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#1
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My New Custom Exhaust SUCKS ...suggestions
well I removed the pre cats, went into a Y-pipe into a single mangnaflow hi-flow cat. From there it goes into a new resonator and then just the stock muffler.
Sounds good, nice and quiet BUT at 3.5k and higher there's a tinny resonating sound coming from the Y section! WTF!!!! Is it too restrictive? Also, it feels like the car has less power now which is NOT good. I think I just wasted money on these new exhaust parts and pipe bends/install. I just don't get why the noise is coming from the Y section ...the piping is fairly big too. The inlets to the Y are = to stock (I think slightly bigger) and the outlet of the Y is = to the stock piping that goes back to the muffler. Should I ditch the Y pipe and get a 2-inlet, 1 out cat and use that as the Y? I'd just hate to buy another cat only to find out that was a waste too. What did all you guys do?
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Mike - Proud owner of a Pearl 92 SVX LS-L 5MT with 78k miles and climbing 5-Speed Status: DONE! Lambo Door Status: On hold but will be a success 04 WRX 5MT, STi Short Throw Shifter, Group N tranny mounts, AZA Z-2 18x7.5 Rims, slotted/cross drilled rotors, stainless steel lines, 35/20% window tint, ecu bead crush, power mode button; 7" In-dash touch screen LCD, mobile computer, voice recognition, alpine PXA-H701 DSP, 2 JBL amps, focal speakers all around, 5 farad cap, and fiberglassed subs in the trunk. The Mobile Computer Interface - featuring the SVX | My Locker | My Secret Stash Last edited by rmjjensen; 02-04-2006 at 11:49 AM. |
#2
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Many people have problems with that same buzzing you speak of. I would suggest a 2 into 1 cat in the first place but I am not sure it will solve the issue. If you were gonna modify the exhaust that far why not go with a magnaflow muffler also??
Tom |
#3
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Sorry it didn't work out. I had a Y into a hi-flow cat to my stebro and it was terrible. I removed the pre-cats and had a huge loss in low end torque and the sound was annoying. I got a used stock set of down pipes with pre cats and it fixed it. I think the SVX likes it's pre-cats to much to let them go without complaining. There are some threads about it and I'm sure someone can explain it a little better as far as reflecting sound waves and low pressures areas goes. Good Luck
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"The things you own end up owning you. It's only after you lose everything that you're free to do anything." 92 Pearl White Ls-l (138k) Euro Headlights & Blinkers, 97 Grill, Euro Tail Lights, SS Brake Lines, Stebro Exhaust, Slotted Rotors, Classic Registration 96 Legacy Outback (206k) 5-speed 2.2 Lightweight Crank Pulley, Group N Trans & Motor Mounts SOLD Wanted: Steering Wheel |
#4
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Stebro
Another vote for Stebro. Pricey and pain to deal with sometimes, but well engineered and in some cases saves money from the trial and error systems installed.
Lee
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SVXx2 92 SVX LS-L Silver 92 SVX LS-L Burgundy (structurally challenged with 2792 miles) 96 SVX LSi Red 92 SVX LS Pearl (Parts) 01 F150 4X4 Red (+6 with other members of the family) FREEDOM IS NOT FREE |
#5
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I had the y pipe setup with no cats but recently ditched it for a 2 into 1 cat and it sounds and feels much better now.
The stebro is only a catback.
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Matt Locker Link 2015 BRZ Limited 6MT 92 Ebony LS-L ECUtune Stage2av1, Z32 MAF, 370cc injectors, TomsSVX intake, BontragerWorks 22mm RSB #003, HID Hi and Lo beams, OT endlink and bushing mods, PWR Aluminum radiator, Harvey's QC shift kit, 2.5" flowmaster 80 exhaust, 17" Michelin Pilot Sport A/S, Poly sway bar bushings, Slotted Bradi rotors, AFBeefcake powdercoated calipers, 97 grill, and a huge set of air horns. 300,000 miles and counting 92 Ebony LS-L. ecutune stage1v4, motorsport 1pc pulley. Garage Queen - sold to Dad in upstate NY 155,000 miles 19 Subaru Ascent Premium - -Hers !. 89 DL 4x4 little red wagon - a.k.a. The immortal suby. 275k R.I.P. |
#6
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Yep, there's definitely a "buzz" once you remove the front cats. You might want to consider the "fix" that Mychailo came up with...
