ok, so heres a stupid question.... I'm looking into a turbo back exhaust. I would really like to get good well known quality stuff thats been proven. I saw a helix (sp) dp... I'm wondering what would happen if i just bought the downpipe for now.... would there be any gain? would it fit up to the stock system? would this cause huge errors? and what is better... a straight pipe or a high flow cat? I was thinking about a helix down, and the spt catback... is this just stupid thinking? I know squat about this kinda thing... so pardon my lack of knowledge
Don't worry, I asked the same type of questions as you since I'm new to my scooby The bigger exhaust piping you have, the more there is an increase in air flow, so you would see a gain. When buying a new DP, from my experience, it depends on what you buy that can hook up to the stock system. Normally, it'll say if it can hook up to the stock system or not. Otherwise, you'll need to do some type of adapting to get eveything to work. I'm currently deciding if I'm going to go with Turboback Exhaust from Cobb or a Turbo XS Stealthback Exhaust. Either way, it'll be replacing all the piping so I don't really have to worry about everything fitting together. You shouldn't get any huge errors unless you or the person who may be doing this for you didn't do everything correctly. You're mainly replacing a pipe and not doing much of anything else As for the straight pipe versus high flow cat, it really depends on you. A straight pipe will allow for better performance because there is no CAT, meaning there is nothing restricting air flow. A high flow CAT restricts air flow a lot less than the stock system, but it's not free flowing. There is still a CAT, so the plus is you wouldn't be spewing emissions everywhere. The scooby is a low emissions car btw. For your last question, no it isn't stupid. I posted a thread awhile ago getting recommendations on a sleeper. Got a lot of good responses and if I get the Turbo XS Stealth Exhuast, it works with the stock muffler. What I give up if I go with the stealth is a few HP, but it doesn't bother me Hopefully that answers all your questions.
Good Advice! Bump for what Sky is talkin about! Since you're in there you might want to consider an up-pipe as well for increased airflow into your turbo allowing the turbo fan to spool up a tad bit faster! ;-) I personnally am using Invidia up-pipe and down-pipe with the SPT cat-back system that's on the STI for my WRX. The Invidia system is 3" exaust while the SPT is only 2 1/2" i believe so you'll have to customize it. I will admit it is a bit of a bear trying to do it yourself unless you have access to tools and a lift, but it depends on how savvy you are! Depending on where you are coming from there are lots of peeps on this site that would help you install with proper tools making it a bit easier. This is my first Subaru and another BUMP goes to Nathan (wrxboy2003) who does excellenct for a great price and owns a Mieneke in Shakopee!!! Just my 2 cents!
is there any welding involved going for the exhaust your looking at and keeping the stock tip? I do like the look of the helix.. but it comes down to effective / proven.... and under the car the only one thats gonna know it's pretty is me. I just don't want to spend a crapload on something that really isn't going to pop my eyes out. I just bought the spt intake ((all arguements are welcome, but it's backed by subaru.... so I trust they know what they are doing more then cobbs bragging... and having cobb NOT backed by subaru)) so having that secondary piece would be nice
When wrxboy2003 did the install for me, he used a 3 to 4 inch gasket which was tapered on both ends to fit inbetween the dp and cat-back. He then used some hardening sealant to keep everything in place and it has been great... No leaks! Worse case scenario you could cut the SPT and weld a flange on the end that would fit your helix dp! Pretty much everything is bolt on and should fit together relatively nicely. At least that was the other option I had... Just some thoughts! Congrats on the car and welcome to the site! Good luck!
