New Magnaflow 2-into-1 3" Hi-Flow cat with 2.5" exhaust system installed

VAP · 08-13-2003, 05:10 AM

This pic is of the old sytem removed, new rear O2 sensors routed and new exhaust ready to be installed.

The new system is fabricated from all mandrel bent aluminized steel tubing. Mandrel U-bends were purchased and cut to size so that every joint is a welded slip-fit "male-into-female joints from front to rear. All cuts were smoothed internally with a die-grinder before being welded. I opted to not use stainless initially as if it didn't work I didn't want to have to cut it all out and toss it.

VAP · 08-13-2003, 05:20 AM

Here's the new cat with the 2-into-1 collector sleeve installed. Also the 3"-to-2.5" outlet cone that was pressed from the same die I use for making velocity stacks.

Took over 3 hours just to get this part test-fitted and made as there was a ton of clearance and alignment issues to deal with.

VAP · 08-13-2003, 05:24 AM

The new cat being held in place by a muffler stand while SS flex joints are installed and everything aligned just before removing once more, installing dual O2 sensor bungs and welding it all into place.

scott12v@pghaudi · 08-13-2003, 05:29 AM

I'm going to have TDL redo mine (the original Vortrag system has alot of leaks and never was really right). And I'm probably going 2.5" (I've found that PA roads and hills are not very forgiving with a 3" system).

However, looking through the Magnaflow website, I haven't found a single rear muffler with tips that has a 2.5" inlet. I just started my search yesterday, but I would have thought that a rear muffler with 2.5" inlet and dual tips would be pretty common.

Thanks,
Scott

VAP · 08-13-2003, 05:38 AM

The system fully installed. I opted for a small muffler instead of a true resonator as I've heard all the stories on how loud the Magnaflow components are. And even with dual mufflers and 2.5" pipe it's still too loud for my tastes but only by a little. When I fabricated the system I provided for a straight-thru resonator to live just aft of the cat by putting an extra joint in which I could cut out later and replace with the resonator if it was too loud. I'll get back to that in a few days.

Driving impressions: Louder of course and I forgot to tighten the O2 sensors before driving away so I'll be on my back under each side of the car this morning doing that.

And somethings just not quite right torque-wise. It's slower to climb to redline in spite of being a far freer flowing and less restrictive system. I have a constant CEL due to my EGR valve "insufficient flow" code so I don't know if I threw any other codes with the installation due to the perpetual CEL from that. I'll pull codes this morning see if there's anything obvious or if the computer simply needs to be reset. I only have 3.7 miles on it driving from the muffler shop home. Today I should be able to clear it all up other than the loudness issue and see what I've really done/created be it silk purse or sow's ear.

VAP · 08-13-2003, 05:42 AM

I'll get a pic up of the tips later today

scott12v@pghaudi · 08-13-2003, 05:45 AM

This is exactly what I want, but the online magnaflow catalog doesn't have a listing for this muffler with a 2.5" inlet.

scott12v@pghaudi · 08-13-2003, 05:46 AM

I never thought about going with a single cat like that.

VAP · 08-13-2003, 05:49 AM

available. Maybe Magnaflow's website hasn't been updated in awhile.

Mr.D-'97 A4q 12v · 08-13-2003, 05:54 AM

are pretty strict. Great job BTW! I never even thought about adding a resonator in combination with the two mufflers to quiet it down more. I may consider that.

08-13-2003, 05:20 AM	#2
VAP AudiWorld Super User Garage is empty, add now Join Date: Mar 2000 Posts: 13,990	Pic 2: Here's the new cat with the 2-into-1 collector sleeve installed. Also the 3"-to-2.5" outlet cone that was pressed from the same die I use for making velocity stacks. Took over 3 hours just to get this part test-fitted and made as there was a ton of clearance and alignment issues to deal with.

08-13-2003, 05:24 AM	#3
VAP AudiWorld Super User Garage is empty, add now Join Date: Mar 2000 Posts: 13,990	Pic 3: The new cat being held in place by a muffler stand while SS flex joints are installed and everything aligned just before removing once more, installing dual O2 sensor bungs and welding it all into place.

08-13-2003, 05:29 AM	#4
scott12v@pghaudi AudiWorld Super User Garage is empty, add now Join Date: Jul 2000 Posts: 6,513	What rear muffler are you going to use? I'm going to have TDL redo mine (the original Vortrag system has alot of leaks and never was really right). And I'm probably going 2.5" (I've found that PA roads and hills are not very forgiving with a 3" system). However, looking through the Magnaflow website, I haven't found a single rear muffler with tips that has a 2.5" inlet. I just started my search yesterday, but I would have thought that a rear muffler with 2.5" inlet and dual tips would be pretty common. Thanks, Scott

08-13-2003, 05:38 AM	#5
VAP AudiWorld Super User Garage is empty, add now Join Date: Mar 2000 Posts: 13,990	Pic 4: The system fully installed. I opted for a small muffler instead of a true resonator as I've heard all the stories on how loud the Magnaflow components are. And even with dual mufflers and 2.5" pipe it's still too loud for my tastes but only by a little. When I fabricated the system I provided for a straight-thru resonator to live just aft of the cat by putting an extra joint in which I could cut out later and replace with the resonator if it was too loud. I'll get back to that in a few days. Driving impressions: Louder of course and I forgot to tighten the O2 sensors before driving away so I'll be on my back under each side of the car this morning doing that. And somethings just not quite right torque-wise. It's slower to climb to redline in spite of being a far freer flowing and less restrictive system. I have a constant CEL due to my EGR valve "insufficient flow" code so I don't know if I threw any other codes with the installation due to the perpetual CEL from that. I'll pull codes this morning see if there's anything obvious or if the computer simply needs to be reset. I only have 3.7 miles on it driving from the muffler shop home. Today I should be able to clear it all up other than the loudness issue and see what I've really done/created be it silk purse or sow's ear.

08-13-2003, 05:42 AM	#6
VAP AudiWorld Super User Garage is empty, add now Join Date: Mar 2000 Posts: 13,990	Magnaflow single 2.5" inlet with dual 3"x2.5" angle-cut, oval, rolled outlet tips. I'll get a pic up of the tips later today

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08-13-2003, 05:45 AM	#7
scott12v@pghaudi AudiWorld Super User Garage is empty, add now Join Date: Jul 2000 Posts: 6,513	Does it look like this one? This is exactly what I want, but the online magnaflow catalog doesn't have a listing for this muffler with a 2.5" inlet.

08-13-2003, 05:46 AM	#8
scott12v@pghaudi AudiWorld Super User Garage is empty, add now Join Date: Jul 2000 Posts: 6,513	Nice job BTW. I never thought about going with a single cat like that.

08-13-2003, 05:49 AM	#9
VAP AudiWorld Super User Garage is empty, add now Join Date: Mar 2000 Posts: 13,990	thats EXACTLY the one. And I found it in-stock locally with a 2.5" inlet so it's definately.... available. Maybe Magnaflow's website hasn't been updated in awhile.

08-13-2003, 05:54 AM	#10
Mr.D-'97 A4q 12v Member Garage is empty, add now Join Date: Jun 2002 Posts: 8,112	Do you think going with a single cat vs. dual cats will have any affect on emissions? MD standards are pretty strict. Great job BTW! I never even thought about adding a resonator in combination with the two mufflers to quiet it down more. I may consider that. __________________ ***** '05 Boxster S (Speed Yellow) '97 A4 2.8Q 12V (Cactus Green) Mods? I got 'em. Baltimore, MD

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08-13-2003, 05:54 AM
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