Mazda Rotary Club

General => General Technical => Anything Engine/Performance/Tuning related => Topic started by: suba on August 17, 2009, 10:24:10 AM

Title: BNR stage 3 turbos - boost pattern issues
Post by: suba on August 17, 2009, 10:24:10 AM
I\'ve recently got a set of these on my car, with the boost being controlled by a Greddy Profec B spec 2 boost controller, and fuelling / ignition controlled by apexi Power FC.  The turbos are setup to run sequentially.

The primary turbo only boosts to 0.6 bar, and the secondary to 1 bar - obviously I want the primary to be boosting harder before the cross-over.

Any ideas as to what could be causing this?:confused:
Title: BNR stage 3 turbos - boost pattern issues
Post by: AtomicRex on August 17, 2009, 10:36:46 AM
Could be the porting on the wastegate like adrians.  If it isnt seating correctly then it will be bleeding off air.
Title: BNR stage 3 turbos - boost pattern issues
Post by: marco on August 17, 2009, 10:58:40 AM
nah i doubt it, the porting was due to me having too much to drink whilst having a dremel in my hand. how is the boost being controlled? if the boost controlled is only plumbed into the wastegate actuator then the turbo precontrol solenoid will still be controleld by the apexi, look at what that is set to.
Title: BNR stage 3 turbos - boost pattern issues
Post by: suba on August 17, 2009, 11:12:44 AM
Thanks - a couple of things to look at then.  Any more ideas?:Thumbs-up
Title: BNR stage 3 turbos - boost pattern issues
Post by: suba on August 18, 2009, 09:41:34 AM
I spoke to Bryan at BNR over in the US yesterday evening.  He thinks that this could be caused by a leaking CRV on the primary (which I dont think is likely)  or that I need a restrictor pill in one of the vacuum lines....:confused:
Title: BNR stage 3 turbos - boost pattern issues
Post by: suba on August 30, 2009, 09:21:42 AM
This has now been sorted - a 1mm restrictor in the vacuum line for the pre-control actuator.  It\'s seems like the transition to the secondary is taking a bit longer (400 rpm) but it\'s not affecting the power curve too much.:Thumbs-up