Switchback's Fiesta Fun Car Build

[Switchback]

Hi Everyone! I've recently purchased my new (to me) 2015 Tuxedo Black Fiesta ST! After looking for a suitable car for a long while, I finally found one and ultimately bought it.

Background
So to begin I want to speak a bit about myself and my history with the Fiesta ST. Back when I was 21 years old, I purchased a Kona Blue Fiesta ST off the lot. I wanted something sporty, learn how to drive stick, and overall have a fun car that didn't break the bank. At 21k OTD (I think my price before taxes was 18 or 19k) with 0% APR for 72 months it was a fantastic deal, especially considering I had just joined the workforce and was making all of 47k a year in a NOC tech support role. I lived with my KB FiST for 6 years, moving from Maryland to Massachusetts to California. It survived multiple brutal winters and overall was a great car. After I moved to Cali, I was getting older and wanting something more. I bought a bigger more comfortable sedan (Kia Stinger GT) and sold my Fiesta ST (for 17.5k, thanks Carvana). It was...okay. Then I moved to a Tesla Model 3 because of the tax incentive and interest in not buying premium gas for a twin-turbo V6. Since I've bought the Tesla, I was more and more longing for something manual and /fun/. One way I describe the Tesla is that it's a Washing Machine with wheels. It's certainly quick, but it's boring. It's an appliance. I'm now older, have disposable income and a driveway where I can park fun things.

I started looking at cars. First I looked at Miatas, specifically the NC. I thought it had the most potential for upgradability, and having a CARB compliant turbo kit was a huge boon. But, after test driving one I realized I don't really...fit. I'm to tall. It also didn't give me a smile when I drove it. Then I looked at Veloster Ns. Went up to Irvine and tested one on a Carmax lot. It was fun, but the price was high and out of my "fun cheap fun car" budget. Looked at a few rebuilt salvage title cars. I loved the concept, it felt like a Fiesta ST that had grown up a bit and gotten more electronic niceties. But reading into it the VN had tons of electrical gremlins that would pop up, so I passed. And then, back to Fiestas. Had a few bought out from under me before finding this one. A MY2015 Tuxedo Black Fiesta ST with Recaros and the Moonroof. I would have preferred a slicktop but this was priced right and had some nice features that I wanted.

My Goals
I know a lot of people say this, but OEM+ is the goal. I want to preserve the spirited driving style but won't be against adding extra power. Reliability is important to me, I want to take it out on the weekends for a spirited drive and not worry about "will this be the day the FiST dies". That being said, I'm not against something like a Hybrid Turbo, as long as the car remains fun. I do want to limit/remove the tripoding if possible, as its a safety concern in my eyes.

The Car
Okay so enough backstory. Here it is! My 2015 Tuxedo Black Fiesta ST!


I lifted these photos off the Facebook Marketplace listing. Mod List when purchased:
- Boomba Wing Spacer Kit
- Mountune Radiator
- Cobb Rear Motor Mount
- Cobb Access Port with Stage 1 91 Octane Tune (Thanks California)
- Enkei RPF1 16 Inch Wheels
- Straight-Piped Exhaust
- Spare Parts Included with Purchase: Replacement Water Pump, Powerflex Rear Spring Bushings

Here's what I've done so far in terms of repairs:
- Replacement Door Handles (Interior): Passenger side was broken on purchase, with driver side really loose. 60$ off amazon later and some time with my power drill and they work better than ever!
- Ford OEM Rubber Fiesta ST floor Mats: The cloth ones where in rough shape, and the Ford OEM ones were pretty inexpensive so I picked up a new set on amazon for $160.

