Exhaust - Downpipes - JHM B6-B7 S4 4.2L by FI
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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NOTE: THESE DOWNPIPES WILL ONLY SHIP VIA GROUND REGARDLESS OF SHIPPING OPTION CHOSEN, FROM MANUFACTURER.
Off-road use ONLY: THIS PRODUCT IS FOR RACING COMPETITION ONLY AND IS NOT LEGAL FOR USE IN HIGHWAY OR STREET VEHICLES OR OTHER NON-RACING COMPETITION OFF-ROAD VEHICLES. BY PURCHASING THIS PRODUCT YOU ACKNOWLEDGE ITS INTENDED USE.
|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|
- 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. (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!
-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, ......... (Posted on 5/18/2010)
Warning: This product may contain a chemical known to the State of California to cause cancer, birth defects, or other reproductive harm.
Learn More: www.p65warnings.ca.gov