[AdrianBrewster]

out of curiosity, would it be totally wasted to install an intake and a catback exhaust without putting a tune on the car? The idea of changing boost levels and having ford deny a warranty claim kind of bothers me since I'm a broke college student. I had an exhaust and intake on my old wrx without a tune and I still gained some performance. What are your thoughts?

 

[RodMoe]

Save your money for a tune all else is not going to pay off as much as a tune and once tuned all the other mods work better.. then get light weight wheels and sticky tires and have fun..

 

[PeteBrace]

Need a tune before an intake if it is a euro car as it brings on the EMU light. Took much air apparently.

Not sure if US cars have this problem.

 

[Dyn085]

US models don't have the problem, but we don't see gains from an intake or CBE either.

 

[djdennehy]

I have a Green Industries pod filter and the FSWerks 2.5 inch exhuast, and I have seen a few horsepower gain but nothing too exciting or even noticeable. SCCA rules don't let us do anything more than this, but frankly the note of the engine is much more enjoyable and I am glad I added the exhaust to the car. She has the proper sound now.

 

[eRic]

also has a Green Filter Air filter and FSWERKS Sport Exhaust system and autocrosses in the Street category. There are gains without a tune.

 

[ISO100]

The reason you won't gain much even though you've added quality mods to the car is due to ECU tuning strategy. Unlike ECU's of yesteryear, the one in our Fiesta ST uses estimated torque targets. What this means is that for various gears and loads the ECU targets a number like 230ft/lbs and once the car is able to make that power, it stays there. Without a revised ECU map that raises this torque limit the engine never even tries to create more torque.

So, there are gains to be made but once you hit those predefined torque targets with your mods, you will not get any more power. You may get to those limits faster or sooner in the RPM range, but you can never go beyond them. A revised tune is the only way.

 

[Methane Herder]

The reason you won't gain much even though you've added quality mods to the car is due to ECU tuning strategy. Unlike ECU's of yesteryear, the one in our Fiesta ST uses estimated torque targets. What this means is that for various gears and loads the ECU targets a number like 230ft/lbs and once the car is able to make that power, it stays there. Without a revised ECU map that raises this torque limit the engine never even tries to create more torque.

So, there are gains to be made but once you hit those predefined torque targets with your mods, you will not get any more power. You may get to those limits faster or sooner in the RPM range, but you can never go beyond them. A revised tune is the only way.

Yup! The last bit is the most you can plan on.
I had been noticing a loss in peak boost. 26k miles, the air filter looked good but I decided to to put a new Wix AF in. I noticed an immediate improvement in throttle tip in and peak boost is back in the 21, 22 psig range.
MH