So here's the generic diagram included with a boost control solenoid.

My question is of the 2, which is the best way and why/how does the 3rd setup control "high" boost better? My guess is that the wastegate is not seeing any reference at all from the compressor, so it must wait to even begin to open until it goes thru the BCS. Where as in pic2, theres always some reference acting upon the wastegate. close?

I tried doing a generic yahoo search, but not much useful info.


So if the primary port hose was cut, then what would happen?
Would it
>boost til the wastegate spring
>never open and overboost?
>never close so you;d never boost

CO2 controlled wastegates are popular on other platforms (Grand nationals etc) anyone implement that into a VQ? Or is that a drag car special

 

i think the only reason the last pic is different, is because the boost solenoid is controlling the pressure the WG sees, so it can control the force at which boost occurs as opposed to 2 where the boost goes straight from the turbo, which is the most accurate but harder to control boost spikes since its right from the housing. if you go thru the solenoid you can make the boost hit slow or fast. i dont know why it would have anything to do with higher boost. just hook up the boost source to the side port of the WG and the other port to the top of the WG via the solenoid.

 

anyone use the longer wastegate reference hose trick to build boost faster?
http://autospeed.com/A_111119/cms/article.html

 

My internal wastegates have only one connection, so I've never looked into this. In regards to the autospeed article, I would think that only applies when you have no control of the bc solenoid. With the Haltech controlling the solenoid, you can decide exactly what the WG sees - ramp rate, starting duty cycle, etc. In that situation, I think you'd want the highest reference boost possible (right off the compressor outlet) in opposition to atmosphere for best control with the solenoid as it pulse width modulates between the two. The JWT kit calls for the boost reference at the base of the charge pipe (after both ICs come together), but Forged tapped off the passenger side compressor outlet. I don't think there's much difference so long as the turbos are both operating properly (similarly).

 

good to know. I had them put an extra bung in the intake pipe to use as a reference, but the turbos also have nozzles on them for reference. I just figured it would be less hosing to use a intake route reference.

 

To determine which method is best I need a little more info on your setup. Is it internal or external gate(s)? What is wastegate boost, and what is max target boost?

Regarding CO2, this works great but is unnecessary for most 350Z street car applications and for most would be unnecessary "stuff" to add. I'm a minimalist, and always prefer to keep the my personal setups as simple/clean as possible while retaining full reliability and performance.