So I finally decided to flash my 2010 legacy with a Cobb AP. Target boost for 93 and 91 maps should be around 17 and 15 psi respectively. Assuming I'm evaluating boost properly (by way of the boost metric in the data feed), I'm seeing on average 13.5 max boost with occasional blips up in to the low 14's on either the 91 OR 93 maps. The "installed stock" map yields a consistent 12 psi. I've been bumming around forums and random documentation and it sounds an awful lot like this could be a boost leak. Unfortunately, I am an apartment dweller and have limited access to tools/workspace, not to mention being a complete noob and having little clue what I'm looking at in the first place other than reading a bunch of junk online. Is there any chance any of you fine folks would be willing to take a look at what's going on here and walk me through troubleshooting? If it comes down to it I'll just head over to RS, but I'd like to save that trip for when the midpipe goes on... Also, I have some logs at home if it helps at all, but I'm pretty sure I'm looking at something mechanical given my research about continually hitting the same low boost threshold that's well under target. I can't detect any funny noises or anything that would make me suspect WG shenanigans or something to that effect either. Then again, I have that aforementioned "complete noob" issue so I might be missing something obvious. Also, also, car is bone stock aside from some minor suspension bits.
Besides the data have u noticed anything irregular when driving it? Is the power consistent and linear? I'm a newb myself but could it possibly your boost control solenoid? Just trying to throw some ideas out there.
Nope, nothing unusual. The 2010 is unusually linear to begin with thanks to the itty bitty turbo mounted directly under the manifold, and that still seems to be holding true. No fluctuations or odd drops in power. Just not as big of a bump as I was expecting.
Have you tried calling cobb? In the past their customer service has been stellar. Its the tuners responsibility to take care of you even after the tune (assuming you havent changed anything of course), so give them a try if you havent already. It could be anything, from a leak at the intercooler, to am intake leak, maybe a borked wastegate... Or it could just be the way your car is responding to this particular generic map on our mn gas. Start with cobb. They should be able to tell you what to log and should give you feedback. Let us know what they say and we can help you sift through any possible bs. Give them the chance to make right (assuming there it's something to make right) and make them stand behind their product. Good luck!
Thanks Idget, I'll drop them a line and see what kind of results they expect I should be seeing at this temp and elevation. 20% off target just seems excessive @ 850'.
DAM is holding steady at 1. Boost targets are pulled from Cobb's stated figures in the OTS map descriptions on the AP itself, also listed here on cobb's site. I tried the 91 and 93 maps separately and saw the same 13.5-14 peak, usually 13.5. I'd ask if you want to do a road tune, but I want to make sure I don't have a mechanical issue first... I have post going on the lgt forums and it looks like she might just be REALLY temperature sensitive. There's one other guy claiming he could barely scrape 14 when the temp was in the 20's. Heading out to do a pull and see what happens with our current temp of 37.
Not silly at all... 3rd and 4th. Obviously I can't to far with 4th, but I do see the best numbers there. Anywho, I'm starting to think it really is just THAT sensitive to temperature. Just saw some fairly consistent 14.9-15.1 peaks.
I am wondering if cobb did anything with the wastegate compensation, intake air temperatures. I should open up the map.
I am no expert, but the OTS maps are simply that - just an off the shelf map the will work ok with a wide variety of the specified car (no two stock (or modified) cars of the same model are exactly alike). I think that it is pretty rare to actually hit those boost targets that Cobb claims are possible with the ots map. For example, when I was running the Cobb ots map, I was not hitting that target boost range either - then combine that with cold weather, and it is very likely that you will be in the 13-14 psi range. I was concerned as well, but after I got a road tune (and got rid of the AP), my car was hitting far higher peak boost (20 psi). Regardless, it wouldn't hurt to do some more research and see where that takes you. Otherwise, an AP protune or an opensource road tune will likely yield much better results.
I would be more concerned with actual power production than boost numbers. Boost is a relative number in regards to airflow. 12psi at 10 degrees F might equal 14psi at 40 degrees F. Granted Cobb's compensation might be a little rough, but it is there for a reason. If you tuned a boost map for temperatures with a 100 degree range, you would see the major variances in airflow in regards to manifold pressure.
I'm waiting on a response from Cobb, but based on what you folks are saying and the feedback I got from lgt.com, I think the right question to ask would have been "should I be concerned about not hitting peak" as opposed to "how do I fix not hitting peak". Pretty sure everything is fine at this point. </noob>
