boost issues? with log

I'm not really sure what's going on with my car. Figured I would post some logs and see what the experts think. I seem to boost fine, then it legs for a second, and then it kicks back in around 5k rpm. It's an 02 WRX with a small 16g. Here's the log:

Code:

seconds/rpm/cal ld/ DAM/ Igni adv./dyn. adv./throttle %/ boost/wgd   /mafv/   fuel trim long
59.82	2961	1.61	16	15.5	8	99.96	7.98	13.33	3.26	-10.16
59.97	3104	1.79	16	14	8	99.96	10.15	18.03	3.38	-10.16
60.14	3199	2.02	16	13	8	99.96	11.89	21.17	3.58	-10.16
60.31	3375	2.26	16	10.5	8	99.96	15.23	25.87	3.78	-10.16
60.5	3537	2.47	16	9	8	99.96	16.97	26.66	3.9	-10.16
60.65	3748	2.62	16	8	8	99.96	19.43	26.66	4	-10.16
60.82	3858	2.71	16	8	8	99.96	20.74	24.3	4.08	-10.16
60.97	4155	2.81	16	7.5	7	99.96	21.9	20.38	4.2	-10.16
61.16	4312	2.79	16	7	7	99.96	22.34	14.11	4.26	-10.16
61.31	4515	2.65	16	8	7	99.96	21.17	10.98	4.24	-10.16
61.48	4719	2.43	16	11	7	99.96	18.71	12.15	4.2	-10.16
61.63	4960	2.35	16	12	7	99.96	16.1	16.46	4.22	-10.16
61.82	5140	2.39	16	12	7	99.96	16.1	19.6	4.28	-10.16
61.97	5304	2.5	16	11.5	7	99.96	17.11	22.74	4.38	-10.16
62.14	5438	2.58	16	10.5	7	99.96	17.98	23.91	4.48	-10.16
62.29	5651	2.61	16	10.5	7	99.96	19.14	23.91	4.52	-10.16
62.48	5841	2.61	16	11	7	99.96	19.72	24.3	4.56	-10.16
62.63	5952	2.58	16	11.5	7	99.96	19.72	23.91	4.6	-10.16

I gotta admit, this whole logging this is a little new to me. Not really sure what I would be logging or looking for, however, you can see in this part where the boost is fluctuating and the throttle position doesn't move. Thoughts?

HTML:

Edit: I added a bit longer run of the log as well as an attachment. Figured that would help illustrate what is going on through most of the gears.

 

Hey man, use the [.code] tags to post your logs (no period). Be sure to edit the headers so that everything lines up right. Are you logging with RomRaider and the newest definitions?

Or just attach the .csv/excel file to your post.

 

ah, that bad boy likes to boost I see, you're hitting over 22psi!:yumyum:

I wish I could help, but I'm a monkey within tuning. Was it doing that immedaite after the tune as well? Or did this just come up?

 

is it me or is that just kinda hard to read...

Edit : nice fix

 

Can you feel the car slow down? or just noticed it on the logs.
What boost control?

 

Thanks for the tip. I'm logging with an AP.

I can feel it slow down, its definitely noticable. The main thing though, I can really feel it kick back in. And you can watch it on the boost gauge in the car as well. It's actually not as bad on the log then i expected. On the boost gauge it drops to half of what it was.

I am running an AP, Perrin three port bcs, an APS 50/50 bov, and an Grimmspeed 38mm ewg.

 

What gear was the log run in? Also, what weather (what ambient temp)?

Your car was tuned at DB, right? Did they tell you what boost targets were? Looks like your car is overboosting significantly and then pulling down WGDC to compensate, which is causing a "rollercoaster" boost curve (boost bouncing up and down, opposite of WGDC). This is very common if you have improperly tuned boost targets, WGDC, or turbo dynamics.

Here's a visual example:



In your case, looks like your tuner failed to "flatten" the turbo dynamics tables, so your ECU is pulling way to much WGDC when it overboosts, which is causing your hesitation (which is actually the boost dropping by around 7 PSI for a few thousand RPM). This can be fixed by raising boost targets or lowering WGDC, in conjunction with flattening the TD tables.

 

It was tuned at DB and that makes sense. The print off I have of it shows the PSI fluctuating, I just didn't realize how bad it was I guess. It was tuned for 20.5psi dropping down to 19 at redline. I admit I'm not sure of the exact gear this one was in, but it doesn't matter, it looks pretty much the same in all gears. Although, I didn't log anything really in first.

