Datalog N54 6466 single 7psi wg spring (each wastegate) test

[N54roop]

N54roop submitted a new graph:

N54 6466 single 7psi wg spring (each wastegate) test

I have Turbo Smart comp 40 wastegates that came pre installed with 14 psi springs. (7psi outer, 7psi inner). I was having over boost cut issues even on just wastegate duty cycle (10). The springs were too stiff to allow the wastegates to fully open/ Reason I say they wouldn't fully open is when I took of the wastegates to remove the inner 7psi spring from each wastegate, I noticed that the valve sleeve only had wear polish marking halfway and other half did not have wear marks. I removed the...

View this graph...

 

[doublespaces]

So you've got 7 psi springs and you're making 15 psi?

 

[N54roop]

So you've got 7 psi springs and you're making 15 psi?

Yeah. I’m having a hard time understand why I’m boosting soo much. I’ve already double checked the wg line plumbing and swapped out the Mac solenoid with a new one. The GFB controller settings are: wgdc-10(lowest possible), gain-0, sen-0, overboost safety-16psi.

 

[doublespaces]

Have you tried to take the boost controller out of the equation?

 

[N54roop]

I’m not sure what you mean to say but I have swapped the Mac solenoid with a new one. Same issue.

 

[SLOWESTN54]

I’m not sure what you mean to say but I have swapped the Mac solenoid with a new one. Same issue.

i believe what @doublespaces meant was to completely disconnect the boost controller, and see what boost it will make on just spring pressure.

 

[N54roop]

i believe what @doublespaces meant was to completely disconnect the boost controller, and see what boost it will make on just spring pressure.

Oh ok ok. I’ll disconnect the power cable to the GFB and remove the boost reference line from the GFB. I’ll cap off both ends on the chargepipe fitting and the line that runs to the GFB. I’ll also do a small log and see what it does.

 

[nyt]

run boost reference from the turbo direct to the lower half of the manifold. If you leave that off, you won't be in for a good time.

 

[N54roop]

run boost reference from the turbo direct to the lower half of the manifold. If you leave that off, you won't be in for a good time.

Could you elaborate a bit more on this? Thanks.

 

[nyt]

Could you elaborate a bit more on this? Thanks.

If you want to see what your wastegate runs on spring pressure, you leave the top of the wastegate vented, and the bottom/side hooked hooked up to a boost source, generally the nipple on the compressor housing.

Otherwise, you will boost until the exhaust pressure overcomes the wastegate spring pressure, which means a lot more boost than you're expecting.

Boost is controlled by directing pressure to the bottom/side port to open the wastegate, this fights against the spring, so if you have a 7psi spring, once you push 7psi to the wastegate and it overcomes the spring, the wastegate opens. This regulates your boost to to 7psi, minus any additional exhaust pressure that pushes against the valve.

Boost is increased by applying additional pressure to the top of the wastegate, this adds force keeping the valve closed.

With a 3 port solenoid, you generally run a boost reference direct from the compressor to the side of the wastegate, then tee it off to the solenoid, which will then control how much additional pressure is applied to the top of the wastegate helping to keep it shut and thus increasing boost.

A 4 port solenoid is similar, except the pressure to the bottom of the wastegate, which opens it, is diverted to the top, which keeps it closed.

The difference is with a 3port, there's always boost pressure to the bottom, whereas with a 4 port, that pressure is removed from the bottom when trying to keep the gate shut. This allows for a bit of additional force to keep the wastegate closed under higher exhaust pressures.


3 port:

4 port:

 

[N54roop]

If you want to see what your wastegate runs on spring pressure, you leave the top of the wastegate vented, and the bottom/side hooked hooked up to a boost source, generally the nipple on the compressor housing.

Otherwise, you will boost until the exhaust pressure overcomes the wastegate spring pressure, which means a lot more boost than you're expecting.

Boost is controlled by directing pressure to the bottom/side port to open the wastegate, this fights against the spring, so if you have a 7psi spring, once you push 7psi to the wastegate and it overcomes the spring, the wastegate opens. This regulates your boost to to 7psi, minus any additional exhaust pressure that pushes against the valve.

Boost is increased by applying additional pressure to the top of the wastegate, this adds force keeping the valve closed.

With a 3 port solenoid, you generally run a boost reference direct from the compressor to the side of the wastegate, then tee it off to the solenoid, which will then control how much additional pressure is applied to the top of the wastegate helping to keep it shut and thus increasing boost.

A 4 port solenoid is similar, except the pressure to the bottom of the wastegate, which opens it, is diverted to the top, which keeps it closed.

The difference is with a 3port, there's always boost pressure to the bottom, whereas with a 4 port, that pressure is removed from the bottom when trying to keep the gate shut. This allows for a bit of additional force to keep the wastegate closed under higher exhaust pressures.


3 port:

View attachment 53746

4 port:
View attachment 53747

Ok I’ll first remove the boost reference for the GFB off of the chargepipe and place it into the stock fitting of the intake manifold to see if it’ll help with anything. I’ve already double checked the wastegate plumbing and it’s all fine. If the issue remains I’ll remove the lines from the top of the wastegate and just let it vent even though I’ve never seen anyone have this much of an issue before. I feel like I’m the only one in the whole Single Turbo N54 world ;(

 

[nyt]

Ok I’ll first remove the boost reference for the GFB off of the chargepipe and place it into the stock fitting of the intake manifold to see if it’ll help with anything. I’ve already double checked the wastegate plumbing and it’s all fine. If the issue remains I’ll remove the lines from the top of the wastegate and just let it vent even though I’ve never seen anyone have this much of an issue before. I feel like I’m the only one in the whole Single Turbo N54 world ;(

uh, no, that's not at all what you should do. You shouldn't be supplying any vac to your wastegate, boost only.

This is the same for any wastegate, nothing is special for N54 here.

 

[DefaultGate]

Just to be sure, are you running any different TMAP sensor (3.5, 4 bar). If so your tune needs to reflect such.

 

[N54roop]

Yes I am running the 3.5 bar tmap sensor with plug and play harness. When flashing custom the custom tune I checked off the option for 3.5 bar.