First Modifications FAQ

Discussion in 'Tech, Tips, Newb Info' started by readymix, May 4, 2007.

  1. readymix

    readymix ...Lest ye be trod upon... Staff Member

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    This should be used in conjunction with the "Common Newbie Questions" sticky thread as a reference to new WRX and STi owners on where to begin with power mods.

    Should I get an intake?
    Your MAF sensor is fickle. For the stock mapping, and even for custom tunes, it likes to reside in a tube that is free of excess turbulence. And for the stock ECU mapping, it definately wants to be in a tube that is the same ID as the one Subaru engineers designed it for. There are many intakes on the market, but for early modding, it isn't required. I'd go so far as to say that you really don't need an intake of any kind until you start running a larger turbo than stock.

    In addition, you will almost never gain power from a "short-ram" intake on a Subaru. This is because the stock airbox pulls cold air from the fender, and when you change that to pull air from the hot engine bay, you lose power -- especially on a turbocharged car. If you absoultely must spring for an intake, get a cold air intake. APS makes one that works very well on most Subaru's.

    But for the early modification stages, you can always remove your intake silencer in the fender well. This will give you a little more of that 'swoosh' sound when the turbo picks up, and it will breathe a slight bit better.

    The most important thing to the health of your car is a good tune. There are two major choices for tuning, Cobb AccessPort and OpenECU. There are many benefits to each solution, but the basics are:


    -More expensive
    -Multiple map support

    There are a large number of positives and negatives to each solution, be sure to do your research and pick the solution that best fits your needs.

    What mods should I start with?
    The following "Stages" are in reference to Cobb's staged upgrades.

    Stage 1: This is essentially a stock car, but with a custom map loaded on the ECU. You pick up a few ponies and things smooth out a bit.

    Stage 2: A downpipe or a full turboback exhaust (both a downpipe and a catback -- recommended). And of course loading a custom map for the ECU. This is a large improvement over stock and is usually enough for most people for a while. But I'm going to throw this in should get a new uppipe while you are doing the downpipe. It is much easier to get at the uppipe when the downpipe is off. Plus, it will free up exhaust flow a bit more adding some more torque and a few more ponies! This is most important on the 02-05 WRX, as they have a cat in the up-pipe -- but all Subarus will still see a slight benefit from an aftermarket uppipe.

    So what uppipe/downpipe/catback should I get?
    This is really personal preference. In my opinion, all uppipes/downpipes/catbacks do the same thing in terms of power, so it really depends on what you want to spend, how much headache you want installing it (fitment), and how loud you want to be. This will require some research on your part. NASIOC is full of reviews on pretty much every part ever concieved for a WRX or STi. And a thing of note, all uppipes/downpipes/catbacks for STi's and WRX's are interchangeable...they are the same sizes. So no need to worry if that WRX owner's downpipe for sale is going to fit the STi. Really, in the end, a pipe is a pipe is a pipe. They will all do essentially the same thing. Just be sure you do not get a downpipe that blocks off the wastegate, that will significantly hamper flow (eg - the HKS downpipe).

    Ok, I'm at stage 2, and it isn't enough, what do I do now?
    My recommendation would be work on the handling of the car. A stage 2 car is alot of power for most people, and it can become unruly if you don't have your ducks in a row in terms of keeping the car planted. But if you absolutely need to go for more power, I suggest searching Nasioc and this site to see what some people have for setups. There are tons of turbo options, and an infinite amount of different combination's of parts, ranging from the mild to the absolutely insane. Go to Firestone on Friday and Saturday nights and see what some of the guys are doing with their cars, go for test-rides (or drives if the owner is really trusting) and see if what they have is right for you.

    Finally, the biggest, most important thing to ask yourself when determining what to do with your car...
    Whenever anyone asks me what they should do next in terms of modifications, I always ask them this question:
    "What do you intend to do with your car, what is the purpose, what do you want your car to do for you?"
    The key to modifying your car is knowing what the modifications outcome is and knowing what outcomes you intend to achieve. Saying "I want 500hp" means nothing, you need to ask yourself tons of questions. I'll pose a few of them for you so you have a place to start. But planning out your car from start to finish or at least having a final outcome you wish to achieve BEFORE modding your car will net you a very well rounded car that caters to the needs you wish for the car to fulfill for you. Here are some sample questions that I asked myself before modding beyond stage 2:

    What do I want to do with my car?
    How reliable do I need my car to be?
    Will this be daily driven or a fun car, track car?
    Will I be drag racing it or road course racing?
    How much power do intend to make, and where do I want my power band to be?

    I hope you found this guide informative. If you have points you think should be added, feel free to post them up and i'll add them to this FAQ. And as always, if you have any questions, feel free to PM me and I'll try my best to help or at least point you in the direction of someone that can.

    P.S. - mods can I get a sticky? ;)

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