 

That is absolutely horrible boost control. The fact that you even paid for this is even more rediculous.

Go back and demand that they fix it FOR FREE.

 

Their fixing it. I sent the log to Shane, he's taking a look at it, will treak the map, and send it back to me. I am just trying to get better at reading logs and what not as well as wanted to get others thoughts on the log.

 

That's cool that they are fixing the issue (as they should). Your long term fuel trim is crap as well.

 

Agree, glad they are looking at it for you. Same as Tom, I'd recommend you see if they can properly scale your MAF or work on your injector scaling as well. That LTFT indicates that the car is pulling 10% of it's fuel at WOT, if you were tuned at 11:1, this means your car is now running 12:1 AFR's.

 

DB can't really scale the MAF or injectors without the car present, can they?

 

They could guess based on his LTFT's, but no, not really.

 

This may be a dumb question, but what do you mean by scaling the MAF?

Shane was trying to say that I shouldn't run higher boost than I am because, if I remember correctly, the MAP? couldn't handle it. I asked if he meant the MAF, and he said no. Any thoughts are being able to run more boost than 20.5psi?

 

Your stock MAP sensor can read up to ~23.x PSI. He is right, the MAP sensor is different the MAF sensor. The MAP sensor is the pressure sensor that your car uses to determine how much boost it is running. The MAF is the voltage sensor in the intake that determines how much air is entering the engine.

The MAF and ECU translate voltage readings (which are inputted by how fast air is passing the MAF), into actual gram/second airflow. "Scaling your MAF" means matching the ECU's translation values to best match exactly how much air the car is flowing per voltage cell.

 

The MAP sensor only reads up to around 22psi.

EDIT: Nate beat me to it, lolz.

 

So, what your saying is that if I want to run higher boost, I need a new MAP sensor. I do appreciate all the help guys, as I said, I'm still trying to learn here.

 

True, the MAP maxes at ~23, but the car will still read calculated load values up to the MAF g/s cap. On 16 bit ECU's, this is 300 g/s. There are work-arounds for this (which are basically multiplying the MAF table by 1/2, and changing the load values in all your other maps to reflected this), so sure, you can run tons of boost and a massive turbo on the stock ECU. You just need to ensure your tuner knows what he/she is doing.

 

:hsugh::hsugh::hsugh:

 

Hmmm. I guess that kinda makes sense.

Alright, let me see if I understand this. The MAP and the MAF are interconnected, in a way. The MAP may max out, but the ECU will still read as high as the MAF will go? So your basically using the MAF sensor only instead of both? Does no one just replace the MAP sensor?

 

Ok, after much research, I think I at least have my options narrowed down (this is me thinking on paper).

New MAP sensor. Either an AEM or a Zeitronix along with a Cobb MAP mounting bracket. GM makes one as well, but I don't know if it's the correct style. Also, would need to figure out how to wire them in.

A Boost Cruncher, which limits your MAP from shutting down.

A zener diod, which does the exact same thing as above and is probably a lot cheaper. Based upon Nasioc, this is apparently what Clark Turner does. He only states that he uses a 2 dollar part to make the MAP reliable up to 30psi with full usage of the MAP sensor. However, he won't say how he does it.

Change the MAF table. My question with this is, does the MAP sensor still provide fuel cut off in over boost conditions, or is it unusable? I would like to keep the MAP sensor available for the safety features.

Those seem to be the options, as for what I can find, no one has any threads posted about actually doing any of them. Only that tuners recommend they change it and arguments ensue.

 

can I say something without it sounding too negative towards your tuner???

When both Nate and Russ tuned my car I had none of these issues. the more recent tune the nate did had my target boost at 21.4 tapering to 18.5 or 19....and the boost was always spot on.

 

It could be the tuner, or it could be the car. Just saying. Shane warned me about a new MAP sensor when I was there, said I should replace it if I wanted to run more boost. But your right, I don't think his expertise is in Subaru's, I think it's Mitsu's/DSM and Mustangs. As for the boost issues, it wasn't like this on the dyno, the graph shows it fluctuating by about 1 psi intermittently. Not seven.

Regardless, this needs to get fixed before I head back for a E85 tune and even higher boost.

 

Issues on the dyno can be multiplied when loading the car on the street.

Anyway, the most common "fix" for the maxing out the MAFv sensor is getting a larger intake that can take more air in at a lower voltage.

With that said, it is extremely unlikely (or virtually impossible) that you will max your 5v MAF with the regular 16g.