jayrex Posted January 27, 2015 Share Posted January 27, 2015 I am over boosting by about 2 - 2.5psi after an inlet, uppipe, turbo back install. Do I have anything to be really worried about here? Sometimes hitting a peak 18.75psi on STG2 91 OTS map. I don't think my 110K motor is going to put up with that for too long. (I'm keeping off the gas until I figure this out.) FWIW - AF Learning and Knock Values are fine. I'm a little confused about Wastegate Duty Cycle, and how to use those values to determine if its overboost or actual boost creep. From 4.5K to redline the boost does level off at around 17psi with the WG Duty decreasing to about 25%. The peak is only high at 19ish. I see HWG maps for some cars on the Cobb website. But I do not see one for the 2005 (or 2005.5) LGT. Before the turboback install I was overboosting by about 1 to 1.5 on STG1 cobb maps. Link to comment Share on other sites More sharing options...
CapnJack Posted January 27, 2015 Share Posted January 27, 2015 Overboost happens often on OTS maps. You will know it's an issue if you start to experience fuel cut. One way to check to see if it's boost creep is to hook the small line off the turbo housing directly to the wastegate actuator to bypass the boost control solenoid then data log a full throttle pull. If it holds steady at about 12psi, it's your WGDC and you need a tune. If it starts to climb by more than 2 psi over 12psi in the higher RPM range, you have a boost creep problem. While its not impossible to have boost creep on a stock turbo, it is very rare. Typically when you see boost creep on a stock turbo, you have a mechanical issue (wastegate hitting the divorced DP wall or a bad actuator). Link to comment Share on other sites More sharing options...
jayrex Posted January 27, 2015 Author Share Posted January 27, 2015 All good info. Thanks for taking the time. I have a non-divorced Cobb DP. Stock turbo. I will try the boost control bypass test. I've read a bunch, but never heard of that test. I watched a short video on tweaking the HWG table using AccessTuner Race, to bump the WGDC by 5% to correct overboost. Would this be an appropriate reaction to an overboost situation, or am I 'going a little too far into the rabbit hole' with limited tuning knowledge? And I would reduce or increase WGDC table values by 5% to reduce boost pressure? Link to comment Share on other sites More sharing options...
iNVAR Posted January 28, 2015 Share Posted January 28, 2015 You need the lwg map, not the hwg map. Flash the lwg map on and see how your boost is. Link to comment Share on other sites More sharing options...
jayrex Posted January 28, 2015 Author Share Posted January 28, 2015 Are they on the Cobb site? Do I need to look into 'Archives' or something. I don't see any of the WG maps listed. Thanks for the correction on the HWG vs LWG, I still don't have that straight. Link to comment Share on other sites More sharing options...
jayrex Posted January 28, 2015 Author Share Posted January 28, 2015 Threw a code on the way home relating to this: P0244 - Turbocharger Wastegate Solenoid 'A' Range/Performance Cobb AP note when I click on code(annotated): Too much Booooost, get a LWG map! The car just cut out for 1 or 2 seconds when it happened... I'm assuming that's the 'fuel cut' everyone talks about. Link to comment Share on other sites More sharing options...
CapnJack Posted January 28, 2015 Share Posted January 28, 2015 That's the fuel cut. I believe it's on Cobb's site here. http://www.cobbtuning.com/Accessport-Off-The-Shelf-Maps-s/40100.htm#/v/accessport/maps/subaru/lgt/LGT-Map-Grid If you can't find it, you can email them. They are very responsive. Link to comment Share on other sites More sharing options...
jayrex Posted January 28, 2015 Author Share Posted January 28, 2015 Thx captJack I will need to contact them for it. Not listed for the 05 year. Link to comment Share on other sites More sharing options...
jayrex Posted January 29, 2015 Author Share Posted January 29, 2015 Cobb was great, sent over maps for STG2 91 LWG and STG2 93 LWG. They replied within a few hours. Great customer service over there. Thanks for the suggestion. Cobb said I should check for vacuum leaks between the boost control solenoid and wastegate actuator because it is odd that I would be boosting so high. That is basically what CaptJack said to test in the first place. Link to comment Share on other sites More sharing options...
jayrex Posted January 29, 2015 Author Share Posted January 29, 2015 Little update: Ran the STG2 93 LWG map for about an hour. Boost peak is not 17psi instead of nearly 19. The maps peak is supposed to be at 16.5, so it seems to be working. I know that I could be covering up a mechanical issue with the tuning fix, but at least its better. I will try the BCS bypass test soon. Will hopefully update with an answer. Link to comment Share on other sites More sharing options...
CapnJack Posted January 30, 2015 Share Posted January 30, 2015 I would say you are probably fine, but doing the BCS bypass is easy and gives piece of mind. Link to comment Share on other sites More sharing options...
Ohoen Posted March 6, 2015 Share Posted March 6, 2015 That's very interesting, because I just heard back from Cobb after requesting the same thing. I was told that they do not offer custom maps and that I should get a smoke test done. Are you on the stock intake? I have the Cobb intake so maybe they don't have high and low WG maps for that... I still need to loop the wastegate to make sure that's all good. I should just get an e-tune anyway. Link to comment Share on other sites More sharing options...
