low boost (0.6 bar) on first and second turbo

[SchuKingR]

Hey guys,

I'm a little confused.
I'm running my FD with OEM sequential twins and getting only 0.6 bar of boost, when my wastegate solenoid is connected to the hoses that it's supposed to be connected.
When I disconnect the pressure hose from the turbo to the solenoid, my car is boosting just fine.
I never had full boost before, because I was on PowerFC and didn't know how to tune that thing, so I ditched it for the LinkECU. The highest Boost on PFC was also 0.6 bar with the normal untuned PFC map.

My first thought was, that the solenoid is bad... pulled that out, checked it -> yep it sticks sometimes...

Changed to a Pierburg solenoid -> same result.
Solenoid is working fine (can test that with my Link ECU). Using only position 2 and 3 with position 1 sealed, so it should work like the OEM 2 port solenoid.

I realised, that the previous owner changed all the hoses to silicon hoses. So could it be, that the pill in the lower hose is missing and now my Pierburg solenoid couldn't keep up ditching all the boost coming from the turbo? That could explain why it boosts without the hose connected.

So what is going on here? Any ideas?

Thanks and sorry for another "boost problem thread"

 

[Ceylon]

What age and model is the car? If using anything but the 99+ n3g1 twins you'll need the restrictor pills to stop you bleeding off the pressure in the actuators too fast and keeping the wastegate open.

 

[SchuKingR]

93 with 88000km on it, so looks like that's really the problem.
If I'm switching to 3 port solenoid completely, I don't need the pills anymore or do I?
So port 1 coming from boost source, 2 goes to intake and 3 to wastegate.

 

[Ceylon]

Yes, correct, you don't need pills for that kind of configuration. A Lot of aftermarket boost controllers also work that way.
What are you using to control precontrol?

 

[SchuKingR]

Yes, correct, you don't need pills for that kind of configuration. A Lot of aftermarket boost controllers also work that way.
What are you using to control precontrol?

Same system. Was wondering why that works just fine and the wastegate didn't, but that's another sign for the missing pills. Printed myself a bracket to hold the two Pierburg solenoids at the same position as the OEM Solenoids. It's a tight fit, but it fits

All controlled by my Link Thunder.

 

[SchuKingR]

okay today I managed to put in some pills into the hoses which leave the turbine housing in front of the car. I used the thing in the picture below (Don't know the english word for it, but it's for a carburettor. Size 1.62mm for wastegate and 1.50mm for precontrol. Should be the right size as far as google told me

Didn't change anything to my boost problem, like before, only 0.5 to 0.6 bar of boost.
It must be something else... I try to order some silicon hoses and connect the solenoids like the should be with all 3 ports connected and then I will try again...

 

[SchuKingR]

another question for plumbing up my wastegate and precontrol setup. what's the best way plumbing it up?
I found this picture from rx7club, where the other port of the wastegate is capped off.

Or is it better to do it like in @Efini-dan 's thread here: https://fdoc.co.uk/forum/threads/wastegate-setup.4362/
is it possible to do it like this with the oem sequential actuators?
my solenoids are 3 port solenoids, so this would be like in the MAC solenoids in the thread.

 

[Tangelos]

Do you have an aftermarket boost controller?

 

[Tangelos]

When I was on my twins I had the boost controller plumbed like this (version 1)
For some reason version 2 didn’t work for me but it works very well for others. Try both

here’s a pic of version 2 in my car

 

[SchuKingR]

I got a LinkECU in my car, so yeah kind of boostcontroller
okay looks like you got the rx7club version then. Thanks! I'll give that a try

wondering why you would go other ways with the external wastegates like in the other thread. Differ the internals of OEM and turbosmart actuators so much from each other? they don't cap one side. it's boost on both sides there So like you have it right now in your car.

 

[Tangelos]

My car is single turbo now so I have external wastegates

What I showed you is what my car looked like when I had twin turbos!

 

[SchuKingR]

yes I know that. but I don't know why you can't run the hoses to the internal like you do on an external wastegate... I just haven't figured it out.

 

[Tangelos]

Well you’re running the hoses to the actuators which control the wastegate flaps inside so it’s very similar to running hoses to external wastegates.

 

[SchuKingR]

My english is not the greatest, so maybe we are just talk past each other. so it's possible to control boost like this with the oem wastegate and a 3 port Pierburg/MAC solenoid? do you know whats the difference to the variant, where one port is capped? it is better than the other?

 

[SchuKingR]

I think I found my answer to my 2 port question. The oem actuator has 2 ports, but both are connected to only 1 chamber, that's why you have to cap one port.
Aftermarket external wastegates have 2 Chambers (see in pic below), that's why you can connect it like you did in the picture above.

Thanks Tangelos for your help

 

[Tangelos]

I think you should take a look at this website to learn a bit more about the turbo system, you may be able to translate ot

Boost Control Info

typically a wastegate has 1top port and 1 bottom port. The bottom port is connected to the boost source and opens the wastegate (releases gasses) once the boost source reaches a certain pressure. The top port goes to the boost controller, which will keep the port closed until the desired pressure is reached and then it’ll open. The wastegate and pre control actuators Only have two top ports so your diagrams do not apply. Sorry, trying to clear things up!

 

[SchuKingR]

Yes this was the thing that didn't want to go into my head until today morning

Just finished plumbing up my solenoids like you did in your twin days. Aaaand it's boost time!!! Thanks alot!! I'm so happy that this problem is now solved!!
Best thing is, I only needed to route two hoses from the boost side of the turbo to the top of my pierburg solenoids. The other 4 hoses are in the oem position

btw here is a cad of my holder (a calbe tie from left to right straps the solenoids in place, while the middle part holds it down too). Printed out of ABS and does it's job now

 

[Tangelos]

Glad it worked out buddy!!!