HKS SC exhaust, then with the MKI.5 swap it received a 2.25" Borla exhaust, and then I fabricated a center-exit Magnaflow exhaust. It included modifying the rear air-dam to accommodate a center hole, and re-fiberglass the old hole. A double-wall exhaust lip (housing vent construction) was fiberglassed into the air dam.

This was the result with the Magnaflow before I designed the complete aluminum setup:

And now that I can finally TIG-weld, I have fabricated a 4" aluminium exhaust, including making the muffler and tip. The downpipe is stainless, increasing (diffusing at the correct angle) from 3 inches at the GT3040 turbo to 4 inches at a V-band clamp. There it transitions to aluminum, and after a short and braced B-pipe, it has a Vibrant Vangen clamp for flex. I am delighted with the sound. It is deep, but no louder than my previous setups, mostly due to the new longer but straight-through aluminum muffler. The mounts are also adjustable, so I can keep it centered and straight once it settles. Click on the picture for a you-tube video and sound:

The stainless external dump-tube, with flex section and its own Supertrapp silencer, is bolted to a brace on the B-pipe:

Ready for install with a stainless mounting plate and VHT ceramic-coated (as with the downpipe and lower section of WG):

After some road-testing, I concluded that the dump-tube was allowing a few extra psi to build, and so I elected to design a much shorter and larger diameter aluminum dumptube that exits out the top of the engine lid. Ceramic-coated, it has held up to rigourous boost-testing, probably due to decent airflow in that location:

It was time to install the LC-1 Wideband setup (with display in my iTouch), and so I welded on the bung and re-coated the ceramic:

Added an aluminum heatsink (from a discarded inverter) for the wideband sensor:

Here are a few pics of the work to the rear air dam. The old exhaust guard area was first fiberglassed, and the new hole cut. Then a 6.5" dual-wall exhaust port from housing venting was cut to a half-circle, and fiberglassed in place.