Profec B Spec-ii Setup And Tuning (help!)

[damuscat]

I've had a Profec B Spec-II boost controller installed for a few months now and I've been determined to get it to run right myself.... no such luck unfortunately. I got the workshop to install it at the same time I had the front mount intercooler installed.

The Problem...

It seems that no matter what I do (with the settings) I either get boost spike or surging, both of which are extremely annoying. After reading many threads on this forum I've tried all sorts of things.

The surging really baffles me. I have the warn limit set to 12psi and then I have the boost level for the limiter set to 4% less than what it's set to for maximum boost. The strange thing is that when the limiter does cut in (i.e. screen goes red and the unit beeps) the maximum boost achieved as shown on the controller is only say 9 to 10 psi. This is below the 12psi warn limit I set so I don't understand why the limiter is kicking in.

I know the right thing to do is to get the car to a tuner... and I will eventually but as most people on these forums could relate to I'm just waiting on a couple of other things to make the most out of the tune. In the meantime can anyone offer some tuning suggestions for the profec? My mods for now are just a 3" high flow exhaust, front mount IC and a pod filter. My desired max boost is 10-11psi.

A couple of other points.

- The control unit for the profec is taking the pressure reading from the inlet plenum (i.e. post throttle)

- The soleniod also has it's pressure line coming from the inlet plenum.

If anyone could help it would be greatly appreciated. It's annoyed me so much that I've considered re-installing the trusty manual bleed valve. It took me all of 5 mins to get that thing going right and I never ever saw any boost spikes or surging.

[180or200]

Mine was plumbed wrong when i got the car, it was connected to the carbon canistor that went to the plenum, and would spike, wouldn't read less than 12 psi, then i moved it into the outlet pipe on the turbo and it works fine, 40% 12-13psi, 50% 17 psi, switched off 8 psi !

[damuscat]

Carbon canister that's one combination I haven't heard of before!

Sometimes I think I've just about got mine right. For example I'll be going along at 80km/h then accelerate to 100km/h in 3rd and get it to work fine. Then when I give it a test in the lower gears the limiter keeps on kicking in and I get a boost surge effect. The opposite will happen when I finally get it right in the lower gears

I had suspected that I set my start boost too high but right now it's only set to 4psi. From what I've been reading this should be quite a conservative setting.

Here are my settings....

Set = 29% (combined with the gain setting below this is producing around 10psi max)

Gain = 8%

Set Gain = 40 (4psi)

Warn = 120 (12psi)

Limiter = 25%

Can anyone else share their settings and results? I know varying levels of mods will produce different results with the same settings but I'm just curious.

[damuscat]

Mine was plumbed wrong when i got the car, it was connected to the carbon canistor that went to the plenum, and would spike, wouldn't read less than 12 psi, then i moved it into the outlet pipe on the turbo and it works fine, 40% 12-13psi, 50% 17 psi, switched off 8 psi !

Having the solenoid take it's pressure source from the pipe between the turbo and the intercooler (I presume this is what you meant above) seems more like the right way to do it for some reason. This is where the stock solenoid takes its reading from after all. The problem I have is that I have an aftermarket intercooler that doesn't have the nipple on the piping to attach the hose to. This is why mine is connected straight to the inlet manifold.

[180or200]

I had brass nipple silver soldierd into the black pipe comeing straight from the turb by a radiator repairer, thought about tapping into the cast piece that bolts onto to it but wanted it to be leak proof ! your set gain could be the issue, your telling it to start opening before the stock actuator has enough pressure ( 7-8 psi )

anyhow here are my settings to run 12-13 psi

set 40%

gain 10%

set gain 100

warn 200

l warn 15%

[Beer Baron]

I would raise the limiter a little. also raise the start a little. and perhaps try lowering the set and raising the gain?

I know mine was far from perfect when I first started using it, but after some more fine adjustment on the dyno (like 5 mins worth and about 3 or 4 pulls) it's now perfect and flat as a tack boost wise. I do notice though that if I'm driving along at say 4000rpm and mash the throttle as it ramps onto boost (happens very fast) it breifly spikes but settles straight back on 1.05bar setting.

