jertfunk Posted April 13, 2017 Share Posted April 13, 2017 Where does the AP get its boost reading from? Just curious if there was a boost leak somewhere would you be able to tell through the accessport? Sent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
HDTurbo Posted April 13, 2017 Share Posted April 13, 2017 Besides noting lower boost, I don't think it could help to pinpoint a leak. Link to comment Share on other sites More sharing options...
cww516 Posted April 13, 2017 Share Posted April 13, 2017 Might show up in your fuel trims as a bunch of added fuel in the lower load ranges (vacuum leak) and pulled fuel in higher load ranges (boost). Edit: by a bunch, I mean way more than a couple percent. I think +/-5% or so is considered pretty normal, this would be pegged at +/-15% (think that's the limit, been a while since I looked that up). Link to comment Share on other sites More sharing options...
FLlegacy Posted April 13, 2017 Share Posted April 13, 2017 You would be able to tell you aren't reaching your boost target. Best way to check for a boost leak is to seal the intake pipe and put air to it. Sent from my SAMSUNG-SM-G920A using Tapatalk Link to comment Share on other sites More sharing options...
Wild Bill Posted April 13, 2017 Share Posted April 13, 2017 One thing to check is TD Boost Error from what I read it is not supposed to be outside of +\- 1.5 and not outside of 0 to 1 at WOT over like 3400 rpm. I still haven't read if this is only to be accurate at WOT or if it should always be in range. I need to send an email to COBB. Personally, I am way out of range at idle / coasting, but in range if I have my foot into it at all. I need to put my OEM BPV back on some day to see if it is just a tuning issue due to using an OTS map that is not meant for a BPV valve that is closed under vacuum. EDIT: This is where I got most of my info. Sent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
jertfunk Posted April 13, 2017 Author Share Posted April 13, 2017 Thanks for the responses will have to do some work. My AP says I'm hitting target but the car doesn't feel like it used to to me. I'm either getting used to it, I have a leak or maybe the computer has changed things over time do to knock or something. I've had the off the shelf on my car for about a year. Sent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
GTEASER Posted April 13, 2017 Share Posted April 13, 2017 Where does the AP get its boost reading from? Just curious if there was a boost leak somewhere would you be able to tell through the accessport? Sent from my iPhone using Tapatalk AP gets the info from the ECU which in turn gets it from the stock MAP sensor on the motor. You would be able to tell if you had a boost leak if you are not hitting target boost. As far as where that leak is, you would need to smoke test. GTEASER's 2012 Legacy GT - Sold GTEASER's 2009 XTeaser - Sold GTEASER's 1992 Legacy SS - Sold Link to comment Share on other sites More sharing options...
FLlegacy Posted April 13, 2017 Share Posted April 13, 2017 I think the td boost error is for a steady state load or something of that nature. If you think about it logically, any turbo lag will result in a td boost error. 100% throttle corresponds to boost target but that takes time to build and during that time you boost error will be significant. Sent from my SAMSUNG-SM-G920A using Tapatalk Link to comment Share on other sites More sharing options...
fahr_side Posted April 14, 2017 Share Posted April 14, 2017 I think the td boost error is for a steady state load or something of that nature. If you think about it logically, any turbo lag will result in a td boost error. 100% throttle corresponds to boost target but that takes time to build and during that time you boost error will be significant. Sent from my SAMSUNG-SM-G920A using Tapatalk TD boost error is just the calculated boost error that the Turbo Dynamics system uses for making its corrections. Basically that is the current boost target value pulled from tables, plus or minus compensations, minus Manifold Relative Pressure. It's normal to see large errors at idle and in cruise. In constant WOT you should be within 1 to 2psi error at all times and see TD activity reducing that quickly. If you are constantly changing throttle angle you cannot expect the physical universe to keep in lock-step with the targets spat out by a computer. Electrons have very little inertia compared to turbochargers I think. Obligatory '[URL="http://legacygt.com/forums/showthread.php/2008-gh8-238668.html?t=238668"]build thread[/URL]' Increased capacity to 2.7 liters, still turbo, but no longer need spark plugs. Link to comment Share on other sites More sharing options...
cww516 Posted April 14, 2017 Share Posted April 14, 2017 Electrons have very little inertia compared to turbochargers I think. [Citation needed] Link to comment Share on other sites More sharing options...
HDTurbo Posted April 15, 2017 Share Posted April 15, 2017 inertia:a tendency to do nothing or to remain unchanged. maybe more like the analog turbocharger can't keep up with the real-time digital (re)directives it is constantly being given...? couch peek Link to comment Share on other sites More sharing options...
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