Help! Little to no boost
 

Hello.

I've was getting an irregular boost issue with non sequential stock twins but was able to get 10psi at times with the avcr. I thought the turbo was just done and decided to replace it. Over the winter I've switched out to a new efr single turbo, twin 40mm external wg vented to atmosphere, turbo smart dual port efr bov upgrade, greddy v mount, 1050/2000 injectors, rails, regulator, Bonez high flow cat.

base fuel pressure set at 40psi
Afrs range from 11-13

My issue now is I'm getting only about 2psi @ around 5k rpm while moving. I can hear the turbo spooling but get little to no boost or even any sound from the bov.

I've already checked

• vacuum lines/plugs
• Sprayed carb cleaner around to look for leaks
• if I left anything in the intercooler/piping
• waste gate is not leaking at idle and they dont sound open while driving
• Turbo spins freely
• Checked ecu programming, boost cut off is disabled.
• Soapy water sprayed exhaust manifold, exhaust temp bung, both wastegate vband.

I've also deleted and blocked off

• thermowax
• Double throttle
• bac
• AWS
• acv
• Air pump/idler pully now

What else could it be? What else can I check?

Does your boost gauge reading match your data from the ecu?
What springs are you running in your wastegates?
How are your wastegate actuators plumbed?

It would have to be a big air leak on the intake side to keep your boost that low, and you would be in danger of over-revving the turbo.

I am a big proponent of starting with the basics, your engine is a big air pump and the entire system revolves around the efficiency of that pump. have you checked your compression?

Yes the boost gauge it's accurate with ECU reading.

I've check each waste gate spring to make sure they were the same before I installed them. They were either 12psi or 14psi springs, I cant remember off the top of my head.

The vacuum lines to the waste gates are plumbed from the efr nipple on the housing to a Y1 splitter to a Y2 splitter then to each of the bottom fitting of each waste gate. Then it goes back up from each top fitting to a Y3 splitter to the apexi avcr solinoid com. Apexi avcr solinoid nc back to Y1 splitter. (Hope this makes sense)

I did a compression test before I started all this when I had the unstable boost with stock twins. I don't remember the exact numbers but both front and back rotor were still in good range.

Not super clear on the wastegate plumbing, but if you are tapped off the compressor nipple there is no reason you would have less boost.

You say you can tell that the wastegates are closed at idle, that would eliminate there not being any seats in the wastegate valves.

You say there was an intermittent boost issue with the old turbo system, Is it possible there could be a restriction in the exhaust? You could disconnect the exhaust at the downpipe to eliminate this as a possibility.

an open BOV could also be an issue. try blocking it off

make sure the throttle is actually opening.

where is the map sensor and boost gauge tapped into?

As already mentioned above, 9/10 times you have blown a coupler off or something in the cold side isn't sealed correctly...

Thank you for all the help, greatly appreciated as this got me pulling my hair out.

Ive just tried after disconnecting the down pipe from the cat. Except for the headache, nothing changed. Expected since the down pipe and cat is new and catback is around 6 months.

How do I block off the bov or check it for leaks? It's a turbo smart dual ports that has 3 bolts and bolts onto the turbo housing itself.

I checked that the petal is moving all 3 butterflys. I did see that my tps was slightly out of whack, but repairs didnt fix the problem.

The boost controller and boost gauge are off one of the nipples at the end of the uim where it bolts down to the lim. There ecu map is off the nipple at the uim by thottle body, firewall side.

they look straight and I've retightened them but i was planning on changing them out to t bolt clamps instead of the cheap worm drive clamps I have on now. I've sprayed both carb cleaner and soapy water on them to try to find leaks on them. I guess I will have to find or make some sort of boost leak tester to really test them.

If you can hear it spooling it will be intercooler or a joint openning up, possibly elbow to throttle body or a BOV.

You probably have a charge air leak that only shows up under pressure. You need to pressurize the system with an air compressor to check for leaks.