That is good news, thanks for the update Eric. The sound between the single and dual exhaust systems is what is going to make my decision for me. Is there anyway you guys can let me hear how the single sounds over at AMS? thanks in advance

-Tom

 

^There have been sound clips and video action of the single exit for a while now. Where have you been? Anyway, it's in one of the older AMS threads in the turbo/drivetrain section somewhere. Look back a few pages and you should find it.

 

The one video that I have seen says that it also has a test pipe on. The test pipe makes things louder...at least from my experience. It is hard to tell how loud the hum is in the cabin from a video...seriously.

 

31 psi.... wow

 

+2 for the Exhaust and those great numbers! Keep the work comin guys...

And question, if the 4b11 can manage to hold 21 PSI at redline when you have it set to 31, why can't we see 21 PSI at redline if set to 23?

Sorry for the newb question, I'm new to small turbo engines. My guess is that the turbo isn't being spooled enough to flow that much???

And what would be the answer to making this engine hit, and hold (to redline) a given boost level?

 

The reason is that without ecu tuning to be able to control wastegate duty cycle mapping at various throttle positions and rpms/load, there is no way to control taper beyond what the mechanical aspects of the wastegate actuator and mbc will allow for. Even if the turbo can flow enough to hold boost straight across the rpm range without dropping, the stock wastegate spring with a MBC won't allow it, and the stock ecu tuning won't allow it. One thng to make mention of is that the twin solenoids that the X is equiped with is an awesome setup, and will give far greater control of the boost curve than a single solenoid setup will. I spoke with works tuning about this, and they said that the J-SPEC evos of the past have had twin solenoid setups for years, and that it gives insane control over the boost curve. They have been messing with it for a while, and told me that it's actually possible to create a reverse taper that rises with rpms instead of dropping. This obviously wouldn't be safe and would be pushing the turbo past it's efficiency range, but the point is the amount of control that you hav with the twin solenoids. Plus, the turbo in the X is almost the same as the 9 according to martin of AMS, but the hotside is bigger. This should mean theoretically that the turbo should be able to hold more boost to redline/flow more than the turbo on the 9 could. The stock tuning on the X is too environmentally friendly and conservative, and a reflash is going to help this car so much it's not even funny. This car is going to be a beast!

 

Interesting information STi.