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Boost spike/creep problem again.

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Old Oct 17, 2008 | 12:26 PM
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Default Boost spike/creep problem again.

Not sure if it's spiking b/c when I take off I keep my eyes on the road, but it's going up to 9.9psi w/ the boost controller off. My springs are 8.5psi and I have the EVC 6 bc. It did it one time before after I disconnected the batt. I had to reset everything on the BC. This time it's just started doing it on it's own and I have no idea what to check.
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Old Oct 17, 2008 | 12:41 PM
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Do you happen to have a TN kit? TN is known to have boost creep, especially the old wastegate pipe.

Oh, I just re-read your post.. You were saying you were fine before?
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Old Oct 17, 2008 | 12:41 PM
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any loose cacuum lines ? this happened to my friend and he found a broken line problem solved.
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Old Oct 17, 2008 | 12:55 PM
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^ 1+ check vacuum lines to wastegate.
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Old Oct 17, 2008 | 02:40 PM
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Sorry, running the Greddy kit. I'l check the VL's and get back w/ you all. Thanks for the help.
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Old Oct 17, 2008 | 03:22 PM
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Has the weather changed recently by you?
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Old Oct 17, 2008 | 03:50 PM
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Originally Posted by gsxrjohn
Not sure if it's spiking b/c when I take off I keep my eyes on the road, but it's going up to 9.9psi w/ the boost controller off. My springs are 8.5psi and I have the EVC 6 bc. It did it one time before after I disconnected the batt. I had to reset everything on the BC. This time it's just started doing it on it's own and I have no idea what to check.

why not just leave the boost controller set to 8.5psi and be done with it then?
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Old Oct 17, 2008 | 08:43 PM
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A slight leak in the lines from the EBC going to the wastegate and/or boost reference might continue to get worse. I'd definitely look for any kind of cut or damage to the lines. Does your EMS have an overboost fuel cut?
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Old Oct 18, 2008 | 09:18 AM
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Originally Posted by USN HM 350Z
why not just leave the boost controller set to 8.5psi and be done with it then?
Because it's doing it with the bc OFF. The springs in the WG's are 8.5 so at 8.5 they should open if the bc isn't on, right?

Originally Posted by rcdash
A slight leak in the lines from the EBC going to the wastegate and/or boost reference might continue to get worse. I'd definitely look for any kind of cut or damage to the lines. Does your EMS have an overboost fuel cut?
I'm running a Utec, I don't think it does. I haven't had a chance to check yet, but I will before I drive again. Thanks everyone.
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Old Oct 18, 2008 | 09:24 AM
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Originally Posted by gsxrjohn
Because it's doing it with the bc OFF. The springs in the WG's are 8.5 so at 8.5 they should open if the bc isn't on, right?
um, I know its off when it does it....that would be why I high lighted the OFF part of your statement.

It does not over boost when it is on correct???
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Old Oct 18, 2008 | 10:54 AM
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Okay, I see what your saying. IDK, I'll try that too.
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Old Oct 18, 2008 | 10:55 AM
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Originally Posted by thom000001
Has the weather changed recently by you?
It's getting colder, yes.
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Old Oct 21, 2008 | 09:11 PM
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Okay, so I got under the car and looked. Everything seemed okay. I when out for a drive and turned the BC on to see if it would hold at 9.5 with it on. Hell no...It went up to 11.2psi w/ the BC set at 9.5psi. It was colder, like maybe 50 deg. Cold or not I don't want to break something. I'm going to put the car on a lift tomorrow and to get a better look.
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Old Oct 22, 2008 | 04:56 AM
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I've had the same issue with my EVC 6 and APS TT. Maybe you've already tried this but if you haven't, this is an easy adjustment...

- With ignition on - with/without car running.
- Push the lower button on the EVC once and the boost number will come up (probably around 100 +/- for you).
- Push the round button next once and the number will start blinking.
- Turn round button until the boost value lowers by 5-10 point increments.
- Push the round button in again.
- Run the car WOT in 3rd to see where your boost goes.

