Blow off valve issue

kentmo280z · 03-28-2015, 03:07 PM

Curious on how those with a plumb back BOV are plumbing their vacuum lines.
I am having an issue where the piston on the valve appears to be fluttering up and down during cruising ( makes an annoying noise), where my vacuum is between minus 20 ~ 0 on my gauge.
I'm running a GTM stage 1 supercharger with a turbosmart 38mm plumb back valve. I have adjusted the cap both tight and loose and even swapped that valve with another. Same issue.
I have the vacuum line running from the valve to a t fitting that goes to the boost gauge and to the intake vacuum line on the passenger side.
Wondering if I should run the boost gauge to the drivers side vacuum line to eliminate the t fitting . In other words , the valve vacuum line only runs to the intake vacuum on the passenger side vacuum line and the boost runs to the driver side vacuum line.
The system does not appear to be leaking. Car runs and idles properly.

kentmo280z · 03-28-2015, 03:57 PM

I have decided to run a dedicated line to the BOV and the gauge will have a dedicated line as well.
Will post with results ...

TTZ34 · 03-29-2015, 08:09 AM

where on the manifold are you pulling from?

kentmo280z · 03-29-2015, 08:49 AM

On the rear corners of the manifold per gtm instructions.

TTZ34 · 03-29-2015, 08:55 AM

Ok. What size line?

kentmo280z · 03-29-2015, 11:00 AM

Ok, have run 2 separate lines to the BOV & boost gauge. 7/32" vacuum lines to a T fittings that run to the rear intake / throttle body vacuum ports.
Going to drive the car and see how it goes.

kentmo280z · 03-29-2015, 12:08 PM

No luck, still fluttering. Actually I'm going back to the original setup where the gauge and bov
are connected to one vacuum line. With the new setup, my a/f gauge is showing a more lean reading

kentmo280z · 03-29-2015, 08:21 PM

Emailed Turbosmart AUS. They recommended a lesser stiff spring. Ordered it this eve.

ANMVQ · 03-30-2015, 02:22 PM

Was thinking that also. Let us know if that was it.

kentmo280z · 03-30-2015, 02:45 PM

Finally getting my tune Tuesday!!

03-28-2015, 03:07 PM	#1 (permalink)
kentmo280z Base Member Join Date: Sep 2014 Location: Akron , Ohio Posts: 199 Drives: '10 370Z Roadster Rep Power: 11	Blow off valve issue Curious on how those with a plumb back BOV are plumbing their vacuum lines. I am having an issue where the piston on the valve appears to be fluttering up and down during cruising ( makes an annoying noise), where my vacuum is between minus 20 ~ 0 on my gauge. I'm running a GTM stage 1 supercharger with a turbosmart 38mm plumb back valve. I have adjusted the cap both tight and loose and even swapped that valve with another. Same issue. I have the vacuum line running from the valve to a t fitting that goes to the boost gauge and to the intake vacuum line on the passenger side. Wondering if I should run the boost gauge to the drivers side vacuum line to eliminate the t fitting . In other words , the valve vacuum line only runs to the intake vacuum on the passenger side vacuum line and the boost runs to the driver side vacuum line. The system does not appear to be leaking. Car runs and idles properly. Last edited by kentmo280z; 03-28-2015 at 03:59 PM.

03-29-2015, 12:08 PM	#7 (permalink)
kentmo280z Base Member Join Date: Sep 2014 Location: Akron , Ohio Posts: 199 Drives: '10 370Z Roadster Rep Power: 11	No luck, still fluttering. Actually I'm going back to the original setup where the gauge and bov are connected to one vacuum line. With the new setup, my a/f gauge is showing a more lean reading Last edited by kentmo280z; 03-30-2015 at 02:48 PM.

03-30-2015, 02:22 PM	#9 (permalink)
ANMVQ A True Z Fanatic Join Date: Mar 2011 Location: Framingham MA Posts: 2,732 Drives: 2014 Q50 AWD Rep Power: 19	Was thinking that also. Let us know if that was it. __________________ 14 Q50 AWD, ARK, ECUTEK (SEB), Takda,

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03-28-2015, 03:57 PM	#2 (permalink)
kentmo280z Base Member Join Date: Sep 2014 Location: Akron , Ohio Posts: 199 Drives: '10 370Z Roadster Rep Power: 11	I have decided to run a dedicated line to the BOV and the gauge will have a dedicated line as well. Will post with results ...

03-29-2015, 08:09 AM	#3 (permalink)
TTZ34 Base Member Join Date: Jan 2015 Location: Aiken SC Posts: 27 Drives: 2011 370z Sport Rep Power: 10	where on the manifold are you pulling from?

03-29-2015, 08:49 AM	#4 (permalink)
kentmo280z Base Member Join Date: Sep 2014 Location: Akron , Ohio Posts: 199 Drives: '10 370Z Roadster Rep Power: 11	On the rear corners of the manifold per gtm instructions.

03-29-2015, 08:55 AM	#5 (permalink)
TTZ34 Base Member Join Date: Jan 2015 Location: Aiken SC Posts: 27 Drives: 2011 370z Sport Rep Power: 10	Ok. What size line?

03-29-2015, 11:00 AM	#6 (permalink)
kentmo280z Base Member Join Date: Sep 2014 Location: Akron , Ohio Posts: 199 Drives: '10 370Z Roadster Rep Power: 11	Ok, have run 2 separate lines to the BOV & boost gauge. 7/32" vacuum lines to a T fittings that run to the rear intake / throttle body vacuum ports. Going to drive the car and see how it goes.

03-29-2015, 08:21 PM	#8 (permalink)
kentmo280z Base Member Join Date: Sep 2014 Location: Akron , Ohio Posts: 199 Drives: '10 370Z Roadster Rep Power: 11	Emailed Turbosmart AUS. They recommended a lesser stiff spring. Ordered it this eve.

03-30-2015, 02:45 PM	#10 (permalink)
kentmo280z Base Member Join Date: Sep 2014 Location: Akron , Ohio Posts: 199 Drives: '10 370Z Roadster Rep Power: 11	Finally getting my tune Tuesday!!