Mazda Rotary Club

General => General Technical => Anything Engine/Performance/Tuning related => Topic started by: joe 93 on May 12, 2007, 08:37:48 PM

Title: leaking boost
Post by: joe 93 on May 12, 2007, 08:37:48 PM
hi all have a question about  Vacuum it goes like this when i rev the car the dump valve starts to open and release boost this is while the car is at WOT not when you let off its like there\'s not enough Vacuum to hold the dump valve closed?any one encounter this any help would be good.Thanks.:god :god :god :god :god
Title: leaking boost
Post by: strange_days_uk on May 12, 2007, 08:40:20 PM
What dump valve you got ?  Is it adjustable can you tighten the spring pressure ?

Check the hoses are the right way round.  Small hose from uim is the vacuum hose should go to top of the bov.
Title: leaking boost
Post by: joe 93 on May 12, 2007, 08:46:07 PM
its a forged motorsport one its on the right way vac hose connected. its like there\'s not enough vac to keep it closed.?
Title: leaking boost
Post by: strange_days_uk on May 12, 2007, 08:48:55 PM
Check all hoses, and see if you can tighten the spring pressure..
Title: leaking boost
Post by: joe 93 on May 12, 2007, 08:53:27 PM
See this is the problem other than the hoses going to the dump valve which ones should i be looking at?thanks
Title: leaking boost
Post by: strange_days_uk on May 12, 2007, 08:54:43 PM
All pressured hoses.  Do you have a boost guage, what boost levels do you get ?

Assuming this is an FD on stock twins.
Title: leaking boost
Post by: joe 93 on May 12, 2007, 08:56:03 PM
forgot to say there is no way to tighten the spring pressure on it.
Title: leaking boost
Post by: joe 93 on May 12, 2007, 08:59:09 PM
not geting great boost on the guage and thought this might be part of the problem.
Title: leaking boost
Post by: strange_days_uk on May 12, 2007, 09:06:15 PM
Yes, most likely you have a pressure leak somewhere.  Check all the pressured hoses you can find for cracks, or lose fitting jubilee clamp etc...