BlackGT

I got the wideband put in last night (Thanks Bayley!) and after some fiddling, here is my 4th gear pull (at 16psi). I was getting some knock on the early runs, so I backed off the timing a few degrees.

 

Comments are welcome. I left it slightly rich as I need to tune the timing curve next.

6-14_4th_gear.pdf

the stock O2 is reacts to the partial pressure of CO in the exhaust to get an AFR estimate. Because it is placed before the turbo, it will also react to exhaust gas pressure. for a given (rich) AFR, it will read richer if the pressure is higher. you need to becareful if you are using its reading as a leaner mix will show up richer than it really is if the exhaust manifold pressure is high.

 

Sounds plausible, wow I bet I was running really lean. Good thing I kept the RPM's low.

 

So, why do we log AFR's off the factory O2 anyway if it is useless under boost?

Copy and past your DA table.

 

Log Turbo Dynamics

 

Also whats the question?

 

DA table is all COBB stage 2

 

Here is a log from last night, 4th gear from 200-6200 rpm. It is not happy up top, do I have too much ignition advance for the boost and IAT I am running?

4th_gear_pull_long.pdf

might want to add a WBO2 trace to the log. The stock sensor trace is saturated so there's no telling exactly how rich the car is running

 

You are so right, I will have access to a wideband this weekend, so I hope to get some traces done with that, but this is interesting:

 

I modified the primary fuel tables to add less and less fuel, the idea being if I made small changes and logged it each time at lower rpm's, I could tell when the AFR started to lean out above the 11:1. But I've gone all the way to 12.22:1 in the map, and the logs still say 11:1, so something is WAY out of whack. I'm getting more fuel in the engine than the ECU is asking for.

 

Me thinks it is my injectors. I have the DW 650cc's. I set the fuel injector scale using the process from COBB, watching the fuel trims at idle, but this only really scales the lower ranges of the injectors, what if they do not follow the same scale up through the duty cycle range....

3rd gear shifting to 4th log attached.

 

It is warmer out now, and it seems that the load has increased.

WGDC is very low since I have a 15psi actuator on the VF39.

3rd_gear_log.pdf

Not in mine

 

Ahhh, I see.

The metric thing did throw me off

 

If it were my car I would figure out what was happening and fix it.

 

It IS your car, it is present in all Subaru's.

Why not try a log in 4th gear from the beginning? That will tell you quickly if it is the shift that is causing the problem.

 

I did log a 4th gear roll-on back in post #227. Maybe you did not understand because it spoke metric....

 

I made about 3 runs yesterday using a more sedate 3-4 shift, and no more pulled timing!!! YAY!

 

Moral of the story: shift slower to go faster.

 

Thanks!

As much as I don't like that answer Christian, it makes a lot of sense as to what I am seeing. The 3-4 shift is the easiest one to execute quickly, so quickly, it seems, that the Subaru ECU gets pissed off. I will log again tonight with more civilized shifting.

 

If you are still tuned in, what is target boost for a Cobb stage 2 WRX STi? XX tapering to XX ? And how much base timing at 2.5 load and 6000 RPM?

 

thanks for chiming in!

That's sounds about right

 

Something is very wrong, that much we know for sure. Have you altered the dynamic advance table? Note that the Dynamic advance is falling through 3rd gear, maybe you should test your thermocouple The most obvious cause is that the charge is being heated too much.

 

I have a stock intake, I have not altered any of the maps from the Cobb stage 2 91 octane map, except for the WGDC and I richened up the fuel at 2.5 load and higher.

thanks

 

Why not just change it to log in Standard units? Makes life a lot easier

 

 

Back to the problem at hand: my car sucks, its probably my fault because I was logging in Bar, and it would all go away if I was logging in psi.

Those logs are in metric units with bar for relative pressure?

 

Yes, metric units. 1.25 bar = 18.375 psi.

Ok, Here are 2 logs. I just installed the 15psi actuator, so I set the WGDC to 0 so I did not overboost. The boost pressure is similar, maybe a little higher, than when I had the regular VF39 actuator in there with a .043 pill, and 90% WGDC. I think this is all the air this turbo will push... I expected more.

 

On to the Logs, the first one is running up through gears 2-3-4, and you can see that as soon as I shift to fourth, the dynamic advance goes all negative. The next one is a log only a couple seconds after the first, only I kept it in 4th gear, let the car slow down, and logged just a 4th gear pull---->notice there was no timing pulled (but I did not go quite as high in RPM as the first), there was actually advance added!

 

Thanks for your help!

LGT 2-3-4.pdf

LGTlog4th gear.pdf

I'm listening!

 

I've wondered why the delay was changed to zero on V1.16. Mine is at zero right now. The only knock event I've ever logged has been on a hot day, during a shift, with like 12% throttle and engine vacuum. I'll try different delay values tonight.

 

I'm still confused about why my load is lower than the rest. I could hit load 2.4X with the VF40, then only 2.54 with the VF39.

 

 

Why didn't you say so It would be nice to see the date from that thermocouple.

