boost not going above 10 lbs. no line on stock accuator. - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

shinobis13hb · 12-16-2010, 10:19 PM

boost not going above 10 lbs. no line on stock accuator.
YES i was watching the boost gauge.
could someone explain why it wouldnt go above 10 lbs? it should have infinite boost correct?
s13sr blacktop.

240sxrb25 · 12-16-2010, 10:23 PM

a wastegate wit no line attatched operates off spring pressure....if no vacuum line is attatched technically the exhaust pressure against the WG piston will open it....

infinateboost pressure is a hoax

roel03 · 12-16-2010, 10:43 PM

Stock wastegate will go to 20psi with no attached line.

shinobis13hb · 12-16-2010, 10:54 PM

Quote:

Originally Posted by 240sxrb25

a wastegate wit no line attatched operates off spring pressure....if no vacuum line is attatched technically the exhaust pressure against the WG piston will open it....

infinateboost pressure is a hoax

Quote:

Originally Posted by roel03

Stock wastegate will go to 20psi with no attached line.

but why would i not be going over 10lb if the line is disconnected?
even if i connect my manual boost controller and close it completly i only get 10lbs.
i would eventually like to go up to 12lbs when i get a front mount.
im jsut stummped

roel03 · 12-16-2010, 11:03 PM

Faulty wastegate? Different spring? It is easily narrowed down to that part so replace it. Even get an adjustable one and get rid of your MBC.

Also, your boost gauge could be wrong or wired incorrectly.

shinobis13hb · 12-16-2010, 11:20 PM

Quote:

Originally Posted by roel03

Faulty wastegate? Different spring? It is easily narrowed down to that part so replace it. Even get an adjustable one and get rid of your MBC.

Also, your boost gauge could be wrong or wired incorrectly.

thanks roel03,
i am most likely going to be replacing it with a hks adjustable and getting rid of that horrid MBC i can drive the car fine for now. but i already replaced it once and got no changed it stayed the same... but if something isn't broken why replace it? as far as the boost gauge it is installed correctly. thank you for your advice.

mikerbike · 12-16-2010, 11:58 PM

Quote:

Originally Posted by 240sxrb25

a wastegate wit no line attatched operates off spring pressure....if no vacuum line is attatched technically the exhaust pressure against the WG piston will open it....

infinateboost pressure is a hoax

False. A wastegate with no line attatched will not open, creating more boost, eventually maxxing out the turbocharger's boost capabilities. And, exhaust pressure won't open a wastegate if it's pushing against the actuator.

Quote:

Originally Posted by roel03

Stock wastegate will go to 20psi with no attached line.

The wastegate reduces boost, not increases boost.

OP, more likely causes of your problem are boost leak and/or bad turbocharger.

shinobis13hb · 12-17-2010, 12:04 AM

Quote:

Originally Posted by mikerbike

False. A wastegate with no line attatched will not open, creating more boost, eventually maxxing out the turbocharger's boost capabilities. And, exhaust pressure won't open a wastegate if it's pushing against the actuator.

The wastegate reduces boost, not increases boost.

OP, more likely causes of your problem are boost leak and/or bad turbocharger.

mikerbike,
i inspected the turbo and its Fing clean no shaft play at all motor has 60k+3k i have put on it. what would you suggest to check? could the stock wastegate me out of play here? . im going to upgrade to t bolts when i get my FMIC after x-mas. even if i close my MBC i only get 10lbs.
thanks for your help.

bardabe · 12-17-2010, 01:35 AM

boost leak test / thread.

R@ddy · 12-17-2010, 01:48 AM

Boost leak indeed

roel03 · 12-17-2010, 11:06 PM

Quote:

Originally Posted by mikerbike

False. A wastegate with no line attatched will not open, creating more boost, eventually maxxing out the turbocharger's boost capabilities. And, exhaust pressure won't open a wastegate if it's pushing against the actuator.

The wastegate reduces boost, not increases boost.

OP, more likely causes of your problem are boost leak and/or bad turbocharger.

