Greddy Profec B Spec II problems

[JimmyJames]

I'm having alot of trouble keeping 14 psi with this boost controller. The weather has been cold lately, so I'm sure that's affecting it. I need to know what other peoples settings are for 14 psi. Right now I just can't seem to get it. I have 10 psi on low boost very well, my settings are 45%, gain at 15%, and start boost at .56 in kpa mode. I've played with any number of variations of these numbers to try to get 14 psi but it just won't take lately. I have had it set to 14 psi very well before, but that was when it was around 50-60 degrees everyday, now its more like 30-40. Can anyone help me out?

BTW, this is for an S14 w/ S13 SR

[Ian]

maybe your turbo is just no good

[JimmyJames]

I don't think so, as little as 2 weeks ago I was making 14 psi steadily, then the weather changed and it wasn't. I just think I need to get my settings right, but every combination I try gives me bad results (when trying to get 14 psi).

[xVaporx]

Well what results are you getting? Overboosting? Not maintaining boost?

[katbak]

I'm getting extremely high overboost and I need some good settings for around 14 psi...

[katbak]

Hey jimmy I just set my profec b spec ii at the same thing ( set = 45%, gain = 15%, and set gain = .56 (kPa)...
I have my warning set at .90 and lower 25%

I still overboost like crazy, 2nd and 3rd gear just on a test run and I hit above 1.0 kPa at 3500 rpms.

Any help?

[WeldingHank]

the instruction manual has GREAT info on setting it. your start boost is probably too high. just use the volume and gain first. set the gain FIRST to get the boost to stabalize, then set the volume from there. then set your start boost. I had one on one of my last cars (turbo 1st gen Probe Turbo) had it holding 16psi up hills in 5th gear on 35* nights.

[nistech]

Greddy Profec B Spec II i have heard alot about how they have a problem with holding boost my friend has it on his srt4 he runs 16psi but he isnt happy with profec b my other friend with a supra has the spec i i m guessing the one with no screen just the buttons and i think that works better then spec 2

[JimmyJames]

Ok, I know this is kind of an old thread, but I just solved my boost problems with this controller. It seems the person who installed my BC neglected to remove the 3rd plug on the valve unit. Nothing goes to the port that it plugs, but you must unplug it. I don't know if this is a common mistake or not, but it certainly solved my issues which others seem to share, immediately. I only did this today, so the weather sensitivity issue may still be a problem, but as of right now, it's great.

[katbak]

Hey Jim, I didnt install my profec either, I'm gonna give it a look, how will I know what to unplug, not tryin to fuck this up.
Was it reading wrong for you, or just not leveling the boost out correctly.
Thanks

[JimmyJames]

Just look on the valve unit, there's two ports that have vacuum tubes connected to it, then another that's just a hole. Make sure there isn't a rubber plug in the hole.

[WeldingHank]

LOL, i had that exact same problem happen to me.

[katbak]

Damn, I have to check this out but I think I'll have to go through alot to find my valve unit. The previous owner wired it through the glove box... With all the guages blocking the removal of the main panel this might get hard.

Edit - I didn't know the below.

[badboy6686]

shouldn't the valve unit with the vacuum hoses be in the engine bay close to the wastegate??

[xVaporx]

shouldn't the valve unit with the vacuum hoses be in the engine bay close to the wastegate??

for best response and control, absolutely

[badboy6686]

for best response and control, absolutely


I thought so... I had a great laugh when me and my buddy went to go buy his mr2 turbo and the guy had ~12 foot of vacuum line connected to a manual boost controller beside the seat... would having that hooked up cause any hard considering the fact that the MR2 has a factory Fuel cut at 12 psi meaning he couldn't have overboosted.