Flowmaster American Thunder Cat-back for the 2014 - 2017 Ford Fiesta ST - Part # 817784YouTube Button

Cat-Back 409S - American Thunder Kit - SOR - Moderate/Aggressive Sound

American Thunder Kit

PART# 817784

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$644.95   Suggested Retail
$579.95   Your Price
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Fits 2014-2017 Ford Fiesta ST Models with 1.6L Turbo Engine.


Flowmaster's American Thunder Cat-back exhaust system for the 2014-2017 Ford Fiesta ST with the 1.6L engine is perfect for the person looking for an aggressive exterior sound level with all of the performance benefits that you would expect from Flowmaster. This bolt-on 409S stainless steel system features single 2.50 inch mandrel-bent tubing and an Outlaw series muffler paired with a resonator for maximum power and exterior sound quality, but with a moderate and pleasant interior tone at cruising speeds. Other features include a polished 3.00 inch dual exhaust tip. This system includes all necessary parts, hardware and instructions for an easy installation.


  • Flowmaster Reliability
  • Dyno-Tuned for Maximum Performance
  • Bright 409S Stainless Steel Construction
  • Moderate/Aggressive Sound


California Proposition 65 Chemical NameChromium (hexavalent compounds)
Nickel (Metallic)
California Proposition 65 RequiredYes
Catalytic Converter IncludedNo
Emission Code5
Exhaust SeriesAmerican Thunder
Exit PositionSOR
Heat ShieldNo
Mount TypeUses Factory Hangers
Muffler Body Length (in)6.5
Muffler ColorBlack
Muffler FinishPaint
Muffler Inlet Diameter (in)2.5
Muffler Inlet LocationCenter
Muffler Material409S Stainless Steel
Muffler Outlet Diameter (in)2.5
Muffler Outlet LocationCenter
Muffler Overall Length (in)25
Muffler Part NumberKit Only
Muffler Quantity1
Muffler SeriesOutlaw
Muffler ShapeRound
Muffler TypeReflection
Product TypeExhayst Systems / Kits
Single DualSingle
Sound LevelModerate/Aggressive
System TypeCat-back
Tip CutAngle
Tip Diameter (in)3
Tip Edge StyleCut
Tip FinishPolished
Tip Length (in)10
Tip LogoEmbossed
Tip Material304 Stainless
Tip Quantity1
Tip ShapeRound
Tip StyleDouble Wall
Tubing Diameter (in)2.5
Tubing Material409S Stainless Steel
Part Number817784


This part is legal for sale or use on Emissions Controlled Vehicles, Uncontrolled (Non-Emissions Controlled) Vehicles, and Racing Use Only Vehicles because it does not affect vehicle emissions and is not covered by emissions regulations.

Tech Resources

Fits 2014-2017 Ford Fiesta ST Models with 1.6L Turbo Engine.



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    Some parts are not legal for use in California or other states with similar regulations.