shazzam00

i had the same problem also... i spiked to 17lbs and my car would jolt really bad... so i added a profec b spec II and fixed after some button pushin here, and button pushin there... it ll keep it 10.3psi alll the way... i have intakes, dp, and hks catback... you will be more than happy with the boost controller...

BoostedTimmy

So than the PFC cannot alter the rate of the precontrol door? Just trying to learn something here and maybe help Victor kill 2 with 1.

DaleClark

iTrader: (55)

Wow, a LOT of misinformation piling up here.

First off, the PFC has basic boost control functions. It can control the stock wastegate control/turbo precontrol solenoids - this can all be set up with the commander. You set the amount of boost and duty cycle percent, and there you go.

The stock ECU has, of course, control over the wastegate control/turbo precontrol solenoids, but runs them on a fixed map that was designed around a STOCK car. Once you open things up, those settings just don't work any more, and you have overboost.

You do NOT have to buy the boost control option for the PFC to have boost control. The option is just an aftermarket boost control solenoid (same one that comes with the AVC-R) and a higher-range pressure sensor to replace the stock MAP sensor. This gives more robust boost control, but the PFC's boost control is EXTREMELY basic.

Now, the problem is the stock boost control setup (two solenoids, pills in the vacuum lines to the wastegate actuators) just isn't very flexible. When I fully opened my exhaust, I had boost control problems that could only be solved by drilling the precontrol pill out a tiny bit, which is IMHO not a way to control boost. Dorking around with pills went away with the Clinton administration.

A good aftermarket boost controller ditches the stock wastegate control/turbo precontrol solenoids and the pills altogether. More advanced ones have even more features, like gear and RPM based boost setting (go AVC-R! ).

So, to sum up -

Stock ECU's boost control - fixed map, boost spiking and loss of control with very minor mods.
PowerFC's boost control - controllable map using the stock solenoids, but boost control can be a problem with full exhaust/intake due to limitations of stock solenoids/pills
Aftermarket electronic boost controller - full and complete control over boost, ditch stock solenoid/pill system.

I think we've confused the original poster enough .

Dale

tphan

Right on...

Apexi Intakes - little pickup...boost ok.
HKS DP - little more pickup...boost still ok 10-8-10
Greddy SMIC - same...
RD DT - real good pickup...2 psi more than 10-8-10

PFC & Steve Kan tuned.

adam c

iTrader: (2)

edit. see next post

adam c

iTrader: (2)

??????????????

Individually, each one of those mods will increase boost over 10-8-10. Any two of them will likely get you to 12 psi ............... NOT OK on stock ecu!!!!

Kento

Just to clarify, though: the vast majority of electronic boost controllers still use solenoids to activate the various functions. They just do a much better job of monitoring and activating them.

Kento

By themselves, not necessarily. A Greddy SMIC by itself may not increase boost if intake and exhaust remain stock. Same with a DP. Each car reacts differently to various mods. Combinations of the aforementioned mods, however, will definitely result in overboost.

adam c

iTrader: (2)

Kento,

I disagree. I believe that any mod designed to increase flow, will increase boost. Certainly, one mod isn't going to increase your boost enough to cause a problem. As you/I/we stated, combinations may get you into a dangerous area.

Kento

If any single mod doesn't increase overall flow enough to overpower the stock boost control system, then you're not going to increase boost. The FD's stock airbox intake is very restrictive (as your stock airbox mod shows), as is the stock main cat. A DP increases flow enough to improve boost response, but not enough by itself to overpower the stock boost control system and increase overall boost level; when I installed my DP without any other intake/exhaust mods, I saw no increase in boost level. Other cars may see a slight increase. A SMIC like the Greddy may have slightly less pressure loss across its core, but if the stock intake can't get any more air in and the exhaust can't let it out efficiently enough, any flow gains won't be enough to overpower the stock boost control system, which is the primarly limiting factor for boost increase.

adam c

iTrader: (2)

I understand what you are saying, but I still disgree with you. I don't think the stock boost control system will keep boost levels at 10-8-10 with any "significant" single mod.

victorFD

iTrader: (1)

Hey, this was my post! Sorry, just joking Well, the fact is that I don't know why but my intake mod makes my FD overboost. That's the true! Combined with the dp and catback now I'm running in dangerous boost levels, still on stock ECU. The Pettit Racing is near, so I will wait until it's installed and in this way I will run the apexi intake. Next step should be a boost controller, but with the pettit I will run safely. Is this what I should do?

adam c

iTrader: (2)

Check it once the Pettit ECU is installed. You may still need a boost controller.

Kento

Like I just said: when I installed my DP without any other mods (even stock catback), I saw no increase in overall boost level. When I removed the stock airbox crossover, then I saw a slight spike at the 4500 rpm transition. Other cars may be different.
Again, every FD is different, and some react to mods more strongly than others.
If you really are running at 14 psi, there is some debate as to whether that is pushing the stock fueling system too close its limit. IMO, you should be OK as long as you don't spike or creep beyond that boost level.

BoostedTimmy

Great post Dale, that clears a lot up for me.

Victor are you considering a MBC?

victorFD

iTrader: (1)

Yes, but I'll install an electronic BC

Farnk

is there a way to tune a stock ecu? say a fd with tbe/apexi intakes?

NissanConvert

iTrader: (1)

Other than buy an aftermarket reflash not to my knowledge. However with only a couple mods the ecu should still be able to control boost. But- of all the mods i've done intake & mid-pipe were the biggest change. I've since installed a cat- as is mentioned in my previous post.

BoostFrenzy

Mine hits 14-15psi @ transition and takes off like a raped ape, but I know it's unsafe so I only did it during the test drive... I know I can purchase 2 mbc's and control the pre-control / wg solenoids independantly, but with a EBC (considering two hallman's are $200), wouldn't I be better off going for a profec b?

Will boost be stable ~10psi throughout once dialed in?

ihavetwins

iTrader: (5)

my advice to you is to get rid of that of tho's filters man i had tho's when i had my stockers in and my intake temps were insanely high. because you get all the heat from off the radiator and all the heat from the engine bay. a nice air box will fix that. maybe it was just me but i couldn't stand them.

gracer7-rx7

iTrader: (16)

In theory Kento is correct as usual. In practice, Adam is right.

On FDs after this many years and mileage the true state of the stock boost control system is unknown and therefore results will vary. My 2nd FD worked fine for a while with the stock boost control system. Then one day it no longer controlled boost properly.

I've had overboosting with nothing more than a downpipe on my FD - especially in colder weather (30-40 degrees). On my old FC TII, it overboosted regularly with nothing more than an adam_c style cheap bastard intake fwiw and that was back in the day when it was new.

Electronic Boost Controllers are wonderful things.

Vlad

i thought that boost creep cannot be fixed with a boost controller simply because the stock internal wastegates aren't open enough to let all the pressure release and that boost creep could only be fixed by porting the gates or welding them shut and getting an external wastegate?

Bear with me im a noob

Wompa164

iTrader: (4)

Technically that's not true. Boost controllers operate on the basis of 'tricking' the wastegate source pressure into thinking it's lower than it actually is by bleeding off pressure, keeping the wastegate closed longer and allowing higher boost pressure to build up.

Vlad

PART THREE!!!

NissanConvert

iTrader: (1)

The only thing that stays stock in your boost control system is the wastegate. So unless you have so little backpressure (mid pipe) that the wastegate is the weak link and *cannot* open fast enough (gain settings) your boost controller will be on top of things. It doesn't "trick" the wastegate source so much as it takes control of the wastegate source away from the ECU.