Fiesta STH

The urge to bolt go-fast stuff on my car is too strong to ignore any longer, so I will be documenting my build of a basic STH-class Fiesta ST here.  I am going to add all of the stuff the kids add to their turbo hot-hatches these days, just what the STH class was created for.  The one thing that I won't be able to do is cram 265-width tires under there, so I have no hope against the WRX, Focus ST and R32. I don't care, I just want to have fun and make it more awesome for back-road driving and all-around fun.  

First up is a limited slip, and I am letting a transmission shop handle that. (Hey, I know my limitations).  They did a friend's FIST and he has more power than me and has had zero issues. I chose the Quaife LSD from Mountune. I figure if Ford trusts it, then its good enough for me.  Ford engineering has been spot-on for this car so far, and they made the Quaife LSD stock on the new Fiesta, so there must be something to it.  I have read all about the pros and cons of this style of LSD as it applies to autocross and the street, and I am comfortable with it.  Lifting a front wheel can be an issue, but I have shocks, sway bars, and camber that I can play with to address it if it becomes a problem.  More on that later. 

Should be back in a few days, I will add my driving impressions then.  Can't wait to start bolting on more stuff! 

I have resisted the urge to modify my FiST thus far. It is very hard to resist. LSD is at the top of my list of wants. I will be following along closely. Looking forward to your build!

I find these cars really cool, and they sound great with the right exhaust system on them. While I haven't had the chance to drive one myself, it's one of the cars that will be up for consideration when I start looking for something a bit more fuel efficient to handle my commute that is going to double in length soon.

lifting the front wheel should a non issue if you don't touch the stock e diff electronics. they should in theory grab the brake of the lifted spinning wheel and it would start forcing torque to the opposite wheel. and as a fwd car, you shouldn't have a front wheel lift issue, if you do, you've got other setup issues. 

Good luck with the build man! I keep talking with Mazdadeuce about doing the same thing to my focus... i may join you... we'll see. 

In reply to spacecadet :

Wouldnt the theory be that if youre tracking the car, you hit a curb, left front wheel goes airborne for a second, diff unloads with no traction on the wheel and diff becomes "useless". This is why they tell you to stab the pedal if you feel like a wheel came off the ground.

I know this doesnt apply to autocross but i figure that the why they list it in the literature. The e-diff in my FiST is absolutely abhorrent about applying itself at the correct moment and seems to have a delay that only exacerbates the problem with the car not having a proper mechanical limited slip diff. I have an MFactory LSD ready to go in and am waiting on Ford for some clutch parts but it always interested me to see how the e-diff logic was programmed and if the car could be faster with an updated electronic e-diff in line with the proper mechanical unit installed.

To OP, the fattest tire i have run so far is a 205/50R15 Federal. They run as wide as a 225 BFG Sport Comp 2 but are much softer. I have also run a 205/40R17 Azenis, 205/40R17 Riken and a 215/40R17 Hankook. The stickiest so far has felt like the 205 Azenis but i havent had but one run on the Federals. Hoping to see how well they do this season versus the 17" sizes. The 15's feel so much different than the 17" in terms of turn in and the overall grip feels just as good if not a bit better than the 17" tires.

I have read all that I can find about the diff and the ESC system. Engineers from Ford and from Bosch have weighed in and say that the torque vectoring, which cannot be turned off, actually compliments the Quaife LSD.  If you should lift a tire, the system will brake that wheel, and it happens rapidly enough to prevent the diff from going open.  This is partly the reason that it is standard on the new Fiesta, which, if Ford weren't complete buttheads they would bring to the US and same me the trouble. But I digress. 

If I run up a curb at a track night and it kills power for a bit, I am not going to worry about it.   If it happens during spirited driving on the Tail of the Dragon, again, I am not going for a trophy so I won't sweat it.  The only time I AM concerned about it at the autocross course.  I often am running tight courses with off-camber turns and traction out of a slow corner is something I am hoping to improve. 

At this point, I am unclear what I need to do to ensure that the car is ideally set up for this situation.  I have a bigger front bar I can use, I can increase negative camber, I can lower and stiffen the springs, and run adjustable Konis.  That is A LOT to play with.  According to the internet, running a front bar is the worst thing you can do in a FWD car.  And the best.  And you need a huge front bar.  And you need a smaller front bar.  And pivot point braces.  And you should switch to a Miata instead.  What I do know is that suspension engineering is complex and my brain is simple. 

