Turbo's not boosting, replaced BOV

[Guest]

I'm in Welly

[lord_jagganath]

ok.. hooked up a boost gauge... but when it idles it is @ 20mm Hg... is that normal? ... and then.... when i am accelerating... at 2000rpm... it barely hits 5 psi...

[Bazza-NZ]

 lord_jagganath said:

ok.. hooked up a boost gauge... but when it idles it is @ 20mm Hg... is that normal? ... and then.... when i am accelerating... at 2000rpm... it barely hits 5 psi...

sounds about right...

not 100% sure how quick your turbo spools, but some turbo's don't reach full boost till about 2500-3000..

[Guest]

differential pressure sensor ? waste gate valve ? intake air control solenoid valve? iv had a twin T and yea didt have it for long, awsome when they work.. did ALOT of reading online when i had it.. now im doing the same with the gf8 i got now...man gota love cars...different versions of code 66

Trouble code 66

66SBSYS (T) è Twin turbo operating area (Both Primary & Secondary turbo are operating.)

66SBSYS (S) è Single turbo operating area (Only primary turbo is operating.)

66SBSYS (H) è High supercharged pressure area

[Guest]

good reading thanks to NASIOC

sequential setup by the way so bla bal bla here it is...good reading man take it in .. [there] is no #2 wastegate. there is only one wastegate and it comes off #1 turbo because that turbo is always on line, therefore you always have a wastegate. there are 4 sets vsv's, actuators, and control valves for the sequential turbo system. each vsv is simply a solenoid that is either 100% open or closed, allowing manifold pressure to pressurize the different actuators that open/close the four different valves.

wastegate: when the manifold reaches 11#'s of boost, the ecu sends a signal to the wastegate vsv, this allows manifold pressure to build in the wastegate actuator which opens the wastegate.

exhaust gas bypass valve: somewhere around 3500 rpm, the ecu sends a signal to the exhaust gas bypass valve vsv, which allows manifold pressure to build in the exhaust gas bypass valve actuator which opens the bypass valve. this is a small opening inside the #2 turbine housing which allows some exhaust gas to go through the turbine of the #2 turbo which makes it start spinning, and dumps the exhaust gas out the exhaust piping coming off of #1 turbo. since it is a small amount of exhaust gas, it pre-spools the turbo and does not get it up to full operating speeds. this will smooth out the transition from 1 to 2 turbos. this valve is similar to a wastegate in design, but is located after the turbine wheel instead of in front of the turbine wheel like a wastegate would be. this is not a wastegate!

exhaust gas control valve: this valve is located in the exhaust piping downstream of the #2 turbo. when this valve is closed, all exhaust gas must go through the #1 turbine wheel to get out through the rest of the exhaust system. at around 4000 rpm, the ecu sends a signal to the exhaust gas control valve vsv, which allows manifold pressure to build in the exhaust gas control valve actuator which opens the control valve. this allows exhaust gas to go through #2 turbo and out the exhaust system which brings the #2 turbo up to full operating speed.

intake air control valve: this valve is located in the intake tract coming off of #2 turbo. it is closed below 4000 rpm so that boost pressure coming off of #1 turbo cannot backup through the #2 turbo and back out the air cleaner/suction of #1 turbo. there is also a 1 way reed valve within the same housing of the intake air control valve. as the #2 turbo starts to prespin at 3500 rpm, it will build some boost. if it builds enough boost, it will open the 1 way reed valve to allow this boost into the intake tract to join with the discharge boost pressure coming off of #1 turbo. at somewhere over 4000 rpm, the ecu sends a signal to the intake air control valve vsv, which allows manifold pressure to build in the intake air control valve actuator which opens the control valve. this allows the full boost pressure coming off #2 turbo to join in with that coming from #1 turbo and you are now fully on line. usually, the exhaust gas control valve will open first, which gets the #2 turbo spinning at full rate so that it is building good boost before the intake air control valve opens, allowing this boost to join in with that coming off #1 turbo.....

[Volcanix]

sorry to jack the thread but for some reason my car secondary turb spools to 16 psi holds fora sec then drops to 10-11psi , which then holds solid till red line, wht could be the matter?

[lord_jagganath]

in other words.... if i am driving the vehicle "sanely" ... keeping revs around 2-2.5k rpm... i won't have much boost?

[Guest boostin]

 lord_jagganath said:

in other words.... if i am driving the vehicle "sanely" ... keeping revs around 2-2.5k rpm... i won't have much boost?

I'm not re-reading the whole thread, so how old is the car and how many km's??

[Volcanix]

 lord_jagganath said:

in other words.... if i am driving the vehicle "sanely" ... keeping revs around 2-2.5k rpm... i won't have much boost?

Lol Not that much that you will feel it, my rs doesnt pull till 3 ish and then vod at 4 its a bit fail set up imo. when im driving at 2-2.5krpm i get 2-5psi tops so ur ok

[Guest boostin]

Sounds like you lot have issues. Primary should be well spooled by 2500rpm.

[lord_jagganath]

car is 10 yrs old and have 180k kays on it... I suspect the vacuum tubes are perishing... because they are quite hard.... and the BOV/bypass valve on the inter-cooler.... should it have equal vacuum pressure on both ends of the tube or one should have a positive pressure ?

The primary blows... but it is low-ish ... 5 psi on the boost gauge... ( but that still has the clear vacuum line... and the t connector for some reason is 6mm ... bigger than the vac tube's inner diameter of 4mm.. ( i have no idea how much that would affect readings..

[Volcanix]

 boostin said:

Sounds like you lot have issues. Primary should be well spooled by 2500rpm.

well it sounds like a sewing machine when full boosting and wistles louder than a steam train when cold and sometimes when warm

[Guest boostin]

Yup, would pay to replace those lines. Just make sure you put the restrictor pills in the new lines too.

Are you talking about the vac line to the bov or the pressure relief line back to the intake?

[Guest boostin]

 Volcanix']

[quote name='boostin said:

Sounds like you lot have issues. Primary should be well spooled by 2500rpm.

/quote]

well it sounds like a sewing machine when full boosting and wistles louder than a steam train when cold and sometimes when warm

Yeah well that ain't good.

[Volcanix]

how much for a quality replacement do u reckon? something with low kays and cheap as poss lol

[Guest boostin]

Depends if its a turbo making the racket or a boost leak etc.

[lord_jagganath]

 boostin said:

Are you talking about the vac line to the bov or the pressure relief line back to the intake?

the two vac lines to the bov ( the 4mm tubes) the two pressure's should be equal aye?

not the HUGE DUMP TUBE back to the intake... ( if i am not mistaken... that shouldn't even be open at the rpm's i am doing)

[Guest boostin]

Really not sure there aye. I've never checked the pressures there before sorry.

[lord_jagganath]

Thanks for your input anyhow, mate. The slightest leak in the vac system can screw the entire turbo set up eh?

[Guest boostin]

Leaks or blockages have a big effect on them.

[lord_jagganath]

well... that i can do... It will be the cheapest "fix" i can think of...

can CEL 66 come on because of leaks in the system?

[Guest boostin]

Definitely.

[Guest]

+1000

66 is failue of system operation, which is opertaed by vac/pressure

electronic solenoids that fail log specific error codes

[lord_jagganath]

^

^ and ^

AWESOME!!! THANK YOU BOTH!!! ( you win cookies and cream from your local Tatua Dairy Co-op)( but i suppose i shouldn't crack the Champagne bottle open.... I'll replace all the tubes first..)

Supercheap's $5/m is ok to use?

[Guest boostin]

Should be fine.

Just make sure you refit all the restrictor pills in the correct places or you'll have even less boost!!