Custom Rally Exhaust for the Ford Fiesta ST

I wanted to increase the volume of exhaust so it would easier to hear the car while racing. I wear a helmet with noise reducing muffs, they are great for hearing protection, and removing all of the gravel noise, but it's hard to get a feel of how the engine sounds and when to shift. An LED tachometer bar is a solution, but I was already used to using the exhaust tone with previous cars.

Just like my Subaru build, I wanted a 3" exhaust. This exhaust will be different though because I wanted to add a v-bands instead of flanges. I wanted to have a removable muffler and a rear catalyst. When I am not racing, a muffler would be nice to maintain peace in-town. When I plan on racing, I can remove the v-band, and install the muffler-less pipe.

I spent several months waiting for the Whoosh 3" downpipe to be available again, but the availability date kept being pushed back. At the time of this writing, it looks like it finally became available! I got lucky, and I found someone selling one on eBay eventually.

While installing the new downpipe, I learned that the bolts that attach the OEM downpipe are know to seize and break when trying to remove them. My screw extractors where having a hard time removing the bolts, and I had three of them to take off. I could have spent time trying to set it up my Haas mill, but it would have been more trouble than it was worth when I found out I can get a used turbo from eBay for $80. The turbine housing was not sold separately.

After taking off the turbo, I noticed that the exhaust manifold had a leak. It turns out, someone had touched it before and snapped a bolt inside the head. This one came out fine with a screw extractor, but it was a bit nerve wracking reaching around to the back of the engine with a drill, not being able to see if you're really drilling the bolt like you need to.

It was annoying that I had to do all of this additional work that I wasn't expecting, but I happy overall because these problems affected performance and serviceability. So finally, after fixing all of these surprises, I was able to start welding the new 3" exhaust.

I picked 304 stainless tubing for longevity, even though I live in Arizona, I want to make sure the car looks like a quality build over its lifespan. The muffler I chose was a 3" oval shaped Magnaflow. I thought the car would be too loud with a cylindrical muffler, so I got this one to be safe, the car has the room for it. The catalyst I chose was also from Magnaflow, you see these everywhere on rally cars. Those parts are actually 409 stainless steel, which isn't as good as 304, but within budget. The v-bands can be pretty expensive, but one of my friends who builds a lot of performance cars has a good experience with these affordable ones from Amazon.

I spent about 2 weekends on and off welding the exhaust. I was tig welding it and constantly test fitting it to make it did not reduce my ground clearance or touch anything else under the car. The nice thing about v-bands, is that you don't have to worry about how the exhaust connects axially. With flanges, you are stuck with the orientation you welded it in, with v-bands you have some wiggle room for rotation when mounting.

After installing the exhaust, I noticed that, just like the factory exhaust, it has a lot of slack. Since the diameter increased by an entire inch, it will hit the heat shields while driving. I installed two polyurethane exhaust hangers near the muffler and the exhaust fit improved even more.

The sound is decent, quite when idling and cruising around and louder when in boost. The sound doesn't seem to change much when going from 3500 to 6000rpm which was kind of a bummer. Maybe when I make the muffler-less version, things will be different.