Planned Fixes/Changes:
- Remove the Boomba Wing Spacers: Not a fan to be honest, it also makes the hatch rattle and I'm not a fan.
- Replace LEDs for interior cabin and License Plate Lights: Rear lights and the license plate lights are dead.
- Left and Right Rubber Windshield Gaskets/seals: Dry rotted, needs to be replaced.
- Rear Door Window Motors: Driver Side Rear Window does not roll, and the passenger rear door has been going slower and slower. Likely both motors need to be repaired/replaced.
- Tint: Its bubbling, turning purple. Probably going to go with a less-absurd tint like 30% or 50%, instead of the 5% that's currently on the car.
- Exhaust: Straight Pipes are loud. I love the burble when decelerating, but highway drone and overall livability is impacted. I don't want to be pulled over by the police if I am on the highway driving to a curvy road.
- Remove the Tow Hitch: I don't understand why someone would put a tow hitch on a FiST. I must right the wrong.

 

[Switchback]

Picture-less update time! So this weekend I set out to install a new short-shift kit, bushings, exhaust and remove the Boomba Wing Spacers. Needless to say it did not go perfectly, and I only got 1/3 items completed.

Short-Shift kit went in without any issues, as well as the Transmission Shifter brackets. The Whoosh Motorsports kit worked fantastically, even if I struggled for a long while getting the shifter cables out from the bracket. Went with the 25% reduction, which works phenomenally and gives me a nice short snappy throw.

Exhaust couldn't go in because I couldn't get the downpipe bolts off unfortunately, and the garage air compressor is currently out for the count due to something exploding internally. (We are trying to repair it to support the Lemons build we are working on concurrently) I'm probably just going to take it to a shop to get someone to give it a few good Ugga Duggas (Yes it's a technical term, trust me I'm an engineer). I bought the Thermal R&D Whoosh spec exhaust for reference.

Lastly, the thing I'm most pissed about is the Wing Risers. So going into the removal I knew the outer-most posts where separated and would need to be repaired. However what I didn't know was how broken it /actually/ was. It took a lot of struggle to remove the wing due to the seized/stripped/completely ruined screw threads, and as a result only 1 of the 6 mounting points on the spoiler is reusable. So I think it's safe to say the Boomba risers are bad and should never be used again. I've purchased a new wing off ebay (Looks to be an OEM wing in gloss black), once it arrives I'll see if the gloss black looks good enough with my current Tuxedo black, and if not I'll take it to the shop for a re-spray to the body color. $233 for an OEM wing, and I was quoted $215 for painting, using the old spoiler as a paint match. Not a fantastic way to spend $448 but at the end of the day I hated the wing risers. If anyone wants them I'll sell them off for a good price. (With the warning that they may implode your spoiler if you ever try removing them. Unless it was just the previous owner who was a dummy, but I don't know)

I also purchased the parts for the Timing Belt service, that one I am going to have a mechanic do because I don't have time/patience for it. Garage I quoted it at said it'd likely be in the $900 to $1000 range, which is reasonable enough for me. Not sure if I should do the Serpentine or accessory belts at the same time though.

 

[Capri to ST]

My shop charged me $1,150 for labor for doing the timing belt, so the estimate from your shop certainly seems reasonable. I would definitely do the serpentine belt and the water pump while it's being done.

 

[Switchback]

My shop charged me $1,150 for labor for doing the timing belt, so the estimate from your shop certainly seems reasonable. I would definitely do the serpentine belt and the water pump while it's being done.

The quote included the water pump and a coolant flush, so that’s planned as part of this refresh. Guess I’ll go add a serpentine belt to my ford parts order (actually going to go pick the parts up today from the dealer), thanks for the tip!

I hate to say it but I just am operating under the assumption the previous owners didn’t keep up with maintenance, so budgeting to bring it back to a reasonable baseline was factored into my purchase cost.

 

[M-Sport fan]

I would even get new serpentine belt tensioners/pulleys (except for the actual water pump pulley, as long as it's true), 'while you're in there'.

 

[Switchback]

I would even get new serpentine belt tensioners/pulleys (except for the actual water pump pulley, as long as it's true), 'while you're in there'.

