Power Modifications: STi Stage 2 and Beyond State 2 on VF-39(most apply to WRX also)

Discussion in 'Tech, Tips, Newb Info' started by mlgez, Nov 1, 2006.

  1. mlgez
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    mlgez Well-Known Member

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    I want to start out by thanking a few people that have been helping along the way. These guys are great. It is nice to have people like this in the club. If I left someone out I am sorry. Mike Wray (LegacyPGT) with all his help with installs, getting parts, and ideas. Russ (WRX1) for his ideas and with tuning. Matt (bikerboy) for all of his ideas, modified injectors, and APS CAI. And last but not least thanks to Shane at DB Performance for all the dyno pulls, tuning, and for putting up with me :).

    All dyno pulls were done at DB Performance to keep a relative base line to compare. Now everyone of course needs to keep in mind dynos are only a tool. They can vary day to day with temp, air density changes, and of course TMIC heat soak quickly on dynos. They are only to give you an idea if the mods you have done have helped or hurt your goals.
     
  2. mlgez
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    mlgez Well-Known Member

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    Stock:

    Here are the stock STi dyno info...
    211Hp and 217FtLbs
     
  3. mlgez
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    mlgez Well-Known Member

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    Stage 2:

    Next was the normal stage 2 modification of a downpipe and catback exhaust. For a WRX an up-pipe would be a good idea too. Frees up some power and a cat going through a turbo is bad. From the first image here you can see why the stock DP is just not going to cut it.
    [​IMG][​IMG]

    Invida V2 downpipe to a Cobb cat-back with the 2 1/2" resitriction removed to a 3" all the way back. I forgot to take a picture of the bell mouth but that is Invidia's photo of what it looks like.
    [​IMG][​IMG]

    The exhaust is a bit larger. Then a Cobb AccessPort Version 1 for ECU managment.

    So here are my dyno charts with the new mods...
    251Hp and 281FtLbs
     
  4. mlgez
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    mlgez Well-Known Member

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    Beyond Stage 2 Step 1 with Stock Turbo

    Now going beyond Stage 2 a little. Next mods after again talking with the before mentioned people was a CAI, turbo inlet pipe, GM BCS, Walbro 255LPH fuel pump, and modified 816cc injectors over the stock 565cc injectors. The GM boost control solenoid acts almost like a switch and keeps the wastegate closed till it gets close to the target boost level and then starts adjusting the wastegate. The stock one starts leaking off pressure almost right away. The dyno graphs will show that the boost starts almost 500rpm sooner with the GM BCS. The fuel pump is starting to get necessary at this point also to make sure that there is enough fuel for the larger injectors.
    [​IMG][​IMG][​IMG][​IMG]

    Oh and I decided with all the mods it was time to get higher pressure radiator caps just for extra margin on the cooling system. Just had to have that STi pink under the hood. Yes, yes, I know... "its not pink".... whatever.
    [​IMG]

    Here are the dyno charts. At this point there was still some tuning to be done as boost comes on. Bigger injectors make a difference....
    263HP and 297FtLbs Sweet.
     
  5. mlgez
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    mlgez Well-Known Member

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    IDC Stock Injectors vs. Larger Injectors

    Here are the graphs of the injector duty cycle. This first one is Stage 2 with stock injectors. The second graph is with the larger injectors. My max then was 95% and now it is 65%. Huge difference.
     
  6. mlgez
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    mlgez Well-Known Member

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    Beyond Stage 2 Step 2 with Stock Turbo

    Next I added a larger TMIC. This will help with heat soak and a lot of people believe the pressure drop accros the aftermarket intercooler will be a lot less than the stock peice.
    .[​IMG][​IMG]
    [​IMG][​IMG]

    The next thing I added was a header that I got from Dream. It is a HKS knock-off as far as I know. I was hoping to have photos of the stock piece versus the wrapped headers but one hard drive failure later and I am without pictures.

    So here are the dyno charts. I do not believe there is anything left in the stock turbo on premium pump fuel....
    280HP and 309FtLbs
    [​IMG][​IMG]

    This is Stock versus Stage 2++....
    [​IMG]

    And here is Stock versus Stage 2 versus Stage 2++
    [​IMG][​IMG]
     

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