Stock Air Box mod questions

[dyn085]

If I'm correct in my thinking the ECU is expecting a certain fixed tolerance of an amount of air. It's not metered as a MAF equipped vehicle would be. So if that volume of air is exceeded on an untuned vehicle I imagine it would go into limp mode.

However, that's all speculation and I could be wrong.

No, not really. Worst-case scenario on cutting your box would most likely be poor fuel economy, and that may not even be the case. A FI system is going to get the air it needs and will bleed the rest off, so there really is no 'too much air' scenario. I haven't looked to see if there are dyno charts associated with the box butchering, but I can't see anything occurring outside of the possibility of increased response and the addition of noise.

The first thing I would recommend if someone hasn't already would be to figure out the cost of the OEM box. I did this to my Mk3 Focus and it destroyed my in-town mileage and then cost ~$150 to replace. It's a totally different application obviously so I can't speak to what actual dyno-results are or could be, but that experience has taught me to think long and hard before having up OEM pieces.

 

[re-rx7]

Is that ? foot or ? inch? Did you happen to take any photos?

How about performance (any?) and/or intake BPV noise?

I'm considering doing the airbox mod combined with a Mountune hose...

1/2'' sorry. I did a drop in Cobb filter as well and the car felt a little more peppy down low. The BOV or "whoosh" is louder and audible in the car with the radio down and windows up. Driving around town with windows down it is decently loud.

 

[Wez1987]

Im gonna installe the K&N filter witch just replaces the factor one u guys think will make a differents ?

 

[Hypntick]

To chime in, I cut the bottom 1/2 inch off of mine as well. Noticebly louder, a little better pick up down low as well. As for fuel economy, no noticeble change at all.

 

[Wez1987]

And if i dont cut it off is there any different or is it just the same

 

[Wez1987]

Because u see the car is still actaully warrenty so cutting the air box is abit difficult 2 do at this point of time

 

[BlueBomber]

1/2'' sorry. I did a drop in Cobb filter as well and the car felt a little more peppy down low. The BOV or "whoosh" is louder and audible in the car with the radio down and windows up. Driving around town with windows down it is decently loud.

This is a safe amount of trimming for the airbox without overdoing it.


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WEZ, to answer your questions, as best I can understand (I know you're from SA so english may be tough for you)

Installing a K&N filter element or Cobb Filter element or Green Filter Element alone, into the OEM Air Cleaner housing, will make very little difference. There is minimal change in noise or performance.

Modifying the airbox is surprisingly easy. You can EASILY remove the airbox by just disconnecting the sensor harness, disconnect air intake hose, disconnect front air scoop connection, remove screw in front, then pull UP and filter housing comes right out. You can then modify it easily off the car.

I have modified my airbox and it has not affected my warranty at all. Your warranty may be different as you're in a different country. I would STRONGLY suggest looking at how SEKRED has modified his airbox, as like you, his Fiesta ST is NOT a United States model. USA model Fiesta ST and Global Fiesta ST have different air metering systems, so not all intake upgrades work the same between USA and globally. For example, you cannot use an INJEN intake.

 

[re-rx7]

This is a safe amount of trimming for the airbox without overdoing it.


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WEZ, to answer your questions, as best I can understand (I know you're from SA so english may be tough for you)

Installing a K&N filter element or Cobb Filter element or Green Filter Element alone, into the OEM Air Cleaner housing, will make very little difference. There is minimal change in noise or performance.

Modifying the airbox is surprisingly easy. You can EASILY remove the airbox by just disconnecting the sensor harness, disconnect air intake hose, disconnect front air scoop connection, remove screw in front, then pull UP and filter housing comes right out. You can then modify it easily off the car.

I have modified my airbox and it has not affected my warranty at all. Your warranty may be different as you're in a different country. I would STRONGLY suggest looking at how SEKRED has modified his airbox, as like you, his Fiesta ST is NOT a United States model. USA model Fiesta ST and Global Fiesta ST have different air metering systems, so not all intake upgrades work the same between USA and globally. For example, you cannot use an INJEN intake.

This dude always says what I'm going too lol! Great post

 

[BlueBomber]

This dude always says what I'm going too lol! Great post

That's what I'm here for, good information.

Oh, and cos I keep mentioning it... SEKRED's SEKTUNE intake

http://www.fiestastforum.com/forum/threads/399-Sektune-Cold-Air-Intake

My mod is VERY similar.

 

[Sekred]

Oh dear, I'm blushing

 

[Wez1987]

Haha ok thanx i understand that typ of English im gonna try it ,got somthing in mind thow ..and i no about the injen kits that wouldnt work actaully shit because that kit looks real good ..

 

[BlueBomber]

Haha ok thanx i understand that typ of English im gonna try it ,got somthing in mind thow ..and i no about the injen kits that wouldnt work actaully shit because that kit looks real good ..

Not 100% sure I understand you. Yes, the Injen intake looks good. Unfortunately it doesn't work for overseas (non USA) fiesta STs. "MAP" vs "Speed Density" for how the engine computer calculates how much fuel, spark, etc.

If you are concerned with your Warranty, I would suggest fitting a MOUNTUNE intake system. This will run great and should be 100% Ford warranty compliant. The MOUNTUNE intake system was originally engineered to work with European Fiesta ST models so this should be fine for South Africa.

There seem to be a LOT of Fiesta ST's from South Africa.

 

[Wez1987]

Lol Yes alot of guys like the fiesta st this side of the world ..can u give me that website of Mountune intake

 

[Wez1987]

There such a lot of St this side but the mods are sooooo limited hey thats shit

 

[rodmoe]

Mountune dot com
http://www.mountune.com/index.php/services/performance-upgrades

 

[Wez1987]

Great stuff thanx

 

[rodmoe]

Glad Blue and I could help get you sorted

 

[Wez1987]

Finally got my drop in K&N so will give it a try

 

[Wez1987]

 

[Wez1987]