GReddy PRofec B Spec-II setting questions

BlackMKIII

BlackMKIII

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Does any one here have experience using the PRofec B Spec-II on a 1JZ with the stock twins? I followed Joe's kindergarten diagram and got it hooked up, but here's what is happening...

I set the boost @ 39% (which, if stock is 10.8 PSI should be around 15) and when I start to boost, it spikes to 13 or 14 then falls to 10, then a slow build up to 11.

It doesn't seem to make sense to me. I'm scratching my head on this one. Anyone have an idea?

Note:
If anyone in the SF East Bay knows their stuff (like Moe... calling Moe... Paging Dr. Moe...) and can help me, tomorrow afternoon is free. PM me if you can give me a personal hand.
 
OneJoeZee

OneJoeZee

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RTFM. Not kidding. I've had two profec Bs before. They're finicky. You gotta really understand what each function does. If you haven't confirmed that the controller is acting the same way with all the settings off as it did before you installed it, do that first.

My advice, put the 3 settings back to zero and set them from left to right one by one. Don't try to set them all at the same time.

I haven't used one in over year, so I'm goinf off mostly memory. I just remember that when I first got it, I tried to set all 3 at once and it got me nowhere. Turn everything back to zero and go from there. Set the set boost setting. Then do the gain setting. Then the start boost setting.

Do the start boost last because it's dependant on the set boost setting. If your start boost setting is too close to set boost, you'll get bad spikes. You could leave the start boost at zero. It controls when the wastegates start to open. If you have it at zero, it will act like the wastegate does without the controller there at all, the wastegate starts opening really early below targe boost. When you turn the start boost up, the wastegate stays closed longer before it starts to crack open. But if you turn it up too close to the set boost, the wastegates will stay closed too long compared to your set boost and you'll overshoot your set boost and get boost spikes.

BTW, the gain percent isn't gonna directly correspond to a specific boost level by mathematical calculation compared to the factory setting. The same settings that you have on your car will yield different results on someone else's car. Everything from exhaust, downpipe, IC, altitude, etc will affect the settings. They're not consistent everywhere.
 
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JASONA70

JASONA70

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i have a spec II and the thing is so confusing, it took me a whole week of trial and error to get the right boost lvls for the stock twins. :nono:
 
BlackMKIII

BlackMKIII

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Okay, so I did some tuning with it today on the way to Clearlake and back, and this is what I learned:

80% = roughly 1.0 bar. That makes no sense to me, but at least it doesn't spike and fall anymore. Does this seem odd to anyone else? I am 99.9% sure I do not have a boost leak, because all the vacuum lines are on and the hose coupler clamps are tight.

Hmmm....
 
OneJoeZee

OneJoeZee

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Are you sure the right ports on the solenoid are hooked up? And the port that isn't in use, is it capped off?

80% should be a lot higher than that. Especially if you're doing 13psi with the controller off.

On stock twins, you should be hitting your target set boost around the same RPM you were hitting base boost before.
 
BlackMKIII

BlackMKIII

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Hmm. Well, I hooked it up using your diagram. Two lines from the compressor housing to the NO port, two lines to the actuators from the COM port. NC port plugged. I had Ace install it, I'm sure he got it right.
 
BlackMKIII

BlackMKIII

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I have a digital camera. Let me go take pictures of a few things and I'll post them up. I know Ace hasn't worked on a 1JZ before so it isn't entirely impossible for him to have flipped the lines around for the rear turbo because they're so hard to see. BRB.

And thanks, Joe. :D
 
annoyingrob

annoyingrob

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BlackMKIII;900748 said:
Hmm. Well, I hooked it up using your diagram. Two lines from the compressor housing to the NO port, two lines to the actuators from the COM port. NC port plugged. I had Ace install it, I'm sure he got it right.
Click to expand...

NC is not supposed to be plugged. It's a vent to bleed off pressure guys!

How's the Profec supposed to bleed off boost to control the wastegate if you close the vent port? It even states this explicitly in the manual.
 
annoyingrob

annoyingrob

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OneJoeZee;900776 said:
You're right. My bad. :) Mine wasn't plugged.

But if it was not bleeding off any pressure, the boost would be uncontrollable, would it not?
Click to expand...

If it's NOT bleeding, there is still a LITTLE bit of control based purely on the "lag" generated between the pressure source, and the wastegate merely by the modulation of the solenoid.

You won't get nearly the control you should though.
 
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