Compound turbo tuning

[Ridin'GMC]

So as the title says, need some tips to get me dialed in on my LBZ. I've done countless research over the web and not much info to get me dialed in. Mostly related to vgt tables and map/boost settings. So far I've taken small changes in the tuning as I've progressed over each tunes I've done and each has made improvements. Trying to clean up the smoke at low end.

Any help would be appreciated, it does seem at this point most people prefer to keep it quiet and talk over DM.

Here's my dilemma, I've already adjusted the MAF and it's reading 41-42 g/s at idle when warmed up but 48-50 when cold, I'm assuming this is due to the vane setting in the cold setup. At full boost, it'll trip a p0108 when it's hitting 38 psi and the vanes back off to reduce boost to prevent over boosting, I'm not sure if I should set the boost setting higher in the desired boost tables, l will be getting a boost gauge for the atmospheric turbo to read what it is pushing, I have my total boost gauge tapped in the y bridge. Turbo setup is 480 billet race cover over JZ 63mm vgt valley turbo. Stock fueling for now, but does have an exergy sportsman cp3. No low rail pressure code, holds 24-25k at wot. I've been tuning my LBZ since 2011 and this is my first compound turbo tuning, it's a different ball game to get it dialed in and taking small steps not to hurt anything.

 

[2004LB7]

For your smoke at low boost, log your air per cylinder and then adjust the fuel mixture limit table

Using the scan tool, you can log the actual boost and build a new table for that. Then actual and expected should more closely match

You can use this same process but for the boost table

Adjusting Vane Position | Fish Tuning

NOTE: This information is for learning purposes only. We do not take responsibility for anything that happens to your vehicle as a result. Please use at your own risk!Adjusting Vane Position on your DuramaxThanks to Tyler at Punisher PerformanceSo you’ve increased your desired boost pressure...

www.fishtuning.com

 

[Ridin'GMC]

For your smoke at low boost, log your air per cylinder and then adjust the fuel mixture limit table

Using the scan tool, you can log the actual boost and build a new table for that. Then actual and expected should more closely match

You can use this same process but for the boost table

Adjusting Vane Position | Fish Tuning

NOTE: This information is for learning purposes only. We do not take responsibility for anything that happens to your vehicle as a result. Please use at your own risk!Adjusting Vane Position on your DuramaxThanks to Tyler at Punisher PerformanceSo you’ve increased your desired boost pressure...

www.fishtuning.com

Thanks. Does this correct the issue for popping an over boost code? As I've read, I should be pushing 55-60 with my setup, can't get over 40. That's when it pops the code and backs off the boost to low 30s. I have my desired set around 40, wasn't sure if I can raise it higher without hurting the valley turbo, wasn't sure if the atmospheric turbo pressure is added to the combination of the valley charger pressure to not over speed/over boost the valley charger.

 

[2004LB7]

The valley turbo boost that it sees is the difference between the incoming pressure and outgoing pressure. So if your large turbo is pushing 30 psi into it and the valley turbo bumps that up to 60 psi then the valley turbo is only doing 30 not 60 psi

If you have the table set to where it should be then it will prevent the codes and limp

 

[Bdsankey]

The valley turbo boost that it sees is the difference between the incoming pressure and outgoing pressure. So if your large turbo is pushing 30 psi into it and the valley turbo bumps that up to 60 psi then the valley turbo is only doing 30 not 60 psi

If you have the table set to where it should be then it will prevent the codes and limp

Correct. The target/desired should be actual not just the valley turbo's contribution tho since it's read off the MAP sensor.

 

[JoshH]

It's actually a little more complicated than that. If you look at a turbo map, you will see there are no boost pressures listed. They list total airflow and pressure ratio. You have to compare the total pressure coming into the turbo and relate that to the total pressure coming out. As a general rule of thumb, you can shoot for double whatever the atmosphere turbo is doing. If the atmo is doing 30 psig, then generally 60 psig from the valley turbo is safe. That said, you will have to disable overboost codes because you will max out the stock map sensor. You will also want to use the minimum vane position table to control total boost or the vanes will open up all the way in an effort to keep boost under control. It helps to have 2 boost gauges (1 between stages and 1 in the y-bridge) to get the tuning dialed in.

 

[TheBac]

Because of Josh's explanation, I've sticky'd this thread so we don't lose that (or any other) info.

 

[Ridin'GMC]

It's actually a little more complicated than that. If you look at a turbo map, you will see there are no boost pressures listed. They list total airflow and pressure ratio. You have to compare the total pressure coming into the turbo and relate that to the total pressure coming out. As a general rule of thumb, you can shoot for double whatever the atmosphere turbo is doing. If the atmo is doing 30 psig, then generally 60 psig from the valley turbo is safe. That said, you will have to disable overboost codes because you will max out the stock map sensor. You will also want to use the minimum vane position table to control total boost or the vanes will open up all the way in an effort to keep boost under control. It helps to have 2 boost gauges (1 between stages and 1 in the y-bridge) to get the tuning dialed in.

Thanks Josh. I haven't been able to do much tuning lately due to the rain won't stop in New England, makes it harder to get an accurate reading at WOT.

I've done a bunch of adjustments to the turbo vane in both minimum and maximum, also made adjustments to the desired boost. The code popping is gone as I've done what you instructed. Atmospheric turbo is pushing 35 psi while it's hitting 45 max, for some reason at WOT, my turbo vanes keep pulling back to 4% when the minimum is set around 40 in that area. Can't seem to find why it's doing that. Desired is set at 54, which is around 39 lbs of boost. If I'm out of the MAP range, would it still command to pull the vane with the p0107/108 code disabled?

