I second RAYD's comments. If you plan to use full VTA then you need to program your ECU so that on throttle lift-off it initiates a fuel cut so you don't send fuel to the engine that is unmatched to its required air and thereby rinse the lube off your cylinder walls with unburnt fuel, get backfires and soot up your cats. I'm sure I covered this one before. If you don't have an ECU that permits such programming, then stay out of 100% VTA territory.
That bottle cap arrangement sounds very risky too, if some part of your contrived blanking plug lets go then
(1) - you will suck unfiltered air that is not measured by the MAF and therefore run dangerously lean and/or
(2) - the bits will head straight down your bypass hose to the TIP and into your turbo.
RULE 1: If you don't really understand what is happening, or likely to happen and why, then don't do it UNTIL you have researched it.
As an afterthought, the possibility exists that you may not be getting backfires because your bypass blanking plug is already sucking air and thereby compensating for the richness. This does not mean that all is well.
Last edited by Doug_MPS6; 14-10-2011 at 11:34 AM.
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