 

The open source tuning people are funny - Street Tuner works perfectly fine and it logs just fine too

 

Now on to your problem. I would check your OL delay. I would bet that it is set too high so that after you shift you are going back into closed loop and because the delay is too long, real knock is occurring. Don't set it too short or it will cause other problems. I used 100 across the board and that has worked out fine. I posted about this a while back. Even though no one listens to me you might find this useful

 

 

http://www.legacygt.com/forums/showthread.php?t=43450

rao, I just re-read and have to clarify, I was not saying that it was 60 degrees coming out of the cold end of the intercooler, I meant to say that it was a cool day out, it was 60 degrees outside ambient air. Even in 60 degree weather, the IC out air is still close to 100 degrees under boost. But my point was that in 100 degree weather, the IC out temp would be more like 175 degrees, and then I could see it pulling a bunch of timing.

How do you know what the intercooler outlet temperature is when you are in 4th gear?

 

Thermocouple probe.

The air that comes out of the turbo after being compressed is not quite as cool, that's what the intercooler is there to deal with. Also, only logging during ideal conditions is a great way to end up with a map that doesn't work very well.

 

Your load is being calculated differently than the rest of us - it does not take a very large turbo to get calculated loads over 3.

 

Yeah I know what an intercooler is for. My point was that the intercooler was not heat soaked, it was a cool day, which lowers the tendency for detonation or pulled timing.

 

My load sounds very low compared to the rest of you, what parameters does the ECU use to calculate load?

 

What kind of MAF voltage would you guys expect to see with a VF39?

I will attempt to post a datalog tomorrow,

 

I do not know Airboys software, is it something available here or on the web?

 

My calculated load peaks at about 2.54 (at around 3500-4000rpm) while logging, do you have a gigantic turbo or something to get above 3?

Is the negative dynamic advance occurring during the shift when the throttle is closed or after you shift into 4th and open the throttle again?

 

When I see the retard is after the shift when the throttle is at 100% in 4th gear.

If I go to a little better resolution on the data logging, I bet I could pinpoint exactly when it happens.

How did you get an LGT figment VF39?

 

1) I had a very very similar issue and with a ProDrive solenoid and a .025 pill (stock is .045) I was able to get around this. What size pill are you using? Mig welding tips for very well for this.

 

2) This is bad...you are overheating the air and the Perrin cant keep up time for Water Injection

 

I disagree that the only cause is overheating the air (I know the air is hot, but there must be something else), and here is why:

 

- It is cool (60deg) when I am doing these runs, and I make sure to cool down the IC before I do a logging run.

- It is only at 17.5psi.

- It happens like a light-switch, it goes from dynamic advance in third, to dynamic retard in fourth gear, always during the shift, and it only takes .2 seconds....

 

I guess I should turn down the boost and see if it happens at say, 15psi.

 

thanks for the discussion

Thanks It was more of a who did it, this is the first I have heard of one

 

Post up some logs

 

I built it myself, have built a couple of them. Also, use a VF34 and come up with what TDC calls a 35bb, put an 18G wheel on it and call it a 40bb. I built them about a year ago, was going to try to sell them if all went right, but decided against it since the only reasonable way to do it is to get used VF39's, and who wants to buy a used VF39 for their nice LGT?

I've been tuning for the past few weeks with ST, and I've got a few questions, would appreciate it if you guys can help out.

 

Car: 2005 LGT M/T, VF39 with LGT fitment and Perrin LGT TMIC. HFC in the COBB downpipe, SPT exhaust.

 

1) With my VF39, I can't get the boost higher than 17.5psi tapering to 16psi, even taking the WGDC's up to 95 percent, and making the bleeder (pill) smaller. I have a 15psi actuator I am going to try next, but I think I have seen people tuned to 20 psi on a stock VF39 actuator.

 

2) For ignition tables I'm running Cobb stg 2 91 oct tables, but I Always run 93 octane fuel. I see a good amount of dynamic advance added in first, second, and third gears, but then as soon as I shift to fourth, I see 5.5-7 degrees of timing removed!!!, even on cool days (shown as negative number). So my log goes from dynamic advance added in the top of third gear, to retarded only 0.2 seconds later. Anybody else ever have this and what do you think the issue is? Did the ECU see some knock during the shift to fourth? It happens every time.

 

thanks!

I'm running 11.3-11.5 at loads of 3.2 (last row of my map, which does need more rescaling)

 

At lowish to part throttle, high RPM I drop into the 10s, drive the WGDC way up and pull timing (something I'm experimenting with right now, it seems to help keep the turbo lit during shifts.... but it could just be placebo). Just below WOT at high rpms I'm running around 11 to keep the EGTs down during continuous high speed runs

 

 

Sounds like the AFR's I'm used to, I was just surprised to see 10:1 on the TDC dyno graphs.

 

Thanks

Hey, what AFR do you guys shoot for while on boost?

Cobb says start with a very rich setup of .68 Lambda, which is 10:1, and I've looked at a few TDC dyno charts which show about 10:1. This seems really rich to me... Do Subaru's just like this much fuel?

 

Thanks,

Jeremy

^ I am for now. If you read over Cobbs tuning progression steps thats one of the last things.

 

Are you on Stock injectors?

 

If you are having spooling issues with a VF39, never go bigger

 

Nope, no spooling issues, I have yet to get it fired up, waiting for one more piece to get the engine back together.

 

I have 650cc injectors, and a good fuel pump. Gives me a little headroom.