I don't think it's the turbo kit or a leak, I think it has to do with the EVC but who knows.
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Old Oct 22, 2008 | 05:21 AM
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I don't know much about the EVC 6. Is it PID tuneable (where you set values for the proportion, integral, derivative parameters for closed loop boost control or is it open loop duty cycle only)? Different boost controllers implement the PID feedback algorithm differently so your mileage may vary (my experience is on a Haltech), but I would recommend setting the proportion value really low [like a single digit #], integral at half whatever the proportion is, and derivative at 0 and start from there. You want to start tuning it without it reaching the target boost, that way any overshoot is still not dangerous. The integral (and derivative for fine tuning) are what help to limit overshoot and oscillation but if proportion is too high, it won't be able to prevent that first spike. The other parameters to consider are when the boost controller comes on and what is the starting duty cycle. If those are too far off, it will be hard to prevent the first spike even if the PID is set properly. Good luck - lot of trial and error.

Last edited by rcdash; Oct 22, 2008 at 05:27 AM.
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Old Oct 22, 2008 | 06:12 AM
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Originally Posted by rcdash
I don't know much about the EVC 6. Is it PID tuneable (where you set values for the proportion, integral, derivative parameters for closed loop boost control or is it open loop duty cycle only)? Different boost controllers implement the PID feedback algorithm differently so your mileage may vary (my experience is on a Haltech), but I would recommend setting the proportion value really low [like a single digit #], integral at half whatever the proportion is, and derivative at 0 and start from there. You want to start tuning it without it reaching the target boost, that way any overshoot is still not dangerous. The integral (and derivative for fine tuning) are what help to limit overshoot and oscillation but if proportion is too high, it won't be able to prevent that first spike. The other parameters to consider are when the boost controller comes on and what is the starting duty cycle. If those are too far off, it will be hard to prevent the first spike even if the PID is set properly. Good luck - lot of trial and error.
What did you just say? ...............Sorry, I'll read it a few more times.
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Old Oct 22, 2008 | 04:18 PM
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Originally Posted by rcdash
I don't know much about the EVC 6. Is it PID tuneable (where you set values for the proportion, integral, derivative parameters for closed loop boost control or is it open loop duty cycle only)? Different boost controllers implement the PID feedback algorithm differently so your mileage may vary (my experience is on a Haltech), but I would recommend setting the proportion value really low [like a single digit #], integral at half whatever the proportion is, and derivative at 0 and start from there. You want to start tuning it without it reaching the target boost, that way any overshoot is still not dangerous. The integral (and derivative for fine tuning) are what help to limit overshoot and oscillation but if proportion is too high, it won't be able to prevent that first spike. The other parameters to consider are when the boost controller comes on and what is the starting duty cycle. If those are too far off, it will be hard to prevent the first spike even if the PID is set properly. Good luck - lot of trial and error.
You know, most of us didnt go to harvard. I would like to understand some of these big words but damn
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Old Oct 22, 2008 | 04:36 PM
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Originally Posted by rcdash
I don't know much about the EVC 6. Is it PID tuneable (where you set values for the proportion, integral, derivative parameters for closed loop boost control or is it open loop duty cycle only)? Different boost controllers implement the PID feedback algorithm differently so your mileage may vary (my experience is on a Haltech), but I would recommend setting the proportion value really low [like a single digit #], integral at half whatever the proportion is, and derivative at 0 and start from there. You want to start tuning it without it reaching the target boost, that way any overshoot is still not dangerous. The integral (and derivative for fine tuning) are what help to limit overshoot and oscillation but if proportion is too high, it won't be able to prevent that first spike. The other parameters to consider are when the boost controller comes on and what is the starting duty cycle. If those are too far off, it will be hard to prevent the first spike even if the PID is set properly. Good luck - lot of trial and error.
Thanks! Now I feel REALLY stupid! lol

I lowered the gain to 90% and it still pulled a 8.8 w/ the b/c on 8.5. It was about 65deg outside.
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Old Oct 22, 2008 | 04:42 PM
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Originally Posted by gsxrjohn
Thanks! Now I feel REALLY stupid! lol

I lowered the gain to 90% and it still pulled a 8.8 w/ the b/c on 8.5. It was about 65deg outside.
i have seen my EVC read peak boost as high as 10 or 11 psi lately. While boosting it holds consistently around 9 psi though, just random rises like that occasionally. It has did this for a long time though and no issues. With the BC off though it stays pretty consistent at 6-7 psi.
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Old Oct 22, 2008 | 04:51 PM
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Serious question Raj; where do you learn all this?

btw, does PID=Proportion Integral Derivative?

Last edited by JAM3Z; Oct 22, 2008 at 04:59 PM.
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