Ok so here's what the car is: It a S4 NA with a complete TII swap. the engine is a rebuilt and newly broken in (~1000k) S5 block setup for the S4 ECU. It has a N332 and a N333 ECU. (both same problem) , turbo trans, Turbo MAF, TPS, BAC, etc.
It has the stock TMIC and BOV, wastegate, and the exhaust is practically straight. There are no Cats and it runs back to the two mufflers in the back (which are new and still under warantee actually). I did the throttle plate trick and that helped a little but hardly noticeable.

I can get the FC to start just fine. It idles perfectly at 750 and everything works just fine on it ie: no vacuum leaks (90% sure) BAC works great, doesn't flood, no smoke, awesome engine. BUT...

So I've just started to boost it because I've been breaking it in. Basically It doesn't see much or at all over 3psi of boost at WOT. The Turbo had no shaft play at all when I put it in and is almost new. I'm not running a Twin scroll system on it so I wired the flap to open. It has a S4 turbo on it so I know its very capable of 7psi of boost. It does however have the standard 3-4K rpm stutter but over that its fine. (I'm going to check the grounds again)

What are your thoughts on this? I've put everything into getting this TII engine swap but honestly I'm pissed that I'm feeling the same amount power the NA was giving me. right now my 12A FB could kick this car's ***. ya thats not good. So what do ya think it could be guys?

PS: For anyone who asks... I did search but most or all of the results were things like "too much boost' or "vacuum leaks with bad idle" etc.

 

The outer set of secondary throttle plates might not be opening. You could remove the rod with it's small surrounding spring and tie them open as a temporary measure to see if this is the problem.

Or exhaust clogged would cause the problem.

FYI: the twin scroll actuator when not seeing any vacuum (as in remove the vacuum hose) is spring loaded to the full open positon. So no wire tieing was required. It fails to the full open positon.

I've no other ideas.

Oh. The spring and rod are shown in this jpg I just stole from another thread: https://www.rx7club.com/attachment.p...5&d=1205651922

 

hate to say it but i had a similiar prob when i first got one of my tIIs. 130k older gentleman owned it, required all new intake gaskets and vacuum hoses to correct. also make sure there are no exhaust leaks before the turbo and that the wastegate arm is both preloading the door shut and that the retainer clip on the wastegate flapper is still on. if that falls off the door will easily be pushed open equally little to no boost. another option is doing a pressure test if you have an air compressor available. get a pvc pipe plug for a local hardware store that is the same size as either the turbo inlet or the intercooler inlet (turbo inlet preferably), a rubber coupler to attach it to the turbo inlet and a spare air fitting for like an air tool. drill hole in center of plug, thread in air nipple, attach to coupler and then to turbo, set air compressor pressure regulator output to 5-10 psi attach to air fitting and listen for leaks.

 

I could have misunderstood you, but did you say you wired the internal wastegate flap open? If you wired the wastegate open, that is why you are seeing no boost. The wastegate should be open when no boost is built and when maximum boost is generated. The wastegate must be closed when trying to build boost.

Just my 2 cents.

 

The throttle body mod I was talking about is the secondary flap mod. they are wired open. this helped but very very little. Before I was seeing about 2psi of boost. I'm pretty sure the exhaust is not clogged cause there isn't anything to clog it. Just straight pipe back to New high flow mufflers. The Twin scroll actuator isn't even hooked up or on the car at all. the scroll flap is in the full position constantly. Thanks for the help Hailers

 

Yup the wastegate apears top be functioning. The rod hasn't fallen off. I'm going to pressure test the system pretty soon here. The entire engine is practically new and I replaced everything on it with new rubber hoses and gaskets...

 

Bama420 I haven't touched the wastegate at all. just the twin scroll flap. Just for testing purposes can I wire the wastegate a certain way that will make it just boost constantly? Like wire it closed? Doing that could help me rule out the Bad Turbo theory a friend has or bad wastegate...

 

don't wire anything. just use vacuum caps.

you probably have a boost leak. places like the brake boost nipples, BAC and little nipples on the AWS and intercooler like to leak. use some worm clamps on all those spots.

 

ya. It will be easy to clamp all the hoses cause this engine has no AWS or emitions. I'm pretty limited on the amount of vacuum hoses I have on the engine. :P