Having issues figuring out WGDC...

Ok, so I tried MickeyD's tune... No dice... I hit the boost cut out and overboost quite often... I'm assuming this is due to the tune being for a gutted downpipe, and not a full 3" bellmouth catless system.

 

So I've raised the boost cut's so I can fix this boost issue without hitting the fuel cutout all the time and I've richened up the a/f's to be safe... Now here is where I'm just stuck or confused I'm not sure.

 

I'm starting with Mickey's Boost Map, now I don't know if thats a good idea or not. I'm using the stock VF46 turbo which is the same as he made that MAP for, so I figured I could use it without any issues, now the WGDC tables is where I'm just completely lost. When I was hitting the boost cut I was told to lower them, but to keep the separation the same... I did that and the car seemed to be better, but only in a few gears, every time I hit heavy load 4th I would easily overboost.

 

I've been talking on Nasioc with bad noodle, and a few others in his tuning guide thread and I'm now understanding of what the TD Proportional and Integral are doing and that I should have them set to 0 while I'm trying to dial in my WGDC... Now here is my delema... I did that, and put all of MickeyD's settings back to the way they were, WGDC and Target Boost...

 

In 2nd gear at 3500 RPM I will be requesting 17.17 PSI and only hit around 15.5, and the primary WGDC will be 32.5 which is BELOW my Initial WGDC in that cell, which is 41 and thats with NO turbo dynamics running.

 

Following that in 3rd gear same pull I'll overboost by 0.88 at the most. Example 4500 RPM target 16.67, actual 17.54 WGDC of 48.63 (map initial value of 62 at 4400RPM)

 

And then in 4th gear at 4600 RPM I'll overboost by 1.54, target 16.55 actual 18.06, WGDC of 49.41 (Map initial value of 62 at 4400 and 65 at 4800)

 

SO... First question... Why am I underboosting and not even hitting my initial WGDC value in 2nd gear?

 

And I'm guessing to stop the overboosting in 3rd and 4th I need to lower my Max WGDC?

 

I can put up the log I took today if necessary.

 

Also I should note it was 40* this am and I'm not sure if that will cause any screw ups with the data, I do know there is not much compensation in my map by MickeyD at those temps though.

 

Car mods are as follows,

Bell mouth 3" downpipe, cat less

3" mid pipe, catless

3" GMK catback with resonator

AEM CAI

GFB Gt Hybrid BOV

Perrin TMIC

Please post your logs. Label them as to which gear you are in. Since it's an freely distributed tune could you either post the .hex or a screenshot with the boost target tables, initial and max WGDC tables and IAT compensation tables.

 

2nd gear issue you could easily have some IAT compensation which changes the target WGDC.

3rd gear issue your initial WGDC could be a little on the high side.

4th and 5th gear issue you might need to lower the max WGDC just in that area you see overboost.

 

Post the logs and we can help you more easily.

 

IME a proper bellmouth DP makes the wastegate more effective in controlling boost, not less.

Wastegate IAT compensation for around 32* to 50* is -29.7 to -10.2

 

So, ok yes I can see that being the result of the under boost in 2nd gear. But why didn't that come into play in 3rd and 4th gear?

 

I'll get some better logs in a few min with the temps around 55* out, also what do you want to see in the log?

 

I've been logging

 

* Engine Load (2-byte)

* Engine Speed

* Manifold Relative Sea Level Pressure (2-byte)**

* Primary Wastegate Duty Cycle

* Target Boost (2-byte)**

* Throttle Opening Angle

* Turbo Dynamics Proportional (2-byte)

* Turbo Dynamics Integral (2-byte)

If you're logging to diagnose boost control problems you could log boost error. Load isn't relevant but requested torque is handy if your WGDC table uses it as an axis rather than throttle angle.

 

Please post the logs rather than ask us to guess what's wrong with so little data to go on? Thanks!

I do have boost error logging, not sure why It didn't copy over in that last post.

 

Yes I know you need data to diagnose an issue but NOT ONE PERSON I'VE ASKED has told me what they want to see...

 

I could have just gone out and made a log then I would have been told, log something thats usefull, so rather than wasting time I was trying to figure out what you want to see and I'll go from there.

There is no circumventing Catch 22

I don't have time to get scans today, and upload them, so I just put the stock WGDC tables in place and now I'm underboosting by 1-2 psi... I'm fine with that till I can take the time to fine tune them, and its better than overboosting.

Wife has the car today, so I'll do some logging and tweak the stock WGDC table some next week and see if I can hit my target under control, and if that works out then that answers most of my questions...

 

I think my biggest issue was I was attempting to reverse tune the WGDC tables when I should have been starting with stock seeing how the Stage 2 file MickeyD posted was for a significantly different setup than mine.

