Turbo building boost at idle - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

1quk240 · 04-16-2014, 09:02 AM

Just finished up things on my SR and so I start the motor and the turbo is building boost. It's a GTX3076. The vaccum is at 0, when I give it a little gas the vaccum drops to where it should be around (17-20).

It's running off the base map of a PFC, has 256 cams.

Also, the downpipe had a crack in it which is getting fixed today but not sure if that big of an exhaust leak would cause the turbo to do this?

Anyone else ever have this type of problem?

wowzers9930 · 04-16-2014, 09:27 AM

vacuum leak I would say

Scott@FontanaNissan · 04-16-2014, 09:30 AM

im going to vote you have your vacuum line in the wrong spot.

*anti tyler* · 04-16-2014, 09:47 AM

Quote:

Originally Posted by Scott@FontanaNissan

im going to vote you have your vacuum line in the wrong spot.

This^^^

Are you sure it's actually building boost, or does your boost gauge just "say" it's building boost?

sr23det · 04-16-2014, 09:53 AM

anti lag ftw!

cotbu · 04-16-2014, 11:30 AM

That not considered building boost at idle so your title is wrong. Most likely case is the vacuum line for your boost gauge is hook up wrong that means to a source before the throttle body or something similar. A vacuum leak that big would be audible from the engine bay, if not boost leak test it.

Driftwire · 04-16-2014, 12:00 PM

As said above you need to use vaccum after the Throttle body, Mine is T'd off from the FPR line and reads -22 at idle.

Boostd2 · 04-18-2014, 08:25 AM

the number 0 vacuum (gauge indicated) is not actually positive pressure. It means that the pressure/vacuum is equal to that of the surrounding atmosphere. Which is 14.7 psi sea level.
anothing above that is considered positive pressure/boost. ( so 0 on your gauge is really 14.7 psi absolute pressure.)

but as others mentioned above, simple fix involving changing the vacuum source of your gauge, and other things you currently have routed that way.

04-16-2014, 09:02 AM	#1
1quk240 Banned from the Marketplace Join Date: Mar 2007 Location: Planet Earth Posts: 768 Trader Rating: (21) Feedback Score: 21 reviews	Turbo building boost at idle Just finished up things on my SR and so I start the motor and the turbo is building boost. It's a GTX3076. The vaccum is at 0, when I give it a little gas the vaccum drops to where it should be around (17-20). It's running off the base map of a PFC, has 256 cams. Also, the downpipe had a crack in it which is getting fixed today but not sure if that big of an exhaust leak would cause the turbo to do this? Anyone else ever have this type of problem?

04-16-2014, 09:30 AM	#3
Scott@FontanaNissan Zilvia Junkie Join Date: Dec 2009 Location: Fontana, CA Posts: 479 Trader Rating: (4) Feedback Score: 4 reviews	im going to vote you have your vacuum line in the wrong spot. __________________ Juan Vargas - Motorsports Specialist Fontana Nissan/Nissanraceshop.com email: [email protected] Scott's Personal Website/Blog: http://www.scottandkerryann.com

04-16-2014, 11:30 AM	#6
cotbu Post Whore! Join Date: Sep 2005 Location: SWFL Age: 49 Posts: 3,318 Trader Rating: (3) Feedback Score: 3 reviews	That not considered building boost at idle so your title is wrong. Most likely case is the vacuum line for your boost gauge is hook up wrong that means to a source before the throttle body or something similar. A vacuum leak that big would be audible from the engine bay, if not boost leak test it. __________________ LoverTechnologies "Half Broken Things!"

04-16-2014, 09:27 AM	#2
wowzers9930 Leaky Injector Join Date: Nov 2012 Location: Pittsburgh PA Age: 32 Posts: 54 Trader Rating: (0) Feedback Score: 0 reviews	vacuum leak I would say

04-16-2014, 09:53 AM	#5
sr23det Zilvia Member Join Date: Jul 2009 Location: norcal Age: 40 Posts: 182 Trader Rating: (2) Feedback Score: 2 reviews	anti lag ftw!

04-18-2014, 08:25 AM	#8
Boostd2 Join Date: Apr 2011 Location: Caribbean Age: 33 Posts: 42 Trader Rating: (0) Feedback Score: 0 reviews	the number 0 vacuum (gauge indicated) is not actually positive pressure. It means that the pressure/vacuum is equal to that of the surrounding atmosphere. Which is 14.7 psi sea level. anothing above that is considered positive pressure/boost. ( so 0 on your gauge is really 14.7 psi absolute pressure.) but as others mentioned above, simple fix involving changing the vacuum source of your gauge, and other things you currently have routed that way.