Mysterious Engine Trouble...knocking and power loss.
The knock is not the main factor for the low power output. I tuned a Evo 10 the other day with a 3076 and it made "proper" power, meaning, it actually made more power than the stock turbo. 
Timing was very close to Boostd4's timing before the knock up top.
Timing was very close to Boostd4's timing before the knock up top.
I found a local who is willing to let me swap out a few parts for some tests.
Another thought that came to mind was maybe a bad cam angle sensor...or something similar?
Another thought that came to mind was maybe a bad cam angle sensor...or something similar?
Does it make sense that possibly the cam angle sensor (or maybe another similar sensor) may be off? And if it were...wouldn't the car throw a CEL?
Okay, I think I may know the problem since I ran into similar problems too. Does your Greddy Catback have a plate on it that says JASMA? JASMA stands for Japan Auto Sports Muffler Association and they have tough standards to clear sound and emission tests in Japan.
A few years ago, the standards weren't as tough so they weren't too bad. The exhaust standards in Japan has gotten tougher and now a days these exhausts are pure 100% Sh*t, sometimes they are worse than stock and are only for looks. I have run into a few of these exhausts including the one I used to have (Kakimoto Hyper N1+) and they have restrictors in them that are only around 50mm (2 inches). When running these exhausts with a stock turbo or the low 300 whp range, you probably wont have any problems. Once you swap turbos, you'll see a drop in your power even if your boost is higher than before. Basically what is happening is back pressure is building up and creating a huge loss. You'll probably see drops in whp from mid RPM and start seeing large counts of knock starting from the 5500-6000 RPM zone.
Please check your exhaust and swap it with another if you can and throw it back on the dyno. If it is a JASMA exhaust, you'll probably see a huge difference if you get a straight 3 inch on there instead.
A few years ago, the standards weren't as tough so they weren't too bad. The exhaust standards in Japan has gotten tougher and now a days these exhausts are pure 100% Sh*t, sometimes they are worse than stock and are only for looks. I have run into a few of these exhausts including the one I used to have (Kakimoto Hyper N1+) and they have restrictors in them that are only around 50mm (2 inches). When running these exhausts with a stock turbo or the low 300 whp range, you probably wont have any problems. Once you swap turbos, you'll see a drop in your power even if your boost is higher than before. Basically what is happening is back pressure is building up and creating a huge loss. You'll probably see drops in whp from mid RPM and start seeing large counts of knock starting from the 5500-6000 RPM zone.
Please check your exhaust and swap it with another if you can and throw it back on the dyno. If it is a JASMA exhaust, you'll probably see a huge difference if you get a straight 3 inch on there instead.
I just did a little research on your exhaust, although it may not have the JASMA plate it may still be the same as the JASMA exhaust. If it is, the resonator on the mid pipe will proabaly have a 2 inch internal diameter. Also, can you look thru your tail pipe and measure the inner diameter of the muffler itself? I see you have 80mm piping but I'm afraid the inner diameter of your muffler maybe much smaller.
Last edited by SiC; Jul 13, 2009 at 11:35 PM.