kevincnc

Nize, could you post a diagram of your boost control setup?

Rogue_Ant

Dual Port in Single Port mode w/ 1.1bar spring & a MBC.


Rogue

Rogue_Ant

Any Datalog?


Rogue

The DareDevil

Is your intake glowing red?

jimbo1111

To the original poster: I have tried numerous maf's. The Vitesse maf is a very nice system. Worth every penny. offcourse you woun't realize it's true potential until you start to modify your vehical. I definately would recomend it to anyone in the market for a maf.

nize

Rogue_Ant; my bet is that the reason you're not holding boost to redline is because you're running the wastegate in single-port mode, which prevents the wastegate from fully closing towards redline. actually what happens towards redline is the wg starts to rely on spring pressure, and since yours is set at 1.1bar spring = 15.95psi that explains why you can't hold boost.

another reason is if you are using mbc, the boost is not variable. as you approach redline, you need less bleed-off on the boost controller (mbc in your case) in order to compensate for the increasing exhaust backpressure. i guess you could manually turn the dial as you approach redline but that's not really practical.

in a dual-port setup, the pressure on the wg spring is equalized on both sides, which allows you to completely shut the wastegate regardless of manifold pressure or wg spring pressure. however, even with a dual port setup, a manual controller will not allow you to achieve variable boost control, which is what's required to hold full boost.

only a dual-port setup with electronic actively variable boost control will allow you to maintain full boost to redline. keep in mind that there are some electronic boost controllers that do not feature actively variable boost, that's important.

here's the dual-port setup;



in my configuration, the 'boost controller' and the 't' fitting in the diagram is replaced by a dual electronic solenoid with both lines connected to each port on the wg. this allows precise control of the wg regardless of the situation. if the solenoid itself fails, the wg will revert to spring mode, which is currently set to .7bar, which is roughly 10psi for safety.

Slantnose!

Hey, thanks for posting this...
That makes sense to me and now I understand.

kevincnc

I'm using a Profec B spec 2 hooked up DP. Maybe the "gain" **** would help, I haven't tried adjusting it since putting on the new WG. I thought that the the EBC would try to keep the boost at whatever pressure it is set to, regardless of RPM. Nize you said you have two solenoids? How does that work? Sorry to continue the hijack, I think the concensus is Vitesse MAF= good choice.

kevincnc

Oops sorry I didn't read the dual solenoid explanation. Wouldn't that mean that you are exhausting a lot of intake air as the valve switches back and forth?

nize

read my post just before this one.

the dual solenoids allow control of the pressure on either side of the wg independently of the other. it's for the maximum control freak. or something.

i'm not familiar with the profec B spec 2. what is the function of the 'gain' ****? is it capable of active variable boost? hmm.

nize

no, because at higher boost it's less active, and it's not active at all until full boost is acheived.

NeoRules

What activates the solenoids? Is it the electronic boost control?
Maybe I missed that.
So with the solenoids closed the pressure to the WG is nil or is it the other way around?
I am just slightly confused.... but that is easy...

Rob

Without getting into the whole debate on the k26 series holding boost to redline....Another point to consider is the altitude you are at and how you are measuring boost.

Rogue, I'm guessing your datalog is from a MAP sensor (absolute?) if so at your altitude you probably have to build a couple lbs of boost just to get up to sea level atmospheric pressure. What pressure does your datalog/sensor show powered up with the engine off?

nize

yes, the solenoids are controlled by the electronic boost controller. if the solenoids fail, the pressure to the wg is equal on both ports, which in turn allows the wg to rely on spring pressure as a failsafe mode. in my case that's around 10psi.

Jake951

Is there anybody who has gotten a K26/8 to hold full boost to redline using the WG in single-port mode?