I wonder if you guys could give some advice. I’m new to LS motors and I have put together a LQ4 with a BTR 2 truck cam and installed a GT45 turbo. With that I have not been able to make more than 3 psi of boost. Unsure if any one has been through the process of boost checking as I am only able to get about 3 psi of pressure built with my compressor. Not sure at this point where the pressure is going. Just seeing if anyone has some pointers on what to look for. Pressure is going out the exhaust but I plugged it at the turbo and wastegate output. Not sure if I need to rotate the motor certain way or cap or crimp anything in the pvc system.

 

Spring in the wastegate? leak somewhere...exhaust or intake....blowoff valve not closing all the way or sealing. You do not use a pcv anymore....unless you put a check valve on it. If you have the pcv still hooked up like normal you are blowing boost into the crankcase. I'd say thats not good.

 

Check for leaks between the turbo and engine.
Check the wastegate fire ring, diaphragm and valve.

 

what do you do with the back port on driver side valve cover? Do you just vent it?

 

must vent both VC if not using a catch can and check valve/valves also need to open up the stock orifice in the driver side VC or weld on a fitting. Need to plug the fitting behind the TB and also the pcv fitting (top middle of intake) if not using catch can and check valves

 

I’m using the top fitting on the intake manifold as boost/Vacuum point for my wastegate, bov and boost gauge. I have the passenger valve cover going to the airfilter. I have the throttle body fitting with a check valve going to the catch can and back into the driver side valve cover with the orfice. Orfice has not been modified.

 

Sounds like you are using a MM PCV catch can, they work well, just be ready to increase the size of your breather lines when you start turning the boost up.
At 14 lbs. I had to significantly modify my PCV system to keep from pressurizing the crankcase.
Good call on the BOV too, mine was actually stuck closed for awhile until my buddy heard the compressor fluttering, I was a noob at that point lol.

 

that will, work and not cause a boost loss , as stated it might not be up to high boost levels but is not your current problem. Was just a possibility, better check the other things already mentioned including bench testing the gate to determine if the spring is correct . Usually has to test a little higher than your target because of back pressure helping to push it open. Using any type of controller ?

 

No controller. Right now I have 12lbs worth of springs on the wastegate.

 

btw do typically have to plug the exhaust on these to pressure check?

 

simplest way would be plug exhaust with engine idling - listening and feel for leaks . Engine may die if no leaks at all, repeat if necessary. Can locate leaks pre and post turbo this way . If you want to get serious you can pressurize with compressed air pre turbo thru a NB O2 fitting , plug exhaust and intake ( can escape if a cyl on overlap ) or remove rockers . Listen ,feel , soapy water check for leaks . Final method would be the same but use smoke machine instead of compressed air - wish I had one !!

 

Is their certain position where there is no overlap? I bought some block off plates for the exhaust out of the head. If I seal that up and find leaks at the throttle body to the head I can focus onto the exhaust. I’ve checked intercooler piping, bov and intercooler to be good so far.

 

If you can seal between heads and exhaust manifolds , that'll work fine

 

Another question where is the air coming from when I disconnect my driver side pvc tube? I have air coming out of the passenger side valve cover still. Is it just getting past the valves or out of the crank case? Is this air blowing by the cylinders?

 

With your drivers side hooked up like you have it and pass side disconnected a very healthy engine (good ring seal ) will Pull a vacuum on the pass side . Could be you have worn rings , or maybe you opened up the gaps a lot ? Hopefully haven't broken ring lands already

 

I would bet if anything worn rings as the motor has 140k miles. There isn’t too much air getting by but it’s something. I’ll do a compression test on it sometime soon.

 

140,000 is nothing , mine had 180,000 when I started now 195 + . Keep boosting it and be careful with the tune