09 Cobalt SS Aftermarket Turbo Low Boost Level Issue?

[tillman speed]

Normally 95 dollars, but 75 dollars for 4 pulls with the wideband sniff-uh! And if you're like 4 runs in and you need another run or two to get it perfect or something, I'm not worried about it. I throw the dynojet wb sniffer on just to have a second AFR source.

We can do loaded or inertia pulls.

Thanks for the help fellas. I'm wondering why the DAL's I'm asking for aren't being seen?

Question about the maf correction. Do I literally just "add" it in?

For example... the third cell down on the left column is 2. The tune file top left cell is .95.

Do I add in .02? So, in this case .97?

[Terminator2]

Have a 2009 Cobalt SS with aftermarket Dejon 5457 turbo and catless downpipe, as well as Dejon intercooler piping, greddy BOV and dejon intake.

Made a base file up with desired air load right below 300, keeping it fairly conservative with a stock timing table. Car just does not seem to be acting right. Boost on the gauge is around 18psi, this last pull the throttle was limited out of nowhere (overboost?? wtf??? I turned it off in the Engine Diagnostics???) and was from 16-22psi (mostly on the low side) and our dynojet boost sensor is jiving with that.... (about 18psi or so on every run). So we're putting down about 300RWHP and air fuels look great.

The actual log shows 255kPa, I'm just confused how we aren't seeing the right pressure?

We're taking our dynojet boost reading from the hose between the turbo and the wastegate selenoid.

Ideas, anyone?

Chris

Disable your underboost as well so you can command better DALs in the less than 100% desired torque columns. Ramp up your max airload to 100% that normally works best with big turbo cars. If I were you I would crank the DALs even n the 70 and 80% columns up more that turbo will like 25-28 psi. Richen the 80% and 90% areas of the PE table as well Get a real analog guage because the stock boost guage is an electronically calculated value not always actual especially with a big turbo set up. It will like more timing too you should street tune it first to see how much timing you can run without knocking. Then fine tune it on the dyno.

[tillman speed]

Took your advice. Here's my tune file now. I'm about to run it and get another log.

http://www.tillmanspeed.com/modified.hpt

[BackyardTurbo_FTW]

I called your shop before, we're looking to come sat morning if possible?? Lemme know

No tune file attached above?

Edit: As for the Maf Cor: If you look at the last column, 3520rpm you see a +7. Goto that cell on the Maf Cor table and put 1.07 into the box up top, then press multiply. If you wanted to subtract 7% you would use .93 and then multiply.

[tillman speed]

I called your shop before, we're looking to come sat morning if possible?? Lemme know

No tune file attached above?

Edit: As for the Maf Cor: If you look at the last column, 3520rpm you see a +7. Goto that cell on the Maf Cor table and put 1.07 into the box up top, then press multiply. If you wanted to subtract 7% you would use .93 and then multiply.

Okay got you, so I'm multiplying by the percentage. Nice.... That should be easy enough. Saturday would be fine! Give me a call tomorrow and I'll get you all scheduled in.

Damn file was too big. I uploaded it here:

http://www.tillmanspeed.com/modified.hpt

[BackyardTurbo_FTW]

Better on the PE table. I would still increase the DAL's quite a bit more tho! They are not a direct correlation to KPa, Term knows the formula for that off the top of his head tho! lol. I have it in a PM somewhere actually. But basically, dont be afraid to jack them up

[tillman speed]

Better on the PE table. I would still increase the DAL's quite a bit more tho! They are not a direct correlation to KPa, Term knows the formula for that off the top of his head tho! lol. I have it in a PM somewhere actually. But basically, dont be afraid to jack them up

You just answered my question. Okay cool.... cause I'm sitting here going:

26psi + 14.7 = 40.7 * 6.895 = 280.62 and so I'm at 285 max on the DAL's thinking I should be at 26psi.

If it's normal for the kpa to be less than what's in the DAL table, then I'll jack em up to like 320 ish?

I'd love to see that formula, lol! I'll bet it's nuts!

Here's a log of the last run before reading your post. Look at timing and lambda

[BackyardTurbo_FTW]

Def looking a bit better, do a few runs leaving the logger running the whole time, even if the car has to sit. It takes averages for the Maf Cor histogram, so if you do a few WOT pulls you will be able to dial in that table for the best performance at all times.

[Iam Broke]

If the MAF correction isn't linear across the board, you can use the multiplier on the freq ranges for say a 5% shift above a certain point. Easier to get it closer that way when the 'ramp' is off on the intake than entering each correction cell in the correction table IMO.

[tillman speed]

I'm gonna do what you said on the MAF correction. I should get it within like 3% throughout the whole table right?

As for the last run.... I went apeshit on the DAL table and no change whatsoever on the boost level. Still around 230-235kpa.... makes sense @ 19 PSI on the gauge. We're asking for "33" or atleast in the mid 20's right?

So what do I do from here? Do you think its an under/overboost thing?

Pill mod?

Here is my DAL right now:

[Iam Broke]

Jack the 90 & 100 % columns up to 300 at the low end and 350 or so up top. The boost duty cycle will spike to 95+%, then cut back to the mid-high 70's no matter what you do. We don't have all the tables unlocked.

I wasn't pleased with the control of the boost with the pill mod, but I gave up early on trying to tune for it.

You should be able to hit 255 kPa then hold around 240 or so, I can on the stock turbo anyway.

[BackyardTurbo_FTW]

The pill mod makes up for the lack of WG control. Try it, prolly start with a .035 tip

[tillman speed]

So at this point without a MBC there's no way for me to get this car to hit 26psi?

20-22 PSI is going to be the max?

This is what I did to the DAL... should I try this DAL with a .035" pill mod?

[BackyardTurbo_FTW]

I would try that DAL setup first, if you still are not getting over 22psi then I would goto the pill and your previous DAL setup. Try that and work it up or down from there based on the log. The "pill" is a lil unpredictable at the moment until enough people play with it and find some common results. Every car I've done it to so far has acted slightly different then the last as far as boost spike and what it holds.

What gear are you dyno'ing in BTW?

[tillman speed]

I would try that DAL setup first, if you still are not getting over 22psi then I would goto the pill and your previous DAL setup. Try that and work it up or down from there based on the log. The "pill" is a lil unpredictable at the moment until enough people play with it and find some common results. Every car I've done it to so far has acted slightly different then the last as far as boost spike and what it holds.

What gear are you dyno'ing in BTW?

4th... correct for these cars right? I figured it would be 1:1 or the closest to it.

[wantedSS/TC]

4th is .98:1. 3rd is 1:35 (I believe off the top of my head):1, so doing 4th gear pulls is correct.

[BackyardTurbo_FTW]

Yea, you got it Chris. We found the car made the best power in 4th on the dyno.

[tillman speed]

Newest log! Was the same boost-wise. Made about 330RWHP SAE corrected out of 232kPa pretty much flat. I'm gonna give this pill thing a shot.

The boost desired DC was around 74-78% pretty much the whole time.

Let's try this pill with the last DAL and see how she does!

[wantedSS/TC]

Yeah, wait until you put in the pill (I have .30 tip in). I know Nick retuned for it though. 1/3rd throttle is full boost!

[BackyardTurbo_FTW]

Its def looking better still. I would go for the pill mod tho and crank it up!! Are you getting clutch slip starting that low in 4th??

Trims are looking quite a bit better! Still needs a lil correction adjustment up top but this is MUCH better then when we started