-Bill
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Retired NASA Rocket Scientist Most famous NASA "Child" - OSIRIS-REx delivered samples from asteroid BENNU to Earth in Sept. 2023 Center Network Member #989 '92 Fully caged, 5 speed, waiting for its fully built EG33 '92 "Test Mule", 4:44 Auto, JDM 4:44 Rear Diff with Mech LSD, Tuned headers, Full one-off suspension '92(?) Laguna, 6 spd and other stuff (still at OT's place) My Locker |
#7
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The tinny sound is caused by a constructive resonance the builds between the left and right side cylinder banks. A sonic wave is emitted from a cylinder on one side when an exhaust valve opens. The sound wave travels down to the primary pipe to the y-pipe, reflects at the y-pipe and goes down to the other side of the engine. It hits an exhaust valve and reflects back down the primary pipe just as that exhaust valve opens. This results in a constructive interference. The process then repeats and the sound wave keeps building in intensity. It only happens at a characteristic rpm. The ways to fix it are to add damping (resonators in the primary pipes), stop the reflection from occuring where the primaries join into the single main pipe, or by making the primary pipes different lengths. The 2-into-1 cat does a pretty decent job of stopping the reflection from occuring at the primary-to-main pipe junction. Moving the junction further back lowers the rpm where the resonance occurs. If you are using a 2-into-1 cat, moving it further back will also improve low end torque.
If you feel like dumping more money into your exhaust, switch out that y-pipe for a 2-into-1 Magnaflow cat and put it in the location of the factory resonator. Then put a couple of resonators in the primary pipes before the cat. It will sound sweet and should have better low end torque.
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Mychailo :: 2006 Silver Mitsubishi Evolution 9, E85, 34 psi peak, 425wtq/505whp DJ :: 1995 Laguna Blue SVX L AWD 5MT (sold) Visit my locker SVX Mods: ND iridium spark plugs, Impreza RS fpr, afr tuned to 13.2:1 using a custom MAF bypass, custom exhaust, WRX 5MT w/ STi RA 1st-4th gear & stock WRX 5th gear, Exedy 13 lb flywheel & Sport Clutch, STi Group N tranny & engine mounts, urethane spacers in rear subframe, rear diff mounts, and pitch stopper, SVX Sport Strut Springs (185f/150r), custom 19 mm rear swaybar, urethane swaybar mounts, Rota Torque 17x8", 225/45-17 Proxes 4 tires, Axxis Deluxe Plus organic brake pads. |
#8
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That would be a good solution.
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. Earl .... ... .... ><SVX(*> Subaru Ambassador [COLOR=”silver”]1992 Tri Color L[/COLOR] ~45K (06/91) #2430 1992 Dark Teal LS-L ~184K (05/91) #0739 1992 Claret LS-L ~196K (05/91) #0831 1992 Pearl LS-L ~103K (06/91) #1680 1992 Pearl LS-L ~151K (06/91) #2229 1992 Dark Teal LS ~150K (07/91) #3098 (parts car) 1992 White LS-L ~139K (08/92) #6913 1993 25th AE ~98K (02/93) #164 1993 25th AE ~58K (02/93) #176 1993 25th AE ~107K (02/93) #215 1993 25th AE ~162K (02/93) #223 1994 Laguna Blue Pearl LSi ~124K (1/94) #2408 1994 Laguna Blue Pearl LSi ~144K (10/93) #1484 1994 Laguna Blue Pearl LSi ~68K (10/93) #1525 1994 Barcelona Red LSi ~46K (02/94) #2624 1994 Pearl LSi ~41K (12/93) #1961 1995 Bordeaux Pearl LSi ~70K (02/95) #855 1996 Polo Green LSi ~95K (03/96) #872 1997 Bordeaux Pearl LSi ~55K (08/96) #097 2003 Brilliant Red LS1 Convertible ~29K (04/03) #8951 1999 Magnetic Red LS1 Coupe ~33K (04/99) #6420 My Email | Old Locker | New Locker | Picture of 15 of the 19 |
#9
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I think mbtoloczk has a good solution. This is what I was planning on doing and for the same reason.
