Engine Drivetrain 1st Gen Cooper S Installed a Detroit Tuned bypass valve now I have really bad yo yo??

Discussion in 'Tuning and Performance' started by jeffster06, Jul 18, 2010.

  1. jeffster06

    jeffster06 Active Member

    Apr 23, 2010
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    Hope this is the right forum for this... I also posted this up over on NAM but lately everything I post gets a whole lot of views but no responses.

    I have an 06 MCS with a 15% pulley and yesterday I installed a Detroit tuned bypass valve, new belt, cleaned throttle body and my IC, and did the VGS Mod found hereMINI COOPER :: North American Motoring - Operation Vacuum Gain System (VGS) The VGS mod was done after (problem remains with or without the mod) I had drove the car and noticed very prominent Yo-yo feel at moderate throttle (seems to happen more between 2500-3500 rpm) but if I go WOT the car drives like a bat out of hell. Is there something I could have done wrong? My car didn't behave this way before the new bypass valve. anything I should be checking? My only thought that I think that could have happened is the intake tube going to the supercharger (plastic tube the throttle body bolts too) is slightly off allowing air to bypass the throttle body. but in that scenario wouldn't the car idle rough? (which its not) any input on this would be great kinda out of ideas where to look.

    Thanks in advance
     
  2. Nitrominis

    Nitrominis Banned

    May 9, 2009
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    The Detroit Tuned BPV is a quality piece and should not give any problems?
    If your intake system is pulling outside air you may not demonstrate a rough idle.

    Double check all of your work chances might be that something was simply overlooked?

    The VGS theory is a interesting idea and easy to install/remove, so removing it temporarily and returning to your baseline will help solve your problem.
     
  3. Dr Obnxs

    Dr Obnxs New Member

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    This happens to some...

    some theory first.... The throttle position is set based on a bunch of stuff, but a lot of it is set based on the pre-SC manifold vacuum. The bypass valve is a mechanical link between the pre- and post-SC manifolds. Some cars just aren't happy with the changes in the DT valve.... Give Chad a call if you want.

    What's happening is that the dynamics of the modified valve and the ECU maps are fighting each other. While this isn't mentioned too often now, there was lots and lots of stuff written about it 2003-2005....

    There are a couple ways to fix this:

    1) Go back to a stock valve.

    2) Get a custom tune (you'll get more power too) that will take into account the opening vacuum level of the modified valve.

    If the car was fine before and then developed the yo-yo, start looking for other wear items or small vacuum leaks and the like.

    It doesn't happen at WOT because the valve is closed and you're on boost.

    Matt
     
  4. Tüls

    Tüls New Member

    Apr 3, 2009
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    I'm with Nitro... try taking the VGS off. Then reset the ECU.
     
  5. werD

    werD Club Coordinator

    May 19, 2009
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    +1

    Pretty uncommon to get any voodoo from the DTBPV...
     
  6. jeffster06

    jeffster06 Active Member

    Apr 23, 2010
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    The yo yo was there before the VGS I had done it after I had drove around for a day. I actually went through and completely redid the install... I didn't find anything missed or broken one thing I will note is the clamp on the hose for the bypass seemed slightly loose (didn't take much force to loosen it). On my initial test run it seems like I may have fixed it I tried to maintain speed in the RPM range where I was getting the yo-yo before and I didn't get it on this run.... hopefully the re-install did the trick. If not I will try removing the VGS again and see where that takes me. I can't recall if I reset the ECU after I did the VGS. I did reset before my reset test run though (VGS still installed).

    I will update this probably tomorrow after I do my normal daily commute. Hope for good news :Thumbsup: thanks again for all the input.
     
  7. Batrugger

    Batrugger New Member

    May 13, 2009
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    IIRC the VGS mod and the DT BPV are both fixes for the same problem. The general consensus was that you do one or the other, not both.
     
  8. Dr Obnxs

    Dr Obnxs New Member

    Jun 11, 2009
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    Both can happily co-exist...

    the DT valve changes the vacuum point where the valve closes, doesn't open as much as stock, and has a very short "transition time" so that it acts like it's fully open (as much as it can be) or fully closed, but doesn't spend much time in betweeen. (Ryan or Andy posted the actuall vacuum levels and the like long long ago.)

    The VGS mod takes the vacuum pick up from a location that can have slight negative feedback in the valve set point (upstream of the SC) to a location where it uses posative feedback (to downstream of the SC) in determining the location of butterfly.

    What leads to problems with none, either or both installed is that they are coupled feedback mechanisms that are indirectly coupled via vacuum levels: the vacuum is used to set bypass valve butterfly position AND is used to set throttle body position, both of which in turn affect vacuum levels. This can easily lead to instability or oscillation. MINI had a heck of a time tuning out yo-yo the first couple years the car was in the US because of just this coupling. (There were many an ECU updates coming out at that time... Some good, some not so good.) Things seemed to settle down in about 05 or so, occational reports of yo-yo kept showing up, just with much, much less frequency.

