Anyone on here tuned a big turbo neon srt4 using factory PCM boost control? Currently trying to tune mine and ive run into some issues so i have a few questions.
Anyone on here tuned a big turbo neon srt4 using factory PCM boost control? Currently trying to tune mine and ive run into some issues so i have a few questions.
What kind of information are you after? I've done a couple big turbo SRT-4s on PCM boost. It's not very easy with all the missing parameters for scanning...Originally Posted by Scottyb_288
First what size spring did you run in the wastegate? Ive tried an 8 and 11 and not matter how i change WGDC i get 10 psi. If i unhook the vacuum line from the WG solenoid i get full boost. Second are you using the top or bottom port on the wastegate? Again ive tried both and no noticeable change. And i totally agree with not enough pids. I had to scale my injectors with help from my diablo handheld.
And also from everything ive seen and read you only adjust WGDC(RPM) and it says to zero all other WGDC tables out. Accurate?
I was using an 11 and 12 psi spring in the 2 different setups.
If you mean the modifier tables, such as Baro, Ambient, Aircharge, Part Throttle Adjust, and Transient Adjust, yeah. Those would be fine to zero out to get a baseline figured out, though, one of the setups I did I left those tables stock, and it still worked very well.
Maybe you can post a copy of your tune, and I can see if there's something screwing things up for you.
I should of done that to begin with. my fault. this is the tune that's currently in the car.
Tune file is locked. Says it's part of a "remote tuning network that I'm not a part of."
I always get this. try this one.
In terms of torque management (boost control), I don't see anything that sticks out like an absolute sore thumb that would cause your boost control not to respond to commands. I would, however, suspect that there is one limiting factor, and that would be the "Boost Torque Limit by RPM". It is set to 350 lbs/ft as the limit. I realize that the 1st RPM breakpoint that it has is 6000 RPM, moving toward 6400 RPM as the final RPM breakpoint. But it's entirely possible that, just like tables that aren't scaled all the way up to a maximum breakpoint value that you plan to run to will simply use the last known value past the last defined breakpoint, it may use the 1st known breakpoint value for anything not defined prior to the 1st breakpoint.
If that sounded confusing, don't worry. I'm finding it difficult to explain. Basically, if you have a table that is scaled for an RPM range of 1000 to 6000 RPM, but your actual operating range is 500 RPM to 7000 RPM, then the PCM will use whatever the value is at 1000 RPM for anything 1000 RPM or lower. And likewise, if you run past the last breakpoint of 6000 RPM, the PCM will use whatever the last known value was before running out of table (ie. the value that was defined at 6000 RPM).
So, I would try adjusting the torque value defined at 6000 RPM to be the maximum torque value you wish to allow in your normal operating range, and then bring it down from there to a value you want to limit torque to above your normal operating range.
A few other things I noticed while looking at your tune, you are running a 3 bar sensor which has an effective range up to 300 kPa, but your WOT spark table is only scaled up to 225 kPa (about 18 psi). In this scenario, the same thing will happen as explained above. If you turn the boost up past 225 kPa, anything past 225 kPa is going to use the last known spark value.
So, for example, using your actual tune in this example:
At 3781 RPM, you have timing set to 15* at 225 kPa. But if you turn the boost up higher, say 285 kPa, your commanded timing isn't going to change from that 15* setpoint. Depending on your setup, that could cause unintended results, up to and including blowing your motor (that's not to say tha 15* is excessive timing for 285 kPa, but again, it's all dependent on the setup and fuel being used). The same thing will happen all the way across the RPM range for any boost value greater than 225 kPa.
Along the same lines, depending on what your atmospheric pressure is where you live and drive your car, the VE map isn't scaled high enough for higher elevations. You have it scaled to 3.0 Pressure Ratio. If you were to come where I live (4500 ft. elevation) and run the boost up to 285 kPa, you'd need the Pressure Ratio scale to go up to 3.35 in order to have the tuning resolution you want for fine tuning. Not quite as detrimental in this map as it is in the timing map, but still something to consider.
Also, the fact that you are resorting to VE values well in excess of 100 % tells me that your injectors likely aren't properly scaled. Again, this isn't entirely critical, so long as you are reaching the desired AFR when you ask for it. But it could cause some strange fuel trims and/or driveability issues in closed loop conditions.
But, back to your boost control issues...
How do you have your vacuum lines ran? I ran lines in a couple different configurations, but it all comes down to what your goals are, what you're trying to accomplish. If you're running a line to the top of the wastegate, it had better be the one that runs to the boost control solenoid, and it requires being ran to a specific port of the solenoid. You had also better be running an unregulated source to the bottom of the wastegate. Any time you run the top port of the gate, you MUST run a line to the bottom port as well. The control scheme in this scenario works upon the theory of adding pressure to the top port to keep the gate closed past spring pressure in order to add boost.
If you're just running a single pressure source to the gate, it would be run to the bottom port only. In this control scheme, it is somewhat the opposite. You are regulating the pressure to the bottom of the gate, decreasing the pressure supply as you wish to increase boost, and relying on the spring only to keep the gate closed. The more pressure you divert away from the bottom of the gate, the higher the boost rises until drive pressure in the manifold overcomes the spring pressure that is trying to hold the gate closed.
