VVEL Question on Intake Manifold Pressure

SonicVQ · 01-08-2016, 06:34 PM

Thanks for the info. After some more searching I found this:

"The engine's speed and output is largely managed by ECU control of the intake valves, not the throttle bodies. By not having the restriction of the throttle blade at partial throttle, fuel wasting pumping loss is reduced.

The engine does have dual drive by wire throttle bodies but they are used only for brake booster vacuum control and quick acting modulation for traction control. Otherwise the throttles are wide open most of the time."

(source: ***************************************/tabid/57/articleType/ArticleView/articleId/14/PageID/62/Nissan-370Z-Review-Engine-VQ37VHR.aspx)
interesting, can't link to own site...
Try the370 dot com /MagazineArticles/tabid/57/articleType/ArticleView/articleId/14/PageID/62/Nissan-370Z-Review-Engine-VQ37VHR.aspx

I guess the MAP PID is being modified by the OBD-2 output to a "expected" value and not actual. If I am 20% throttle, constant speed, there should be none to little intake manifold vacuum - but the MAP PID shows ~15" vacuum.

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
[FOR SALE] (BNIB) OEM Intake Manifold Gaskets///Exhaust Manifold Gaskets	BlkNismo	Parts for sale (Private Classifieds)	19	08-13-2016 12:01 PM
selling used stillen G3 intake.Motordyne M370 Intake Manifold	01206	Canada	4	04-14-2016 01:31 AM
VVEL question	Wilson2608	Engine & Drivetrain	0	11-26-2015 07:15 PM
Why is intake manifold pressure and exhaust temperature important?	Arrvaxx	Engine & Drivetrain	9	09-07-2013 02:18 PM
VVEL Only on Intake Valves?	drisko	Engine & Drivetrain	14	09-12-2011 07:35 PM

01-08-2016, 06:34 PM	#4 (permalink)
SonicVQ Base Member Join Date: Jan 2016 Location: Ontario Posts: 232 Drives: G37 Sport Rep Power: 6722	Thanks for the info. After some more searching I found this: "The engine's speed and output is largely managed by ECU control of the intake valves, not the throttle bodies. By not having the restriction of the throttle blade at partial throttle, fuel wasting pumping loss is reduced. The engine does have dual drive by wire throttle bodies but they are used only for brake booster vacuum control and quick acting modulation for traction control. Otherwise the throttles are wide open most of the time." (source: ***************************************/tabid/57/articleType/ArticleView/articleId/14/PageID/62/Nissan-370Z-Review-Engine-VQ37VHR.aspx) interesting, can't link to own site... Try the370 dot com /MagazineArticles/tabid/57/articleType/ArticleView/articleId/14/PageID/62/Nissan-370Z-Review-Engine-VQ37VHR.aspx I guess the MAP PID is being modified by the OBD-2 output to a "expected" value and not actual. If I am 20% throttle, constant speed, there should be none to little intake manifold vacuum - but the MAP PID shows ~15" vacuum.