Apexi intake = overboost????
 

I don't understand. I've just finished the apexi intake installation and I've gone for a nice ride. My car keeps the boost pattern (10-8-10) with some little 11.5-12 spike around 4500 rpm. But with the intake all is gone. I'm scared! In third gear boost have raised 14 psi (keeping it for more than 1000 rpm). Obviously this is not good.
And one more thing. Sometimes I hear water boiling when I shut off the engine. Some slight sound in some hose. But today I've heared it louder, stronger. I've put on the key and the fans have started to work instantly. I think I'll need a CAI box, cos the lower filter is just on the lower radiator hose and breathing directly from the radiator fan...
Any advice? Has anybody had this issue with only an intake mod???? :uhh:

When you open up the intake, you get more airflow, and higher boost. Get a boost controller.

I know, I know... but, don't you think it's too much increase just for only an intake mod?

What other mods do you have?

My Performance mods are only catback + downpipe

a boost controller won't lower boost. I don't know why you're experiencing boost spike/creep w/ cat back and dp.

I had dp, midpipe, and 3" all the way back, the engine couldn't control my boost so i had to be really light on my right foot. I installed a cat & my PFC and it holds strong at 10lbs.

Some misinformation here. First off, you're at 3 mods on your car - intake, downpipe, catback. With that setup with the stock ECU, you WILL get boost spiking.

Next, a boost controller will help. The stock ECU's boost control map is VERY hardcoded, and will run away with the boost if you open things up. Putting on some sort of boost controller will take care of that problem.

The PowerFC gives you control of the factory boost solenoids, which will give you boost control to a good extent, but once you go farther (high-flow cat or midpipe) the factory pill-based boost control system won't cut it.

Anyhow, if you need something short term until you can afford a PowerFC, get a manual boost control setup. If you don't want to re-buy mods, get a good electronic boost controller. With either, keep boost at 10psi and the ECU will be mighty happy.

Dale

how does a boost controller lower boost if all it does is trick the factory ecu into thinking boost is lower than it is? I can understand how my PFC can lower boost but that's because it replaces the ecu.

An aftermarket boost controller will manage the wastegate and precontrol solenoids.

The PFC will no longer have any say in the matter, except maybe to fuel cut if the boost gets too high.

Because a good electronic boost controller doesn't "trick" anything...it takes over control of the precontrol and wastegate from the stock system, which the PFC will still only be able to control by itself without an additional boost control setup.

Okay, i'm a little confused. what i do understand is that a good boost controller takes control of the wastegate actuator away from the stock ecu.

What i don't understand is: Does *my* pfc driven car have any reason to have a piggyback boost controller?

His car has no pfc, no boost controller.

If it has enough mods to overpower the stock boost control system, yes.

Not if it controls your boost.

Personally, I believe my manual boost controller is more responsive and more consistent than my PFC, but that's just me.

I did not know it possible to push 14psi through the stock cat w/ the stock ECU. I ran same mods as you for a while on stock ECU with no spikes, but I guess every car is different.

The PFC controls boost just like any other EBC would, and has a multitude of other options, its a great investment for your car. I would recommend keeping a light right foot until you get a PFC or some sort of EBC. Don't waste money on an EBC if you plan to get the PFC in the future, it controls boost just fine.

Does your car slowly raise to 14psi and stop? Does it ever go higher? Or is this an instant 14psi holding steady?

Okay, for the record i have 3" exhaust turbo back, high flow cat, anti-rice cannon. I installed the cat last week, i installed the pfc yesterday. before i did that my boost controller was my right foot. since installing the cat and the pfc my boost holds strong at 10 lbs although some times at full throttle at the top of 3rd or fourth it'll creep to 12lbs. my peak injector duty cycle is 70.0%.

How can another boost controller actuate the wastegate to maintain my boost more efficiently than my PFC. I can understand doing it faster or what-not but if the problem is my unported wastegate then how would I fix that with another electronic box?

It won't make a difference, PFC controls boost just any boost controller. You are correct that the problem is now the stock wastegate. As long as your only creeping to 12psi you are fine though, just be careful on really cold nights.

Not necessarily. Every FD's stock solenoids/boost control will work differently, and from what I've seen, EBC's do a much better job of controlling boost spiking. At the very least with an EBC, you'll be using new solenoids rather than heat-weathered 10+ year old ones.
See above about boost spiking.

If the problem is specifically boost creep, then no, an EBC won't help.

+1

also PFC IS "NOT" A BOOST CONTROLLER. they sell additional add-on "boost controller kit" for PFC that cost around $350ish.

Anyone care to elaborate on this one?

As I understood that kit just replaced the already existing solenoids and gives you the option to quickly jump between a couple boost level settings. I can see that and a standalone EBC being useful for single turbo cars but what could it possibly do on the stock TT system? The only advantage I see with that or any other EBC would be the preset boost levels and new solenoids. I can adjust boost levels from my PFC already with the commander. If the PFC does not control boost than somebody please tell me what controls the boost on my car?

VERY SIMPLE ANSWER

i had the exact same problem

PROFEC B SPEC II fixes it completely

i had more severe spiking than you are experiencing...up to 17lbs of boost...i thought for sure that a boost controller could not fix it...well i was completely wrong

for now pull off the pressure tank and unclip the electrical connectors to the two solenoids u will run at 7psi on the primary turbo only (safety until a boost controller arrives)

pfc cannot control the boost as the solenoids do not respond quick enough even with interrupted duty cycling control

Makes sense that it would help control spiking but that seems like a band-aid to another problem.

You can easily get 14 psi on the stock ecu at lower rpms.

It's not just "setting boost levels"; it's about controlling the boost buildup more accurately. The stock control system is set up to build boost at a set rate, which is why spiking occurs with a certain level of mods. An EBC like the Profec B can alter the rate at which the precontrol door closes, controlling boost more accurately so that spiking doesn't occur in the transition phase.
Well, then the "problem" is modifying the intake/exhaust well past what the stock sequential twins and their system of boost buildup and control with both turbos were designed for...