I think try and do it on the dyno. it can be hard to tune on the street as there are not many places you can load it up in 4th or 5th gear!!!

[damuscat]

Thanks guys. Those suggestions make sense so I'll give them a try and see how it goes.

Richard, I've seen what you've described with the slight spiking at high RPM. When I manage to get rid of the surging I see this brief spike too. But I'm always thinking that it's bad and hence continue to fiddle around with the settings.

[GTR_Legend]

Everything installed correctly?

Not using the original hoses with the restrictors etc... and blocked off the hose coming from infront of the turbo?

what happens when you turn the unit off? still measures boost! what does it hit?

[damuscat]

Everything installed correctly?

Not using the original hoses with the restrictors etc... and blocked off the hose coming from infront of the turbo?

what happens when you turn the unit off? still measures boost! what does it hit?

The hose going to the control unit in the cabin is simply tee'd off one of the hoses coming from the inlet plenum. For the soleniod, one hose goes straight to the turbo actuator and the other is connected to a hose which goes directly to the inlet plenum.

If I turn the controller off everything runs as if it were stock. The boost gauge hits 7psi and stays at 7psi. The boost reading on the control unit also indicates around 7psi.

I've adjusted some of the settings this afternoon as per the suggestions from Richard and Adrian. However until I either get the car on a dyno or this rain holds off I won't be able to test it out properly. I'll post up results when I have them.

[Spraderz-33]

Am i having a similar problem tuning my Profec B spec 2. I have set it up to a point where i can achieve my max boost of around 11-12psi, the problem is that it reaches that boost very quickly and then drops off and starts again. I could be in any high gear and have the throttle 1/4 to 1/2 in and it wil creep up to 10-12 psi rather quickly at low revs(2k-3k) and then once it hits the a decent psi level it drops back to around 6psi or so and starts creeping up again this time only even maxing at 9psi-10psi close to the rev limiter. You can feel the car "jerk" and kick back as this happens

These are my current settings:

set 40%

gain 10%

set gain 100

warn 150

l warn 15%

I have tried turning up the gain as high as it goes but the problem is still there. Any help would be much appreciated guys since currently i am happier with just the bc turned off since at least then its a smooth power curve just doesnt have the boost i am looking for.

Cheers Jason

[Douse]

From memory these are the following settings for my Profec B Spec 2 on my RB20.

SET = 55%

GAIN = 5%

SET GAIN = 0.53bar (7.687014 psi)

WARN = 0.95bar (13.77861 psi)

LIMITER =15%

I find reving out in high gears it sometimes reaches 1.00 bar (14.5038 psi)

I also find, that it does not reach optimal boost until i am reving at about 4500 to 5000 rpmish. I would like it to reach max boost sooner and hold all the way out through the rev range without creeping to much at high rpm. But the gain is turned down all the way....

But if i increase how hard the boost comes on (set gain) too much i find that it comes on too hard and reaches full boost and bounces back of the boost.

The current settings are fairly good, some would say i am pushing my stock rb20 turbo a little hard, but it don't normally hammer it in third gear all the time so 1 bar isn't reached that often.

[Spraderz-33]

From memory these are the following settings for my Profec B Spec 2 on my RB20.

SET = 55%

GAIN = 5%

SET GAIN = 0.53bar (7.687014 psi)

WARN = 0.95bar (13.77861 psi)

LIMITER =15%

I find reving out in high gears it sometimes reaches 1.00 bar (14.5038 psi)

I also find, that it does not reach optimal boost until i am reving at about 4500 to 5000 rpmish. I would like it to reach max boost sooner and hold all the way out through the rev range without creeping to much at high rpm. But the gain is turned down all the way....

But if i increase how hard the boost comes on (set gain) too much i find that it comes on too hard and reaches full boost and bounces back of the boost.

