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Anyone knowledgeable with the greddy profec b?

2K views 10 replies 3 participants last post by  CrucialProspect 
#1 ·
Looking for help with this boost controller, all info I found was somewhat contradictory, dated, and mostly in the import communities.
 
#3 ·
Well thanks for any help you can give me! My tuner actually set it up on the dyno and it seemed to work real well. The problem I had is that it was a 8psi spring in the wastegate and I was running around 12-15psi. I recently switched out the springs for 15psi springs, and can’t seem to get it to make any more boost.
My gain and set gain percentages are pretty low, and I’ve been creeping them up 3% at a time and really not seeing changes. I’m currently at 8% start boost at 10%

On the old springs I was running 16 gain and 19 and was getting 15psi I have to double check my warning yet, it may be set too low.
 
#4 ·
Well thanks for any help you can give me! My tuner actually set it up on the dyno and it seemed to work real well. The problem I had is that it was a 8psi spring in the wastegate and I was running around 12-15psi. I recently switched out the springs for 15psi springs, and can't seem to get it to make any more boost.
My gain and set gain percentages are pretty low, and I've been creeping them up 3% at a time and really not seeing changes. I'm currently at 8% start boost at 10%

On the old springs I was running 16 gain and 19 and was getting 15psi I have to double check my warning yet, it may be set too low.
How do you have the vac lines ran?
 
#5 ·
The side ports of the wastegates tee together, tee into the pressure side of the cold side post turbo,and then into the nc port on the solenoid. Bov tee into vacuum manifold, and the top side of the gates tee together to the com side of the solenoid. Basically just as it's diagram shows in the instructions manual for external wastegates. The only difference is that the turbos and wastegates are tee'd together (being a twin turbo setup)

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Fluid Font Glass bottle Plant Material property
 
#6 ·
From my research, the start boost value is actual psi, so I’m thinking if I don’t have a value over 15psi (the spring) it won’t make any more boost.

The set value may be the reason it’s actually making more boost than the start boost.

Also, I will have to check again in the morning, but I need to confirm the warning (which is also in psi) to make sure that wasn’t set too low.
 
#7 ·
I made a cheat sheet based on the two threads I've found in the internet, one was from a Mitsubishi forum, another from a Mazda forum. If the information is correct, and the strategy is good, then to run 20 psi boost, the start boost would be around 20, and warning would be 21, and limiter around 10 percent to back it back down closer to 17psi

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#10 ·
If it pulls timing as a safety function you may want to raise that value a few more psi b/c of boost fluctuation/spikes.

ks
 
#11 ·
It doesn’t pull timing, just bleeds off boost, but you are correct, if target is 20, having it around 22-23 would be safe. It’s not going to hurt the motor.

I’m just wondering if my small increments of adjustment are just not enough.

My previous settings with a blue spring was

gain 16
start boost 7
warning 16
Limiter 10

i think the blue spring was around 8.7psi on a 38mm Tial gate. This yielded me around 15psi, and was close to maxing our the duty cycle (2x spring pressure) I figured by increasing base spring pressure, the new values would be lower, but I assume the controller doesn’t see that change in spring pressure and only cuts off when it reads the incoming warning pressure?
From what I read, the percentages are from 0-100, and psi values up to 42 psi. As you can see, I’m nowhere near any of those numbers.

I’m just not sure why the percentage was fairly low on the gain and start boost, yet almost doubled the boost value versus spring pressure? That’s the main reason I started low, with the new gate springs.

Maybe I need to start second guessing what “weight” spring was in there before?
 
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