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Check out this log. Map sensor or boost control issue?


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Hey guys,

So I finally got everything dialed in and decided to do a quick 3-4 hit the other day. I like the closed loop boost control and its ability to adjust duty cycle to stay at target boost. However, on this run, boost was exceptionally low in 3rd and too high in 4th. The log shows WG duty cycle attempting to compensate for both errors. It shot to 100% to try to raise boost from 35 ish to a target of 42 psi (390 kpa) with no effect. And it dropped duty cycle to try to correct an over boost situation in 4th gear with no effect (seemingly).

I have two problems.

1. Is there anything apparently wrong with my boost control setup. PID values, etc. What would cause lack of response. (It's highly unlikely that it's a mechanical issue with turbo or associated plumbing as it is perfect with a hallman pro rx manual boost controler)

2. Kind of the bigger issue. I have an Omni Power 4 bar map sensor. During the 4th gear pull in the attached log, I saw 42.7 psi and then, BAM, boost cut/MAP limit reached. I was no where near 450 kpa when it happened. Is there a limit that I'm missing somewhere for the map sensor that would be causing this? It seems like it might be that it reached 400 kpa and that is the limit of my map sensor. But it should just continue to output a max value to satisfy the vipec, yes? I looked and didnt see any conflicting values that might cause this issue.

My map limit is set to 450 kpa right now and I know I havent actually hit more than that. Though the log shows 94 psi when this issue occurs. That pressure is just not possible with my setup.

I have attached my PCL and I was going to attach the log. It will not let me attach a ".llg" vipec log file.

Thanks for any help.

closed deck tune 2 40 psi timing4.pcl

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It is interesting looking at your log and base-map. I can see what you mean about the MAP being under the boost target in 3rd gear, yet the wgate dc% is at 100%.

Interestingly once you are in 4th gear it has no problem raising the MAP to reach the target. I see you have a stage 3 ON delay of 0.3 seconds, which is the time that stage 2 is active for before entering stage 3.

As you said the ECU seems to be taking the right steps to try and control the boost.

Is this a new setup or has it been run before? Have you run this on Open Loop Boost Mode? The MAP reading certainly rockets up in the log. Did it feel like there was a huge surge in boost? If you have access to a second MAP sensor or a boost gauge with the relevant range this should help identify what is going on.


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I have a boost gauge that reads to 45 psi. When the spike occurs, I'm 99% sure it isn't actually hitting that amount of boost. I have the cal table setup for my map sensor correctly. It should stay at its highest value even if it sees more pressure. I would think anyways. My thought is that maybe I am maxing out the map sensor and for some reason it reports a weird voltage after a certain pressure causing the vipec to think that its a super high pressure and that's what triggers the map limit and all that. I have looked at an aem 5 bar map sensor. Any other suggestions on a 5 bar?

I have run the car in open loop. No issues really. I haven't done any multiple gear pulls with open loop though. I also have no issues with consistent boost pressure with a manual ball and spring controller.

So stage 3 at 0.3 is the time stage 2 is active before stage 3 comes online? Would it be beneficial to change that? And what exactly would it change in the way closed loop controlled certain situations. (Quick shifting, etc.)

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looking at your data log, confuses the crap out of me.

Confusing me isn't hard but.

In the log I see a peak MAP pressure of 740 odd KPA but also looking at your boost PID's seem to be staying low and not responding much at all.

You did have 100% TPS at 740 odd Kpa, however when you look at the log it just looks wrong.

Surely your not running 93 odd psi of boost.

Maybe faulty MAP sensor , or scaled incorrectly or the engine had a huge back fire.




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It is starting to sound like your MAP sensor is not accurately providing data on what is happening. I haven't used an AEM MAP sensor, but so long as it comes with the calibration data I'm sure it won't be a problem.

The Stage 3 delay is there just to allow time for the MAP level to stabilise. If you have the system well tuned then you could reduce the delay down to zero.

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