how i connected a boost controller on the 2JZ-GTE

[brett_celicacoupe]

this is how ive plumbed mine in. im also still running the sequential setup

i dont like the idea of pushing one turbo faster then the other on the second stage. all the diagrams for connecting boost controllers only deal with the rear turbo. i believe my way pushes the 1st turbo a little harder in the 1st stage and then pushes BOTH turbos equally harder in the second stage. im using a turbotech ball&spring type boost controller ($30 ebay)

how it performs:

i get about 14.5psi on the 1st stage. i suspect the turbo is close to its limits at this point. when the second stage comes on, it dips to about 12psi then shoots up to 16psi. on a normal NQLD day (30+deg) it wont hit boost cut. im running a home made $2 FCD and it works perfectly

note that the pressure feed line that originally went to the rear turbo needs to be blocked off.

diagram:



note: modify your engine at your own risk.

cheers,
Brett

[PlacentaJuan]

so you used one of those ball and spring controllers or just a bleed controller?

its looks like a bleed controller because you have tee'ed the output of the controller with the wastegate and the prespool valve (2nd turbo 'wastegate' or "Exhaust Bypass Valve") is this right?

i have beenn thinking about this but would rather a ball and spring valve on the wastegate and a bleed valve on the pre-spool (its the prespool opening that acts as a second wastegate for the first turbo BEFORE the second turbo come online which is responsible for limiting the boost on first turbo.)


so this would effectivly add 'lag' to the prespool valve (bleeding off pressure to the actuator to make it open later like a wastegate) to increse boost for the first turbo,

how dooes this affect the point at which the solenoids open to engage the second turbo in sequential mode, does it still feel right?

i dont know if the solenoids open according to revs or a pressure signal, but i thought the EBV was an important part of the process of transferring gas to the second turbo.

if the EBV is opening later in sequence and the ICV and ECV are still opening at the same time then the second turbo is going to be spinning slower than designed when it gets full gas pressure.

higher boost on the first turbo would certainly make up for this but the shock load to the second turbo and risk of compressor stall would be greater if the ECV opens before the EBV or before the EBV is fully open.

this is a really good experiment that i had planned for my 2jz before messing aaroudn with the sequential system, i would be really interested to know how it goes.

[brett_celicacoupe]

edit:

i forgot those boost figures i quoted are with the boost controller screwed right out.

i took it to the drags last night and screwed it in properly.

i get about 14.5psi in the 1st stage and about 16psi in the second stage.

im using a turbotech ball and spring type.


lag.......i dont notice any difference at all in the transition point. mine seems to hit stage 2 at exactly 4krpm, like clockwork nearly.


the boost controller gets T'ed off and goes directly into the both wastgates

[PlacentaJuan]

that is woerd, im going to have to think a bit more to understand it.

because the wastegates dont open at the same time; the EBV should be the first one to open, then the wastwegate should open to controle boost.

but if the EBV is opening at all then it means the ball has lifted in your controller and therefore would have no effect on the wastegate.

unless the EBV has been somehow disabled by this mod (which would increase the boost on mo1 turbo) and the controller is controlling the wastegate only it would make sense (except you have no prespool on the second turbo)

the solenoids are rev operated im sure (since they are electronic) so i guess that is why they are working like normal.

the other thing i am thinking is that both actuators operate in unison (like the 1jz wastegates) except that once the secodn turbo somes online the EBV has no effect weather is is open or closed, and only the wastegate is controlling boost.

very fucken confusing.

i have one of these actuators arriving next week i will do that same thing.

i would like to know the difference in transition (if any) between the controller hooked up only to the wastegate (no 1 turbo) then like you have it now.

[brett_celicacoupe]

the way i see it is that both wastegate actuators have a lower base level of boost available for them to use. the VSV's probably dont care that there is less pressure they just function as they've been programmed. the no reason to suggest they open together at the same time by the same amount, they probably open as they did before just 10-15% less - giving me the boost increase

if they were trying to compensate then they would open less. maybe even not open at all - but i doubt it

[PlacentaJuan]

ok i get it now:
wastegate and ebv dont operate together.

at <4k rpm the EBV is working as a wastegate for the no1 turbo, and a prespool for the no 2.

at >4krpm the second turbo is online, meaning both the EGV and IGV are open, which renders the EBV useless; it has no effect on boost or anything while the second turbo is working (and therefore is probably closed by the vsv).

the only thing controlling boost while both turbos are working is the wastegate on no 1 turbo.

i still reckon the prespool wont be up to the factory speed when the other valves are open, but at least it will be spinning and the extra boost makes up for any lag, however i would be more comfortable doing this on upgraded (steel wheel) turbos.

thanks brett this is an awesome thread i am going to try this once my car is running again.

also i would like to try the controller hooked up to the EBV only too see if you can get more boost out of the first turbo and not affect overall boost levels.

[brett_celicacoupe]

do it at your own risk but im sure it will be fine.

ive had the boost controller on for about 3 months now.

[PlacentaJuan]

brett what do you think about this article:

http://www.supraforums.com/forum/sho...d.php?t=409342

he does it a bit differently but i think its essentially the same thing that you did but a bit more complicated.