Last edited by B00STJUNKY; 04-23-2016 at 05:49 PM.
thought I had adjusted them all up to 450 or 500. clearly I missed one good catch.In terms of torque management (boost control), I don't see anything that sticks out like an absolute sore thumb that would cause your boost control not to respond to commands. I would, however, suspect that there is one limiting factor, and that would be the "Boost Torque Limit by RPM". It is set to 350 lbs/ft as the limit. I realize that the 1st RPM breakpoint that it has is 6000 RPM, moving toward 6400 RPM as the final RPM breakpoint. But it's entirely possible that, just like tables that aren't scaled all the way up to a maximum breakpoint value that you plan to run to will simply use the last known value past the last defined breakpoint, it may use the 1st known breakpoint value for anything not defined prior to the 1st breakpoint.
If that sounded confusing, don't worry. I'm finding it difficult to explain. Basically, if you have a table that is scaled for an RPM range of 1000 to 6000 RPM, but your actual operating range is 500 RPM to 7000 RPM, then the PCM will use whatever the value is at 1000 RPM for anything 1000 RPM or lower. And likewise, if you run past the last breakpoint of 6000 RPM, the PCM will use whatever the last known value was before running out of table (ie. the value that was defined at 6000 RPM).
So, I would try adjusting the torque value defined at 6000 RPM to be the maximum torque value you wish to allow in your normal operating range, and then bring it down from there to a value you want to limit torque to above your normal operating range.
haven't touched timing yet. tryin to get boost where I want it before I mess with anything else.A few other things I noticed while looking at your tune, you are running a 3 bar sensor which has an effective range up to 300 kPa, but your WOT spark table is only scaled up to 225 kPa (about 18 psi). In this scenario, the same thing will happen as explained above. If you turn the boost up past 225 kPa, anything past 225 kPa is going to use the last known spark value.
So, for example, using your actual tune in this example:
At 3781 RPM, you have timing set to 15* at 225 kPa. But if you turn the boost up higher, say 285 kPa, your commanded timing isn't going to change from that 15* setpoint. Depending on your setup, that could cause unintended results, up to and including blowing your motor (that's not to say tha 15* is excessive timing for 285 kPa, but again, it's all dependent on the setup and fuel being used). The same thing will happen all the way across the RPM range for any boost value greater than 225 kPa.
Along the same lines, depending on what your atmospheric pressure is where you live and drive your car, the VE map isn't scaled high enough for higher elevations. You have it scaled to 3.0 Pressure Ratio. If you were to come where I live (4500 ft. elevation) and run the boost up to 285 kPa, you'd need the Pressure Ratio scale to go up to 3.35 in order to have the tuning resolution you want for fine tuning. Not quite as detrimental in this map as it is in the timing map, but still something to consider.
started to scale my injectors and my upstream o2 decided to stop responding so your correct on them not being scaled correctly. have a new sensor on the way so that will be done.Also, the fact that you are resorting to VE values well in excess of 100 % tells me that your injectors likely aren't properly scaled. Again, this isn't entirely critical, so long as you are reaching the desired AFR when you ask for it. But it could cause some strange fuel trims and/or driveability issues in closed loop conditions.
But, back to your boost control issues...
ive got my boost source run to the top port of my solenoid and ive got the wastegate line run to the middle port of it.How do you have your vacuum lines ran? I ran lines in a couple different configurations, but it all comes down to what your goals are, what you're trying to accomplish. If you're running a line to the top of the wastegate, it had better be the one that runs to the boost control solenoid, and it requires being ran to a specific port of the solenoid. You had also better be running an unregulated source to the bottom of the wastegate. Any time you run the top port of the gate, you MUST run a line to the bottom port as well. The control scheme in this scenario works upon the theory of adding pressure to the top port to keep the gate closed past spring pressure in order to add boost.
.I'm running single pressure source so I need use the bottom port only and make all the changes you suggested. I appreciate you taking time out to look at it and make suggestions. ill make the changes and run it and see what happensIf you're just running a single pressure source to the gate, it would be run to the bottom port only. In this control scheme, it is somewhat the opposite. You are regulating the pressure to the bottom of the gate, decreasing the pressure supply as you wish to increase boost, and relying on the spring only to keep the gate closed. The more pressure you divert away from the bottom of the gate, the higher the boost rises until drive pressure in the manifold overcomes the spring pressure that is trying to hold the gate closed.
Pcm boost control is now functioning. Thanks for the help. Its much appreciated
Glad to hear it.
Do you have a vacuum diagram on how to set up the lines for pcm controlled boost? I have a stock turbo with an external gated wastegate. I want to set up to control boost through the diablo tuner
Do you have a vacuum diagram on how you set it up?
not sure how they did it .. mine is stock, like https://www.google.com/url?sa=i&url=...AAAAAdAAAAABAD
if you have a mvip2, you don't need a DS to change torque
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