Still having the boost spike problem, even under acceleration

Biggest problems:
1. Plex is limiting by cutting boost even when in "OFF" mode...
Even I have 12psi spring WG that used to work perfect before (only GT3076 turbos) now I see often more boost- 0.9bar or even 1.0bar, and Plex comes in and cuts power??? Why does that, i dont know... How does it know its overboost and how should I avoid this? Putting another WG spring maybe ?

How is possible to reach 1bar when having BIG 44mm WGs set at 0.85bar (12psi) ????

2. Boost isnt very configurable in some areas, for example (not exactly real values, just examples):
45% duty cycle - 1.3bar
46% - 1.33bar
47%- 1.38bar
48% - 1.4bar
49% - 1.5bar !!!!!! having set boost limit at 1.45bar I can not use anything bigger than 1.40bar...

any ideas?

Boost was running perfectly before and as far as I know nothing was changed hardware and tune is the same as we run external WGs

 

it is very much possible to hit 1 bar with .85 WG springs in fact that is normal. You have the cracking pressure of the WG and the wide open pressure. your PLEX has a setting somewhere for overboost protection, you have to find it and set it 2-3 psi over the max boost you normally run.

 

Mark thanks, makes sense. Did know about the overboost protection when EBC turned on, when off I am just surprised to be able to set anything

I had the same setup with Greddy and GT3076 worked well
Kept Greddy and chenahed to GTX2863 and saw the overboost but Greddy wasnt reacting
Switched to Plex and gtx2863 and now the problem is as above, and seen in addtition the sensitivity problem

 

Fadi - I'm running plex with same gates and 1bar Spring.

Can you tell me more about how you have the gates setup and lines run? Are you running both ports - upper and lower?

Also - once you get a feeling for the plex in open loop and the base settings, switching to closed loop is a good idea to really dial in the boos control. I can share these but let's start with how you have the gates setup.

 

Yes both upper and lower, like you have them, lower to the turbo and upper to the Ypipe before TB

 

also if you have aquamist too, would be great to have a pic/details of the failsafe you have in place, I'm trying tomorrow to set it up for the first time with Plex

Boost by rpm works well, still boost by gear not sure..

 

Disconnect the upper port from the y-pipe and you'll boost at spring pressure.

 

Fadi - I'll send you some info on the aquamist tonight. It's pretty simple.

With respect to the controller. Your duty cycle is roughly where mine is - I run a base of 45 and it holds 1.35bar solid when I have PID zero out. Can you send me a log file of boost vs rpm - where your not increasing duty with rpm. I will overlay it with mine.

 

60% was pump+meth, the others just pump as I remember

 

3 logs

 

Hi Fadi,

If the controller is set to OFF, then DC will be 0% and nothing can be cut, because there is no boost than what your springs allow. No need to disconnect the lines.

Running wastegate control from boost before TB is fine. If you need more control, then run the control pressure from the turbo compressor housing if you have a connector for a line there.

I guess you are running in closed loop. I usually set my target a little below my boost limit.

@LQQK: when you run PID=0 then you are not using closed loop. Do you use that as regular setup, or just for testing?

 

Problem is with the plex OFF - I see the LED in front going RED and limits my power ... this wasnt happening with Greddy, guess I have to read the instruction manual with more attention

I have both as said earlier, lower Wg connector directly to compressor and higher WG connector to a T line going from the other turbo and put into the Ypipe before TB.

 

Check your OFF setting. Set it to open loop (no feedback) and DC to 0%. A limiter might kick in, but it can't do anything except for flashing a screen.

 

I'm not familiar with plex, but you do have a functioning solenoid on the hose between your y-pipe and top wastegates, correct?

 

Yes will check, not sure there are any settings available when OFF


Yes we run solenoid in between