Ive just converted to non-sequential and all is sweet EXCEPT I dont seem to have enough vacume to open the new BOV properly.

The vacume line is as short as I can get it and its a good seal to the intake manifold.

The BOV is an australian GFB unit and Im told its a standard spring, there are no softer springs available from them. The valve is currently set to its softest setting and only just winks open.



Is there a way to get more vacume to the valve...I'm eyeing up the brake vacume line as a possible solution??? Or perhaps sourcing a softer universal type spring to stick in it??



Any ideas??

Wait a tic... Your sig says single, and you say non-seq... Which is it? That way we can help. It's easy to cunfuse most of us.... Well, me anyway. https://www.nopistons.com/forums/pub...IR#>/smile.png

My apologies. Its a single turbo. The standard twins are now sitting where they belong on my garage floor behind the lawnmower.

I had figured non-seq meant the same as going single.....but after your post I did some more reading and well yeah. Its not the same, doh.

ahhhh....well then....



could be a vacuum line, as well as the connection itself. where/how is the BOV mounted?



and, is it new or old?

The connections are really good. I've checked them several times, nothing is leaking or kinked.



I am using the same vac line nipple from the inlet manifold that the factory BOV use, but with a new tube of the same dimensions (supplied with new BOV).



The BOV itself is hose mounted with a new hose clamp into a ~30mm dia stainless tube welded into the plumbing between the turbo and intercooler...may not be the best spot for it but it was..er..convenient. I had been using one of the factory BOVs as a temp measure for a day till I got the new one. It was opening ok...just seemed a tad to small for the job.



Yes the BOV is brand new....and very shiny.





I have since heard that rotors are a bit like 2 strokes and produce less vac than a 4 stroke engine....may be this is the cause?? What sort of aftermarket valve do most ppl use after going to a single turbo?

what kind of BOV are you using? that will tell us more...

I think I see the problem.. j/k https://www.nopistons.com/forums/pub...DIR#>/wink.png https://www.nopistons.com/forums/pub...IR#>/bigok.gif



It may just be a defective unit. I think the vacum location you picked (IM) is as good as any.

Technical Specifications



GFB Mach 1 (BOV 1)

Venting: Single trumpet atmosphere venting.

Inlet area: 506 mm2

Outlet area: 255 mm2

Flow capacity: 54.5 cfm (at 20.5 inches of water)

Piston seal/cushioning: Yes, tapered acetal.

Quad-ring piston seal: No.

Total length: 125 mm

Materials: 6262-T6 aluminium except the piston (brass) and seat (acetal).

Fitting method: Fits 35 mm I.D. rubber hose or 1" O.D. steel/alloy pipe. A short length of 1" pipe is included in the kit for weld on applications.

Spring adjustment: Yes, via the vacuum nipple.

Maximus boost: Factory tested to 110 psi.



I fitted the unit to my mates GTiR pulsar and it worked fine so the unit is ok I think.

However it seems I did nothing stupid installing it, there just aint enough vacume to open the bitch so I'm gonna take it back and swap for an Apex unit.