Thanks, I'll add it to the list. Certainly the definition of scope creep adding all this stuff in, but worth doing on a late 2014 built MY2015 with 120k miles on it.

In other news, I finally got all the parts needed for a Sync 3 Upgrade. Spent $474.49 for all the parts, in part due to the fact I hoped that LKQ Online would send the whole unit (and not just the screen). Alas, they did so I had to buy the APIM separately, which kinda sucked. Plug and play install though, I do want to verify all the asbuilt data is valid. (Pulled out of an unknown fiesta per ebay listing, not sure if its a ST vs regular fiesta) Next step in this project is using Syn3 Updater from Cyanlabs to bring it up to sync 3.4 and update the maps. (The APIM I bought was a factory nav unit)

 

[isis]

Those look like some nice chubby tires on your RPF1s. Do you know what width the wheels are and what size the tires are?

 

[Switchback]

Those look like some nice chubby tires on your RPF1s. Do you know what width the wheels are and what size the tires are?

I'm not sure the width, but they are 16 inch RPF1s in Matte Bronze(Fairly certain 16x7 but haven't measured yet), with some ancient 205/50/16 BFGoodrich Advantage TA Sport tires circa 2019. I'm planning on going to some nice 205/45/16s once all the mechanical work is complete.

These are my tire options I'm looking at right now:
Federal 595RS-Pro
Yokohama Advan Fleva V701
Firestone Indy 500
Maybe Yokohama Advan Neova AD09

Trying to keep prices in check given how much I'm spending currently to bring the car back from it's no-maintenance history. Fun fact though I did find a receipt for new brake pads from May 2025 so at least I've got reasonably new pads. Doubt they are worth anything on track but at least it's something.

 

[isis]

The only available RPF1s i can find are 7.5” or 8” wide. 205s seem too little for either to me. Yours also don’t look bronze but my silver stock wheels don’t look silver with the dang motor craft brake pads.

I just put 215/45-17s on my stock wheels and love them. Got EV spec extsa sport tires. No more spinning in 2-3 gears.

 

[Switchback]

The only available RPF1s i can find are 7.5” or 8” wide. 205s seem too little for either to me. Yours also don’t look bronze but my silver stock wheels don’t look silver with the dang motor craft brake pads.

I just put 215/45-17s on my stock wheels and love them. Got EV spec extsa sport tires. No more spinning in 2-3 gears.

Now you've got me second-guessing myself, so I just walked out and checked. They are def matte Bronze, the lighting has to hit it properly (And they are caked in brake dust which is part of what I need to clean when I get the car detailed after all the chaos) I attached two photos, one with the tire fitment/size on the wheel. And yes I know I'm missing the spoiler, UPS still hasn't delivered the replacement.

 

[rallytaff]

I too got rid of the wing risers as they had damaged two of the wings. I splurged and got the Delta wing riser from the UK, had it painted and this was 2 yrs ago. This thing is rock solid, NO rattles or shaking and worth every penny!

 

[M-Sport fan]

I'm not sure the width, but they are 16 inch RPF1s in Matte Bronze(Fairly certain 16x7 but haven't measured yet), with some ancient 205/50/16 BFGoodrich Advantage TA Sport tires circa 2019. I'm planning on going to some nice 205/45/16s once all the mechanical work is complete.

These are my tire options I'm looking at right now:
Federal 595RS-Pro
Yokohama Advan Fleva V701
Firestone Indy 500
Maybe Yokohama Advan Neova AD09

Trying to keep prices in check given how much I'm spending currently to bring the car back from it's no-maintenance history. Fun fact though I did find a receipt for new brake pads from May 2025 so at least I've got reasonably new pads. Doubt they are worth anything on track but at least it's something.

You could also consider the Conti ECS 02, although yes, that donut is a bit more coin than the ones you've listed, except for the AD09s, which are $20+ more than even the Contis.

