Stock 2007 TR WRX max boost at 10-11 psi ?? - Page 2
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This is a discussion on Stock 2007 TR WRX max boost at 10-11 psi ?? within the General Maintenance, Troubleshooting & Accidents. forums, part of the Tech & Modifying & General Repairs category; Originally Posted by mjboudreaux77 restrictor pills are not directional, but you need the right one with the right turbo. You ...

  1. #16
    Registered User Spiffy's Avatar
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    Quote Originally Posted by mjboudreaux77 View Post
    restrictor pills are not directional, but you need the right one with the right turbo.

    You can try adjusting the wastegate actuator arm, it may be the wrong length and not fully shutting the wastegate. If you search this forum, you will find how to do it. Pretty easy - just have to take the intercooler and heatshield off.
    Good to know. I pulled the entire vacuum assembly apart yesterday and gave everything a thorough cleaning.. re-assembled it all and still no difference,. After spending a couple hours browsing forums i found out about a test one can do to test the vacuum lines/solenoid.. Basically what you do is unplug the waste-gate then see if the car will boost over 9 psi and if it doesn't, you got bigger problems. Of course there is now nothing but your right foot controlling boost so be careful and let off right as you hit the target (13-14psi). Is this a safe diagnostic test? Haven't tried it out yet, wanted to get feedback on it first. Sounds safe enough to me but then I'm still an FNG.

    Thanks for the advice!
    Last edited by Spiffy; 06-13-2011 at 06:24 PM.

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  3. #17
    Supporting Member mjboudreaux77's Avatar
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    I don't see how your experiment would work - so I won't say if its safe or not. Your BPV is what protects too much pressure from going in the engine.

    How are you getting your boost reading? Do you have a boost gauge? You could just have a leak on that line.

    I noticed I lost boost after I installed the vf39 - I had ripped the turbo inlet. How do you know your car was always stock? Feel around the turbo inlet and see if there are any tears.
    If I don't die by Thursday, I'll be roarin Friday night - Jimmy Buffett

  4. #18
    Registered User Spiffy's Avatar
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    Quote Originally Posted by mjboudreaux77 View Post
    I don't see how your experiment would work - so I won't say if its safe or not. Your BPV is what protects too much pressure from going in the engine.

    How are you getting your boost reading? Do you have a boost gauge? You could just have a leak on that line.

    I noticed I lost boost after I installed the vf39 - I had ripped the turbo inlet. How do you know your car was always stock? Feel around the turbo inlet and see if there are any tears.
    the boost pressure is regulated through the wastegate. Once the correct pressure is reached the solenoid activates which reduces wastegate bleed off pressure created by the compressor, which activates the waste gate Actuator, redirecting exhaust through the wastegate valve instead of through the turbine. As long as the wastegate valve is closed exhaust gas will "only" travel through the turbine speeding up the turbo thus compressing air. By unplugging the wastegate you are essentially forcing the wastegate valve to stay closed. The bpv is designed to release built up boost pressure back into the intake (pre turbo). The purpose of a bpv or bov is to give the engine a way to release pressure when the throttle is closed. Its entire purpose is to keep that boost pressure from being forced back into the turbo when the throttle is closed... However, it has nothing to do with boost control.

    All my lines are fine, they are essentially brand new still. (they call them vacuum lines but in truth they actually plumb pressurized air).

    After doing all the research required to make me feel comfortable about doing this test i went ahead and tried it.. Worked like a charm! Boosted right up to 13psi (turbo would have kept boosting higher but i felt 13psi was enough to prove my test). The issue is in the solenoid, which isn't functioning correctly.

    P.S. I have a prosport boost gauge and when i was test driving the car i took it to a subi dealership and had them pull the codes,. They told me the ROM was still stock. (not that it could have been flashed back to stock, they said no way to check for that). Also, looked at all the bolts on the heat-shield for wrench marks,.. there were non at all. Its a 23k mile car that had one owner who said he used it as a family sedan. turns out, he said, that its not very good car to haul kids around in.. go figure. He sold it to buy a minivan.