The current settings are fairly good, some would say i am pushing my stock rb20 turbo a little hard, but it don't normally hammer it in third gear all the time so 1 bar isn't reached that often.

Thanks for that man much appreciated

So if i turn the set Gain down it should stop it from cutting the boost back and starting again?

Il have a fiddle and see how i go, Cheers

[geraus]

i had the same thing on my GTST! its so confusing! so i sold it!... its very wierd to tune! But i remember mine would spike constantly...

[Spraderz-33]

Turned Gain down to the minimum of 5% since that is the lowest my unit is capable of but still the same thing although a little better. Boost spikes alot more apparently in higher gears. Anyone got any ideas?

[Beer Baron]

guys, it can be very hard to tune the EBC nicely on the street. spend some time on the dyno and it should be easy. the weird thing is I have a profec B II in the GTR which is amazingly good. works very well. then I have a profec E-01 which is like 3 times the price in my silvia and theoretically should be the same but it doesn't seem as good. and actually I have another GTR now with profec B II and again, works very nicely.

[Spraderz-33]

Here are the pics of my install, Just wondering if you guys could tell me if that is correct. If thats not the problem then at least i know i can isolate it to the tuning of the unit.

Here is the main pic of the two ports going to the actuator and the IC piping after the IC and near the inlet plenum:

Here is a piece of piping that for some reason has been blocked off before i got the car, dont know what is was for or if it is needed?:

Thanks guys Any input would really be appreciated

Cheers Jason

[Douse]

The GAIN which I have set to 5%, is used to control boost high up in the rev range.

If the boost is dropping off in high rpm, you can increase the GAIN and this will increase the boost in higher rpm to maintain a steady level.

Be careful increasing the GAIN and this will increase the maximum boost achieved which can be HIGHER then what is SET.

I have mine as low as it can go as i don't need to GAIN as my turbo is stock and i am not reving my car harder than 7000rpm...

If you are experiencing the boost bouncing off when full boost is reached, decrease how hard you want the boost to come on. This is done by the SET GAIN.

In your case I would say to try and reduce this value. About half of full boost should result in a nice come on, and if you want it to come on more aggresively increase the SET GAIN.

I am no expert, this is just what i found when messing around with my EBC, as it was confusing as all hell when i got mine....

And BeerBaron is right, tuning a EBC for street driving is difficult, as i find the EBC settings act differently when in WOT in lower gears and higher gears.

Edited April 17, 2008 by Douse

[Douse]

I have my controller unit mounted right next to the turbo, as i was under the impression it should be as close a possible.

But this probably wouldn't make too much of a difference..

[Douse]

According to your settings you have the SET GAIN set to 100 right?

Does this mean 10 psi?

If this is the case, then this is your problem. You want to set the SET GAIN to 50 which would be about half of your max boost...

Am i having a similar problem tuning my Profec B spec 2. I have set it up to a point where i can achieve my max boost of around 11-12psi, the problem is that it reaches that boost very quickly and then drops off and starts again. I could be in any high gear and have the throttle 1/4 to 1/2 in and it wil creep up to 10-12 psi rather quickly at low revs(2k-3k) and then once it hits the a decent psi level it drops back to around 6psi or so and starts creeping up again this time only even maxing at 9psi-10psi close to the rev limiter. You can feel the car "jerk" and kick back as this happens

These are my current settings:

set 40%

gain 10%

set gain 100

warn 150

l warn 15%

I have tried turning up the gain as high as it goes but the problem is still there. Any help would be much appreciated guys since currently i am happier with just the bc turned off since at least then its a smooth power curve just doesnt have the boost i am looking for.

Cheers Jason

Edited April 17, 2008 by Douse

[Spraderz-33]

Yep thats right Douse it is currently at 100 or 10 psi. My turbo is also stock so i am only looking for about 12psi to be the max boost. Ill change it down to 5psi and see how things go tomorrow. Does the rest of my setup seem correct? Do you know what the blocked off pipe is? Be good to know that its all down to the tuning so i can tackle that and maybe one day get it right