Ohoen Posted March 6, 2015 Share Posted March 6, 2015 Hmm. So I flashed the stg 2 91 octane map and drove around a bit. Things seemed good so I logged a few 3rd gear pulls. Now I peak at just over 17psi. I should note that it was significantly colder when I was getting over 18. Af learning and knock seem fine. I'm new to this, I think I logged the wrong dynamic advance because I got a lot of zeros and then some 4.5s and 5s... Anyway, I will maybe give it another try tomorrow and also bypass the bcs. Good luck jayrex, looking forward to an update. Link to comment Share on other sites More sharing options...
jayrex Posted March 6, 2015 Author Share Posted March 6, 2015 Hi Ohoen, I am using the stock intake. I had an SPT intake installed for a while, but I did not like the log values, and AF Learning numbers were high. The logs are much better with the stock intake. They asked about checking for boost leaks when I requested the maps. I had already tried the 'carb cleaner leak test' with no indication of a leak. I did not do a smoke test though. I still haven't done the bypass test because its been so cold here in NY.. and lazy. lol I would be curious about your results. I can give you the maps but they are for AT. I don't know the difference but would assume they are not for your 5MT. Here is my email to Cobb: I just installed: Cobb Downpipe Invidia UpPipe Magnaflow Catback Perrin Turbo Inlet (Stock intake) I am overboosting by 2 to 2.5psi. During hard acceleration I get the code: P0244 - Turbocharger Wastegate Solenoid 'A' Range/Performance I do not see a LWG map for the 2005 LGT as an option to download. Could you please send me unlocked AccessTuner Race compatible maps for STG2 91 and 93 with a LWG table. I believe I am getting boost spikes around 19 PSI max I am reading little to no knock. Most (if not all cases) during low loads - typically -2.00 value and rarely -4.00 AF Learning B, C, D are all +/- 0.50 with A around +3.5 I am pretty sure my vacuum system is leak free. Please let me know if you need any more info. I could provide a log if necessary, but the fuel cut is a little alarming. Thanks, Jay Link to comment Share on other sites More sharing options...
joeleodee Posted March 7, 2015 Share Posted March 7, 2015 Hmm. So I flashed the stg 2 91 octane map and drove around a bit. Things seemed good so I logged a few 3rd gear pulls. Now I peak at just over 17psi. I should note that it was significantly colder when I was getting over 18. Af learning and knock seem fine. I'm new to this, I think I logged the wrong dynamic advance because I got a lot of zeros and then some 4.5s and 5s... Anyway, I will maybe give it another try tomorrow and also bypass the bcs. Good luck jayrex, looking forward to an update. Sharp swings in temperature can cause a difference in actual boost like you are seeing. Touch want to check Dynamic Advance Multiplier (DAM). The figures you were seeing are the degrees of advance the ECU adds using the dynamic advance table depending on learned knock. Link to comment Share on other sites More sharing options...
Ohoen Posted March 7, 2015 Share Posted March 7, 2015 Thanks guys. I bypassed the BCS and did a couple of pulls. Peak boost was 12.9 at just under 5k RPM. Does that sound about right? Its about 30f right now. Assuming it is I'm just going to continue with the Cobb tune for now and not worry about it. Will probably get an etune this summer after I do the timing belt and some other stuff. I logged DAM this time... Solid 1. Link to comment Share on other sites More sharing options...
jayrex Posted March 7, 2015 Author Share Posted March 7, 2015 I have never seen my DAM go down, even with moderate knock values. If that is dropping below 1 you probably have a serious issue. Mine will sit at .75 for about 5 minutes right after a map change, then right up to 1.0 You really want to keep an eye on Feedback Knock during a pull. I heard some FBK can show up right when you hit the pedal (but does not seem to for me). I do get some at low loads, like city driving. But I've read knock at low load/RPM is nothing to really worry much about. The other value is Fine Knock Learn, that will pull an amount of timing in certain RPM ranges. For example I get -1.2 FKL around 4500 RPM because the computer has seen knock repeatedly at that specific RPM. Its trying to minimize the possibility of knock in the future based on past events. FKL values will only show up over time, and gets reset when you change maps. Here is thread that has a bunch of info: http://legacygt.com/forums/showthread.php/knock-do-you-have-anyi-97539.html This is another good one: http://www.romraider.com/forum/topic1840.html I've read a lot, but still pretty new to all of this. Anyone with experience please feel free to correct me. I did some logs today with boost staying at 17psi, it was 30 deg here as well. Link to comment Share on other sites More sharing options...
Ohoen Posted March 8, 2015 Share Posted March 8, 2015 I did log feedback and fine knock. They looked ok based on a Cobb write up I had printed out. I will double check though. I just got things back together. Replaced all the lines between the BCS and turbo/wastegate with sassy blue silicone stuff. Was feeling pretty chuffed about that until I test drove it. I forgot all about the restrictor pill. Durr... It's back together again. I should have just waited till I have the intake manifold off this summer. Things are fiddly in there. Thanks for the links, I have a lot to learn. Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.