profec b spec II - definitive thread needed
I have a version II JDM FD, low kms. It's been noted that version II's *may* run slightly higher stock boost. My boost pattern, before profec, was around 13-11-13 or thereabouts. Relevant power mods are trust sp cb and hks dp. As the weather gets colder, I started to see 1bar peaks (14.5psi) - time for control.
here's my profec experiences thus far: * factory setting * set: 0% gain: 10% set gain: 0 (start boost) warning: 1.20 (17.4psi) limiter: 0 peak boost = around .6 (approx 8.7psi) Before anyone states the obvious, I know you can switch to psi, I just prefer not to. The first problem with boost control, is where to start, so I took a look at some of the #s used by people on this forum, and ended up with the following = * hi setting * set: 26% gain: 14% set gain: 16% warning: .9 (13psi) limiter: 20 (maximum) peak boost = .89 (12.9psi) Obviously the controller had the clamps on - which was good to see. Boost pattern wasn't too much different than pre-profec - I couldn't notice a significantly faster spool up. So, I went back to the original settings and decided to work up (my aim is for a lo setting peaking at 12psi) * lo setting * set: 7% gain: 10% set gain: 5% warning: .9 (13psi) limiter: 20 (maximum) This gave me a relatively smooth pattern and a 12psi peak. These #s are a lot different than any I've seen on here, though. If I went above a set of 7%, it would push past 12psi. The limiter of mine is different to what I've seen in the greddy USA pdf - it has a range of 0-20 (the pdf seems to have a 0-100%) - I assume it works the same. There really isn't much solid info on this function. At max setting, I get a clamp down (doesn't exceed the warning level) - why would/should I play with this setting? I'd really like to have some more info/discussion on the SET and START BOOST functions. When should the wastegate be opening?? |
Are these difficult questions?
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You will get higher boost when the air is cooler due to a more dense charge of air regardless of how your boost controller is set. I get between 12-14 psi at the same "set" setting depending on whether it is 90 degrees or 50 degrees.
I would do exactly as you are doing and gradually increase the "set" first to get your boost where you want it. Then, I would gradually increase the start boost until you get a spike and then back it off some. I'm no expert, but it seems that would work fine. I wouldn't worry about what other's numbers and settings are if you are getting the correct pattern. |
I understand the relationship between cold air and boost (thanks anyway).
I'd be interested to hear from anyone who can elaborate on the way the limiter works - for example, how it would operate differently with a 50% (11) or 100% (20) setting |
Ok,let me tell you my personal experience after 4 months with the profec B spec II.At the beginning,and with the help of the forum,i used the following settings:
ambient temp: 26C humidity :55% pressure :990 kpa elevation :110 m set : 27%-29% gain : 8%-10% set gain(start boost) : 0.55 warning : 0.70 limiter(warning) : 5% The result was a 0.75bar(10.8psi) in all gears and always a fall to 0.5bar(7.2psi) bar after 5500 rpm.Also,everytime after the transition,a 0.8bar(12.7psi) spike for a .5 sec.I was dissapointed from that,until i decided to go the other way:high gain and low set.So,i ended up like this: ambient temp: 12C humidity : 67% pressure : 1012 kpa elevation : 110 m set : 10%-12% gain : 50% set gain(start boost) : 0.55 warning : 0.70 limiter(warning) : 5% I can tell you that in my car,the difference in spooling is HUGE(better than before).Also,i have almost zero spikes,and the boost goes to 0.7(10psi) and falls to 0.65(8psi) from 5500+.So,my conclusions-observations are: 1.It seems to me that its better to have the solenoid valve more sensitive(gain),than to have a high duty rate(set). 2.You cannot avoid boost drop,if you want to eliminate spikes.You will have some boost drop to the high rpm . 3.The "start boost" logically(and practicaly to my car),opens the wastegate.So,you have to open it somewhere to 0.55bar(so it can "catch up"the spikes. 4.The limiter indeed works,but it has a few ms delay,so you cannot avoid the spike.In other words,its practicaly usseless. 5.If you set the "set" mode to 35% + the boost will keep up climbing no matter what the other settings are. 6.I believe that profec doesn't like the transition.Maybe a non-seq would be ideal for the profec... 7.The profec displays 0.1 bar less than my defi boost gauge. Bear in mind that my "mods" are:efini y-pipe,downpipe,and hks filter in the stock box.I was getting 0.8,0.9bar spikes before the profec and a rb dual is on the way(lol).Also,my stock cat is in mint condition. I think that you should try my settings and write your results(if you blow your engine don't blame me :-)). Regards, Stathis. |
my gain setting goes no further than 35% (?)
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anyone else have a gain that maxxes @ 35?
I note a couple of changes in the manual I have (which, conveniently, is in english and japanese), as opposed to the online pdf. I had to wait a while for trust to send my unit out - I wonder if I have a slightly modified version to others here? (or something just isn't right...) |
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