Inconsistent boost vac hose prob?

[JohnP]

Hi guys,

Had my rx for 3 years, been fitted with blitz bov since i got it, changed the vac hose from BOV>Plenum today as I had some spare, and started to get inconsistent boost when burying the throttle..

yes, i\'m gonna try the obvious and put the old hose back on, however, shouldnt 3mm silicon do the job for a vac pipe? secondly, i used the new 3mm pipe to go from the 2nd nipple on the plenum, back to the boost guage.

the figures go crackers on the guage when it happens... +10psi > 0 > +10 > 0 and as a result the car feels lumpy.

anyone had anything similar?

[JohnP]

replaced plenum>BOV with 5mm, works fine.

dont use 3mm. it\'ll gay your car.

[Prof]

Yep - unless you get thick walled 3mm id hose, as the standard stuff gets sucked flat by vacuum far too easily.

[RXSpeedy]

4mm or 6mm is what ive read on various websites, someone used 3.5mm and was told dont go smaller or it will be restrictive.

[JohnP]

someone used 3.5mm and was told dont go smaller or it will be restrictive.

they were right...