guys, take a step back, slow down and think this out.

 

ill have to look into that too. i do have some oil coming out of the exhaut side of things. i did have oil on the intake side, but after i put a smaller restrictor on the feed and shortened the pre pump hose, it hasnt been a problem on the intake side. I did have a decent amount of frothy oil when i cracked it open at one point to clean to put didfferent washers on the compressor housing. i might clean out the turbo to have a fresh start if theres any left over oil in the wheel areas.

my preivious BOV wasnt sealed. it was V-banded but still didnt seal well. i switched to a 2bolt flange EMUSA BOV i had laying around to see if it will make a difference and tightened the adjustment screw almost all the way down to keep the valve damn near seated at idle. its just barily up at idle. im gonna test it out tomorrow when i get the car out form behind the expedition parked in front of it lol
if that doesnt at least have me seeing 2psi, im going without a BOV and see what happens.

 

What spring is in the waste gate?

 

mine has a 10lbs spring in a 44mm wastegate.

 

Try putting bigger spring in it and see if it will build boost. It's possible you have a big pressure drop from front to rear.

 

lets start over, List your engine combo, turbo (including turbine mm & AR)and hotside pipe sizes, and how high of rpm (driving, while loaded, at WOT) you have gone to.

If you suspect the BOV being bad then test it, pressurize the entire cold side with a cap, remember to apply the same pressure to the BOV reference line. See if its leaking or leaks from any other spot.

You also need to check for leaks on the hotside, one real quick easy way is to start it up and use your hand or a thick piece of rubber against a board to seal off the downpipe. it will build up some pressure in just a few seconds. Fix any leaks you find and pay close attention to see if any is escaping from the wastegate.

 

i do have a 4lbs sping that i can add to the 10lbs sping with the wastegate to increase the pressure tad. i just dont want to have too much cause i only have a 2bar map. ill get a manul boost controller to adjust the pressure to 10psi. for now i just want to see what the spring regulated pressure can hold.

 

I would put the bigger spring in and see what happens. A 2bar will read up to 15psi. I would make a pull and watch the boost gauge. I bet you have some pressure drop front the rear to the front.

 

combo

INTAKE
Cone filter tucked into wheel well
3” intake into turbo
2.5” charge piping
T-bolt clamps and reinforced silicon hose couplers
31x11x3 bar and plate intercooler
50mm BOV and pipe
LS6 intake manifold
80mm Throttle body
LS6 valley pan
4 port vacuum manifold

ENGINE
Stock 5.7L LS1
Stock 98 ls1 Heads

EXHAUST
OBX stainless steel headers 1 ¾ primary, 3” collectors wrapped
Catless 3” ypipe with 3” OBX resonators wrapped
Stock I-pipe wrapped
Sts style T4 header pipe with 44mm wastegate port
3” after turbo resonator
2” Wastegate dump exhaust
3” turbine exhaust
4” corsa clone tips/3” inlets
Exhaust wrap from turbo back to headers

TURBO SPECIFIC
ON3 T76 w/ (.96 later)
Compressor Wheel - 76mm /.80 ar / 4” Inlet and 2.5”
Compressor Outlet - Inducer- 76.71mm / Exducer- 102.36mm
Exhaust Housing - T-4 Flange .96 ar / 3.0" Vband outlet
Exhaust housing - Inducer- 74.5mm / Exducer- 65mm
44MM wastegate (10psi spring for later)
50mm BOV
AEM water/Meth kit

TRANSMISSION
Stock 4L60E
Revmax stage 5 billet cover 3200 stall
B&M tran cooler
Glowshift trans temp gauge

OIL SYSTEM
4an feed
4an Summit check valve
.040 restrictor feed flange
10an drain
Gear scavenger oil pump
10an return line into oil pan

PCV system
LS6 valley pan with PCV valve
Catch can
Check valve
Vent line ran to fresh air intake tube from valve cover

FUEL SYSTEM
Stock fuel rails
Racetronix 225 fuel pump and harness
Aeromotive boost referenced fuel pressure regulator with 3/8 line return
60lbs siemens injector

ELECTICAL
NGK Spark Plugs BKR7E-11 5791 gapped at .032
MSD wires
Stock coils

ENGINE MANAGEMENT / MONITORING
Innovate MTX-L wideband
Glowshift digital boost/vac gauge
Glowshift digital fuel pressure gauge
(HP tuners later)
GM 2 bar MAP sensor
Dynoed at shop

MISC ITEMS
GM 93-97 radiator cover
Glowshift 3 gauge a-pillar pod

I pressurized the charge system to find the leaks where i found that the BOV is leaking excessivly.

The exhaust side has been checked for leaks and fixed where needed. Ive also hightemp RTV'ed any bolted connections to ensure a leak free seal.

