Question on AEM TruBoost

[gottadiesel]

I have been using the AEM TruBoost since my re-build, now have about 6k miles since start-up, all is going very well!

One of the minor issues I am still working through and would like to get resolved before I go for a dyno run next weekend, is the settings and responses on the boost controller.

I understand how it works, but am curious if anyone else experiences the same issue I have.

My settings are currently 7.5psi spring pressure and setting A/45%DC and setting B/35%DC - This nets be 14.5psi / 12psi respectively. Spring pressure is suppose to be WG pressure, which it is, as I will net about 7.5psi of boost with controller off.

My issue is if I am at partial throttle and at about 8psi of boost, it begins to fluctuate up and down by about 1psi, based on my changing of the spring pressure, I am assuming this is where the controller goes from full close to its duty cycle and is somehow bouncing between the two. The only way to do not get this symptom is to run at 2-3% spring pressure, but of course slower spool time...

Anyone know if this is a common issue or isolated to something else in my setup? You can see my mods in signature below.

Thank you - Charles

 

[SideWinderGX]

Spring pressure is the pressure the boost controller cracks/opens the wastegate. The wastegate opens, less air is spooling the turbo, boost pressure goes down...below the spring pressure threshold...wastegate is closed, turbo spools up again. This is for a constant throttle/pressure situation.

Nothing you can do about it, but it's an indication your wastegate/Truboost is working as intended.

 

[gottadiesel]

Thanks for the reply. This is what I assumed was happening, I guess my question is, there is no settings known to smooth the transition from the solenoid staying closed to going to x or y duty cycle and or back again?

My issue is that if spring pressure is set to 7.5, which by their manual is correct, this then tells the solenoid not to open and allow pressure to the WG to open until 7.5. If I am going up a hill and just have 50% throttle and reach around 8 psi of boost, of course it opens up WG, then drops back to to 6-7, EBC says oh close solenoid, boost goes back up... then my BOV (Synapse) goes oh gotta open have change in pressure, it is recirculated and it begins this cycle of up/down and will cause the car to start to almost lurch...

The only solution I have it keep spring pressure at 3psi for DD and re-program to 7.5psi if I know I am going to run it hard and the fraction of seconds in spool time will make a difference... I am going to put a call into AEM and see if they have any further insight. Wish there was a A and B setting for spring pressure also...

Any further thoughts would be appreciated!

 

[gottadiesel]

I talked to AEM... How the book describes this setting seems a little off, but never the less, the setting is variable for every vehicle and you just need to adjust until it no longer spikes or oscillates as in my case (I have seen mine spike when I set mine as high as 9, just to see what reaction I would get). My assumption is that even though my turbo will create 7.5 psi of boost without the controller, means nothing as far as that setting is concerned, it is based on the fact that the WG must start opening slightly between 3-4psi, therefore I have to set mine around 3psi not to feel any issues with oscillation.

So unless anyone knows differently, then guess I am set good now and ready for the Dyno this Saturday:icon_bigg and of course getting new wheels and tires tomorrow so it'll look better strapped to the Dyno

 

[twan]

good to hear you got it figured out. im getting my trueboost friday. any issues with installing? thanks

 

[gottadiesel]

good to hear you got it figured out. im getting my trueboost friday. any issues with installing? thanks

Nope, I thought it was easy to install, just make sure you follow the diagram for the vacuum lines, as it is different routing depending on whether you are using an internal or external WG...

If you have any questions or concerns, feel free to PM me or even call me... 360-749-6103 cell#