I have the AD09s in 215/40-17 on 17x8s for my pure summer setup, and they are great so far.
By far the quietest and smoothest 200 tread wear sticky donut I've ever driven, hands down!
I am not sure how they will wear/last, but they are in that 'endurance' category of 200 TW offerings, so I am hopeful.

The bronze RPF1 was offered by Oakos in both a 16x7, AND a 16x8 for our PCD application.
So until you take a wheel off of the car, and look at the cast in markings on the back, it is hard to tell which size you own.

 

[Switchback]

New wing installed! Looks like it was old-stock from when you could put the ST Wing on a standard Fiesta, manufactured in 2011 according to the sticker. The Gloss black contrasts a bit with the Tuxedo Black Metallic paint but I think it's close enough to really matter.

Regarding tires, yeah the ECS2s are a bit spendy. I threw the Advan Neova AD09s in just because I found someone with a set of new ones on Facebook Marketplace. The Federals are apparently not manufactured anymore according to Phils so it's mostly old-stock at this point apparently. I think I'm likely going to stick with the Indy 500 or the Yokohama V701, still debating it. The cost is similar (Indy 500s beat out the Yokohama if I go through Costco) and likely I'd just want to buy another set of wheels and put something stupid like a Federal RS-RR for pure track-performance. (Not as a canyon/fun car given the road noise)

Maybe I should just jack up the car and pull a tire off to check. I do want to replace the lugnuts because there's one mismatched nut and my OCD is killing me.

 

[M-Sport fan]

The Federal RS Pros are supposedly a bit less 'banshee screaming/mudder tire' at speeds above 20 MPH than the older RS-RRs, and I believe that Phil's <-(where I bought my wheels, but he does not deal with Yokohama at all) has those as well.

 

[Switchback]

The Federal RS Pros are supposedly a bit less 'banshee screaming/mudder tire' at speeds above 20 MPH than the older RS-RRs, and I believe that Phil's <-(where I bought my wheels, but he does not deal with Yokohama at all) has those as well.

So Phils only has RS-Pro's on the website, but those are end of life apparently. They still show on Federal's website so it could be there's just less of them coming in, or they actually /are/ gone. I thought the RS-Pros and RS-RRs were the same era, with the RS-R being the precursor to both of them.

 

[grimlock212]

Hi Everyone! I've recently purchased my new (to me) 2015 Tuxedo Black Fiesta ST! After looking for a suitable car for a long while, I finally found one and ultimately bought it.

Background
So to begin I want to speak a bit about myself and my history with the Fiesta ST. Back when I was 21 years old, I purchased a Kona Blue Fiesta ST off the lot. I wanted something sporty, learn how to drive stick, and overall have a fun car that didn't break the bank. At 21k OTD (I think my price before taxes was 18 or 19k) with 0% APR for 72 months it was a fantastic deal, especially considering I had just joined the workforce and was making all of 47k a year in a NOC tech support role. I lived with my KB FiST for 6 years, moving from Maryland to Massachusetts to California. It survived multiple brutal winters and overall was a great car. After I moved to Cali, I was getting older and wanting something more. I bought a bigger more comfortable sedan (Kia Stinger GT) and sold my Fiesta ST (for 17.5k, thanks Carvana). It was...okay. Then I moved to a Tesla Model 3 because of the tax incentive and interest in not buying premium gas for a twin-turbo V6. Since I've bought the Tesla, I was more and more longing for something manual and /fun/. One way I describe the Tesla is that it's a Washing Machine with wheels. It's certainly quick, but it's boring. It's an appliance. I'm now older, have disposable income and a driveway where I can park fun things.

