lol slow Posted March 23, 2012 Share Posted March 23, 2012 I cut my mufflers off, car sounds good and all...but someone mentioned something about back pressure. Does me having less back pressure decrease performance? I've been trying to figure this out for a while now. Link to comment Share on other sites More sharing options...
cseagle08 Posted March 23, 2012 Share Posted March 23, 2012 I've heard every possible discussion on this (elsewhere, not on here), and I never could get an absolute answer. I don't think anyone will know for sure without dyno-testing it. Link to comment Share on other sites More sharing options...
lol slow Posted March 23, 2012 Author Share Posted March 23, 2012 my take on it, seems it pulls fine in low end, but dies out on top end, i was getting caught up with by a 2012 STI with ONLY an intake... Link to comment Share on other sites More sharing options...
bnguyenbb6 Posted March 23, 2012 Share Posted March 23, 2012 You need to log to see if there is big change. You are increasing the VE but who knows by how much. NSFW runs a 30r on stock mufflers and it puts down pretty big numbers still. And if anything, decreasing backpressure is better for a turbo car. Link to comment Share on other sites More sharing options...
robinlsb Posted March 23, 2012 Share Posted March 23, 2012 If you have a stock downpipe, you won't gain anything. "Belief does not make truth. Evidence makes truth. And belief does not make evidence." Link to comment Share on other sites More sharing options...
MDKSDMF Posted March 25, 2012 Share Posted March 25, 2012 i would say it doesnt decrease performance because i know of friend that runs his 2010 wrx on stock open downpipe...its not even that loud. not to mention take into consideration the theory behind an electronic cut out etc Link to comment Share on other sites More sharing options...
pillboy Posted March 25, 2012 Share Posted March 25, 2012 Less weight, car accelerates quicker. Cut off other unnecessary parts for more of an effect. It is still ugly. Link to comment Share on other sites More sharing options...
wengermi Posted March 25, 2012 Share Posted March 25, 2012 You just need pressure leading up to the turbo to spool it and it should be fee flowing afterwords. If you have pressure after the turbo the it would slow the turbine down and boost would be lower. Going from stock to stage 2 just makes the car more of a free flowing exhaust after the turbo Link to comment Share on other sites More sharing options...
wengermi Posted March 25, 2012 Share Posted March 25, 2012 my take on it, seems it pulls fine in low end, but dies out on top end, i was getting caught up with by a 2012 STI with ONLY an intake... The sti has a bigger turbo so he has more top end also the gearing and weight affects it too Link to comment Share on other sites More sharing options...
MDKSDMF Posted March 25, 2012 Share Posted March 25, 2012 yep..its all about the gearing. thats why he was reeling u in Link to comment Share on other sites More sharing options...
lol slow Posted March 26, 2012 Author Share Posted March 26, 2012 I gotcha, I was going to do an Invidia N1 racing muffler single exit, but now I'm thinking I might do straight pipes to a quad tip basically like the Q300 or whatever invidia exhaust, no mufflers just straight pipe. Link to comment Share on other sites More sharing options...
FPerron Posted March 29, 2012 Share Posted March 29, 2012 I gotcha, I was going to do an Invidia N1 racing muffler single exit, but now I'm thinking I might do straight pipes to a quad tip basically like the Q300 or whatever invidia exhaust, no mufflers just straight pipe. I ran a single 3" straight pipe all the way to the back. Sounds great and is much lighter than the silly Y-pipe and mufflers. Link to comment Share on other sites More sharing options...
MDKSDMF Posted March 30, 2012 Share Posted March 30, 2012 so u have no y or mufflers? any cops ever tail u and or give u crap for it? Link to comment Share on other sites More sharing options...
tytek Posted March 30, 2012 Share Posted March 30, 2012 my take on it, seems it pulls fine in low end, but dies out on top end, i was getting caught up with by a 2012 STI with ONLY an intake... What idiot put just an intake on an STI?!?! Did he tune for it? At stock power level the stock intake is not a bottleneck. His intake will lean out the mixture like crazy, since the ECU can't compensate for it and will probably contribute to him blowing his engine up doing WOT pulls. Link to comment Share on other sites More sharing options...
FPerron Posted March 30, 2012 Share Posted March 30, 2012 so u have no y or mufflers? any cops ever tail u and or give u crap for it? Only until they see it's a senior citizen behind the wheel:lol: Link to comment Share on other sites More sharing options...
