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This thread is designed for "newbies" to ask questions or find answers. To ask a question, just post a reply to this thread and ask the question. When someone answers your question(s) the question and answer will be copied to the first post to make finding answers easier.

Before you post a reply and ask a question, please review the very first post (the one you're reading now) and see if the answer to your question is already here!


------ QUESTIONS & ANSWERS ------


Q: What is a Cobb Accessport?

A:
An AccessPORT (known as AP) is a device that costs roughly $600 and flashes new maps (rewrites software on your car's ECU (computer)) to improve perfomance. In VERY basic terms, the AP makes your ECU tell the car to create more boost, which in turn, creates more power.

Q: What is Stage 2? etc.

A:
Stage 1 is JUST the AP by itself; no other mods necessary. This is good for roughly 15-17 whp.

Stage 2 is the AP combined with a Turboback exhaust. This is good for roughly 40 whp (or an additional 20-25 whp over Stage 1).

Q: What is a protune?

A:
A protune is when a professional tunes your car. This can be done using various software/devices, but a "protune" is most commonly done using an EcuTek or the AccessPORT. In the case of the AP, the pro tuner will make a special map (the software file the ECU reads) that is designed specifically for your car. This is good for roughly 20 additional whp over the "off-the-shelf" stage 2 AP map (assuming all you have is a Turboback Exhaust (TBE)).

Q: What is WHP?

A:
WHP -- WHP is wheel horsepower, or "actual" horsepower after all drivetrain loss. While the STI has 300 HP, this is engine or crank HP, not wheel HP. Depending on the dyno, a stock STI has anywhere from 200-240 whp (approximately). Generally when talking about mods you express the increase in horsepower in WHP, as anyone that tells you a mod makes X HP at the crank is usually estimating.

Q: What is a Turboback Exhaust (TBE)?

A:
A Turboback exhaust is a downpipe(3) + a catback exhaust(4) (or simply and exhaust that goes from the turbo all the way back).

Q: What is a downpipe?

A:
A downpipe is a pipe that starts at the exhaust end of the turbo and goes from the engine bay down to the bottom of the car, meeting up with the center-pipe.

Q: What is a catback exhaust (CBE)?

A:
A catback exhaust is an exhaust consisting of a center-pipe (or mid-pipe), a catalytic converter (cat), and a muffler (or tail pipe).

Q: Is there a diagram of the complete exhaust system?

A:



In the diagram above, the first piece is the downpipe. Next is the catylitic converter, however, this piece is commonly combined with the downpipe and is actually 1 piece. The third piece is the center-pipe (or mid-pipe) and finally there is the muffler (or tailpipe or axle-back exhaust).

Q: What is a wastegate?

A:
The wastegate is a device that helps control the amount of boost the turbo creates. When the wastegate opens, boost is released. Any modification to the wastegate can cause serious problems, but the most common are:

1) using a different spring which makes the wastegate harder to open. This will cause the wastegate to open later and result in the turbo holding more boost. This is generally NOT recommended. If you want more boost, get an AccessPORT and do it safely.

2) "porting" the wastegate which makes the wastegate hole bigger and makes it easier for boost to escape. This is also generally NOT recommended but is used to solve problems in the rare case that are car is producing too much boost and there is no other way to control it.

Q: If I have an SPT catback, and want to jump to Stage 2, all I need now is just a downpipe & accessport flash, right? (my confusion comes from stating that the cat is sometimes combined with the dp, but then stated that it's part of the catback too).

A:
The short answer to your question is YES. All you need is a downpipe and an AccessPORT flash to go Stage 2. As to your confusion, there are actually two catalytic converters on the STI. One is part of the downpipe, and the other is part of the midpipe. When we say "catback" exhaust, we mean coming after the cat in the downpipe, and as evilsti7 said, it should really be called a "downpipe back" exhaust.
 

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Discussion Starter · #2 ·
The first question came from someone in a different thread:

hoagie79 said:
I'm a relatively new STi owner, had one for about 6 months but haven't started thinking about mods until now. And, I'm not ashamed to say, as I've been looking through some of these threads I have no idea what a lot of these modifications are. You guys use so many abbreviations and initials, that even that commonly-used-intitials thread doesn't completely clear things up. So....I'd like to propose a dictionary of mods presented kindergarten-style, like we're learning our ABC's for the first time, just that it's STi kindergarten. Please, don't provide definitions of things that just make them more confusing, just simple like: "a transmission transfers power from the engine to the wheels," as if we have absolutely no clue. And other newbies who are as confused as I am--I know you're out there--please don't be afraid to ask as well. It seems like the people on this forum are more than happy to help. So, I'll start off with a few ques.:

What is a Cobb Accessport? Stage 2?, etc., etc.
What's a Protune?
What are the downpipe and wastegate and how are these parts modded and how do these mods help with power/performance?

Thanks everyone!:)
 

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...if I have an SPT catback, and want to jump to Stage 2, all I need now is just a downpipe & accessport flash, right? (my confusion comes from stating that the cat is sometimes combined with the dp, but then stated that it's part of the catback too).
 