    Anyway, the stiffer spring of the DT valve changes both the frequency of the oscillation, as well as the vacuum point where the issue can come up. If it moves the problem spot off of a bad part of the tune (bad being defined as a place that can lead to oscillation), the yo-yo goes away. But there are also cases where it has moved the problem spot onto a place in the tune with issues, and has induced oscillation. Those that run into that where it isn't fixed by checking the install tend to just sell the vavle in the marketplace as they move fast and move on. But it can and does happen.

    The VGS mod is more interesting from a stability point of view. On the transition from open to closed, the vacuum pick up is moved to a location where closing the valve leads to increased boost, closing it further. This type of posative feedback tends to really kill oscillations. As it opens, the same type of posative feedback will occure.

    The VGS mod is more directly coupled to oscillatory supression, but doesn't really do that much to engine control and driving feel. The DT valve isn't directly targeted at yo-yo (even though it's roots are from working on that issue), but does have a very large effect on how the car behaves, with the SC boost coming on earlier and more abruptly. I'd guess that now Chad sells the valve to customers more for how it changes the driving feel than for yo-yo problems.

    Matt
     
  9. panaphobic

    panaphobic Club Coordinator

    Jul 19, 2010
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    the problem could be that you live in georgia. i think if you move to massachusetts, the problem would be resolved.

    :beer :D
     
  10. jeffster06

    jeffster06 Active Member

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    LMAO Some how I don't think that will fix my car issues.... maybe my missing friends one....

    Just a little update on my issue. The ride to work I noticed the yoyo wasn't as extreme as the other day it was kind of subtle. I will be removing the VGS mod tonight hopefully that remedies it completely.
     
  11. Johngo

    Johngo New Member
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    May 18, 2010
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    Only issue with Massachusetts is the silly accent. Well, that and those winters... Y'all can have that white stuff. We like to drive too much to have to worry about snow.

    :D:wink2
     
  12. BThayer23

    BThayer23 Well-Known Member

    Jun 12, 2009
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    You've never driven until you're going sideways in the white stuff on a mountain road. You want to learn car control? Ok, we'll just hide the road and make your tires virtually useless. That'll teach ya some car control. :cool:
     
  13. Metalman

    Metalman Well-Known Member
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    So...... Jeffster06, did you try to re-set the ECU, and did you notice any difference with the yo-yo afterwards?
     
  14. jeffster06

    jeffster06 Active Member

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    So I removed the VGS mod last night and reset the ECU I didnt notice much yoyo but its still there. then today coming home from work it appears that running the AC amplifies the yoyo because it's very apparent. I'm slightly getting used to it but I never expected to have this kind of issue when I installed the bypass valve.

    On another note not sure if this may have a factor for the past few months whenever I drive on the highway I would get a P1125 (TPS fault) and P1687 (some diagnostic) codes with the SES and EML lights coming on. (usually turning the car off cleared the EML and I'd be on my way) since I've done this mod/cleaning the throttle body I noticed the SES and EML lights come on whenever. I actually had one last night just driving on the back roads. perhaps I need to bite the $300 throttle body bullet finally? I've been pushing it aside because I rarely drive on the highway and when I do it occurs once then seems to just go away for the rest of the day or even days.
     
  15. Dr Obnxs

    Dr Obnxs New Member

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    TB codes...

    Are not that uncommon. Before you spend on a TB, undo the electrical connector, use some really good contact cleaner, and make sure that the. Connector is really well seated.

    Matt
     
  16. panaphobic

    panaphobic Club Coordinator

    Jul 19, 2010
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    i still think that moving back to massachusetts would solve the problem! i miss my drinking buddy! who knows when you'll be back up here and if i'll ever get the chance to head down there! just remember who gave you that final push to buy your MINI! i think this is your car's way of saying "move back jeff"

    :deadhorse:
     
  17. jeffster06

    jeffster06 Active Member

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    I've tried cleaning the connector already with some electronics cleaner I had laying around (called deoxIT) perhaps it wasn't good enough? any recommendations on a contact cleaner?

    If I had the money and could find a job up in mass i'd probably move back.....GA is nice but its not really home for me.
     
  18. Metalman

    Metalman Well-Known Member
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    Let's see now.......

    Vinegar pork BBQ ........

    Lobster dripping in butter.......


    I'd be chasing the lobster :D
     
  19. BThayer23

    BThayer23 Well-Known Member

    Jun 12, 2009
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    [​IMG]

    Wait till November - you'll still be enjoying late summer while your friends up north will be seeing early snow. I moved from Boston to NC five years ago.
     
  20. jeffster06

    jeffster06 Active Member

    Apr 23, 2010
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    Guess ill try some of that cleaner.... Do you think the TPS issues is adding to the yo yo?

    I've lived in GA since 06 love the roads and the weather but no matter how hard I try I can't seem to find friends like the ones I have up north. oh and the lobster comment while that may sound tempting to you, it would be death for me....I'm allergic to shellfish.
     

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