 

Trying to get

<this thing to get another 12sec slip tomorrow at Epping so I'm working on that tune.

Not sure if you've crossed this bridge already, but the biggest key, by far, is not WGDC's or TD but rather setting up the right boost targets. Maybe take a step back if you need to so you aren't tuning around bad targets. You need to have a rough idea of what you want your peak value to be and a rough idea of what your taper (redline) value should be. I would start with conservative values past peak torque and get a couple 3rd gear runs in cold temps. Plot that out and set your pre-peak-torque targets 0.5psi above that 3rd gear boost line. This, with appropriate TD, is what will allow the turbo to spool as quickly as possibly in gears 1-3 but will cause very quick negative boost error in higher gears to prevent overboosting. If done correctly, you will see boost plots of 4th and 5th gears slightly lower and flatter than 3rd gear at rpms<3500. What I'm saying is... don't worry about WGDC or TD until getting your WOT boost targets set just where you want them... then you'll use WGDC and TD to get actual boost to follow your pre-conceived boost line..

The logs you sent me show that your boost is pretty stable, and a nice taper up top. WGDC correction factor was not too bad either. I think whatever you did put you in the right direction. I made tables A and B the same and my boost fell right into target.

Not sure if you've crossed this bridge already, but the biggest key, by far, is not WGDC's or TD but rather setting up the right boost targets. Maybe take a step back if you need to so you aren't tuning around bad targets. You need to have a rough idea of what you want your peak value to be and a rough idea of what your taper (redline) value should be. I would start with conservative values past peak torque and get a couple 3rd gear runs in cold temps. Plot that out and set your pre-peak-torque targets 0.5psi above that 3rd gear boost line. This, with appropriate TD, is what will allow the turbo to spool as quickly as possibly in gears 1-3 but will cause very quick negative boost error in higher gears to prevent overboosting. If done correctly, you will see boost plots of 4th and 5th gears slightly lower and flatter than 3rd gear at rpms<3500. What I'm saying is... don't worry about WGDC or TD until getting your WOT boost targets set just where you want them... then you'll use WGDC and TD to get actual boost to follow your pre-conceived boost line..

 

 

Well this is where I'm getting many different replies on how to tune it... I've been active on NASIOC with Bad Noodle and the suicidal eggroll, The best method that I agree with on how to tune it is to work with WGDC after you have a target boost map, which I already have since I'm using that from MickeyD's stage 2 tune, and to disable the correction system, aka TD so you can get your WG operating correctly without the correction and then once you have that stable you re-introduce the TD to keep the boost stable, and assist in the spooling aspect of it.

 

So after talking with suicidal eggroll, I'm going to do exactly that, I'm going to tweak my initial and max WGDC tables till I'm reaching my target boost correctly and stable, and then re-enable TD and that should simply assist in getting there and holding it during atmospheric changes.

 

GTTuner I'm surprised you say that my boost looks stable in those logs since if I were to put all the limits back to the way they should be I'll smack the boost fuel cut on a regular basis and see 18.24 as peak boost on a datalog when my target is 17.17

 

Let me know if these boost targets are crazy or not... As noted I did not come up with them, MickeyD has them in his general Stage2 tune.

 

http://www.barnett73.com/Legacy/Target%20Boost%20Graph.pdf

 

http://www.barnett73.com/Legacy/Target%20Boot%20Table.pdf

^^ I don't like those boost targets at all. Mickey and I tune boost differently though, and he taught me how to tune. Still, I acknowledge he is the grand master of tuning but those really high boost targets before peak torque are going to give you a lot of trouble. Those targets less than 3200rpms are way too high and that is why you are overboosting in high gears. Plain and simple.

 

You need to get a cold-temp 3rd gear WOT run 2krpms-5krpms to set your boost line up. Plot it out. Set your boost targets under 3200rpms a half psi higher than actual. Watch your high-gear overboosting issue go away...

So your saying to do a pull with no WG operation and get a plot of what it does mechanically and then use that line to scale it up to the peak that I want and to add .5psi to the targets between 2k and 3200rpm?

 

 

Am I reading that right? If so then I can do that I have no issues understanding the purpose behind it either.

 

You tuning guys have a tendency to leave out some "common sense" "to you" details that us new guys need to know to get things right

 

As I've stated before I'm not new to tuning, just new to the boost aspect.

Yes, exactly. Set Init and Max WGDC to 100% and boost targets to ~16psi straight across the board in WOT cells. Just get a cold 3rd gear run from 2k-4krpms. Set boost cut low at 18psi or so.. you might hit it but you aren't hurting anything. Stop the run if/when you hit it. No need to go past 4000-4500rpms at most.