Most downpipes will give around the same power gain. It's basically just a hollow pipe. the only ones that'll make a difference would be bellmouth downpipes that tapers off or devorce bellmouth downpipe which seperates the flow between the wastegate and exhaust to a point to smooth out the flow. I was gonna pick up a invidia devorce bellmouth downpipe myself but haven't gotten the $$ to do so yet. here are the differences. this is a regular downpipe. it restricts the flow of the waste gate but it still gives you a pretty good power gain. this is a HKS one but any other brand will look the same if it's of the same design. here is the differences between the bellmouth downpipes. this bellmouth isnt the best design, since it goes from the bellmouth straight into the 3inch pipe so the air isnt traveling smoothly. here is a better design where the bellmouth tapers off into the pipe for a much more smoother flow. any finally, here is the one with the devorce wastegate. which would have the better flow between all the downpipes. i hope this helps in deciding downpipes.... as for exhaust. any 3 inch exhaust will give you the same amount of power gain. all a matter of brand and how long they will last and not rust up. and yes catless is better than cats....there's no emissions here so i'd go catless. there's also a bunch of members here running catless as well.
will any of these pipes be messing up my ecu I guess is the main question. I just don't want to dea lwith future problems because Iwant a little extra.. Oomph
it shouldn't. At the most it'll just give you boost creep but that can be easily tamed by porting the waste gate of the turbo. Matt(bikerboy) can port it for you for a fair price. he has done alot of work on many members of this site who can back up his work. Otherwise, buy a cobb acessport to fix the boost creep.
Yup. Basically the increased exhaust flow is too great to be relieved by the wastegate. So some of that extra flow will still go through the turbine section, causing the turbo to build boost even when the WG is completely open. Tuning can help just a little bit, but this is mainly a mechanical problem.
I thought this car was getting shown at SEMA? if it is, then I wouldn't put a helix exhasut on it, i'd buy the more expensive and showy invidia that its a basic copy of. Don't put budget brands on a show car if you can avoid it. I doubt PPG would prefer a generally ok but knock off exhaust on a show car when you could go with a much slicker one.
NO NO AND NO!.....expecially if its NOT an sti...in fact, if its NOT an sti, (even a 2006 wrx with the 2.5) it wont creep...even some STIs wont creep, i think there are a couple sti guys just running TBE on here
esper - I agree with you on the cheapnes... I was trying to be somewhat original, but I realize prolly what i'm thinking has been done many a time before. the main construction is going to happen in the springtime. I was thinking I wanted to keep it along the lines of the SPT seriese... as it feels like it's staying subaru, but not. I'm trying really hard to not aim at extreme ricer. Effective, adds power, but at the same time not overly grossly in your face. The main focus of course will be on the paint, but SEMA doesn't like to show cars unless they have pretty inards to. Belive it or not I was JUST looking at the nvidia stuff... I just don't want an overly obsurd exhaust like i've seen on some. no need to stick a babys head in there. only thing I've really pickedup so far is the spt intake.... the rest is all unsure.... I thought pre winter i'll get a catback, just so I don't void warrentee in case anything happens this winter. ((or purchase and not install till spring and slap it on with the rest of the stuff.)) so please all advice or ideas welcome.
here is the one I was looking at (store listed just for description)) http://store.mauromotorsports.com/infutuexwr.html
I have a similar set up but with the v3 downpipe and race catback. I can tell you first hand that Invidia has show worthy welds and nice products as long as they don't keep sending you dented mufflers
Totally understand what you mean Skarecrow. I don't want the car to have like some crazy neon color (wtf? pink? ), a muffler that will announce to everyone and their mothers that your coming, and crazy stickers all over it. Besides, most ricer's have cars that look like total crap. It's all about performance and a stylish look What color is your STi right now?
shes a 2006 sti... rally blue now, but this sprint were stripping down the clear, adding bio-mechanical dragons hood to rear panel and layering a deep candy blue over the design.... re clearing it. with a higher quality, stronger clear. Should make the rally blue REALLY sing and give the dragons a ghost apearence. the idea was to then roll with the subaru blue, and move to the engine bay.. do a bunch of blue piping and stuff... hence the main reason I went with the spt intake. Like to keep it as clean / mean looking as possible, all while not getting that awefull ricer look.
