# Apexi AVC-R and Tial F38 can't hold boost



## napkin (Mar 8, 2008)

hi everybody. i got a big problem controling boost correct with the avc-r.

at the moment i am running an external f38 tial wastegate and a gt3071 on a vr5 engine (similar to the 12v vr6 .. but with 5cyl. i think the engine is only available in europe)

wastegate spring 14.5psi

the avc-r is connected as on the manual setup for external wastegates with the t-piece.

i was trying to start boost at 16psi/3200rpms and raise it up to 26psi/6000rpms to hold torque stable.

problem is i cant reach over 23psi. and for reaching 23psi, i need to set the controler to max boost and max duty (not the best way to handle that baby)

even if i program 26psi at 4000 it will not let me go over 23psi. 

closed the wastegates ports it will shoot over 32psi, so its a avc-r setup problem.

i got some ideas and hope you guys can help me.

fist of all. the manual says i need to reach max boost with 70% duty.. i will never get that high with 70% 

second idea and question: should i run a bigger WG spring? i already use 14.5psi. is it to small to hold up the max boost of 26psi?

third. is there another way connecting the tial wastegate? i read this in another forum. anybody can discribe me how to set it up, so boost will be stable?

_*When controlling boost from the top port port, use the COM and NC ports. When controlling from the side port only (like an internal wastegate), use the COM and NO ports for interrupt style boost control. 

As far as which setup to use, controlling from the top port is most useful when your target boost is significantly higher than your spring pressure. The EBC will supply air to push the wastegate valve shut to fight backpressure. I prefer using the top port on any external wastegate becaue it gives very fine control over how quickly the wastegate opens and exhaust backpressure is not really an issue.*_

so can someone post a drawing, how to connect the solenoid? i thought the lower port is holding the pressure, or am i wrong?

please help me, i am on the end of trying and testing 

sorry for my bad english, i am german :wave:


----------



## PapioGXL (Jun 3, 2008)




----------



## napkin (Mar 8, 2008)

sorry that wont help me in any way 
as i wrote above, i already connected it like this :banghead:


----------



## HidRo (Sep 19, 2003)

Lower port of the wastegate will always bleed in the TIAL etc design. If you suck on the hose going to the lower port, you will feel the air moving, and you will suck exhaust (car off, obviously  ).
If you do the same on the top port, it will hold the pressure or vaccum you provide.
So, you need to have a direct boost connection to the lower port, and the controller output of boost to the top port.
0% duty on the controller, you will have just spring pressure
100% duty on the controller, you will have boost to the moon










So, the output of the valve, will be as it's described in the text you are using.
Maybe you can take some pictures of your setup?


----------



## PapioGXL (Jun 3, 2008)

I thought I had text in there too. Oops.

What happens if you disconnect the line to the bottom port and cap the hose off?


----------



## bonesaw (Aug 8, 2004)

Running no side port is not going to open the wastegate and will most likely over boost. You need line from turbo to side port then turbo to boost solenoid. And then solenoid to top port. You can use any combination of Ts on turbo air spice on side port etc.


----------



## sTT eV6 (Oct 26, 2010)

Plumbing up correctly is one issue and ensuring your spring hasn't gone weak is another.
If your running 26psi then use a spring 2/3 rating which will allow for some softening down the road.
Steve


----------



## JettaG60MK2Rider (Feb 13, 2005)

some what un-related, but... you guys seem to be able to answer this.
three port Manual boost controller.
one port is vacuum/boost source(from manifold) the second horizontal port goes to top waste gate port, and the adjacent(bottom) port goes back to the intake(after the maf so it doesnt read that air twice) as a bleed off(as to not cause a vacuum/boost leak)..... correct?

thanks for your time, guys
:thumbup:


----------



## HidRo (Sep 19, 2003)

I've used a 3 port manual, and bottom was source/boost, one of the side ones was to the bottom of the wastegate (used in the internal wastegate as well), and the other was vented.


----------



## napkin (Mar 8, 2008)

i need to pull this out gain. i am having troubles again.

my boost has startet pulsing a while ago. i had a problem with my speed signal in the engine ecu. i now had it fixed and took the speed signal from the gala cable running to the ecu
after that i had a very fast pulsing under wot. now i cut the wire for the speed signal and the boost pulse is going more slower, but its still there.

my duty is set to 45% and i am running a 14psi spring. 

is the duty to low to maybe hold a stable boost? should i run a softer wg-spring?

i am now goiing to get the speed signal directly from the gearbox and see if it helps. donno what to do.
when i turn setting a or b to OFF, the pulsing is gone. so it has to do something with the duty setting.

if you got any ideas let me know


----------



## 24vGTiVR6 (Sep 14, 2010)

sounds to me like you're speed and rpm signals aren't coming from the right source, and when the controller adds boost through duty cycles etc it starts to pulse as the input is confusing the EBC.

I get VSS (speed) signal from the blue plug on the back of the cluster.
RPM signal from T10 orange connector under the harness cover in the rain tray.
throttle signal not needed.
(not sure on exact pin #'s for VR5 harness.... never worked on one)

they don't really need to be accurate, they just need to be relative. my RPM and speed are both inaccurate on the AVC-R display, but since they are accurately relative, the boost controller can calculate gear ratio's etc successfully. also turn off auto learn etc if you have that active, and do everything manually.


----------



## napkin (Mar 8, 2008)

24vGTiVR6 said:


> sounds to me like you're speed and rpm signals aren't coming from the right source, and when the controller adds boost through duty cycles etc it starts to pulse as the input is confusing the EBC.
> 
> I get VSS (speed) signal from the blue plug on the back of the cluster.
> RPM signal from T10 orange connector under the harness cover in the rain tray.
> ...



yeah i think so too. i took the signal directly from the ecus pin. maybe i should get it from the clusters line. thats the gala signal for raising the speaker loudness on higher speed.
normaly this is the same line that runs to the ecu. but i will give it a shot. 

i will disconnect tb signal and see if something changes. 

maybe i get a rectale signal on the ecus pin and need a continous voltage that raises and lowers. when i ad 12v to the apexis speed signal line i dont have vibrations.


----------

