I have a lot of flow coming out my pipes, and the pressure feels even. The cats I have on the car are the size of coffee mugs. I'm going to pull the plugs tonight and see how they are burning. Hopefully that will give me answers.
What part of Ma. are you in?
I'm in Hopkinton, MA. Re the cats, I seemed to have good flow too but under boost the engine is really trying to push a lot of exhaust out and even a partially plugged cat is too restrictive.
In my case engine RPMs would climb into the 5s if I didn't push it. If I went WOT then RPMs would climb very slowly and the car didn't feel right, felt like a dog. Chuck says one cat is a 1/3 plugged up and there are bits of stuff in them that he's never seen before. Doug Levin says that the aftermarket high flow cats are all junk on a supercharged car, they plug too easily. He prefers to eliminate the downstream factory cat and just run one OEM upstream cat. That's what I'm going to do.
By the way, my plugs all looked fine, no detonation evident, no fouling of any kind. My fuel pressure was also ok but because boost is related to load and RPMs the boost level and fuel pressure didn't really go full because RPMs were slow to rise. The split second box could also be a problem as it interrupts Cam and Crank sensor input to retard timing under boost. Not sure if you are using the box or whether you have another tuning device (SCT, AEM,VEC, etc.) You would likely throw a P1391 code though if the split second box failed - intermittent loss of cam or crank sensor input. The people that make the box for Paxton claim the car won't even run if it fails but others say that's not true and they've seen some weird stuff.
Another test you could try is tee in a vacuum pump to the line going to the bypass/blowoff valve. The valve that sits under the intercooler tank. Put 5 lbs of vacuum on the line and see if it holds. If it doesn't then you have a vacuum leak or bad bypass/blowoff valve. A bad valve will bleed off boost and reduce performance. The o-rings are known to fail in the valves. A leak will not allow the split second box to see true boost/load levels and hence it will not turn on the fuel pumps when needed or adjust timing properly.
Hopefully my plugged cat is my problem, but I'll post when I know for sure. Chuck is still waiting on the blower to return from a freshening. Doug Levin is doing the blower. More of my story can be found in the thread "Paxton Help - Again"
