We snaked the exhaust around the Fisch Racing Tech transmission crossmember and the CD009A transmission, maximizing clearance to every component while not protruding below the plane of the bottom of the car.
This photo shows every step of the fabrication process. The first segment was finish welded to the muffler. The next two segments were tack welded in place. The next segment was held in place with tape and marked, while the 3.5” Vibrant Bellows (P/N: 68935) and V-band Clamp (P/N: 1492) are being mocked up. On the next visit to the fabricator, the tacked segment will be finish welded and the marked segments will be tack welded. The entire exhaust was built in these stages with 1 hour drives between visits.
Next, we fabricated the 4” downpipe for our Borg Warner EFR 8374 & EFR 9180 Turbos. These turbos have the same external dimensions and can be swapped without having to change the exhaust or downpipe.
EFR Turbos do not come with turbine exhaust flanges, so we bought a BorgWarner EFR 3″ Downpipe V-band Flange from Full-Race (P/N: FR-UNI-VBAND-3-EFR) and welded a Vibrant Performance 3-4” Transition Adapter (P/N: 2632) to it. After making the down-turn (hence, ‘down’-pipe) we used a 4” Vibrant V-band clamp (P/N: 1493) to further improve serviceability of the turbo system, and ease of swapping out lower intake manifolds.
With the main 4” downpipe in place, we started to figure out the routing of the 1.75” wastegate tubes. “Screamer-pipes”, or wastegate “dump tubes” are significantly easier to fabricate than recirculating the wastegate gasses back in to the exhaust. I personally find most of them obnoxious and unrefined sounding, and from a fabrication standpoint, they are a lazy way out.
Connecting the two 4” exhaust pipes and 1.75” wastegate tubes was not going to be a lot of fun.
The entire FD’s exhaust was built just a few feet off the ground while the car was on QuickJacks outdoors. With very little physical room to work and the fabrication shop an hour away, I had to take a selfie to capture the emotion during the most challenging section of building the exhaust.
3 comments
Billy, the exhaust looks fantastic. Every update gets us close to the full reveal of this monster!
Thank you! I’m a bit behind on articles so there will be more updates that will come out soon. The car is close to firing up!
I see you’re also a glutton for punishment wrenching on cars while laying on our backs, ha! Excited to see this up and running with all the extensive and detailed work on it.