Running only 3psi, what gives??
 

I know Im probably going to get ---- for this but there are alot of knowledgeable people on here and I am just seeking some help here.

So I just put on a new 50 trim Garrett turbo onto my JDM GSR (B18C) and now my boost gauge only shows 3 psi and full throttle and man, does it take a long time to get to that 3psi. I initially had a normal ebay 50trim on it and it worked just fine but I wanted to go more "legit".

- Checked all intercooler pipes and no bursts or broken welds or cut couplers.
- Thought it might be the bov so we blocked that off and still dont gain PSI.
- Took off the TIAL WG and the spring isnt stuck open.
- Tried to pressurize the intake side and didnt hear any leaks, also inspected all vacuum hoses and dont see any rips or tears.

Honestly I think I am just clueless here, does this sound like my buddy sold me a ---- Garreet? But I keep thinking if that was the case I would leak oil or the turbo would smoke alot... PLEASE HELP!

Its a good turbo, so can you hear it spool up?? If you do then the leaks on the charge pipeing or on that side, if you cant hear it spool at all then look at the exhaust side of your set up.

I would look on the exhaust side for leaks mainly the manifold and the flanges that the turbo bolts on to. You may not physically hear the leak on the exhaust but there could be one, as small as a few pin holes can ruin boost and make it so laggy its sad(let alone make little boost)

Only making 3psi and it taking awhile spells pre turbo boost leak or charge pipe leak. Just my 2 cents though

Okay well that would make sense from what I can see. But a buddy and I just put the other c shaped clamp on the comperssor side of the turbo to see if that would make a difference and it doesnt. I will have to check again to see if I am leaking out of my turbo manifold but I dont think I am.

When I first put the turbo on I hit all the boost and it ran great but on my third pull I heard a strange pshhh noise and it sounded like a coupler blew off but as you can hear from me, that wasnt the problem.

and this doesn't sound like a boost leak to you? Check all yours couplers and the intake itself (especially around the idle valve depending on how it's implemented). Something blew itself loose.

It does sound like an boost leak but the thing is, ive taken off all the intercooler piping and havent found a thing! Ive checked the intake itself but its very difficult to hear a noise around the intake that its leaking, next step is to go the soapy water route but its about 100f up here in mn so not doing that for a few days.

Spray some carb cleaner over every possible place that may leak when its idling, look for vac. leaks. Happend to know what sort of vac in Hg" that the car usually pulled?

Im still calling boost leak somewhere, they can be a PITA to find. But only pushing 3psi sounds like a substantial leak.

Can you hear the turbo spool up when your making that 3psi?

Okay so update:


So I did a little boost leak down test with my buddy and it was in the dark and was hard to see anything but when we started to blow compressed air into the air inlet to the turbo it would go up to 3psi than drop right away. While doing this, I noticed substantial air coming from the BOV, is that supposed to happen?

I'm pretty sure that no, the BOV should not leak air. Does it have an adjustment?

No your BOV shouldn't open like that with only 3psi. Keep in mind that without the reference line hooked up to the car the BOV will open with less pressure then when he car is running. The reference vacuum line that goes to the BOV should be pushing positive pressure in the BOV when under boost so that the thing doesnt open. But IIRC my BOV wouldnt open untill I applied about 10Psi to it if I did NOT have the reference line hooked up and the car running.

What BOV do you have?

Welll I have a greddy bov and it would defintly not hold 10psi, it would only hold 3psi with your hand over the bov. I also have that line you speak off hooked up to my intake manifold and the car not running

Does the greddy have an adjustment screw?

I think so, I know it has a bolt on the top of it that looks like it screw down.

You can try to adjust it hard..screws in.
Are you positive the reference line from the BOV to the intake is leak proof? That line is so positive pressure will feed into the BOV and hold the spring closed unless you let off the thtottle(cause a vaccum)

It was actually screwed in all the way, It was very hard to break it loose. But we did another leak down test and it seemed to be leaking very badly out of the throttle body so I put a new gasket aroung the TB and about to do another leak down test to it.

keep us updated. hope its fixed

you may also want to check your exhaust to make sure there isnt any blockage/restriction.

the bov should be adjusted at idle vacuum. titghten the bov adjuster to the point where the valve stays closed at idle vacuum. once you get to this point. tighten the screw 1/2 turn more. this will allow the bov to only open when the throttle is closed just coming off boost. the vacuum is higher when the throttle is closed under boost.
if your bov is open under natural aspiration then it will create a lot of boost lag until the turbo can produce enough air volume to compensate for the massive air leak.

Update: So we figured out it was the TB and fixed it and took it for a drive.

Well it was working really well but than all of a sudden my gauge went from 6psi all the way past 20psi and I hear a loud pop and smoke came out from under the hood and when I parked I noticed I had alot of coolant coming fromthe back of the engine bay. Well crap!! So now I have to see what I broke, ughhhh

Hope its just a blown head gasket, I hope theres not too much damage, sorry to hear it man.

Hey thanks man, all I know is that the head gasket is ---- and i dont have the time or money to fix it as of right now, so im closing this thread, thanks though for everyone that put input through, it was very thoughtful!

yeah! 20+ psi will kill a motor quickly. sorry to hear that. did you research why you were boosting over 20 psi?

Hey guys,Im back, I have officaly found out whats wrong, the turbo I had was ---- so I threw a different turbo on 63trim godspeed and everything worked out great now except for the fact my turbo spools all the way untill I let my foot of the throttle. I have a tial WGand I think it might be stuck becuase I just keep building boost untill i makeit stop building.

Either your waste gate is stuck closed or the vacuum reference is bad. If you are running a MBC (Manual Boost Controller) or no boost controller at all, make sure you have a vacuum line running from the lower waste gate nipple to your MBC or vacuum reference. If you have a EBC (Electronic boost controller), make sure you are running at least one reference hose from the solenoid block to the top port on waste gate.

Aaron