My plan is to bolt on everything that I have, then play with settings. With the bigger front bar on, I can remove an end link at a test n tune to see both extremes.   If a bigger front bar is not the answer, I can always go back to the OEM bar, or no bar.

Maximize front grip within the rules, then tune to car to turn. Different cars need different recipes for #1 so they also need different answers for #2. I do think you're headed down the right path with the quaife. 

Picked the car up at lunch, minor sticker shock at the installation cost, but I am paying for peace of mind that the job was done right and that's worth a little extra to me. Initial impressions are...none. It was raining and I drove home on a congested highway so no real opportunity to test things out. It made no new noises, didn't drive funny, business as usual for normal driving.  Relief. 

Car finally made it into the garage. 

Lots of stuff gets removed to install the Cobb Intake.  

Lots of junk under the cowl, going to do some cleaning before reassembly

New intake is in place with no blood or busted knuckles. Next up, FMIC. 

Do the Fiestas have the grill shutters like the focus?

spacecadet said:

Do the Fiestas have the grill shutters like the focus?

No. Just a 1.6L that sips gas as long as you stay out of the pedal.

Got the front end off, but the new intercooler is still in transit. Found a lot of broken plastic bits from hitting cones and a collision with a jet ski, so I will be investigating the best adhesive to put it back together again. 

Oh, and the intercooler was just hanging, the mounts popped out who knows how long ago. 

The front end of the FIESTA ST is one big piece of plastic.  (Or ABS or whatever). One one side, there is this little tab. On the other side: 

And on this side, there is a mounting point: 

One the opposite side, not so much:

 It certainly looks like they were glued to the fascia and not molded as an Integral part. They seem to be a harder plastic than the fascia.  The good news is that I have the parts that snapped off, and it’s inside where no one can see it so I can scuff it up and use what are ever color adhesive I want.  I can even add reinforcements, but I’m hoping to avoid rivets.

I’m going to see if I can find some of these suggestions locally.

Got the new intercooler finally (2 weeks to deliver, the storms must really be messing  with UPS ground).  A nice unit from Whoosh Motorsports, much heavier than OEM, and no installation instructions at all. Who does that?  Had to fit and refit several times to get it right. But it should be an improvement over stock and it fits without any trimming or modifications, important for STH. 

Was just checking the rulebook.... the Tib would go into STS which means no diff.

Tib?  The Fiesta skips STS and goes to STH, where the LSD is OK.  The FMIC is cool, provided you don't cut or remove to install it, or replace piping to it. 

pinchvalve said:

Tib?  The Fiesta skips STS and goes to STH, where the LSD is OK.  The FMIC is cool, provided you don't cut or remove to install it, or replace piping to it. 

I believe he's referring to the 1.0 Ecoboost Fiesta. which is stuck in STS. 

spacecadet said:

pinchvalve said:

Tib?  The Fiesta skips STS and goes to STH, where the LSD is OK.  The FMIC is cool, provided you don't cut or remove to install it, or replace piping to it. 

I believe he's referring to the 1.0 Ecoboost Fiesta. which is stuck in STS. 

No I was referring to the newly aquired old Hyundai pile. An LSD would pop it to mod or prepared/slicks class. I've driven enough peg-legged Korean cars to know I won't do it again on an open diff. 

Ah, I see. 

Got her all buttoned up again. The panel gaps to the fenders look like an 80’s Yugo, Not sure why because everything went back together nicely. May have to pull the headlights and play with it some more. But for now, it’s time for a test drive. 

With snow tires on cold roads, it easily spins the tires through 4th gear. Once the weather improves a bit, I will drop it an inch, add braided brake lines and maybe even wax her. 

Looking good.  Looking forward to a warm weather review.

Decided not to wait because schedules fill up fast. Got her in the air and pulled the wheels.

Not too much tread left, looks like new snow tires are on the budget for next winter. 

Pulled the cowl again to make access to the strut tops easier. HUGE wasted space in there, might be a good spot for a secret nitrous bottle. 

New Swift R springs.  The rears are easy, have to wait to borrow a compressor to do the fronts this weekend. 

Surprised the lowering springs needed a compressor, or maybe you needed one to get the old ones off.  Looking forward to results.  Have you thought about alignment settings you are targeting?

84FSP said:

Surprised the lowering springs needed a compressor, or maybe you needed one to get the old ones off.  Looking forward to results.  Have you thought about alignment settings you are targeting?

Getting the old ones out safely is my concern.  For alignment, I am going to set the camber as negative as I can, with a little toe out. I will have to see where it all lines up, I have a before readout as a reference.