  5. #19
    Supporting Member mjboudreaux77's Avatar
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    Quote Originally Posted by Spiffy View Post
    The bpv is designed to release built up boost pressure back into the intake (pre turbo). The purpose of a bpv or bov is to give the engine a way to release pressure when the throttle is closed. Its entire purpose is to keep that boost pressure from being forced back into the turbo when the throttle is closed... However, it has nothing to do with boost control.
    I am very aware how a turbo works... My point was the BPV (at least our stock one) won't allow boost pressures over some value - I think a stock BPV opens around 20psi or so. Therefor - since you were suggesting you may create a situation where the turbo spools to be unsafe for the engine, my point is the BPV will start opening and not let all of the spike hit the cylinders.

    I am glad you found it. That should be a cheap fix.
    If I don't die by Thursday, I'll be roarin Friday night - Jimmy Buffett

  6. #20
    Moderator Donkey's Avatar
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    Quote Originally Posted by EJ257 View Post
    Stock '07 WRX:
    Okay,since everybody seems to be totally missing this. THERE IS NOTHING WRONG WITH HIS CAR. Stock boost from the factory is 10-11psi with altitude as a factor. There is no need to touch his wastegate or anything else. All that causes is a brief boost spike as the ECU will reduce wastegate duty cycle via the turbo dynamics tables to hit target boost.
    Last edited by Donkey; 06-19-2011 at 08:43 AM.
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  7. #21
    Registered User mudferret's Avatar
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    The table that EJ257 posted sums it up. 10-11 psi at your elevation is completely normal for the stock tune.

    The factory map is awful enough, if you're going to be tweaking boost, get a proper tune, and let a pro do it, you'll be much, much happier.
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  8. #22
    Registered User Spiffy's Avatar
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    (sigh...)so did i just ruin my engine by pushing it to 13psi when its supposed to be 11 (one punch up a hill in 2nd gear)? I've got an appointment to get it pro-tuned tomorrow. There is so much conflicting information on this topic that it makes me want to pull my hair out
    Last edited by Spiffy; 06-19-2011 at 09:57 AM.

  9. #23
    Master Baiter EJ257's Avatar
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    Quote Originally Posted by Spiffy
    (sigh...)so did i just ruin my engine by pushing it to 13psi when its supposed to be 11 (one punch up a hill in 2nd gear)? I've got an appointment to get it pro-tuned tomorrow. There is so much conflicting information on this topic that it makes me want to pull my hair out
    Quote Originally Posted by Donkey
    Okay,since everybody seems to be totally missing this. THERE IS NOTHING WRONG WITH HIS CAR. Stock boost from the factory is 10-11psi with altitude as a factor. There is no need to touch his wastegate or anything else. All that causes is a brief boost spike as the ECU will reduce wastegate duty cycle via the turbo dynamics tables to hit target boost.
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  10. #24
    Registered User mudferret's Avatar
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    Quote Originally Posted by Spiffy View Post
    (sigh...)so did i just ruin my engine by pushing it to 13psi when its supposed to be 11 (one punch up a hill in 2nd gear)? I've got an appointment to get it pro-tuned tomorrow. There is so much conflicting information on this topic that it makes me want to pull my hair out
    No, you're fine. Your car's fine too, so don't pull your hair out. The TD04 spools ridiculously fast and in a high load situation like that it's not uncommon for it to overshoot slightly.

    Here's a good example of the OEM tune vs a stage 1 tune. A little bit of power to be had and much better drive-ability. The OEM power (peak #'s) are ALL spike and not really all that indicative of what's truly going on. This is from a Dyno Dynamics, stock baselines will look a little different on other dynos, but you can see how spikey the stock tune is and how much smoother the tuned curves are. Standard dyno disclaimer, ignore peak #'s, look at gains. Those spikes sure make the car "feel" faster though.

    ...Rob.
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  11. #25
    Supporting Member mjboudreaux77's Avatar
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    Spiffy - You didn't hurt your car. I don't know how much altitude affects the boost tables so the pro tune will clear everything up. Let us know what you find. My 07 hit ~14 psi all day long on the stock tune. When I google it, I find this (~14.5psi) pressure is what people are saying the target is.