What I am saying is, if the wastegate is running no vacuum or is seeing a regular vacuum source and not a boost source, the car will maximize at 20PSI and no more.

mikerbike · 12-19-2010, 06:00 PM

Any vacuum source is also a boost source. But a boost source before the throttle body is not a vacuum source. So, I don't really understand what you're getting at.

And My turbo maxed out at 17psi when the wastegate line broke. But 20 at lower altitude is probably possible.

rb25_s13*CHUKI · 12-19-2010, 06:49 PM

yea wastegate with no line is sick! haha I forgot to connect It one time and my car was pulling like a mother fucker for being a stock t25. Then I pull out my plugs after I seen It was off and they were all melted

roel03 · 12-22-2010, 04:46 PM

No, not every vacuum source is a correct boost source.

12-16-2010, 10:19 PM	#1
shinobis13hb Zilvia Addict Join Date: Dec 2008 Location: la crescenta Age: 35 Posts: 982 Trader Rating: (12) Feedback Score: 12 reviews	boost not going above 10 lbs. no line on stock accuator. boost not going above 10 lbs. no line on stock accuator. YES i was watching the boost gauge. could someone explain why it wouldnt go above 10 lbs? it should have infinite boost correct? s13sr blacktop.

12-17-2010, 01:35 AM	#9
bardabe Post Whore! Join Date: Aug 2005 Location: SoCal Age: 35 Posts: 4,719 Trader Rating: (10) Rides Gallery: bardabe Feedback Score: 10 reviews	boost leak test / thread. __________________ Review Thread

12-19-2010, 06:00 PM	#12
mikerbike Zilvia Junkie Join Date: Apr 2007 Location: SLC, UT Age: 42 Posts: 461 Trader Rating: (0) Feedback Score: 0 reviews	Any vacuum source is also a boost source. But a boost source before the throttle body is not a vacuum source. So, I don't really understand what you're getting at. And My turbo maxed out at 17psi when the wastegate line broke. But 20 at lower altitude is probably possible. __________________

12-19-2010, 06:49 PM	#13
rb25_s13*CHUKI Post Whore! Join Date: Mar 2007 Location: Cali Age: 36 Posts: 2,759 Trader Rating: (16) Feedback Score: 16 reviews	yea wastegate with no line is sick! haha I forgot to connect It one time and my car was pulling like a mother fucker for being a stock t25. Then I pull out my plugs after I seen It was off and they were all melted __________________ Obliterate

12-16-2010, 10:23 PM	#2
240sxrb25 Zilvia Junkie Join Date: Aug 2006 Location: omaha, ne Age: 35 Posts: 451 Trader Rating: (2) Feedback Score: 2 reviews	a wastegate wit no line attatched operates off spring pressure....if no vacuum line is attatched technically the exhaust pressure against the WG piston will open it.... infinateboost pressure is a hoax

12-16-2010, 10:43 PM	#3
roel03 Zilvia Addict Join Date: Oct 2006 Location: florida Age: 37 Posts: 807 Trader Rating: (23) Feedback Score: 23 reviews	Stock wastegate will go to 20psi with no attached line.

12-16-2010, 11:03 PM	#5
roel03 Zilvia Addict Join Date: Oct 2006 Location: florida Age: 37 Posts: 807 Trader Rating: (23) Feedback Score: 23 reviews	Faulty wastegate? Different spring? It is easily narrowed down to that part so replace it. Even get an adjustable one and get rid of your MBC. Also, your boost gauge could be wrong or wired incorrectly.

12-17-2010, 01:48 AM	#10
R@ddy Nissanaholic! Join Date: Jul 2008 Location: SoCal Age: 35 Posts: 1,632 Trader Rating: (32) Feedback Score: 32 reviews	Boost leak indeed

12-22-2010, 04:46 PM	#14
roel03 Zilvia Addict Join Date: Oct 2006 Location: florida Age: 37 Posts: 807 Trader Rating: (23) Feedback Score: 23 reviews	No, not every vacuum source is a correct boost source.