Vacuum and Boost Line Plumbing on Turbos

[horndog]

Got this pic today off the guys on turbobikes.org I had my IAP sensor plugged into one throttle body and the pulsing vacuum was making the ECU bounce around the idle map making it lean rich lean rich and so on. The IAP needs an equalised vacuum from all throttle bodies. Yet another lesson learnt for me.

If your building your own turbo kit, this will help. The x's are check valves, only vacuum to the IAP. Only boost to the FMU but it must come from the throttle body.

I was also advised to run 2 check valves on the IAP as the boost can damage the valve if you only run one.

Happy to be corrected by anyone if they see a flaw
   

[Matturbo]

Got this pic today off the guys on turbobikes.org I had my IAP sensor plugged into one throttle body and the pulsing vacuum was making the ECU bounce around the idle map making it lean rich lean rich and so on. The IAP needs an equalised vacuum from all throttle bodies. Yet another lesson learnt for me.

If your building your own turbo kit, this will help. The x's are check valves, only vacuum to the IAP and BOV. Only boost to the FMU but it must come from the throttle body.

Happy to be corrected by anyone if they see a flaw

Nice diagram but I think the BOV see's both??? Mine does and i run it off 2 throttle bodies, please correct me if i'm wrong. But i'm not using enough boost to set it off YET.

[Maj]

BOV is opened by vacuum and held closed by pressure,, decellerating where you have lots of vac or gearshifting where there is vac on the diaphram and pressure from the plenum on the valve will open it too(that one is your typical bov noise) It can be made respond quicker by opening up the nipples on the throttlebody or using more of them..

[horndog]

Nice diagram but I think the BOV see's both??? Mine does and i run it off 2 throttle bodies, please correct me if i'm wrong. But i'm not using enough boost to set it off YET.

Thanks Matt good pickup. I have ammended the original post to avoid confusion.