RomRaider

Hey team. Hoping someone can sanity check me here. I've got this weird boost cut/fuel cut when getting to WOT.

Car is an 07 JDM LegacyGT Spec B with a turbo inlet pipe and pod filter, a new catless turbo-back exhaust, an adjustable boost controller, TGV and Secondary Air deletel, spark plugs at .030 one step colder, and a 265lph fuel pump. Engine has studs, but is otherwise stock.

We live at sea level and is running 98 BP, which should be 93 for USDM octane calculation methods. It's colder here for you lot in summer, low 60s or high 50s in F, about 14Celcius.

This is the sputtering I'm seeing



It feels like it's just pulled all the timing.. Maybe boost cut or fuel cut.. it just hits a wall. Doesn't do it in Intelligent mode, when the boost is lower. I combed the tune over and over to see if there was another boost cut or fuel cut or ignition cut. Even tried expanding the cuts that exist. No change. Tried adjusting wastegate duty cycle, no change. I have started to think maybe I'm blowing the spark out wit the plug gap being too large.

Will attach log and map to see if anyone else can an idea or two to try. Was hoping to take it to the track this weekend, but not lookin good.

Log
Map

It either ended up being spark plug gap or moving the WBC’s port 1 to open. Hard to tell with this one, because we did both at the same time. However, since a day at the track it has started intermittently sputtering.

Haven’t been able to log it yet. Will report back with more once diag’d

There's still some occasional sputtering after a track day, but it looks like the main problem was the spark plug gap being too large. Had it set at .030", but closed it to .025 and not hitting that "wall" anymore.

Just have to clean some things up in the tune now. Speaking of. Anyone know of a way to get the MerpMod or any other patch to work for A2TB100K to enable Launch Control and/or Antilag? This thing is an animal, but would love the extra features.

sputtering is back. Anyone have any ideas?

It only seems to do it when the throttle is opened to 100%. Cleans up after 4k

I'm not going to lie, some of this looks weird:

On the newest log, you never hit 100% accelerator pedal, meaning your target boost is very low <11lbs. That being said, you are over boosting constantly. There's spots where your TD is pulling >45% because you are so far past your target boost. You might be at 100% throttle but the target boost is driven from your requested torque.

You might want to take a peek at your ebcs again. Or set your initial wgdc to 0 or something and see what boost it makes on spring pressure and move your targets up. There's a spot where there's only 7% wgdc and you are over your target by 2 psi.

I don't see any wideband data here but if your stock o2 is showing 13's my guess is that is pretty lean. There's a point where you are making 18psi at 13+ afr. My 2013 wrx shows 11.02 when I'm in the low 12's with a fair bit of boost.

You've got your fine and rough knock sensor's off above 2.9g/s and there are plenty of spots where you are hitting over that.

So if you are getting knock over 2.9 g/s it wouldn't register.

You gotta get a wideband but in the mean time I would at least bump the rough correction up to 3.5 g/s. You're hitting 3.13 g/s at 2400 rpm. Maybe that will show you are knocking and you need to look at fuel/timing.

Also you should think about rescaling your timing tables. They are way past maxed out. You only have them out to 2.55 g/s

Honestly with the amount you are over boosting there might be some hidden logic built in to pull timing back on this thing.

And a note on logging, the less columns the better resolution. You've got 2 manifold pressures, 2 loads, 2 VE's, 2 af learning's and a whole host of parameters you don't need.

Lastly, are you really doing these pulls in 5th gear or is that bogus data? That's really hard on the engine. Switch to 3rd or 4th for diag purposes.

Sorry for the so much info, I just kept finding more things as I went.

Deano,

Thanks for getting back to me. And I 100% understand what you mean by just going on and on as you see more and more.

I haven't been making 100% pulls because once it starts stuttering there's really no need to go any further. I did find that it stopped stuttering when I closed the gap even further. Running .023 now and most of the stutter is gone.

Now I need some help getting my head around how Subaru is doing their WGDC and TD tables. Nothing I do with the WGDC tables seems to really affect it. Now that the stuttering is solved, my biggest problem is that it overshoots the boost for a second, and then starts bringing it down and never recovers. If I set a target of 18, for instance, it builds up to 20, then immediately tapers it off to 15 or so and leaves it there 'til I shift or back out.

The wideband is running through the TGV on the right-hand side. I don't think it really ever gets to 13 unless I'm cruising. Mostly between 10.5 and 11.5 depending on the strength of the pull. It's an AEM 3000.

How can I rescale the tables? Is it as easy as changing the column at the top?
For instance, if these are my Target Boost column headers: 0 120 140 160 180 200 220 240 260 280 300 320 330 340 350 360
Can i change them to something like: 0 120 140 160 180 200 220 240 260 280 300 320 340 360 380 400 and have the intended effect?
Same with timing tables. Can I just edit the column headers to get the data to extend beyond 2.55?

I have cleaned up my logging with some forum reading, and looking at which might require 1 byte, 2 byte, 4 byte.

Pulls are mostly in 3rd or 4th. The car has a trans from an flat 6 Outback. I did change the gear thresholds to get it reading mostly right. It still has trouble seeing when I'm in 6th, so I need to do some editing there.

did you ever figure out the problem going thruw some s*** like that right now after switching back from e85, changed spark plugs already got a bit better but still sputter on high load

CJ,

Sorry for the delay.

If you haven't figured it out, yes you can change the column headers to rescale.

I would say on the Target Boost headers, that's based off requested torque and I don't think you need to change those much. If you see in your logs your RT hits 375 at WOT and stays there, so you really only have to play with the last column in that table.

For the boost target overshoot and dip, that is going to be related to your WGDC. You might have it a tad too aggressive on spool and not enough to hit your target after. Or you're asking for it to hit boost earlier than your setup can handle and it's winding the turbo dynamic up so your WGDC is much higher than you intended(if you're asking for 40% and it's adding 15%, then you're at 55% total). You aren't logging that in your screen shots so it would just be a shot in the dark. Best practice is work it up slowly. Reducing(zero if you like) your turbo dynamics may help you get a better idea of what's going on. This way the computer isn't trying to help you out by adding a bunch of WGDC for you. Start at 20-30 through the whole rpm range, see how close you are to your boost target, then add 5-10 where you are low until you are pretty close. TD will take care of the rest.

I like to set my TD activation close to my wastegate spring pressure so it's not adding WGDC too early. I also keep my target boost pretty low until an RPM where I know the turbo can make boost. Personal preference though.