Protune - boost problem. Help!

So, went to have my wagon protuned for E85 and had an issue getting boost to come up on the dyno. It seemed like it was working fine at first, but as he started turning up the boost table the boost wouldn't follow. We were only getting 14# on the dyno.

 

At first he suspected the BCS, but swapping it out for a GM BCS made no difference. Eventually he concluded that the wastegate sping had gotten soft, and wasn't keeping the wastegate closed.

 

But...

 

When I was leaving I hit an on ramp, and when I nailed it in third I got 20.5#.

 

After playing with it a while (and pissing off the wife), I found that if I start a pull ~2k, it'll just slowly climb to a max of ~16#. If I start a pull at 3k, or let off and re-stab the gas mid pull, I get full boost no problem.

 

I loaded my re-scaled Infamous tune, and it shows none of this behavior. Just builds boost like normal.

 

So I'm lost, not sure what would make it do what it's doing, but I'm reluctant to believe it's a hardware problem...

 

 

Attached are 3 logs:

 

1. Full 3rd gear pull from 2k, then decel to 60mph & WOT in 4th.

2. 3rd gear pull with dropping & re-applying the throttle at 4.5k.

3. Partial 3rd gear pull with dropping & re-applying the throttle at 2.9k.

 

Note how quickly the boost comes up on the second half of each.

 

 

Any ideas guys?

 

 

 

 

BTW, it made 270 AWHP @ 14#, and the Cobb AP "dyno" run I did that got the boost to come all the way up read 313/364.

 

http://i140.photobucket.com/albums/r16/turkeylord/2005%20Legacy%20GT/IMG_6416.jpg

datalog1.csv

datalog2.csv

datalog3.csv

Bump. Anyone?

You need a retune - something funky is happening with your WGDC. If you look at the logs where you maxed at 16 psi your WGDC max is ~60-70%. On the log where you got to your 20 psi target - WGDC was 80%+.

 

I have no idea what could cause this...but since switching maps fixes the issue, its pretty clear it is a tune issue IMO. Maybe a typo in the WGDC table or in the boost target tables.

 

If you are using Romraider to log, use the fast polling option it provides a lot more data.

 

You should also note that your fuel trims are a little off..but that is not the cause of your problem

since switching maps fixes the issue, its pretty clear it is a tune issue IMO.

 

This. I assume you already know who I'm going to recommend.

This. I assume you already know who I'm going to recommend.

I really don't think there's any other logical answer. And yes I know, but "because dyno"

 

I need to spend some more time playing with it, too bad it's a licensed tune and locked up...

*shrug*

 

The price you'll pay for "that other guy" is well worth it just for exploratory purposes if nothing else. It's not like you're stuck with it.

Why so little WGDC at lower revs? Interesting approach to boost control in the spool area that doesn't seem to work too well.

You do normally see earlier spool on the road than on the dyno, especially when you start booting it up hills. Did you not get the tune finished up on the road?

If you want to see what's going on better, get rid of your AF parameters and log TD Integral and TD Proportional and also boost error. Also get rid of MAF voltage.

 

Your first log starts at 1400 RPM WOT. Bear in mind that depending on how your boost target table is setup and your TD activation thresholds, you may be accumulating a lot of negative TD Integral when you floor it at 1400RPM which is forcing your WG to be very low during spoolup. But that's just a theory. Won't know until you log the TD parameters.

As for why when you "pump" the throttle on the second part of the log the boost shoots up high, if you log the TD parameters, that will help immensely but you can see immediately 2 things

1) The PWGDC is 80 after you pump is, which is nearly DOUBLE the value immediately before you pump it. Of course you're going to make a lot more boost.

 

2) The turbo is already spooled up so it'll shoot to your target and past it very easily.

Why so little WGDC at lower revs? Interesting approach to boost control in the spool area that doesn't seem to work too well.

You do normally see earlier spool on the road than on the dyno, especially when you start booting it up hills. Did you not get the tune finished up on the road?

No, we didn't get that far.

 

If you want to see what's going on better, get rid of your AF parameters and log TD Integral and TD Proportional and also boost error. Also get rid of MAF voltage.

 

Your first log starts at 1400 RPM WOT. Bear in mind that depending on how your boost target table is setup and your TD activation thresholds, you may be accumulating a lot of negative TD Integral when you floor it at 1400RPM which is forcing your WG to be very low during spoolup. But that's just a theory. Won't know until you log the TD parameters.

