[Quick335XI]

I have a JB4 with an MHD bef, and I have the overall safety max boost setting set to 28psi. This is a custom map. I did a third gear pull today and was horrified when the boost went to about 31psi. Has anyone seen the jb4 max boost safety not work before?? Here's a log:

https://datazap.me/u/quick335xi/toom...log=0&data=1-4

[Mike@N54Tuning.com]

You'd have to exceed that boost for more than a second for it to trigger a safety. I see it triggered right as you left off.

Going forward you should disable RPM FF gain and enter the suggested hybrid turbo duty bias profile for starters. PID Gain should also be 25. You've dampened the system by lowering it to 20.

Mike

[Quick335XI]

But why is the target boost so far away from the actual?

[buster84]

You need to adjust your FF settings and duty bias settings until it matches your target.

Read this, it'll help you understand what you need to do to fix it.

http://www.n54tech.com/forums/showthread.php?t=29893

[Mike@N54Tuning.com]

Originally Posted by Quick335XI

But why is the target boost so far away from the actual?

The short answer is you didn't enter the right settings for your hybrid turbo. If you need additional tuning help after fixing the settings post a log in n54tech's support area.

http://www.n54tech.com/forums/showthread.php?t=33200

[Quick335XI]

Does anyone know why the jb4 is allowing the maximum boost to shoot up to 30 when I have the max set to 28? Seems like that's a failsafe measure that should be working and isn't...

[buster84]

Originally Posted by Quick335XI

Does anyone know why the jb4 is allowing the maximum boost to shoot up to 30 when I have the max set to 28? Seems like that's a failsafe measure that should be working and isn't...

With aftermarket turbos you will always have overboost issues until you dial it in with the jb4. The fail safe cuts in after a second or two and by the time that happens you could already be done with your quick pull. If you were doing a full track like pull it would switch to map 4. I've seen mine do that when I was also overboosting, it takes a second or two for the jb4 to recognize the overboost and switch to map 4. If it worked instantly youd probably end up in map4 a lot if you had a small boost leak, change in air temperature, or change in altitude because boost is a restriction of flow and more or less dense air will effect it too making your ecu/jb4 adapt with wategate changes.

Go to n54tech and post your csv logs, they will help you dial it in. These things are a normal part of tuning when having turbos that push a lot of air. Once its dialed in and you learn the jb4 you will be able to adjust these things on the fly without worry on your own. The reason it's good to learn this is because if you ever change your boost target you have to re-adjust FF or your duty bias settings again.

[Quick335XI]

N54tech?

I did find out why it was boosting so high the boost additive setting was set to 30! Lol. A typo obviously. It should have been 3.

[buster84]

Originally Posted by Quick335XI

N54tech?

I did find out why it was boosting so high the boost additive setting was set to 30! Lol. A typo obviously. It should have been 3.

Yes, that's the jb4 help forum. FYI your overboost issue is not because of a 30 being typed in boost additive..

You really need to learn the device before messing with settings. Your log was map 6, are you in map 6 or map 3 now? The Boost additive setting is set for map 3 according to jb4s settings pages that say it's an additive map.

Takes Mike's advice and go there.

Originally Posted by Mike@N54Tuning.com

The short answer is you didn't enter the right settings for your hybrid turbo. If you need additional tuning help after fixing the settings post a log in n54tech's support area.

http://www.n54tech.com/forums/showthread.php?t=33200

[Quick335XI]

Originally Posted by buster84

Yes, that's the jb4 help forum. FYI your overboost issue is not because of a 30 being typed in boost additive..

Yes, it was. That was the issue.

Originally Posted by buster84

Your log was map 6, are you in map 6 or map 3 now? The Boost additive setting is set for map 3 according to jb4s settings pages that say it's an additive map.

Yes, its' a custom map on map 6. There was a typo in the boost additive field of 30 - causing it to go way beyond what it should. I fixed that and it's fine now.

Originally Posted by buster84

Takes Mike's advice and go there.

I'm ok but thanks