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-Mike ECUTune2v7 - 4.11 5 Speed - Sprung 6 Puck Clutch - D&S Rotors - SS Brake & Clutch Lines - HKS Panel Filter - HeaderBack Exhaust -80GB Hard Drive - GroupN Engine Mounts - - some other "tricks"
[SIGPIC][/SIGPIC] In progess: track down mystery noise <-identified, paint the new dash, get better pic Spring plans: Replace Trans - Integrate ECU with the carputer - Suspension - Go back to STI Filter - Paint? Maybe not - Next Oil change: Purolator L30165 Member #995 | My Locker | My New Locker Catch you next at: ? Auto-X ? |
#10
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Thanks Mr. Wizard, I will put that on my to-do list
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Subyluver '92 Subaru SVX Ebony 216k miles (Magnaflow Custom Cat-Back, ES Stablizer Bushings, Permacool Relocator, 2.5RS FPR, SS Brake Lines, EBC Green Pads, Raceconcepts D/S Rotors, Pirelli P-Zero Nero M&S) (To-do list Koni Struts & Springs lacking funds) |
#11
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Thanks for all the replies.
I guess what I will wind up doing is moving the resonator and cat as close to the muffler as I can and then put two more resonators before the cat in place (one for each bank). Oh and replace the cat with a 2-1 cat What a pain though. As a temporary solution maybe I'll put the pre cats back in. I think there was nothing wrong with them - it was the stock 2-1 cat that was leaking and the stock resonator that was buzzing. That's kinda what pisses me off - tried making it better and it didn't work. Thanks again!! And aren't resonators restrictive? What would be better - the stock precats or resonators?
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Mike - Proud owner of a Pearl 92 SVX LS-L 5MT with 78k miles and climbing 5-Speed Status: DONE! Lambo Door Status: On hold but will be a success 04 WRX 5MT, STi Short Throw Shifter, Group N tranny mounts, AZA Z-2 18x7.5 Rims, slotted/cross drilled rotors, stainless steel lines, 35/20% window tint, ecu bead crush, power mode button; 7" In-dash touch screen LCD, mobile computer, voice recognition, alpine PXA-H701 DSP, 2 JBL amps, focal speakers all around, 5 farad cap, and fiberglassed subs in the trunk. The Mobile Computer Interface - featuring the SVX | My Locker | My Secret Stash |
#12
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By resonator, I just meant a straight through tube muffler with a perforated inner tube like the ones sold by Magnaflow and Vibrant racing. I don't like the louvered style ones that are so popular at Summit Racing.
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Mychailo :: 2006 Silver Mitsubishi Evolution 9, E85, 34 psi peak, 425wtq/505whp DJ :: 1995 Laguna Blue SVX L AWD 5MT (sold) Visit my locker SVX Mods: ND iridium spark plugs, Impreza RS fpr, afr tuned to 13.2:1 using a custom MAF bypass, custom exhaust, WRX 5MT w/ STi RA 1st-4th gear & stock WRX 5th gear, Exedy 13 lb flywheel & Sport Clutch, STi Group N tranny & engine mounts, urethane spacers in rear subframe, rear diff mounts, and pitch stopper, SVX Sport Strut Springs (185f/150r), custom 19 mm rear swaybar, urethane swaybar mounts, Rota Torque 17x8", 225/45-17 Proxes 4 tires, Axxis Deluxe Plus organic brake pads. |
#13
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Quote:
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Mike.... 8/96......Vin 100109 1997 LSI,18 inch Axis wheel(summer),16 inch ALT wheels(winter),Trans temp/Volt gauges,Iridium plug's, Autotechnica intake,silverstar high/low and fogs,polyurethane sway bar bushing's front and rear,Smallcar shift kit,Stebro exhaust finally..SWEET!! Motorsports drilled/slotted rotor's front and rear with ceramic pads and SS brake lines. 1997 SUS Legacy,finally got the engine in after a year!! My Locker www.myspace.com/devilhornz |
#14
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Resonator
Stebro also has a Euro Resonator that fits in place of the 3d cat if you are not concerned with emissions or a dummy oxygen sensor for an OBDII car (96-97). It would flow more air than their free flow cat.
Lee
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SVXx2 92 SVX LS-L Silver 92 SVX LS-L Burgundy (structurally challenged with 2792 miles) 96 SVX LSi Red 92 SVX LS Pearl (Parts) 01 F150 4X4 Red (+6 with other members of the family) FREEDOM IS NOT FREE |
#15
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I think you 2 are referring to the same piece.
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David B. SVXipedia @ SVX-IW.COM -- SVX Information Warehouse 2.0 coming...eventually! Ebony 1992 SVX LS-L 5 spd Koni/GC Stebro 187k miles RIP (Rust In Pieces) 1993 SVX 5 spd Koni/GC Stebro Polyurethane bushings still available! |
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