 

In the end of your post you say you have pressurized the cold side and found that the BOV your currently using is leaking. Did you apply the same amount of pressure to the BOV reference line? in order to test it correctly it needs to be given the same pressure.

Also how high of RPM @ WOT have you gone? what gear?

Your 100% positive the waste gate isnt leaking at all? It sounds silly but Ive read on forums where people forget to put the wastegate valve seat in and they cant make any boost.

 

it didnt make boost on the dyno at WOT all the way up...
on the street ive done stand stills and cruising pulls. im not sure if ive seen 4th but ive been through 1-3 and even dropped into 1st while cruising. i spin the tires violently so I cant do that all the time on all the streets. ive been up to 80pmh on the highway pedal down and still nothing more then a split second of 1psi once that ive seen, but 0psi is the furthest it will go any other time.

ive been all over the RPM ranges. cars set to shift at abuot 5900-6000 in the tune. when i get a new cam ill get the springs in it and set the rev limit to 6200ish.

ive taken the wastegate apart twice already to make sure i didnt pinch the diaphram or somthing. ive even went the route of placing a thin amount of high temp copper sealant around the base between the diaphram and the base and the did the same on the caps screws. The firering is in it and i also applied copper sealant around the wastegate flange to the turbo header just in case.

as for the the first BOV, im not sure what spring it had but its adjustable and it was at first lose so i tightened it but i dont think it was enough. just to test things out and try a different BOV without a leaking flange, im trying this 2 bolt flange to see if it can hold boost better and i also tighten the adjustment on this one damn near all the way. i have yet to test this current BOV, but i will be tomorrow when i get back on the road.

when i pressure tested it i just applied pressure to the charge piping. the spring holds down when the cras not running. so i can hear stuff leaking around it. i applied soaky water aruond the BOV flange and seen it around the base. i couldnt see inside the valve area though.

 

well the EMUSA BOV is definitly stayiong closed lol instead of a BOV going off im hearing a PFFT shhhh shhhh shhh.... in the back by the turbo lol so im imaging im hearing compressor surge lol so i can defintly lossen the BOV a touch then so that its doing its job lol
unfortunatly im still not getting any boost. its getting to 0psi faster though now lol
im thinking of taking the car to a muffler shop to see if they can run some smoke through the exhaust to see if its leaking. Im also gonna buy my own boost leak tester so i can do it myself. the tune shop was kinda not helpfull with theirs. for one it didnt have a pressure gauge on it so i had no idea what pressure was going in and it had to be put on an extention pipe since they didnt have a 4" coupler to go on my turbo inlet.

so yeah, somthings leaking horribly and i cant seem to locate it.

i also got a manual boost controler coming. im wondering if i should switch the 10lbs spring out with the 4lb spring.

 

its been a minute, but just thought id mention that I fixed mine initially before I moved my intake design, but I was getting 9psi reliably.

ive since sealed up the exhaust. I still have to reseal the intake side, but while relocating pipes, I noticed a bunch of frothy oil in the long return pipe :/
ive replaced the pump and its running much better then the old used one I had but im still wondering why its doing this. im wondering if the turbo is already shot I hope not.

 

I had a similar series of problems with mine after installing a new kit.

• Problem 1 - Barely building any boost and making quite a whistling noise.
• Answer 1 - Fire ring not installed.
• Problem 2 - Installed Fire Ring, but making low boost (5psi) on the spring .
• Answer 2 - Took out weak/low pressure WG spring and installed heavier spring.
• Problem 3 - Now making 8psi on the spring (boring...). Installed Manual boost controller. Now only making 12 psi with BC on max setting.
• Answer 3 - Felt sure that I was losing boost in the cold side somewhere. Bought some 3" test plugs. Disconnected the cold side at the MAF coupler and the turbo output. Installed the plugs, set my air compressor regulator to 15psi and connected the air hose. Getting under the car and listening, feeling and using soapy water, I Found the leaks and fixed them.
  

The test plugs...




I had my kit to 19 psi this past weekend so all is good. Keep looking! You'll find it.

 

yeah, mine was a combination of massive exhaust leaks that the welders just couldn't seem to seal. Fixed that by removing the 3" y-pipe and installing a 2.5" SLP y-pipe. Exhaust is sealed.

The intake was sealed, but now that I redid the intake portion, I have intake leaks again. the pipes charge up to about -2psi and you can hear the turbo slightly spool but not pushing anything in the engine. I know where the leak is this time. I have a new pipe that goes over the front wheel and I cut it to fit but part of the pipe is flat and isn't sealing correctly. I gotta fix that pipe somehow.
I also got to wrap the SLP ypipe. I was spooling quite nicely when I had the ypipe wrapped