Ok, thanks for the advice. I changed my logging params and did some more pulls. Sorry for the data overload, but I wanted to make sure I got it, lol...

 

As for why when you "pump" the throttle on the second part of the log the boost shoots up high, if you log the TD parameters, that will help immensely but you can see immediately 2 things

1) The PWGDC is 80 after you pump is, which is nearly DOUBLE the value immediately before you pump it. Of course you're going to make a lot more boost.

 

2) The turbo is already spooled up so it'll shoot to your target and past it very easily.

Ok, that makes sense. The attached logs are full pulls to redline without any pumping shananigans.

Pull 1 - 2000.csv

Pull 2 - 2000.csv

Pull 3 - 1500.csv

Pull 4 - 3000.csv

Pull 5 - 3000.csv

Pull 6 - 3000.csv

This is very weird.

 

There are 2 tables that set initial WGDC when tuning boost. The values in those tables should always be exactly the same. Since (I think) no one knows exactly why/how the ECU chooses the table to use..they need to match.

 

My theory (a complete guess really):

 

The tables do not match on your map and something is causing the ECU to pick one or the other.

Pull 1, 2, and 3 are all very weird, and the commonality I see between them is

 

1) they all start at lower RPM

2) Turbo Dynamics Integral AND proportional are ZERO all the way throughout the log

3) WGDC is very, very, low.

 

Pull 4, 5 and 6 look fine, except it looks like your TDI is capped, but really, that's the least of your worries.

 

Like SpecB said, something's not right with the tune. Maybe mismatched tables or something... but that wouldn't explain why your TD is completely deactivated for pulls 1-3. VERY VERY weird... There's no reason your WGDC should be one thing in one pull and a completely different thing in another pull... There will be variance in actual WGDC seen due to TD but not like what you're seeing. Plus, you can see it's not a result of TD.

 

Your tuner should go over your tables with a fine tooth comb and maybe even just get another base map to start over with. Something is very not right here.

 

On the plus side, your car's probably mechanically fine. Better software than hardware!

Found this, and found it interesting as he mentions starting pulls at different RPMs:

 

[CLIPPED]

 

I think the big issues with real world turbodynamics are:

 

1. Boost behavior is completely different below boost threshold. For example, on the LGT, it is ridiculously easy to stabilize boost if you start your WOT run at 4000 rpm but very different if you start your WOT run at 2000 rpm.

2. The actuator itself behaves as an accumulator and is like a secondary integral that responds based upon the previous WGDC and time.

3. The speed in milliseconds at which boost builds is dependent upon which gear you are in. The TD tables are all built around boost error as the independent varaible so d(TD)/dt will be different depending upon which gear you are in.

Thanks for your thoughts guys, I sent the logs to my tuner and he said he'd send me a revision :crossing fingers:

No, what MickeyD explains has nothing to do with your problem, believe me. Something's messed up with your tune.

Understanding fail...

What MickeyD describes explains fine tuning boost control and minor fluctuations.

 

You're completely off the mark. TD isn't even functioning in your first 3 logs and you have over a 40% WGDC difference at the same RPM between the first 3 and last 3 logs. That is NOT explained by MickeyD's post.

Well, after a week back on the stock DP, I'm putting my new-to-me Cobb on tonight. Then I can resume trying to figure this out.

 

I sent all logs to my tuner, but he's not exactly great about getting back to me...

After a bit of help from Cobb, rev 3 has fixed the problem! Something to do with "Wastegate Duty Cycles Alternate (High)" table being fixed or disabled, so you guys were right on track!

 

Cobb AP dyno thing (FWIW, anyway) says 329 awhp & 347 ft-lbs.

Oh good, it's fixed. See you Saturday for real numbers then?

I wish! Bad timing - local street legals & a Bison game Saturday...

After a bit of help from Cobb, rev 3 has fixed the problem! Something to do with "Wastegate Duty Cycles Alternate (High)" table being fixed or disabled, so you guys were right on track!

 

Cobb AP dyno thing (FWIW, anyway) says 329 awhp & 347 ft-lbs.

 

Im suprised that wasnt caught on the dyno, thats been an issue that was figured out years back on the romraider forums and the tables are the same for cobb.

 

Glad to see everything is fine now and you can enjoy it.

 

Dave