Fiesta ST Mods

[ScaR]

I was just wondering for the ford fiesta. Are the best mods for that car COBB? I would like to know what are the best mods for the ford fiesta St in regards of performance. I also don't if for the fiesta engine is only limited to 300 hp or if it can handle more.

 

[Capri to ST]

I was just wondering for the ford fiesta. Are the best mods for that car COBB? I would like to know what are the best mods for the ford fiesta St in regards of performance. I also don't if for the fiesta engine is only limited to 300 hp or if it can handle more.

Mountune makes high quality aftermarket parts for the car, they generally fit and perform well, and there are many other options besides that for tunes .
From reports on here, it appears that the car can handle up to about 300 horsepower reliably. After that, it may be pushing it a bit too far.
Here's a helpful analysis which looks at different specific areas of the car, and how much increased power it thinks they can handle. Their goal was doubling the power to 400 horsepower. It has been a while since I read the article, but if I recall correctly I believe that they concluded that most of the parts of the engine could handle it, with the connecting rods being least likely to be able to handle that much extra power-
https://dsportmag.com/the-tech/ford-ecoboost-1-6l-analysis-turbocharged-direct-injection-ccvtc/

 

[ScaR]

So Technically Mountune would most likely be the best way to go to get the best performance for the Fiesta ST.
https://dsportmag.com/the-tech/ford-ecoboost-1-6l-analysis-turbocharged-direct-injection-ccvtc

 

[Capri to ST]

So Technically Mountune would most likely be the best way to go to get the best performance for the Fiesta ST.
https://dsportmag.com/the-tech/ford-ecoboost-1-6l-analysis-turbocharged-direct-injection-ccvtc

I think they make some of the best hard parts. I got their MP215 tune because it preserved the warranty, and was a simple and set it and forget tune, I didn't want to do data logging. As I said, there are lots of other good options for tunes. I did find their customer service to not be so great, it was hard to get anybody on the phone, but it's been a couple years since I've dealt with them so I don't know if it's better now.
Before you start changing everything, just know that the car is pretty damn good stock, a lot of thought was put into it by some very competent engineers, and they did a really good job.For that reason, I have been conservative with mods on the car.
When and if you start changing things, if you have driven it stock or relatively stock for a while, then you will have a good basis for comparison as to whether the mod is really an improvement or not. Also, if you do a whole bunch of things at one time, it's hard to tell what effect each individual change has made.

 

[Dialcaliper]

As far as performance goes, the factory setup is already pretty good. There are gains to be had and a few econobox defects to rectify.

I think the best “low hanging fruit” engine mods are a flash tune, intercooler and ST200/Mountune Airbox.

For tunes, the Mountune MP215 is decent in conjunction with the Airbox if you want a well sorted drop in mild upgrade. But if you want to go farther, picking up a regular Accessport and aftermarket tune - Dizzy, Stratified and Tune+ are favorites here. I’m on the Dizzy stage 2 and really happy with it. Stratified is good, but only if you like hair-trigger throttle response with limited modulation which I didn’t like.

If you ever drive the car hard and not just the occasional gun it on the on-ramp. You’ll want to look into an upgraded radiator. The stock one is inadequate even for the factory tune.

Good tires are a must. Downsizing to 16” or even 15” with slightly less skinny sidewalls will give you a lighter combo and better ride quality ,as well as a slightly better performance Summer tire selection.

The stock suspension is decent, but Bilstein B6, or if you want to lower the car, B8+Swift springs are popular, but lowering is not beneficial in this car because of suspension geometry (basically it’s only cosmetic) - Ford already lowered the Fiesta as much as they could for performance improvement. Sway bars are worth considering if you want to change the handling balance, but the car already has a very mild liftoff oversteer from the factory.

Other bolt-on engine mods (intake/exhaust) offer fairly minimal gains unless you are looking at turbo upgrades. E30 mixing is another big gain if you have E85 available, but can be a slight hassle unless you don’t mind that sort of thing.

If you really want to upgrade more, the stock turbo is the limiting factor. A hybrid (like the Whoosh Hybrid or S280) will get you to 250-300 whp which the stock motor should handle. Above 300 hp you’ll start to run into issues with fueling and eventually be looking at built motor territory. There are upgrades to the stock fuel system, but the DI system is not really adequate to run full E85. Aux port fuel injection is another workaround.

Dizzy put together a really good typical power upgrade “progression” that’s still pretty valid:

https://dizzytuning.com/blogs/technical-documents/the-ultimate-guide-to-modding-your-fiesta-st

 

[ScaR]

thank you for all this information. I’m going to save the this source to then come back when I get the car. I first plan on working on the body then doing mods for the car. I have heard it’s a lot of fun. My previous car was a WRX. But I’m trying to find another fun car like the WRX.

 

[Dpro]

thank you for all this information. I’m going to save the this source to then come back when I get the car. I first plan on working on the body then doing mods for the car. I have heard it’s a lot of fun. My previous car was a WRX. But I’m trying to find another fun car like the WRX.

