So finally nailed down my boost control issues after committing a day to it and reading the manual and the threads here again and again. It's been a long time coming.

Anywho, now i'm in the process of setting it up. Stock boost for now as i've been happy with that for two years now. First i was cranking up the "Set" then tweaking the gain... yadda yadda yadda... found another thread, read it set it up as follows:

(units set to psi)
Boost Mode: Lo
Set: 45%
Gain: 15%
Start Boost: 85
Warn: 110
Limiter: 8%

in order that they come up on the screen:

Gain: 15%
SetGain: 85
Warn: 110
WarnL: 8%
Set: 45%

So what happens is first my boost will shoot up to almost 9 lbs (pfc reads .62kg/cm which is 8.8psi then drop and hold at 5-6psi 'till redline. Then in every gear after that it will slowly build up to 8.8psi and then drop back down. I don't understand. My limiter isn't set to activate until 11psi and i'm really starting to crank up the settings.

(Note: Profec B-spec II settings setup stock boost twins)

 

NissanConvert,

I'm running the Greddy E-01 boost controller which uses the same solenoid w/full non-seq and ported wastegate, my settings are as follows:

Boost mode: hi
Set: 35
Gain: 17
Start: 10

these settings give a solid 12.8 psi

Boost mode: lo
Set: 30
Gain: 15
Start boost: 10

These setting give me a solid 11 psi

The start boost is supposed to be set at a psi that you want to have the wastegate hold the pressure til it reaches the select psi then opens. Helps with spool.

The gain is used to stabilize the boost by changing the solenoid duty cycle , the higher the value the faster the response the lower the slower. set it too high and the boost will spike.

The set is your max psi, so finding the set value that gives you the desired boost is the trick.
Try my settings it might work, a friend of mine uses settings very close to my settings just a little lower boost with great success and is using the same EBC you are.

 

My set and gain are both higher than yours but it won't hold boost. It never reaches my warning setting but the boost drops to the wastegate spring as soon as it builds past my start boost. I'll try putting my start boost up to 9.5 but i doubt it will hold it.

 

Maybe because you set the values way to high and the wastegate can"t flow that much boost, is your wastegate ported?

A set value of 45% and a gain value of 15% should give you 14+ psi of boost, maybe its not the controller maybe it's some other issue.

If everything is hooked up correctly with boost controller turned off it shouldn't boost past the wastegate spring of 7psi and with it on it should boost to controller settings.
I know you have most likely double checked your install but triple check everything and make sure you have no vac line's disconnected. Also if the boost control solenoid is bad it will not boost past the wastegate spring pressure.

 

My wastegate isn't ported, that's a job for this winter. I've never seen 7psi, it's always holding steady around 5-6 but since it "spikes" to 8.8 i'm reliant on the boost gauge for where it holds. When the boost controller was not installed it went straight to 5-6psi and held, so i am certain that it is activating.

 

Something else might be wrong then not associated with the boost controller. everything has got to be in good working order for the boost controller to do its job.

Your boost gauge might be off as well because you should see a peak of 7psi if the car is running solely off the wastegate. If your not even seeing stock boost levels there are some other issues to fix.

 

rx7club ate my post. The wastegate is working fine. Opening 1psi early isn't a terrible concern to me, a flaky boost controller is.

 

Where are you sourcing the pressure for the boost controller solenoid? If you are sourcing it before the IC instead of After, you will notice lower then 7psi on your boost gauge because you have it on the UIM like the rest of us. You are forgetting the pressure drop due to the IC. This is probably why you are seeing less then 7 psi.

Figure 8.8 psi at the UIM is about 10 psi Before the IC. According to the settings and the pryor posts, this sounds like where the boost controller is. It sounds like you will have to raise the settings a bit to see the desired boost because it is setup like this.

I do not have the boost controller you are using. So take my words with a grain of salt, but it is something to consider.

 

Pressure for the solenoid is taken from the primary turbo outlet. Pressure for the control unit is sourced from the manifold nipple, t'd off of the same line that feeds the boost gauge.

The trouble is that the boost "spikes" to 8.8ish psi and then drops back down to the wastegate spring until redline. It doesn't fluctuate, it doesn't give me the warning beep. It builds boost and then it dumps it.

 

it'll drop back down because your engine is taking in more air and your turbo(s) can't keep up. Even stock, it'll drop boost near redline.

I have a profec b spec II that you can throw in your car at the next fudds meet if you want to see if that's the problem.

 

Eage8, At 7 psi which is what he wants to run, it shouldn't trail off at red line. If he was pushing a higher boost on the stock twins then yes i would understand that completely.

NissanConvert, What do you have the other nipple on the UIM doing? When i had my twins still, i had my Profec setup similar to that, but i had no issues. I had my boost gauge on one nipple, and the controller on the other nipple on the top of the UIM. As i said before, i am not that familiar with that unit, and it sounds as though it is hooked up correctly. I initially thought you had both the controller and solenoid after the IC.

 

I want to run 10psi. When my wastegate wasn't moving at all (I didn't realize it was a 2 port actuator!) I made 10psi easy. I'd have to look at it because i'm only aware of one nipple off of the back of the UIM and that one feeds both my boost gauge and the profec controller. For totally unrelated reasons i'm thinking about putting a vacuum plug on that nipple and t-ing them both off of the MAP sensor.

I don't know why, but it's my opinion that the controller is holding boost up to my start boost setting and then opening the wastegate 100% It holds that boost until redline all day.

 

So i tried something today. I unhooked my boost switch and plugged up all the related vacuum ports. I t'd the boost gauge and the controller in to the MAP sensor line. (the line to the sensor is short and direct) and lowe and behold, 20" of vacuum (mechanical gauge) again. Apparently my boost switch was in fact choking the vacuum line causing my boost gauge and boost controller to read incorrectly.

Since i remedied that problem the gauge, my PFC commander, and boost controller are all in agreement (boost controller is off by about 1psi of vacuum, i'm chocking this one up to the moisture filter).

Boost is faster, and no longer drops like a stone to the wastegate spring. Now, i get 8-9psi it drops to the wg spring, then back up to 8-9psi. That was with IAT's too hot to continue.

So now i need to get more vacuum line to hook up my boost switch (water sprayer), and start adjusting. I think *crosses fingers* i've got this taken care of.