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unrequited said:
...if I have an SPT catback, and want to jump to Stage 2, all I need now is just a downpipe & accessport flash, right? (my confusion comes from stating that the cat is sometimes combined with the dp, but then stated that it's part of the catback too).
yes. all you really need to run stage 2 is a downpipe, but running a turbo back exhaust (which is made up of a downpipe and a cat back exhaust) is fine too.

cat back is kind of misleading. almost every aftermarket sti downpipe ive seen has the cat placed pretty close to the turbo. so technically a cat back exhaust should be called a downpipe back exhaust, but they've been called cat back forever, so no one is going to change that.
 

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unrequited said:
...if I have an SPT catback, and want to jump to Stage 2, all I need now is just a downpipe & accessport flash, right? (my confusion comes from stating that the cat is sometimes combined with the dp, but then stated that it's part of the catback too).
Yes, all you would need is a downpipe, but it's your choice weather you want a catted or non-catted one. The catback actually mates after the catalytic converter on a stock setup hence being called a "catback."



Edit: Evil beat me to the punch! :lol:
 

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Discussion Starter · #7 ·
unrequited said:
...if I have an SPT catback, and want to jump to Stage 2, all I need now is just a downpipe & accessport flash, right? (my confusion comes from stating that the cat is sometimes combined with the dp, but then stated that it's part of the catback too).
The question (above) and answer (below) have been added to the first post.

A: The short answer to your question is YES. All you need is a downpipe and an AccessPORT flash to go Stage 2. As to your confusion, there are actually two catalytic converters on the STI. One is part of the downpipe, and the other is part of the midpipe. When we say "catback" exhaust, we mean coming after the cat in the downpipe, and as evilsti7 said, it should really be called a "downpipe back" exhaust.
 

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What's a sticky?

Hello,

Obviously I'm a newbie. I don't have an sti yet, but I'm doing the research for when I'm able to get one (please Lord, soon!!).

My question is, what exactly is a sticky and how do they work?

Thanks, Leo
 

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A sticky is just a thread that stays at the top of the forums. All "normal" or "non-stickied" threads will be sorted by date of most recent post. Sticky threads stay at the top regardless of most recent post date.

Moderators can make threads a sticky and remove their sticky-ness also. Typically these threads are 1) Of general interest to the population -or- 2) High traffic threads
 

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gt9729b said:
A sticky is just a thread that stays at the top of the forums. All "normal" or "non-stickied" threads will be sorted by date of most recent post. Sticky threads stay at the top regardless of most recent post date.

Moderators can make threads a sticky and remove their sticky-ness also. Typically these threads are 1) Of general interest to the population -or- 2) High traffic threads
Nice answer! :clap: :lol: :tup:
 

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A buddy of mine won't listen to me so I told him I would post his question and show him the answer I have been telling him for a week now.

If you run an external wastegate do you still need a BPV or BOV on your TMIC?

Hopefully he will listen to what you have to say and this way I am not pursuading you to give him my answer like he did with another guy we work with. Thanks for your help.
 

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ErichCS said:
Why can't i post things for sale? Do i need a certain number of postings?
Thanks!
Erich
It`s a sticky on classifieds.
ATTENTION: New Requirement for Posting Classifieds

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Due to member demand, we have added a requirement for posting Private for Sale Classifieds on this board: you must be a member for 90 days. This is so that hopefully only our active users use the classifieds and will hopefully decrease the amount of transactions that result in scams. Please still use discretion when dealing with another member who you don't know on the internet, and if it sounds too good to be true, then it probably is. Please also be sure to make good use of the seller feedback system. As a note, donating members are able to bypass the 90 day waiting period
 

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hi just a question on downpipes. when and if we decide to change it without ECU tuning, will the ECU run in SAFE mode. if so, how does SAFE mode run compared to NORMAL and how would you overcome this? thanks chaps...
 

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also another Q - would it be better run undersize/lightweight crank & alternator pulleys (GFB) or just lighthen crank pulley but same dia. as original? Any thoughts? Thanks.
 

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Irishman said:
A buddy of mine won't listen to me so I told him I would post his question and show him the answer I have been telling him for a week now.

If you run an external wastegate do you still need a BPV or BOV on your TMIC?

Hopefully he will listen to what you have to say and this way I am not pursuading you to give him my answer like he did with another guy we work with. Thanks for your help.
If I understand you correctly, the answer is YES.

Reasoning: An external waste-gate will do the same thing an internal waste-gate does - gives the EXHAUST air a place to go once the maximum limit of boost has been achieved. The BPV/BOV lets go of INTAKE boosted air before it goes into the throttle body once you let off the gas pedal.
 

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Thats the answer I was looking for about the BOV/BPV. Now that he heard it form someone else he is starting to believe me. Hickabilly's
 

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STI Tiff said:
Is it true that if I change my dp to delete the cat I will lose my cruise control?

I think I know where you derived this question from.... When you put in a dp and delete your cat you get an cel and the cruise control light flashes on the most recent subaru's. Beacuse of this, you cant use the cruise control until you clear the cel.
 
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