 

[JoshH]

If you want to post your file, I'll take a look at it for you. If you don't want to post it, shoot me a message, and I'll give you my email address.

 

[Ridin'GMC]

If you want to post your file, I'll take a look at it for you. If you don't want to post it, shoot me a message, and I'll give you my email address.

Sent you a PM

 

[Dozerboy]

With twins I figured you would want to disabled the boost reference and controle boost via vane position only. Thats how I do it with my modified VVT even. I would think once the atmosphere turbo starts making 10-15psi you want the vanes on the VVT at 0% so it can flow as much exhaust as possible and let the atmosphere do the work. I've never tuned twins. That just how I figured it was done.

 

[Ridin'GMC]

The problem with the vane going to 0%, you start losing the valley charger boost and the atmospheric charger starts working harder, so you lose the overall boost. During driving, I would watch my boost climb to spike at 45-50 psi, atmospheric charger is pushing 35 psi then when the vane backs off to 4%, the overall boost would drop to 34 psi as the atmospheric charger is doing all the work while the valley charger is relieving its pressure to direct the exhaust flow to the atmospheric charger. So I'm not getting a combined charger pressure as it should be doing.

Unless I'm wrong but that's what I'm seeing first hand.

I'm still working more on the tuning, can't do much when it's raining so much here, spinning the tires everywhere on a slick road doesn't give me a good reading to get me dialed in. I've figured out the quicker boost spool up by dropping the timing a lot more than I thought I would have to, about 4-5 degrees more in the spool up area. Probably can do more but don't want to chance of having too hot of an exhaust that could burn up the turbine on the valley charger. Increasing fuel pressure, torque based to pedal and torque based fuel also did the truck but did little at a time until I felt it was good enough not to push it past it's capabilities.

 

[Dozerboy]

I don't think your atmosphere should need the support of the valley and would be very concerned with over speeding it. Boost number ain't everything. I'm sure some others will correct me if I'm wrong.

 

[Ridin'GMC]

Got the vanes almost dialed in, still trying to get it to spool like near stock. I'm uncertain at the moment if lowering the vane position would assist with the turbo spool up, I've made 5% adjustments by going more and less and didn't get much of a difference to notice. Also still adjusting the lambda to help with the smoke control, it's strange how it would smoke much more when trying to spool with nearly same fueling as I had on single stock turbo.

Another note, what are you guys doing to make it pull harder? Punching the throttle from a 30mph roll, it feels like it's slow to react to make full power and doesn't spin my tires like my 06LLY used to do on stock turbo and 35" tires with just a lift pump and tune. I've made adjustments to the timing and fuel pressure, no

 

[2004LB7]

Got the vanes almost dialed in, still trying to get it to spool like near stock. I'm uncertain at the moment if lowering the vane position would assist with the turbo spool up, I've made 5% adjustments by going more and less and didn't get much of a difference to notice. Also still adjusting the lambda to help with the smoke control, it's strange how it would smoke much more when trying to spool with nearly same fueling as I had on single stock turbo.

Another note, what are you guys doing to make it pull harder? Punching the throttle from a 30mph roll, it feels like it's slow to react to make full power and doesn't spin my tires like my 06LLY used to do on stock turbo and 35" tires with just a lift pump and tune. I've made adjustments to the timing and fuel pressure, no

Unlocked and looser/higher stall converter. Downshifting can help too depending on your rom and mph

 

[Ridin'GMC]

Unlocked and looser/higher stall converter. Downshifting can help too depending on your rom and mph

It does downshift depending on how fast I'm going with light throttle then mash it. I have a 1078 converter, that shouldn't be my issue? I do feel like it's in the tuning that I'm not aware of. Maybe more fuel down low in the pulse width?

 

[2004LB7]

It does downshift depending on how fast I'm going with light throttle then mash it. I have a 1078 converter, that shouldn't be my issue? I do feel like it's in the tuning that I'm not aware of. Maybe more fuel down low in the pulse width?

This may be the issue. Depending on what rpm and mph you are doing. Most don't like mucking around in the TCM and try doing it all in the ECM. Sometimes you can get it and sometimes you need to match the shifts and TC locking with your desires.

More fuel down low may help or it may just smoke more

Give it a try. If you don't like it, but it back

 

[Ridin'GMC]

That's what I figured. The only thing I did to the tcm was to raise the shift points to keep it in the torque range. In factory, it would be too low of an rpm and lug especially when I'm towing with the t/h on. I did this with my single turbo setup to keep it from smoking at low rpms. Now it shifts beyond 1500rpm every time. Before it used to shift low as 1300 from 5th to 6th.

Guess I have more playing around to do in the tune. It personally doesn't feel like it's putting down the torque early enough to give that hard pull.

 

[juddski88]

That's what I figured. The only thing I did to the tcm was to raise the shift points to keep it in the torque range. In factory, it would be too low of an rpm and lug especially when I'm towing with the t/h on. I did this with my single turbo setup to keep it from smoking at low rpms. Now it shifts beyond 1500rpm every time. Before it used to shift low as 1300 from 5th to 6th.

Guess I have more playing around to do in the tune. It personally doesn't feel like it's putting down the torque early enough to give that hard pull.

Is it a 10 blade turbine in the vvt?

 

[Ridin'GMC]

Is it a 10 blade turbine in the vvt?

I believe so. It's a JZ Mfg 63mm, got them through Brad. I originally wanted Danville and thought they were gone for good until Brad mentioned that JZ is practically a Danville turbo. I'm very curious what's Mark's tuning would be like with this turbo.