    Donkey - If the wastegate arm isn't allowing the wastegate to fully close, then adjusting the arm will fix that and allow more spool. I agree it will cause boost spikes if you adjust too far, but I was suggesting it as something to look at.
    If I don't die by Thursday, I'll be roarin Friday night - Jimmy Buffett

  12. #26
    Registered User Spiffy's Avatar
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    Alright so the new numbers are in.. Modifications performed yesterday in garage; Invidia catted divorced wastegate downpipe to cobb cat back (complete 3in turbo back) with a cobb heat shield, and a grimm speed 3port solenoid (couldn't resist for $50). Just got done with the protune,. custom conservative stage 2 maps with max boost now at 17.5 psi. (don't know exact wheel hp/tq numbers but tuner said rough gains of 45-50hp and 85-90tq) The first map pulled off the ecu, the stock map was the exact same map posted by EJ527 with the max target boost at 11.6psi.

    I decided to go with the conservative maps just to be on the safe side.

    There was a little bit of an issue mating the flat flange of the Invidia DP to the concave flange of the cobb mid pipe.. I used the hardware provided and the stock donut gasket as instructed by Invidia but still have a small exhaust leak. Will call around tomorrow to find a shop that can basically delete the 2.5 mid pipe flange and donut gasket by cutting it out and welding in place a 3in flex pipe with a 3in flat flange so the dp and mp mate correctly with out any restrictions in the pipe. The tuner said its not a huge deal but it will decrease turbulence in the pipes and therefor reduce back pressure which in turn will help with the longevity of the entire system... as well as free up a little bit more power. He said that another tune after the fix would be unnecessary,. the biggest draw back in power is from the cat, and that the half inch restriction is nominal. It will bug me until i get it fixed though.
    Last edited by Spiffy; 06-20-2011 at 11:56 PM.

  13. #27
    Registered User mudferret's Avatar
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    Sounds good, I'm at 17.5 psi as well. I wouldn't worry too much about the reduction at the mid-pipe, at a stage 2 level it's likely not even measurable on a dyno.

    Enjoy your new found power.
    ...Rob.
    MMVI WRX - VF43 Airboy Tuned @ 3500'

  14. #28
    Moderator Donkey's Avatar
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    Quote Originally Posted by mjboudreaux77 View Post
    My 07 hit ~14 psi all day long on the stock tune. When I google it, I find this (~14.5psi) pressure is what people are saying the target is.

    Donkey - If the wastegate arm isn't allowing the wastegate to fully close, then adjusting the arm will fix that and allow more spool. I agree it will cause boost spikes if you adjust too far, but I was suggesting it as something to look at.
    The arm will always open and be open well before max psi on the stock boost system especially when running lower boost. Once again look at what EJ257 posted. That is the stock ROM boost table from an 07 WRX. The STI was 14.5,not the WRX. You totally missed what I was saying about spiking as that was probably exactly what you and everyone else was doing as well. The ECU will remove wastegate duty cycle to hit target boost if you go over. So adjusting the arm does nothing but cause more problems if your hitting target boost already ready,which the OP is. Did you even pull your ROM to see what the target boost was set at? Have you ever datalogged your car to verify the gauge was accurate against the factory MAP sensor? Romraider is free. Anyone can easily look at the factory ECU setting if they want to. I know from tuning these cars how the system works. With the Td04 it happens so fast anyways people mistake a spike for what its supposed to be since the boost tapers so quick.
    This is a pretty reliable source of info. Has the boost pressures listed.
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  15. #29
    Supporting Member mjboudreaux77's Avatar
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    Donkey - I really am not trying to be argumentative... You seem very knowledgeable, but my 1 experience with my 07 doesn't seem to be in line with what you and EJ257 are saying. My statement of hitting boost is based on the factory installed boost gauge I had on the car. I believe I know what spiking is, and I don't believe that was happening. The boost would only hit ~14psi in 4th and 5th gear - but it would hold, then decrease as RPM's went too high.

    I only data-logged with my accessport after I went to stage 2 - then again when I installed the VF39, so I can't say what it was before I did that. However, stage 2 and vf39 boost levels matched between my accessport and boost gauge and were in line with what the target boost was being set at.
    If I don't die by Thursday, I'll be roarin Friday night - Jimmy Buffett

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