Ok, I'll start with that on Monday... as noted I'm booked solid this weekend with the Pink beast.

 

Thanks for your input Legend I appreciate it and value it coming from you.

Yes, exactly. Set Init and Max WGDC to 100% and boost targets to ~16psi straight across the board in WOT cells. Just get a cold 3rd gear run from 2k-4krpms. Set boost cut low at 18psi or so.. you might hit it but you aren't hurting anything. Stop the run if/when you hit it. No need to go past 4000-4500rpms at most.

 

Also, revert to the mickeyd map TD completely. It is very good and likely does not need to be messed with at all. And my "cold 3rd gear run", I'm talking cold ambient temps after you've done a run or two in second gear to get the turbo nice and hot.

Yeah I knew what you meant by cold run, and thats actually going to be quite easy with how cool its been in the morning's lately.

 

Now for the TD someone told me to leave the stock values in there since I'm running a stock boost solenoid. Do you not agree with that statement and believe that Mickeyd's TD tables are more refined to work better?

^^Honestly I think either would probably work. But mickey was very, very good so I would use his TD tables. His tables are designed for the stock boost control (solenoid and ecu).

Ok, so I did the method suggested.... Now I've noticed from a 2k pull there is tons of turbo lag which is making my graph looking quite sad at least on the low end of things...

 

The stock target boost is higher than what I can make of my current graph.

 

Here is a link to the graph I made with stock target put in, my Stage 2 target from Mikckey's map, and my current PSI with no WG solenoid assistance.

 

The green line is the one with the .5 PSI added, obviously I would fether it in so it would be a large drop after 3200 but I just dropped it in there to see what it would look like.

Target Boost Graph New.pdf

Here is a link to the graph I made with stock target put in, my Stage 2 target from Mikckey's map, and my current PSI with no WG solenoid assistance.

 

No... you need 100% WGDC (init and max), not 0%.

Thats gonna hit the boost cut in like instantly, at least I would think so.

 

So I should take my whole WGDC table and set it at 100% and do a pull? Keep TD disabled or enabled? and what should my boost cut be set at? and what boost targets should I have in there? A stock target graph?

 

As noted I guess I'm missing a few of the details on how this pull should be made since I'm new at this.

 

I was working from this info

 

FIND YOUR MECHANICAL PROPERTIES.

1) Make sure you removed some timing, are running rich, and all your WGDCs are set to 0. You are doing this to test the mechanical efficiency of the turbo and wastegate first. So we want to see how the turbo and wastegate behave without any help from the ECU and boost controller.

2) Drive around logging your

a. RPM

b. Throttle Position,

c. Relative Pressure corrected (boost)

d. FBKC to make sure you’re not knocking.

3) The boost map is a 3d map broken down by rpm and throttle position. The goal here is to try and see how your car behaves in each cell (Each rpm and throttle position value).

4) Now you need to sort the data

a. Make a blank boost map with the same throttle and rpm values as your map

b. Rearrange the data so that you match up each line in the log to the closest rpm and throttle position combination

c. After you have data for each position, average the data for each cell.

d. Graph the map and make sure all the transitions are smooth. If not, smooth them out by altering the values in the cells.

e. Flash the map, go collect more data, and check again.

The idea behind this is since your turbo changed, your stock map no longer matches the turbo so you can't start from it and since you need a starting point, this is a good one.

B-BGL, I got my boost dialed in really close. Screw the Alt WG duty fix, I turned it off. I used the alt tables and used the turbo dynamics neg and I'm boostin awesome. Solid, steady, no spike. We should get together one night and frig with it. Be carefull with those WGDC tables! After adjusting and testing I have a good understanding waht to do in the TD tables and such.

 

I also rescaled my MAF with RR maf logger. What a diffence and it's easier to do than most make it out to be. You only need a 15 minute ride, the run it in different load and rpm areas to fill in the graph corrections.

Yeah I've been working with the maf scaler, no different than any of the functions I've done with my beretta so thats all easy stuff to me.

 

I guess my only concern is I need a better target boost graph for my turbo.. I know how to get the wastegate tables to work with it, but I just need a better more obtainable graph since the current one had a very high target for a very low RPM.

Yes, exactly. Set Init and Max WGDC to 100% and boost targets to ~16psi straight across the board in WOT cells. Just get a cold 3rd gear run from 2k-4krpms. Set boost cut low at 18psi or so.. you might hit it but you aren't hurting anything. Stop the run if/when you hit it. No need to go past 4000-4500rpms at most.

 

This. And run mickeyd TD. First run go to 3500rpms. If no boost cut, repeat to 4000rpms.

I guess I read over that part to quick, my bad.

 

now my WGDC limit will come into play and stop it at 90, is that ok?