DaiOni

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??

DaiOni

Are these difficult questions?

pianoprodigy

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.

DaiOni

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

EFS.O

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.

DaiOni

my gain setting goes no further than 35% (?)

DaiOni

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...)