I started looking at cars. First I looked at Miatas, specifically the NC. I thought it had the most potential for upgradability, and having a CARB compliant turbo kit was a huge boon. But, after test driving one I realized I don't really...fit. I'm to tall. It also didn't give me a smile when I drove it. Then I looked at Veloster Ns. Went up to Irvine and tested one on a Carmax lot. It was fun, but the price was high and out of my "fun cheap fun car" budget. Looked at a few rebuilt salvage title cars. I loved the concept, it felt like a Fiesta ST that had grown up a bit and gotten more electronic niceties. But reading into it the VN had tons of electrical gremlins that would pop up, so I passed. And then, back to Fiestas. Had a few bought out from under me before finding this one. A MY2015 Tuxedo Black Fiesta ST with Recaros and the Moonroof. I would have preferred a slicktop but this was priced right and had some nice features that I wanted.

My Goals
I know a lot of people say this, but OEM+ is the goal. I want to preserve the spirited driving style but won't be against adding extra power. Reliability is important to me, I want to take it out on the weekends for a spirited drive and not worry about "will this be the day the FiST dies". That being said, I'm not against something like a Hybrid Turbo, as long as the car remains fun. I do want to limit/remove the tripoding if possible, as its a safety concern in my eyes.

The Car
Okay so enough backstory. Here it is! My 2015 Tuxedo Black Fiesta ST!
View attachment 67254 View attachment 67255

I lifted these photos off the Facebook Marketplace listing. Mod List when purchased:
- Boomba Wing Spacer Kit
- Mountune Radiator
- Cobb Rear Motor Mount
- Cobb Access Port with Stage 1 91 Octane Tune (Thanks California)
- Enkei RPF1 16 Inch Wheels
- Straight-Piped Exhaust
- Spare Parts Included with Purchase: Replacement Water Pump, Powerflex Rear Spring Bushings

Here's what I've done so far in terms of repairs:
- Replacement Door Handles (Interior): Passenger side was broken on purchase, with driver side really loose. 60$ off amazon later and some time with my power drill and they work better than ever!
- Ford OEM Rubber Fiesta ST floor Mats: The cloth ones where in rough shape, and the Ford OEM ones were pretty inexpensive so I picked up a new set on amazon for $160.

Planned Fixes/Changes:
- Remove the Boomba Wing Spacers: Not a fan to be honest, it also makes the hatch rattle and I'm not a fan.
- Replace LEDs for interior cabin and License Plate Lights: Rear lights and the license plate lights are dead.
- Left and Right Rubber Windshield Gaskets/seals: Dry rotted, needs to be replaced.
- Rear Door Window Motors: Driver Side Rear Window does not roll, and the passenger rear door has been going slower and slower. Likely both motors need to be repaired/replaced.
- Tint: Its bubbling, turning purple. Probably going to go with a less-absurd tint like 30% or 50%, instead of the 5% that's currently on the car.
- Exhaust: Straight Pipes are loud. I love the burble when decelerating, but highway drone and overall livability is impacted. I don't want to be pulled over by the police if I am on the highway driving to a curvy road.
- Remove the Tow Hitch: I don't understand why someone would put a tow hitch on a FiST. I must right the wrong.

Have you ever gone to an SCCA Autocross? I’m guessing not. If you do, you’ll see guys showing up in Corvettes and Vipers pulling trailers. It’s the easiest way to get your race wheels, tools, etc to the event. I’m not saying that is what your FiST was doing in its prior life, but it’s possible. He also might have been towing a motorcycle or small recreation vehicle...or maybe a camper!

 

[M-Sport fan]

So Phils only has RS-Pro's on the website, but those are end of life apparently. They still show on Federal's website so it could be there's just less of them coming in, or they actually /are/ gone. I thought the RS-Pros and RS-RRs were the same era, with the RS-R being the precursor to both of them.

The RS Pros definitely came about after the RS-RRs, at least partly due to the annoying, whining cacophony caused by the RRs tread pattern.

Yes the RS-R was the very first in that specific series of Federal tires.

 

[Switchback]

So update time!