FUIAAE Posted March 30, 2012 Share Posted March 30, 2012 Didnt read anyone elses posts but here's the low down on backpressure. Exhaust pressure is BAD Exhaust velocity is GOOD High velocity does create pressure, but it's not the pressure you're seeking it's the velocity! Cutting off the mufflers will decrease the resistance in your exhaust system, but in order to make use of it you'll need to "redesign" your exhaust system. The most important exhaust parts are the header-runners, once you hit the cat go as big as you want because the scavenging effect is done at that point and you just want to get rid of the exhaust asap. Link to comment Share on other sites More sharing options...
MDKSDMF Posted March 30, 2012 Share Posted March 30, 2012 Only until they see it's a senior citizen behind the wheel:lol: nice! hahaha i like how the legacy draws the more mature non ricey crowd.. Link to comment Share on other sites More sharing options...
Max Capacity Posted March 30, 2012 Share Posted March 30, 2012 You just need pressure leading up to the turbo to spool it and it should be fee flowing afterwords. If you have pressure after the turbo the it would slow the turbine down and boost would be lower. Going from stock to stage 2 just makes the car more of a free flowing exhaust after the turbo Well at least someone has it right. I guess these guy's have never had a turbo charged race car. 305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD). CHECK your oil, these cars use it. Engine Build - Click Here Link to comment Share on other sites More sharing options...
lol slow Posted April 3, 2012 Author Share Posted April 3, 2012 thanks for all the comments, I currently do have it off, I've gotten one ticket, and that was an accident I tried to catch a light right by a cop, otherwise if I shift low and keep it calm which I do a lot now since my coils, no issues at all. I am a tool, so you know how that goes... one thing I hate it, how it looks with no tips yet bumper cut outs. http://a6.sphotos.ak.fbcdn.net/hphotos-ak-prn1/s720x720/541010_426872610663070_100000210044220_1917337_121881854_n.jpg I'll get something figured out eventually. Link to comment Share on other sites More sharing options...
authenticamd Posted April 3, 2012 Share Posted April 3, 2012 Are you really a tool? Link to comment Share on other sites More sharing options...
FPerron Posted April 3, 2012 Share Posted April 3, 2012 thanks for all the comments, I currently do have it off, I've gotten one ticket, and that was an accident I tried to catch a light right by a cop, otherwise if I shift low and keep it calm which I do a lot now since my coils, no issues at all. I am a tool, so you know how that goes... one thing I hate it, how it looks with no tips yet bumper cut outs. http://a6.sphotos.ak.fbcdn.net/hphotos-ak-prn1/s720x720/541010_426872610663070_100000210044220_1917337_121881854_n.jpg I'll get something figured out eventually. You miss the bogus dual exhaust tips? If the Legacy had a real dual exhaust, I could see keeping the original look. Before I ran a single big pipe out the back, I used to cringe everytime I looked at my fake dual exhaust. However, don't you get exhaust gass sucked up into the driver's compartment? Link to comment Share on other sites More sharing options...
halwith Posted April 3, 2012 Share Posted April 3, 2012 lol nice video. good pictures of your license plate also. why dont you just sent the state police the fine money now and save them the minimal effort it will take to find out who you are. Link to comment Share on other sites More sharing options...
lol slow Posted April 4, 2012 Author Share Posted April 4, 2012 go ahead they can find me, considering the video was recorded in Mexico, I don't care. Plus don't pay attention to what it was, just the sound. Anyways, no smell or anything, it's cut off by rear axle. Fake or not, it looked filled and "meant to be there" you know? Link to comment Share on other sites More sharing options...
praedet Posted April 4, 2012 Share Posted April 4, 2012 go ahead they can find me, considering the video was recorded in Mexico, I don't care. Plus don't pay attention to what it was, just the sound. Anyways, no smell or anything, it's cut off by rear axle. Fake or not, it looked filled and "meant to be there" you know?Didn't realize Mexico had interstates exactly like ours... One more time and you are out of here... Link to comment Share on other sites More sharing options...
lol slow Posted April 4, 2012 Author Share Posted April 4, 2012 they do, i swear. But alright, understood. Link to comment Share on other sites More sharing options...
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