Farkel Jr.

iTrader: (10)

I'm having some boost problems, mainly I'm boosting past 10psi in 3rd-5th gear very easily. I have a restrictor plate in as well...


While I was looking into all this, I read that you could do something or another with the hoses under that little black plastic box on the top of the engine bay? And this will restrict the max boost to 8 psi?

Could someone tell me exactly what needs to be done for this? I figured if I restrict my boost to 8 psi, and I can creep a bit and be much safer than now

Thanks

SonicFD

iTrader: (17)

What is the PFC tuned for?
Post a modlist

kyleaudio

iTrader: (22)

if you lift up that little black plastic air tank that is right on the top center of the engine right in front of the upper intake manifold, right under the left side of the UIM you'll see two green solenoids that are mounted together. if you pull the top vacuum hose off of both of them and cap the hose (make sure that you cap them or else instead of setting them to minimum boost, you'll be setting them to maximum boost!) then if all else is good, you should be restricted to 7psi.

Farkel Jr.

iTrader: (10)

^Nice I went to go try that, but when I took off that little black air tank, I saw that one of the hose wasn't connected to anything.

The other hose was connected to that green solenoid, which was connected to another hose to the engine... but is it normal for the second hose on the air tank to be hanging free like that? What should I do




Also, here's a picture of under the black plastic air tank. There's 2 pipes that are just open, which I've marked... is that supposed to be that way?



And you're saying I should cap the Hose but not the top of the solenoids (leave them open)? I'm not sure exactly which 2 vacuum hoses I'm supposed to pull off and cap

Farkel Jr.

iTrader: (10)

In continuation with my previous post, I looked at a vacuum wiring diagram and I think I know what to do about the hose off the black air tank that wasn't connected to anything. And as for the other pipe that was left open, it looks like it's just an "Empty Pipe" according to the diagram. I can't believe that one line off the black air tank was never connected...

My new question is, what's going on with this weird vacuum line just sitting in the middle? I circled it with a "?" :




Also, I think I found the solenoids you're talking about kyle... There looks to be 2 vacuum lines that come off each solenoid, an upper and lower. So just pull off the Upper lines on each, as marked in Red in the following picture?



What's a good way to cap off those 2 vacuum lines that I just pulled off? And should I leave the solenoids open/uncapped?

dgeesaman

iTrader: (7)

You don't need to cap off those two lines although you could. I've just unplugged those two solenoid connectors and seen 8psi. Trace the lines coming from those two solenoids and make absolutely sure they are not leaking.

The thing you circled is a filter it's fine.

I'm not used to seeing stock hoses anymore.

Dave

kyleaudio

iTrader: (22)

hmm, good point. unplugging them would definitely set you to waste gate pressure. but it looks like its about time to do a vacuum hose job and test your solonoids and check valves while your under there. look in the FAQ thread, there are good hose replacement threads that will help you out.

Fritz Flynn

iTrader: (263)

No the second hose on the pressure tank can't hang free. Find the vacc hose diagram print it and put the hose where it belongs

Yes unplugging the wastegate solenoids is your best option for running off of the TCA spring.

shmacklepap

iTrader: (15)

That empty pipe is supposed to be empty just like that. Its used only on FD's with Automatic transmissions....unless your FD is automatic I'm not sure where that goes to.

The open vacuum line coming from the vacuum box is very important. It goes a nipple in the middle of the y-pipe.

gracer7-rx7

iTrader: (16)

What you want to do is replace the 2 hoses at the front of the turbo that lead to the actuator and wategate. Those hoses have pills in them. Removing the hoses w/ the pills and replacing them with hoses w/o pills limits you to 7 PSI of boost which is the waste gate pressure iirc.

If you still can't find them and happen to be around Mountain View, you are welcome to come by and I'll point them out to you.

Farkel Jr.

iTrader: (10)

So just by simply unplugging the 2 Electrical Connectors that go to wastegate and turbo pre-control solenoids will do the job in limiting boost?

Does anyone see any adverse / negative reliability side effects to doing this, just checking..


and sorry gracer I'm not sure which 2 hoses you are referring to, are they still under the UIM or more near the air box lines? either way it seems like unplugging the electrical connectors is the easiest?

thanks for all the help

dgeesaman

iTrader: (7)

I've run with my solenoids unplugged. I still do it during track days to keep the power output and temps down. It effectively leaves the solenoids closed all the time which is the same as capping the lines. A stock ECU will post ghost codes due to the lack of the solenoids but it won't cause any problems or CEL. I did this during a period when I installed a mod that pushed my boost above 12psi but hadn't gotten my boost controller installed yet. Obviously you'll want to make sure this produces 8psi before really romping on the car, but if you verify it's keeping you around 8psi you're good to go.

Alternate methods are to remove the pills or cap the lines that lead from the wastegate and precontrol actuators to their solenoids. All of these approaches will cause the boost to revert to actuator spring pressure.

Take care with stock hoses they will get brittle and sometimes pop loose. If one of the hoses branching off the wg/pc actuators pops loose you'll have uncontrolled boost and maybe a big pop. When you fix that hose under your pressure tank check the other hoses for loose/leaky connections also.

David

Farkel Jr.

iTrader: (10)

^ Right on

I unplugged the connectors to the 2 solenoids, put everything else back and tested it out. I did some pulls, and the boost stays firm at 0.5 Bar, in 4th it creeps a little bit to about 0.6 at around 5-6k

Here are the stats off the commander (I have stock inj, full exhaust with midpipe, airbox):
Peak Inj. Duty was ~58%
Peak Knock was 80

Is that reasonable at all?

Also in retrospect, I think that one hose off the air box was previously connected to one of the pipes, but it was just so easy to pull off when I took the box off.


The car doesn't pull as hard now with the solenoids unplugged, but before it was boosting past 0.8 bar very easily, so this is a worthy trade off imo. I figured I'm not going to go for high numbers regardless on a stock twin set up anyway.

Thanks for the help!!