Spoiler replaced with a Ford OEM aftermarket spoiler kit. Turns out Ford sold the ST Style hatchback spoiler as an aftermarket accessory for the regular Fiestas in Gloss Black. It looks close enough(tm) that I'm not going to bother getting it painted Tuxedo Black, and honestly if I was ever to wrap the car it would look pretty nifty with a slightly different black. Not sure. What I did find really interesting is on the Ford Aftermarket spoilers they have white plastic retention clips that are not used on the factory-installed spoilers. On the FiST the holes in the trunk are actually taped off with some red tape, but the holes are used when mounting the aftermarket spoiler. I think it's to make installation easier, but can't be sure. Won't say no to extra attachment points though!

Went to a junkyard and got all manner of random Fiesta plastics that were bad on the FiST. The wiper was missing the plastic covering for the wiper, an interior window trim piece was just missing, and the rear mirror was deglazing and horrible. After hunting through the local LKQ yard I got a new mirror for $15, Antenna for $7, and plastic trim for $9. Also some Prius electrical components for a project I am not allowed to talk about until it makes its debut at the 24 Hours of Lemons. (Soon.tm)

Exhaust, Timing Belt, Water Pump, Serpentine Belt, Tensioners all completed by my Mechanic. Also did rear spring pad mounts while they had the car. Mechanic said it looked like the timing belt had previously been done (Doh!) but the Crankshaft pulley was a bit mangled so they may not have done a fantastic job. Ended up replacing the Crankshaft Pulley (and the requisite bolt because torque to yield etc etc). All in, $1337.23 including parts, coolant, etc. The labor was 900ish dollars, the Crankshaft Pulley brought the price up but given it was pretty mangled I figured it was worth spending the money. Fun fact, the mechanic also changed the odd-man-out lugnut with something that was closer to the rest of the lugnuts on the car. Outside of it being chrome silver vs black they are all spline lug nuts now! Yay mechanic!

After that, took it out to Julian CA. to put it through some twisties (and also have an excuse to get Apple Pie and Cider). Car performed great overall, a bit of loss of grip on the tires but sorta to be expected from older All Seasons.

Few days ago I tried pulling the Symposer out, however in attempting to undo the clamps one of the posts on the clamp actually sheared off. I didn't do it tonight but eventually I'm likely going to have to remove the whole cold-side intake pipe to get better leverage on ripping the Symposer out. Now that I have a good exhaust I want to yeet that Symposer out and throw it into a fire.

Tonight, I got the car on the lift expecting to do an oil change. Alas, the oil change did not occur (I did rotate tires though so I have that going for me I guess), but I found a few concerning...issues.
- RMM is NOT a Cobb part like the seller told me. It looks like a Boomba RMM, or at least a Boomba style RMM. Sort of makes sense considering the Boomba wing risers.
- The RPF1s are 16x7, not bad but unfortunate I can't run wider tires on it.
- The car has Bilstein B6 Shocks (OEM springs it looks like) on the front only. Not sure why the previous owner (or owner before prev) only swapped out the fronts but ride hight seems the same as stock and drives great still. One note is the rubber that protects the shock is kind of...not there anymore. Don't think it impacts drivability but it doesn't look great. It's nice to have nice shocks though!
- Oil Drain Plug is basically a circle. Looks like whoever did the oil change last gave it to many ugga duggas and it's a mess. Probably going to have to sacrifice a 12mm socket to get it out. Luckily I have a new Whoosh magnetic ready to go so not a huge deal. Annoying but not the end of the world.
- Looks like the turbo oil return line is leaking, at least from my untrained and slightly inebriated mind. Does the turbo return just come out the bottom of the turbo and run to the block just above the oil pan?

After finding the leak I decided to abort the oil change until I can get the oil return line on order to replace it after I drain the oil. Not ideal all things considered but I'm still catching up on preventative maintenance and un-fucking what the prev owner did.

Edit: Oh I forgot to say. Tires are on hold a bit, friend has a hookup at Bridgestone so I may get some discounted Indy 500s, but in the meantime these All Seasons are /ok/ after rotating them.