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#1
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backpressure
I think I've gone too low in backpressure with all my exhaust mods. Can anybody tell me how I can raise it a little bit temporarily to see if mileage/power seem to increase? I just want a temporary test solution...like sticking a potato in one tail pipe
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Time for my very own long list of mods: 92 SVX LS-L - Ebony Pearl - 2002 WRX 5MT trans w/STi gearset (rebuilt & installed myself ) - BMW E46 HID retrofit - Kenwood Headunit - Phoenix Gold 75x4 RMS amp - Alpine Type R 6.5" front components - Alpine Type R 6x9 3way rear speakers - 18"x9" Rota G-Force wheels w/225/40ZR18 Toyo T1R's - Mychailo's custom springs - Urethane front & rear sway bar bushings - KC exhaust (2.5" dual magnaflow) - Escaine seat swap - Removed Spoiler I don't care if Subaru says it's STI...it will always be STi to me |
#2
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Re: backpressure
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Harvey.
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One Arm Bloke. Tell it like it is! 95 Lsi. Bordeaux Pearl, Aust. RHD.149,000Kls Subaru BBS wheels. 97 Liberty GX Auto sedan. 320,000Kls. 04 Liberty 30R Auto Premium. 92.000kls. |
#3
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hmm backpressure.....dont you mean scavenging?
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~Phil Teal 1992 Subaru SVX Turbo - Sold in May 2011 to peace-frog. |
#4
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Some backpressure is actually necessary for low-end torque. Open exhausts make high-end HP at the expense of low-end torque. You either need a good compromise or a power valve, like some motorcycles.
CJ |
#5
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Like a Vulture!
Yea I mean scavenging. It's related to backpressure and exhaust flow, so I just called it backpressure. Anyway, I have the 2.5" cat back pipes from the KC kit with 2 magnaflow mufflers. That alone should reduce backpressure. I also made the mistake of cutting out the first 2 cats and replacing with straight pipe. The guy at Midas told me one was cracked and falling apart, so I decided to just get rid of both before they damaged the third one. So, I think there may be a problem because I have a mad buzzing noise (probably a leak...I'll explore that when I have a chance to get the car up), but I also seem to have lost low end power. I have also dropped in gas mileage by 1-2MPG city and 5-6MPG highway. Finally, the check engine light comes on often. Usually it comes on after I've driven for a while and stop for just a few minutes (gas, grocery store), and restart. The light usually goes off, but sometimes it remains on. Also, probably unrelated to the exhaust, I have a problem with hesitation and stumbling when the car is cold. So, there's a whole lot of info to work with. Can you tell me what's wrong, Doc?
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Time for my very own long list of mods: 92 SVX LS-L - Ebony Pearl - 2002 WRX 5MT trans w/STi gearset (rebuilt & installed myself ) - BMW E46 HID retrofit - Kenwood Headunit - Phoenix Gold 75x4 RMS amp - Alpine Type R 6.5" front components - Alpine Type R 6x9 3way rear speakers - 18"x9" Rota G-Force wheels w/225/40ZR18 Toyo T1R's - Mychailo's custom springs - Urethane front & rear sway bar bushings - KC exhaust (2.5" dual magnaflow) - Escaine seat swap - Removed Spoiler I don't care if Subaru says it's STI...it will always be STi to me |
#6
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Re: Like a Vulture!
Ask your ECU what's wrong.
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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! |
#7
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ah dun did!
I axed the ECU what was wrong, and the ECU dun said Knock Sensor #?. The same Knock Sensor that has been replaced. So, I don' trust that thar ECU. I shuud, but I don' cuz I don' wanna re-replace mah Knock Sensor.
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Time for my very own long list of mods: 92 SVX LS-L - Ebony Pearl - 2002 WRX 5MT trans w/STi gearset (rebuilt & installed myself ) - BMW E46 HID retrofit - Kenwood Headunit - Phoenix Gold 75x4 RMS amp - Alpine Type R 6.5" front components - Alpine Type R 6x9 3way rear speakers - 18"x9" Rota G-Force wheels w/225/40ZR18 Toyo T1R's - Mychailo's custom springs - Urethane front & rear sway bar bushings - KC exhaust (2.5" dual magnaflow) - Escaine seat swap - Removed Spoiler I don't care if Subaru says it's STI...it will always be STi to me |
#8
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hmmmm welll thatr mad buzzing sound is fro mreomving the cats/resinators....install a 14" straight through resinator before the mufflers..or two smaller ones where youtook out thecats.....this will get rid of your buzzing sound as long as tou dont have a bad gasket somehwere...
speaking from experience on this subject, phil
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~Phil Teal 1992 Subaru SVX Turbo - Sold in May 2011 to peace-frog. |
#9
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interesting
Hmmm, sounds interesting. What kind of buzz was it. Mine is there only from about 2000-5000 rpm...was yours like that. I'd gladly put resonators where the cats were cut, but I wanna make sure its the same kind of buzz as you had. I'll also try the gasket thing firts too, cuz that costs alot less. Also, how do I pick a resonator...don't some make your exhaust sound like a$$? Do you know why this buzzing occurs when you don't have cats?
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Time for my very own long list of mods: 92 SVX LS-L - Ebony Pearl - 2002 WRX 5MT trans w/STi gearset (rebuilt & installed myself ) - BMW E46 HID retrofit - Kenwood Headunit - Phoenix Gold 75x4 RMS amp - Alpine Type R 6.5" front components - Alpine Type R 6x9 3way rear speakers - 18"x9" Rota G-Force wheels w/225/40ZR18 Toyo T1R's - Mychailo's custom springs - Urethane front & rear sway bar bushings - KC exhaust (2.5" dual magnaflow) - Escaine seat swap - Removed Spoiler I don't care if Subaru says it's STI...it will always be STi to me |
#10
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buzzing occurs due to severe resonation, and the fact that without any sort of resontaors nothing is there to catch the the exhuast that" doubles back" in the piping......you need to get a STRAIGHT THROUGH resonator, not a glass pack., A straight through resonators has little pockets to catche the air from doubling back and keep if flowing correctly, which is is succeeded in the stock exhuast system by the beeds in the cat and the primary/sec muffler to an extent, maybe not directly speaking, will keep resination to a minimum. Ever here a honda "fart" thats becuase honda owners have no clue what they are doing and install a canister and remove the chambered resinator becuase they feel it is restrictive. They dont however know that a straight through resinator is not restrictive, especially on a NA car. You get it between certain RPM's becuase the wavelength is resinating at that range......ya physics!!....anyways im not completly accuareate on this....but as much as needed. IM me at BIGDHILLL if you want to talk about it further.... But i spent alot of trial and error getting the exhuast system on my last SVX to growl and not fart or blurb...ask svxboy about it....it was mean....
phil
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~Phil Teal 1992 Subaru SVX Turbo - Sold in May 2011 to peace-frog. |
#11
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Re: Like a Vulture!
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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. |
#12
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Re: Re: Like a Vulture!
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Like my wifes car, Kim's car is faster than Matts!
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Down to none |
#13
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I should have known you'd pounce on that one
Todd: 2 Matt: 1 I'll be watching...
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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. |
#14
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Game ON!
Bring it brother!
Todd (fat old non-threatening white guy trying to sound tuff)
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Down to none |
#15
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Re: Re: Like a Vulture!
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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. |
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