Do suspension mods first , followed by power leave anything body for the last. As your suspension and power mods could dictate body mod decisions.
For instance if you lower the car more you may decide that putting a front splitter was pretty much a bad idea as it will scrape over speed bumps and driveway entrances all day long unless you live i. the land of no speed bump or practice going up driveways at an angle.
Also most aftermarket splitters for the car offer no functional differences over stock. Most track guys pulled custom ones that are huge!
Same deal with wing risers may look cool in your eyes actually adds drag to to the vehicle which it really does not need. Our rear wings stock are cosmetic the openings in them were not designed aerodynamically to work. Actually sealing up the slots in the rear wing reduces drag on the car. Ya we have tested this out with flow strips .
Basically there are not many body mods for our car . Ya you flare it for wider wheels but then you get into much lower offsets to fill the flares which on our cars has a big effect on turn in. Most track guys try to stuff as much tire as they can under stock wheel wells to keep from resorting to really low offsets for that reason it seems. Oh and doing flares with lower-offset wheels starts costing as well . Great looks for show car impractical for fun daily driving.

 

[FiestaSTdude]

Be careful with wing risers, they will cause your wing to break.

As far as performance goes, the factory setup is already pretty good. There are gains to be had and a few econobox defects to rectify.

I think the best “low hanging fruit” engine mods are a flash tune, intercooler and ST200/Mountune Airbox.

For tunes, the Mountune MP215 is decent in conjunction with the Airbox if you want a well sorted drop in mild upgrade. But if you want to go farther, picking up a regular Accessport and aftermarket tune - Dizzy, Stratified and Tune+ are favorites here. I’m on the Dizzy stage 2 and really happy with it. Stratified is good, but only if you like hair-trigger throttle response with limited modulation which I didn’t like.

If you ever drive the car hard and not just the occasional gun it on the on-ramp. You’ll want to look into an upgraded radiator. The stock one is inadequate even for the factory tune.

Good tires are a must. Downsizing to 16” or even 15” with slightly less skinny sidewalls will give you a lighter combo and better ride quality ,as well as a slightly better performance Summer tire selection.

The stock suspension is decent, but Bilstein B6, or if you want to lower the car, B8+Swift springs are popular, but lowering is not beneficial in this car because of suspension geometry (basically it’s only cosmetic) - Ford already lowered the Fiesta as much as they could for performance improvement. Sway bars are worth considering if you want to change the handling balance, but the car already has a very mild liftoff oversteer from the factory.

Other bolt-on engine mods (intake/exhaust) offer fairly minimal gains unless you are looking at turbo upgrades. E30 mixing is another big gain if you have E85 available, but can be a slight hassle unless you don’t mind that sort of thing.

If you really want to upgrade more, the stock turbo is the limiting factor. A hybrid (like the Whoosh Hybrid or S280) will get you to 250-300 whp which the stock motor should handle. Above 300 hp you’ll start to run into issues with fueling and eventually be looking at built motor territory. There are upgrades to the stock fuel system, but the DI system is not really adequate to run full E85. Aux port fuel injection is another workaround.

Dizzy put together a really good typical power upgrade “progression” that’s still pretty valid:

https://dizzytuning.com/blogs/technical-documents/the-ultimate-guide-to-modding-your-fiesta-st

Yes, totally agree with @Dialcaliper. An accessport is expensive but it’s a good spot to start imo. You mentioned wanting to make you car like a rally car, so I would definitely recommend downsizing your wheels as well. I have 16inch wheels with UHP all seasons and 15inch wheels with snow tires that are my gravel tires.

 

[ScaR]

Well what I wanted to do is get like a rally build. So I actually wanted to pick up the car a bit like how a rally car looks. Then buy the parts from M-sport

 

[Dialcaliper]

Well what I wanted to do is get like a rally build. So I actually wanted to pick up the car a bit like how a rally car looks. Then buy the parts from M-sport

Tooting my own horn a little, but if you want some stiffer spring rates without lowering the car, I’ve come up with a neat little custom spring solution that is a definite handling improvement, using stock struts, or better yet Bilstein B6’s (or something like a Koni). No coilovers required.

https://www.fiestastforum.com/threa...-rally-springs-for-stock-b6-suspension.30829/

If you bump the rates to 250/225 instead of 225/200 it will add another 0.25” of lift F/R if that’s your thing, but I wouldn’t go that stiff without upgrading the struts unless you dig the “Honda Bounce”

Looking at the Dizzy list, I realized I left out the other supporting mods - upgrade the Rear motor mount to reduce torque-steer/wheel hop, and unless ground clearance is an issue, look into a lower 2-point (or more) front brace.

 

[M-Sport fan]

Well what I wanted to do is get like a rally build. So I actually wanted to pick up the car a bit like how a rally car looks. Then buy the parts from M-sport

Which parts from M-Sport?

There is very little we can use from them, and still remain street legal here in the states.

Also, they are almost exclusively dealing with the Mk8 Fiesta currently, so the stock of their Mk7 (our) Fiesta parts is rapidly dwindling at this point.

Eventually, they will probably be forced to use the Puma over there, even for the lower, lesser power, 2WD FIA rally classes, once Ford totally gives up on even the Euro/rest of world Fiestas.

 

[M-Sport fan]

and unless ground clearance is an issue, look into a lower 2-point (or more) front brace.

Even on relatively smooth SCCA RallyCross courses, all of the currently available, off the shelf, tubular front lower 2-point braces WILL become a ground clearance issue.
Also, if ScaR is able to find an off the shelf skid plate for his car, they definitely will not clear those braces without major tweaking, or a custom built plate.