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    Thread: Help! Boost issues

    1. 06-30-2020 02:08 PM #1
      03 GTI 1.8t
      Mods: Cold air intake, 3” down pipe & 3” back, Stage 2 tune, 4 bar fpr, and some Dv that came on the car

      Alright guys so I finally found someone with a scan tool to diag my 115 blocks.. It’s a stage 2 (2step & NLS) my problem is that I’m not peaking over 15lbs when the tune calls for 22lbs peak. I bought the car with the tune already on it so I was skeptical if it was actually true or not. Today I did a couple pull with the tool hooked up and the MAX Specified boost was 2550 mbar (22.xx lbs) and the MAX actual boost I achieved was 2070mbar (15.3x lbs). So where would I start trying to find a boost leak ? Is there a way to troubleshoot the DV ? And a proper way to test N75 valve (can’t find a true step by step without having questions on a old thread)? What could cause this much of a boost loss ? Any and all help is appreciated. Thanks !!

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    3. 06-30-2020 08:33 PM #2

    4. 07-02-2020 12:34 AM #3
      Check the faq in the 1.8t forum. There is a great DIY on finding boost leaks.

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    6. Junior Member
      Join Date
      Mar 19th, 2020
      2003 Volkswagen Jetta 1.8T
      07-02-2020 03:31 PM #4
      What fuel are you running. When I got my stage 1 unitronic tune I wanted a stage 1+ but I couldn't because it needed higher octane fuel. They wanted me to run an octane booster every tank. Your car may be tuned to run higher octane. Call the company that tuned your car and see what their stage 2 requires.

    7. 07-05-2020 10:07 AM #5
      It wasn’t a company. Previous owner shipped it out to some guy and had it done. I always put 93 in; also have tried running octane booster with the 93 and it made no difference.

    8. Member Rockerchick's Avatar
      Join Date
      May 10th, 2005
      Cary, NC
      '16 GTI Autobahn PP, '84 Jetta TD, '82 Rabbit Pickup
      07-05-2020 11:10 AM #6
      Quote Originally Posted by xxdnfxx View Post
      It wasn’t a company. Previous owner shipped it out to some guy and had it done. I always put 93 in; also have tried running octane booster with the 93 and it made no difference.
      I would get in contact with who tuned the car. It would be good to have the full specs on the tune so you know if you have the right parts, etc. for it.
      Quote Originally Posted by TM87 View Post
      VW-making mechanics out of owners since 1957.
      The Long Term Resident - '84 Jetta 1.6TD
      The Project/Future Wheelbarrow - '82 Rabbit Pickup, Supercharged ABA
      Hers - '16 GTI Autobahn PP, '03 BMP 20thAE GTI
      His - '15 Audi A3 2.0T Quattro

    9. 07-05-2020 09:47 PM #7
      So I believe I found my issue

    10. 07-05-2020 09:52 PM #8
      So here’s a Pcv hose diagram. https://images.app.goo.gl/ycABjrypyaVe9QXC7

      The #5 t connector to #9 hose has somehow broke right at the hole of the T. Correct me if I’m wrong but could this be the underlying boost loss ? I have all supporting mods for the tune .

    11. 07-05-2020 09:53 PM #9
      I would add photos but I do not know how 😂😒

    12. Member THEWIDOWSON's Avatar
      Join Date
      Nov 6th, 2018
      MK4 GTI 1.8T 2DR Manual / B4 Audi Quattro
      07-06-2020 09:11 AM #10
      It wouldnt cause it to not make peak. But it will cause idle issues. Thats a really common failure point. They tend to sludge up and will get melted through. I got the pcv refresh kit for mine on ebay for dirt cheap. And it was good quality for the price. Cant beat it for under $20.


      And I know I must sound like a broken record at this point but you will 100% have a leak at the intercooler charge pipe. Its this bad boy here https://forums.vwvortex.com/showthre...-to-use-sealer They never hold up to mapped boost levels. What will happen is air escapes around the oring causing symptoms just like you have. They where never designed for these boost levels. So when you come onto boost the seam will literally start to lift off. Creating a horrendious leak. And it will settle back down in the housing when you come off. If you have isses with part throttle that appears to clear up once you floor it than its definently this pipe.Alot of time itll cause surge as well. The fix is easy you just need an autozone coupler and some clamps. I personally hated all the factory piping so I went with an ebay intercooler kit to get rid of all of it. You might have other leaks but I gaurentee this is one leak source.

    13. 07-06-2020 09:52 PM #11
      Thanks for the reply man ! Could you possibly send me a couple links of the easy diy on the charge pipe ? This is my first turbo car so I’m learning as I go with all these things. I’m also ordering an entire pcv hose kit just for peace of mind

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