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Exhaust - Downpipes - JHM B6-B7 S4 4.2L by FI


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JHM Stainless Steel Downpipes are MADE TO ORDER products built by Fast Intentions.


These Downpipes fit Sedans, Avants, and Cabriolets


Why did JHM decide to sell Fast Intentions Downpipes instead of making their own? Well after we went 12.97 @ 109.1mph in the quarter mile (fastest all motor time) with a car we tuned with a Fast Intentions cat back and downpipes we knew they built high quality products. We also wanted to have an option for those who didn't want to step up to JHM Longtube Headers but still wanted a little more performance potential than a piggie style downpipe.


Why 2.5" piping diameter? After much testing and calculations based on the 4.2L 40v V8 engine's demands it is the optimal size. With a 2.25" exhaust or smaller you leave yourself no room to grow with more mods. We have also found with a 2.5" downpipe torque is not sacrificed and the top end gains and the room for growth far outweigh going with a limiting 2.25" cat back.


Includes: Both 2.5" stainless steel downpipes with flanges, high quality flex couplers, mid pipes and all hardware necessary.


-Automatic or Manual Transmssions: Specify with the drop down box below your transmission
-With or Without Cats: You can have these downpipes made with 300-cell, high-flow, race cats. Select your choice from the dropdown box below.
-Cat Back Connection: If you have a full 2.5" cat back that is not necked down select the dual 2.5" connection. There is only a $25 charge to pay for our cost on the larger clamp. If you have a stock cat back or a necked down cat back then select necked down. NOTE: If you have a dual 2.5" cat back and it is necked down, it hurts perfromance. You should get the full 2.5" and then have a local muffler shop or fab shop modify the end of the cat back to be a full 2.5" so you do not restrict these downpipes.


NOTE: Like ALL aftermarket catalytic converters these downpipes are technically not legal in the state of California and other states (check your state laws for details). In California ONLY stock catalytic converters are technically smog legal. All others are not since the DO NOT have a CARB E.O. number.


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This product fits the following vehicles:
Make Model Chassis Engine
Audi S4 B6 (2003-2005) 4.2l V8 40v
Audi S4 B7 (2005.5-2009) 4.2l V8 40v
Audi allroad C5 (2001-2005) 4.2l V8 40v
Customer Reviews (3)
Can confirm what Dirk said
Still NA, so my experience only matches Dirk’s at the moment. Quiet at mid 2500-ish rpm is key to peace with the neighbors. Not like they don’t hear me coming or going, though! They definitely help the motor breathe better. Excellent quality. Install wasn’t bad, no gasket needed between downpipes and stock header. I got my DPs coated before installation, and that had helped reduce engine bay temperatures considerably. Review by Zolli (Posted on 11/29/2021)
I purchased the JHM supercharger kit, Cat back, Downpipes, Trio and more.
My car finally feels like how it should have been built from the beginning. The visceral connection is hard to describe, the power is extraordinary, the shifting is incredible, the exhaust note is so sublime I keep turning off the radio just so I can hear it better. I am now dreaming of a built motor. You are the best!


Review by Mark (Posted on 11/1/2013)
Installed downpipes with cat together with FI exhaust (resonated). System has excellent sound at low rpm, low and aggressive, but well rounded. At sustained mid rpm, system runs fairly quiet, but as soon as you push the pedal, the aggresive sounds returns.
Noticed immediately increased acceleration throughout the entire rpm range and better throttle response.
I would recommend the system to anybody who is looking for better sound, better performance, yet wants to remain friends with neighbors. But when you are out of the neighborhood, .........
Review by Dirk (Posted on 5/18/2010)
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You're reviewing: Exhaust - Downpipes - JHM B6-B7 S4 4.2L by FI
Off-road Use

By Purchasing any Off-Road use ONLY products from JH Motorsports, Inc. I acknowledge and understand the following disclosure. (This notice is located at the bottom of the page description of affected products on our website.)

Vehicle Code § 27156:
(b) No person shall operate or leave standing upon a highway a motor vehicle that is required to be equipped with a motor vehicle pollution control device under Part 5 (commencing with Section 43000) of Division 26 of the Health and Safety Code or any other certified motor vehicle pollution control device required by any other state law or any rule or regulation adopted pursuant to that law, or required to be equipped with a motor vehicle pollution control device pursuant to the National Emission Standards Act (42 U.S.C. Secs. 7521 to 7550, inclusive) and the standards and regulations adopted pursuant to that federal act, unless the motor vehicle is equipped with the required motor vehicle pollution control device that is correctly installed and in operating condition. No person shall disconnect, modify, or alter any such required device.
(c) No person shall install, sell, offer for sale, or advertise any device, apparatus, or mechanism intended for use with, or as a part of, a required motor vehicle pollution control device or system that alters or modifies the original design or performance of the motor vehicle pollution control device or system.

Health and Safety Code § 43000:
43001. The provisions of this part shall not apply to:
(a) Racing vehicles.

As the aforementioned code sections outline, it is against the law to operate or use a vehicle on public streets or highways with modified, altered, or disconnected motor vehicle pollution control devices. This may include but is not limited to, Evaporative Fuel Controls, Catalysts, DPF, PTOX, PCV Systems, Exhaust Gas Recirculation Systems, Oxygen Sensors, Thermostatic Air Cleaners, Air Intake Systems, Fuel Injectors, Regulators, Adjustable Cam Gears, ECU Programming, Mapping, or other Computer Modifications. Air Pumps, Air Injection, Timing, and any other Emission System Modification(s).

Purchaser acknowledges and certifies to JH Motorsports Inc., that Purchasers vehicle will only be used for racing applications or off road vehicle use only. Purchaser requests these modifications for the purpose of enhancing the vehicle for competitive Racing Applications and will not use this vehicle on public streets or highways. Purchaser agrees to indemnify JH Motorsports Inc., all employees, officers, owners, and subsidiaries for any civil or criminal liability arising out of use of Purchasers vehicle on public streets or highways as Purchaser has been duly notified of the laws and regulations regarding disconnecting, alteration, or modification of a vehicle’s pollution control devices. Purchaser understands and has been advised the driving of a vehicle on public streets or highways could result in criminal or civil penalties.

Prop 65

Warning: This product may contain a chemical known to the State of California to cause cancer, birth defects, or other reproductive harm.

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Q and A

Product Questions

Will these down pipes work with millitek exhaust b6 s4
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