MR_Rick

iTrader: (7)

OK... I am seeking help.. again...

It seems as though the twins are gonna be on the car longer than expected... SOoo.. I will like to clear up the spiking issues once and for all...

Here's the deal to the one's that didn't follow my last thread.

I had a boost spike issue... boost would spike to 15-16 psi before goin back down... I went non-seq, it still does it. It sucked... I was getting pissed, I checked out the pills, there are none. and I still spike... so I decided to unplug the wastegate control selenoid... now the car boosts only 8psi with no hint of spikes or anything... now I want my 10-12psi back... but without the spikes.. it may be possible that I switch back to seq after this.

So, here is where I need your help folks...

I tried using the HomeDepot boost control method with no success. it was either 8psi or no control of boost, but nothing in between (selenoid still unplugged).

I would like to hear suggestions as to what I should do/try in order to solve this.

In case that some of the ones that reply didn't see my earlier posts... here are my mods.

PFS Exhaust
PFS CAI
PFS Intercooler
PFS IC & CAI Duct
No Airpump (recently done yesterday)

We have not determined anything about the ECU... i do not know what it has, but I doubt that it is stock since I can hit over 13 psi without a boost cut.. I have yet to find a Fuel Cut Defender.

SleepR1

Recall that the turbo precontrol allows primary turbo exhaust pressure to vent to the secondary turbo's exhaust pressure for primary turbo boost control. Check the hose between the primary turbo compressor and the turbo precontrol actuator. If this hose has popped off or has a loose connection, the turbo precontrol "valve" will be slow in opening, thus causing a boost spike (the primary turbo's exhaust pressure is not bleeding off fast enough).

The above info is located at this site:

http://www.autosportracetech.com/RX-...leshooting.htm

If you're running nonsequential twins, your secondary turbo is running in parallel with your primary. If your precontrol is not working properly, the boost spike will still be present regardless of sequential or nonsequential. Most people who convert to nonsequential have a problem with the SECONDARY turbo NOT coming online fast enough, or at all...

MR_Rick

iTrader: (7)

But dont you make the valves stay open when you are non-seq and therefore the precontrol doesn't matter anymore
?! If you look at the instructions, you rig everything open and then you unplug the vaccum hoses from the precontrol selenoid.

SleepR1

Not sure. If the precontrol and wastegate "valves" are rigged to stay open, then no exhaust pressure builds for boost?

MR_Rick

iTrader: (7)

That is why you get a lot of turbo lag with non-seq

SleepR1

Sorry I can't offer anymore help. It's a real pisser when the FD ain't running right...good luck!

911GT2

Correct. In non-seq the precontrol valve lines are plugged or removed, so the solenoid controls nothing.

Assuming that everything with the HD boost controller was hooked up properly, I'd fault your wastegate solenoid or actuator. Have you looked into those?

MR_Rick

iTrader: (7)

Thats exactly what Im thinking... you are right inline with me here... I just plugged it back in and reset the ECU... tonight when I drive the car I will see the reaction... if it still does this... then my next step is to run new vaccum lines to it and try again, if it doesn't work still, then it is time for a new selenoid... That to me is a safe assumtion.