True or false? Upon installing an FCD, on a stock T2 minus cat back and cone filter, you still need a boost controller to manage any actual increase in boost. Actual meaning more than 3 PSI constant. Why? Because the twin scroll turbocharger valve.

I have been told that more boost is possible with the removal of my cats.

 

Huh? The FCD only changes the boost signal from the sensor. If you go above the stock limit(what like 8psi?) then it will retard and give fuel for 8 psi even though you might be at 10psi. Up to you selected fuel cut it shoudl act normal.

I'm not totally sure how it would make you need a boost controller which adds boost .

 

Everything you've said is false. A FDC does not control boost, it simply removes the fuel cut that would occur at 8.6psi. The twin-scroll system does not control boost, it just helps the turbo spool quicker at low revs. Any mod that improves engine breathing (intake, exhaust) will increase boost.

 

Just trying to figure something out, I have an 87 t2 and I just installed an FCD. I also installed a boost gauge and it doesn't go over 5 psi. I have a cone filter and the stock cats. Just I even expect more boost? My engine runs strong and I believe I no longer hit fuel cut.

 

5psi is where it should be. you don't need the FCD unless you plan to run higher boost. over 8psi.

 

If you want more boost get rid of the stock cat. It is probably clogged anyway. You will probably have boost creep issues and will need to port the wastegate if you open up your exhaust that much.

 

So if I put a boost controller on there and crank it up to say 8 Psi, I won't even reach 8 PSI because my cats. I don't believe that, I understand there be some unwanted exhaust manifold pressure. I figured if the WG is kept close till 8 PSI than 8 PSI is what I would max out at until the compressor false off and PSI drops. Who has an FCD with no boost controller and is producing more than stock boost after they put the FCD on. I understand that with the FCD second rotor continues to make power thus more CFM's going into the turbine but on my car with my mods I have yet to overwelm my WG. I am pretty sure that if I removed my cats I still wouldn't be able to boost over stock. And for those who are using BC's aren't you tapping into your actuator line for a BC output and your intake manifold for input, eliminating the twin scroll.

 

There is another variable effecting boost - outside air temp.
A stock TII on a really cold morning can hit fuel cut.

 

If they are clogged (many are at this stage) then no matter what you do, you will simply not get enough airflow through the exhaust to generate 8PSI.

The FCD does not effect how much boost the turbo produces.

Huh?

Sure you would. You would see an instant 2-4 PSI increase, and major boost creep as well. If you do not have an FCD, then fuel cut will occur a little past 8 PSI. If you do have an FCD, the car will continue to build boost, and then run lean and detonate.

Twin scroll has nothing to do with a boost controller, nor the wastegate system.

 

That would be most TII owners...
As I already said, the twin-scroll has nothing to do with boost control or the wastegate. They are totally separate.

 

C%$ gone boost up no creep yet.......Thanks for the info guys, I apoligize for my stubborness. ANSWERS with EXPLANATIONS are a little easier to comprehend.

 

***Who has an FCD with no boost controller and is producing more than stock boost after they put the FCD on.***

A FCD does not produce boost. If you car isn't putting out more than say five and a half psi, the install of a FCD will do nothing for you and the engine will still put out....five and a half psi.

If you read this article, you will get the idea behing what a FCD is for: http://www.teamfc3s.org/info/articles/fcd/diy_fcd.htm

 

If you open up your exhaust/intake boost will raise slightly or significantly depending on how much you free it up. A FCD only stops fuel cut. You need a FCD if you are boosting past the stock boost levels. If you still have stock exhaust and intake you dont really need a FCD. Simple as that.