polyfc

i've had this problem for a few months but didn't have time to deal with it when i first got my boost gauge, and since i don't drive it very often i forgot about it. both turbo's it only goes around 7.5-8 max. could that be a clogged cat since it's consistent across the board? it was probably what way when i bought the car but w/o a guage just didn't realize it. the actuators look to have no problems so i don't think that's it. turbo's are in really good shape, clean my intake filters once a month minimum. i'm at a loss for what it could be, appreciate the input.

Gamezilla

Maybe a boost leak that only occurs under pressure? I bet one of your actuator failed. Had the same problem. Replaced it and started making a nice 10psi again.

dgeesaman

iTrader: (7)

Leaks. Not the cat.

Start with the y-pipe coupler - remove and do a thorough inspection. Then check the other couplers, working toward the intake elbow.

Dave

DaveW

Are you still using the stock boost control system? Have the boost/vacuum hoses been replaced? This sounds suspiciously like the pills are missing - that will limit boost to the WG-spring pressure of 7 psi, and if your boost gauge is just a little bit off, that's what you're getting.

polyfc

as far as i know none of the hoses have been replaced. the engine got a rebuild right before i bought it, not sure if they botched anything though. i'll try going through the hoses, the ones on there are a bit old so i'm sure they could stand being replaced. and i thought pills were something put there to increase or lower boost as a type of controller, didn't know they were supposed to be there.

DaveW

In the stock system, boost is controlled by balancing the pill size (restricting flow from the turbo outlet to the PC & WG actuators) vs duty-controlled solenoid valves (a pseudo-orifice restricting flow from the actuators to atmospheric pressure). The solenoid valves are controlled by an open-loop ECU map.

If the pills are missing, all boost pressure goes to the actuators directly, limiting the boost to the WG-spring-controlled 7-psig.

There are some good sites for learning how the FD boost control system works. Here's one:

http://robrobinette.com/boost_note.htm

polyfc

i see now, that's very helpful, my car does have a boost controller in it that wasn't hooked back up after the rebuild could that be a reason for this?

polyfc

just read a bit more and answered my own question, now another, with the mods i have should i hook it back up or is it better to leave it alone until i have say a catback or something else?

DaveW

If you're only getting 7.5 psi of boost (due to controller being off), and you want to go to the stock level of 10 psi, either hook the controller back up and set it to 10 psi per the instructions, or go back to the stock setup by reinstalling the pills in place of the controller and opening the lines from the actuators to the solenoids.

With your mods (99spec turbos, m2 dp, hks intake and ic elbows, hks boost controller) you should be OK on the stock boost-control setup. However, since the stock solenoids are (I assume) blocked off now, and may or may not be working properly, I'd hook the controller back up (assuming it is functional). Remember that to use the controller, the pills should be removed (they were probably already removed to put in the controller).

polyfc

i'll have to double check it when i do then, after that i'll probably start another thread trying to figure out how to use the controller since it's an older evc model

Narfle

iTrader: (16)

Potential sources: boost leak(could be anywhere, pipes, couplers, intercooler), check valves(those lille buggers!), clogged cat, the stock solenoids open the wastegate at 7 with all the pills removed(I believe) have you been changing hoses? Oh and my rubber hoses were actually sucking shut Im pretty sure so that could be it......good luck.