No Boost?

[Phish]

Lets say i have a supra that has a 2jz swap with a decent size turbo. Worked fine and everythign was great. Motor was pulled fuel system and exhaust were redone along with some other little stuff. Motor goes back in starts and drives fine. Air fuel is tuned to a decent ratio but now it will not build boost. .4 bar is the most it will go at full throttle and max RPM. I know the setup has a quck spool valve and the boost controller is unhooked in trying to figure out the issues. No boost leasks to speak of. Unhook the wastegate to make sure it stays closed and still no boost being built. Any ideas of whats goin on guys.

Obviously this is a friends issue, i will see if i can get him on here to get some more info on the situation. Thanks.

[SLVR7]

Exhaust leaks, exhaust to restrictive, restriction in air intake, wastegate not closing all the way or not sealing,quick spool valve not opening all the way. Is the turbo in good shape?

[Phish]

I bleive there is a very minor exhaust leak that will be taken care of tomorrow. Exhaust is nto restrictive at all. Its something like 3 or 3.5 all the way back. Not sure would need to verify that one. We have tested the wastegate and it snaps shut with a good amount of force. Believe it would be closing all the way. Turbo is in good shape and should be producing boost with no issues. quick spool valve i brought up, not sure if he has looked into that yet.

[AutoMods]

I've seen people forget to install the wastegate valve seat or buy a used gate with one not included which causes very poor boosting. easy to check if the gate is dumping to the atmosphere

[Phish]

Gate is not to atmosphere. however, I believe its the same gate that he was using last year. Its worth checking out though.

[Newgen]

The exhaust is 3.5 and doesn't leak. I'm going to wire the quick spool valve open tonight and see what results that produces. I'm also going to put the car through another pressure test and check for leaks.

I don't believe the wastegate seat is the issue. It's a tial series wastegate that vbands on is it possible to mess up the seating?

[TbTalon94]

Was anything done to the motor, or was it just removed and reinstalled?

[Newgen]

The only thing done was the timing belt. I had thought maybe it could be the mechanical timing but I figured the car wouldn't start if it was off.

[Phish]

My thought from the first time we went out in the car and it did not build boost, was the wastegate. That night we even though some air at it to make sure we heard it kick in and out. I still believe it has to be something with the wastegate to let that much exhaust go by to not spool that turbo. Maybe stuck partially open? In my opinion the WG needs to come off and be thouroughly checked. Maybe swap it with a spare? (I dont know if you our your bro would have one that bolts up - i just sold and shipped the one i had on the shelf)

[Jappbox]

You do have a open Scrow Manifold, not a twin scrow with that quick spool valve right... just ruling something out

[Phish]

I am not sure what he has, but your thinking that if its a twin scroll the spool valve would not open because it would be hitting the center section of the divided housing causing it to stay closed?

[Phish]

turns out it is a divided housing. He has opened the spool valve by hand and it opens with no issue without any problems. I believe he is going to wire the valve open tonight to make sure that its not the issue. But Yes, divided housing.

[Jappbox]

is the manifold divided houseing as well?

[TbTalon94]

Even if the quick spool valve wasn't working, or if it was on an open/twin the turbo would still make boost it would just be REAAALY slow.

My guess is either the timing is off, or something is hurt in the motor. Either that or the wastegate is at fault.

[Jappbox]

A 2jz motor never gets hurt, inless you guys messed it up! JK what size turbo is this? and you got .4 bar? at what RPM and gear....

[Jappbox]

another thing, you said the boost controller is unhooked, what spring is in the wastegate?

[Phish]

I believe ao 10lb spring is what i was told. Its running off an emanage for tuning. So the timing is running off of the stock computer since the timing has not been touched yet. We have also tried running it off of the map that was used last year to the same result. My money has always been on the wastegate. I am going to try to get him to take it off and inspect it a little closer tonight.

[Phish]

Although, timing would explain alot of it. Because even though its not building boost, it feels extra slow and turdy when going through the RPM. Wonder if a sensor could be putting it into some type of limp mode and retarding timing like whoa.

[Newgen]

Yup I have a drew go turbo manifold if your familar with supra's. The turbo has a divided housing. I'd like to rule out anymore boost leaks first and wire the spool valve open. I don't have a spare wastegate with a vband flange so i'll pull the wastegate as a last resort. It's not the easiest thing to put back on either.

[SLVR7]

Since it feels sluggish off boost, I would verify the cam timing too.

[Phish]

I believe the mechanical timing was checked, but it can be anohter thing to add to the list to check again.

[sparkles]

The physical cam timing has got to be off. Keeping the exhaust valve open slightly longer than supposed to or something. Especially if it's running like a turd.

[Phish]

Well i believe its running like a turd, granted i dont know much about 2jzs but if its running awesome, supras are slow lol.

That being said, i am anxious for the kinks in this thing to be worked out, should be a beast when at boost and everything working correctly.

[Drifte]

ive seen some dumb wastegate and vacuum line hook ups. I kinda skimmed through this but it usually results in max boost not, no boost. I cant imagine a shop assembling a motor wrong enough it runs and wont build any boost? Maybe I should read the thread yet but it just sounds like a boost leak.

[TbTalon94]

My money is cam timing, or a sensor related to timing.

[AutoMods]

In your first post it says you unhooked the wastegate. You can't do that because the wastegate uses vacuum on the bottom of the diaphragm (side port) to stay shut. backpressure will push it open early if you dont have vaccum hooked up. Also if your using both top and bottom wastegate ports, try just using the side port and leave the top open to the atmosphere, thats most common for mbc's.

[Phish]

Hmm... not sure how he has the wastegate hooked up. He stated to me that he "unhooked the wastegate".

[Newgen]

I haven't unhooked it yet. It was an idea i had mentioned. There isn't a boost controller on the car and i'm using the side port on the wastegate straight to a charge pipe.

[AutoMods]

In your first post it says you unhooked the wastegate. You can't do that because the wastegate uses vacuum on the bottom of the diaphragm (side port) to stay shut. backpressure will push it open early if you dont have vaccum hooked up. Also if your using both top and bottom wastegate ports, try just using the side port and leave the top open to the atmosphere, thats most common for mbc's.

actually i think i'm wrong, vaccum on the wastegate is optional like when fed from a compressor outlet there is no vacuum there. its the bov were you would always need vaccuum/boost signal.

[Phish]

Agreed. I was thinking differnt but i figured maybe i was backwards.

[Newgen]

I wanted to update everyone on what I’ve found with the car. I checked the mechanical timing this weekend. The cams were retarded quite a bit. I realigned everything and the car fired right up sounded a lot more responsive. I also checked boost leaks and everything is sealed up now. Took the car for a spin and it's holding a solid 6 psi now. I'm guessing it's possible the waste gate could have a 6psi spring. Phish has some extra's I’m going to try soon.

Thanks everyone for your help!

Matt

[sparkles]

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