v6 Twin turbo Help

[KFranklin11]

Hey guys, I have a problem. Me and a buddy of mines did a custom twin turbo on my car. The componets consist of twin 54mm precision turbos, tial wastegates with 3.6 psi springs, these are the duel connection ones. With aem true boost controller. I cannot build more then 5 to 6 psi on a 80 % duty cycle and spring pressure at 1.6. I disconnected all lines going to the wastegates and it boosted to 11-12 pretty fast so I got off of it. My car has a base tune on it. Any suggestions guys? This has been a 5 month project with nothing but trouble. If it wasn't for Pt.Killa this project would never be where it is today, he has helped every second of the build, but we are now confused. Thanks guys

[JantzenOKC]

Do you have the boost solenoid hooked up right? Should be like this.

[KFranklin11]

Originally Posted by JantzenOKC

Do you have the boost solenoid hooked up right? Should be like this.

We have external wastegates. But I believe the solenoid is hooked up correctly. The top ports of the wastegates are going to port 2 of the boost solenoid, the bottom ports of the wastegates and manifold pressure are going to port 1 of the boost solenoid, and port 3 has a muffler on it venting into the atmosphere.

[JantzenOKC]

Oh ok well that seems right from this diagram.

Have you tried bypassing the tru boost solenoid and just run off the wastegates? If you get 3-4psi or whatever your springs are then it seems like it might be a faulty controller?

[Pt_killa]

The car runs fine off just spring pressure, and to eliminate if its a weak spring, he disconnected the lines to the waste gate and boosted it and held up to 12psi, 3x spring pressure like expected. Also, there are no boost leaks or pre-turbo leaks, so signs point to the tru-boost or connections to top wastegate ports. I've never used a tru-boost, always dealt with manual air regulator so not 100% sure on the internal valve design of the controller and if the internal valve is 1 for 1 with the duty cycle setting (ie 10% duty cycle means the valve is letting through 10% of the air to the top of the wastegate, etc)

[KFranklin11]

Fixed it. Upgraded springs to 7.25psi springs (small green). AEM true boost controller only allows for double the spring pressure so I ended up maxing out the 3.6psi spring with their controller.

[JantzenOKC]

Originally Posted by KFranklin11

Fixed it. Upgraded springs to 7.25psi springs (small green). AEM true boost controller only allows for double the spring pressure so I ended up maxing out the 3.6psi spring with their controller.

Glad you figured it out!

I have never heard that about the tru-boost. Never really though about how much boost it would make. I wonder if its the same for internal wastegate actuators because I have 7psi actuators now. It was always hard to tell how much boost I was running before but I had the tru boost set at 50-55% duty cycle. I thought I was running 14psi but honestly it was always hard to tell.

So how much boost are you seeing now and what % is your tru-boost set on?

[Pt_killa]

Could it be that the amount of boost control from the tru-boost is slightly different between an internal gate and a dual port external wastegate? For an internal setup the controller just limits the air to the actuator to allow boost to rise while for an external setup the controller applies an offsetting amount of air to the top of the wastegate to control the boost, therefore the delta of the duty cycle and boost may be different for the two. Also, there is no extra pressure on the diaphragm while controlling boost on an internal gate but there is extra diaphragm stress on an external gate so maybe its a durability/safety thing?

[JantzenOKC]

Originally Posted by Pt_killa

Could it be that the amount of boost control from the tru-boost is slightly different between an internal gate and a dual port external wastegate? For an internal setup the controller just limits the air to the actuator to allow boost to rise while for an external setup the controller applies an offsetting amount of air to the top of the wastegate to control the boost, therefore the delta of the duty cycle and boost may be different for the two. Also, there is no extra pressure on the diaphragm while controlling boost on an internal gate but there is extra diaphragm stress on an external gate so maybe its a durability/safety thing?

Makes sense to me, I have no experience with external wastegates. This is the first turbo car I have owned so I've been learning as I go. I hope there is a difference though and the internal setup can reach more than double the springs because I will want to run more than 14psi. We shall see