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Hitting overboost protection no matter what I do

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Old 08-05-2020, 10:34 PM
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Default Hitting overboost protection no matter what I do

I have been running without any ebc or mbc since I have boosted this car. Since the wastegate is rated for 7psi, that is all I have been reaching, except for some boost creep to 11psi near the end of the pull.

I have tried an AEM truboost ebc standalone, with no luck. No matter how I set it, I am getting oscillation and hitting boost protection (13.7 psi) by the time I make it to 3rd gear.

I now am trying a Grimmspeed MBC, with the same issue. I am only at 4-5 "clicks" (1 click is .25 psi) yet I am still hitting boost protection by 3rd gear during a pull.

If I run off only the WG actuator(no ebc or mbc), I am never hitting boost protection.

What am I doing wrong?
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Old 08-06-2020, 02:31 AM
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Where is the signal line for the mbc coming from?
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Old 08-06-2020, 02:33 AM
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The signal line is coming from the intercooler piping (after the intercooler)
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Old 08-06-2020, 03:37 AM
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https://www.turbosmart.com/news/manu...%20ends%20with
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Old 08-06-2020, 10:37 AM
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I have read through that before and I have everything set up correctly. Post-IC is a better signal than right at the turbo, based on what I have found on here. Pressure closest to throttle body is more accurate.
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Old 08-06-2020, 10:40 AM
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How much higher is over boost set over what boost level you want?

If you wire open the wastegate, do a WOT run and log. What is the max KPA you get?
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Old 08-06-2020, 11:33 AM
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Okay I can try and do that

​​​​​I am aiming to just get it steady at 12psi. The BP limit is13.7.
What makes no sense is that I am only 4 clicks on the MBC. Which should be about 1 psi. Yet I still hit BP at 13.7
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Old 08-06-2020, 11:40 AM
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Don't believe the clicks mean anything.

I would set the KPA over boost limit at 200 or 205kpa.

MS can kick into over boost if it looks like you are approaching it very quickly.
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Old 08-07-2020, 02:14 AM
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What turbo? You probably need to Port the wg on the turbine housing. You could try ever boost controller every invented and it wouldn't fix it.
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Old 08-08-2020, 01:00 AM
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I think it could be the preload on the actuator causing the creep. Is this too much?
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Old 08-08-2020, 02:55 AM
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Originally Posted by andyNB
I think it could be the preload on the actuator causing the creep. Is this too much?
That could definitely cause that. Loosen it so that there is just a little tension on the wg. If that still doesn't fix it you're gonna have to Port it
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Old 08-09-2020, 02:15 AM
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Okay so I straightened out the actuator rod, got it so that the hole on the rod is about half on the peg. That way it has just a bit of preload to keep shut.

This seemed to fix my creep problem! Boost is now steady at 11psi through all gears. So mission accomplished.

I am now facing a NEW problem. My boost protection is set at 205kpa now. I am aiming for 14psi. However, I cannot get close to that because I am hitting the boost protection due to a 2psi spike.

Is there any way to fix this spike? Would an EBC help? I would like to get it to 14psi consistently without a dangerous spike.
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Old 08-10-2020, 02:13 AM
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Originally Posted by andyNB
Okay so I straightened out the actuator rod, got it so that the hole on the rod is about half on the peg. That way it has just a bit of preload to keep shut.

This seemed to fix my creep problem! Boost is now steady at 11psi through all gears. So mission accomplished.

I am now facing a NEW problem. My boost protection is set at 205kpa now. I am aiming for 14psi. However, I cannot get close to that because I am hitting the boost protection due to a 2psi spike.

Is there any way to fix this spike? Would an EBC help? I would like to get it to 14psi consistently without a dangerous spike.
Yes, an EBC will help because you can open the WG a little sooner.That way it can catch up with the spool of the turbo. Porting also helps as well. I have a FM manifold and downpipe just like yours. I had to port both the wg and the turbine outlet to get it to not creep. I usually set my boost cut 3 psi past target, but I have a built motor so there is a little more margin for error.
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