To skip all the reading below, how much backpressure should a supercharged engine have under full throttle?
I have been trying to track down a power loss problem on my 03 Tacoma with a supercharger for several months now. Nothing I have tried has helped. Feels like I am towing a boat anchor up hills. Requires much more boost than usual to drive. Feels like I am fighting the truck to get it too accelerate. Engine is also running a little hot and drinking fuel. I have changed plugs, air filter, wires, fuel filter, fuel pump, injectors, MAF, cleaned throttle body, run sea foam, timing belt, dynamic tensioner, s/c belt, nose cone, bypass actuator, cleaned bypass valve. No engine codes. Only definite problem that I can find is that bypass valve closes slower than normal when throttle is applied. It takes a sec or two instead of being instant. It also doesn't close completely accept under full throttle and a couple of secs.
Mechanic on Expo recommended getting catalytic converter checked. They said it was fine. Several more months and more money and still have the problem. Take to said mechanic and he says he got 12 psi on his gauge under load while driving around. Take it to muffler shop to get cats replaced. They double check and can only get 5psi under full throttle on lift. Hold off on replacement.
Mechanic insists that he got more and tells me to drive it while monitoring pressure. Make little part to mount into 02 sensor hole with fitting. Drive around with buddy holding gauge inside cab. Only a couple of lbs with normal driving but it pegs out at 10psi (my gauge max) under full throttle at high rpm.
I know normal for a N/A vehicle is around 4-5psi under load. Should a supercharger engine have that much more backpressure? Hoping to get this truck running right and considering gutting the cats to see if this is my problem. Don't want to waste them if I don't have too.
Btw, I have driven the truck around with just straight headers but couldn't tell a perfromance difference. Didn't let the computer reset so I am not sure if that would affect it.