hi guys ive been thinking this for a while now, bear with with though ok then, so far we think that fitting a new induction kit on a tt gives a much better airflow through the system, but by doing this decreases the vacum 2 the turbo actuators and the recuirc valves due to the extra air flow, this in turn i think is causing the recuirc valve not to close properly????

 

so bearing that in mind if i fit boost jets in the recuirc valve signal pipe ( signal pipe i mean the pipe going into the top of the valve that makes it open and close bout 6mm i think ) would the increase of vacum due to the boost jets cure the problem or am i going to make a huge balls up by tallking ball@ks hope this makes sense guys any advice please cheers!!!

??????????? wow quite a theory there my friend! nice to see someone putting some idea`s together but checking them out before implimenting them.

 

Right as I understand it you feel the addition of a free flow air filters may be responsible for recirc problems due to reduced vaccuum pressure available to close the recircs (and act on the turbo actuators) and have concluded that fitting reducing jets to the recirc vacuum line will increase the closure pressure on the recirc diaphram.

 

 

First it will help to understand how the turbo actuator and the recircs work.

 

The turbo actuators have springs in them to hold the waste gate closed as + boost develops eventually the spring rate keeping the waste gates closed is overtaken by the + boost pressure this in turn opens the waste gates and thus boost maximum boost levels are maintained, boost jets reduce the action of the + boost and so delay the actuators action end hence boost levels are raised.At no point does VACUUM enter the equation with the turbo actuators although due to a misnomer they are called vacuum lines.

 

On to the recircs they too have springs in them keeping them CLOSED and hence No recirc action or dumping off boost into the other side of the intercoolers.As - vacuum is produces after a sudden closing of the throttle in the inlet manifold this is used to open the circs to prevent turbo stalling due to excess back pressure, this is required as we know at this point the wastegates will be closed so a release is reqired when the throttle plates are shut.

Reducing the vacuum pipe size by using 6mm jets will just delay the recirc opening and could cause damage due to over pressurisation(although unlikely)

 

So as you can see Do Not fit jets in the recirc vacuum pipes it will not work as you thought.Also the removal of the standard air box means the recircs actually dump to atmosphere and strictly stop becaoming recircs and more like dump valves and hence a some associated odd noises

Recent experience has shown me recircs springs do go weak over time and can leak slightly but this is due to wear and tear not the air filters, it is most likely the case that many zeds with standard air boxe`s have recircs with weak springs but as they are still recircing rather than dumping it is wholey less noticable.

 

Hope that helps

 

Jeff TT

 

Damn I wish I was as clever as either of you two. Doesn't mean a thing to me but it sounds really clever.

Removing the stock airbox will not change the function of the re-circs The recircs dump the air back into the intake AFTER the MAS. This is essential as the whole idea of recircs is that the air measured by the MAS stays in the system...

 

Fastredz - I came up with this same idea about the recircs honking a few days ago http://www.300zx.co.uk/forums/ubbforum/Forum6/HTML/000973.html see

 

Of course the goose honk may already be there with the stock airbox - the less restrictive filter will not deaden the sound as much...

 

If you really wanted I suppose you could try fitting a larger spring in the recirc to push it shut harder BUT then it may not open at the correct point so it's at your own risk.... Just fit BOVs and blank the recircs

 

CheerZ,

 

Andy

thats why im buying bovs m8!!!

cheers guys loads of help there fellas lucky i didnt boost the recuircs or big trouble ahead, and so my next question where can i get some bov's that r quite cheep and cheerfull cheers guys.

apexi m8

Originally posted by jaylox:

apexi m8

 

That's what i have in mind. If you find a good deal on the Apexi's let me know.

Cheers

Ian

Removing the stock airbox will not change the function of the re-circs The recircs dump the air back into the intake AFTER the MAS. This is essential as the whole idea of recircs is that the air measured by the MAS stays in the system...

 

Andy the recircs dump into the inlet tract to the original air box, if this is removed the recircs are effectively dumping to atmosphere.The air mass meter does not need to know about this "lost" air as the throttles are closed at this point

 

Jeff TT

jeff is it possible to clean the MASS,or should i buy a new 1( i read somewhere that its easy to break?),

mine is covered in oil and i dont no if this is good or bad but when i asked a guy in a local performance shop he said just clean it with carb cleaner

hope im on about the right place(name?)its the black box near the cone filter i have?

the small wire inside?looks delicate

thanks jay

Originally posted by Jeff TT:

Andy the recircs dump into the inlet tract to the original air box, if this is removed the recircs are effectively dumping to atmosphere.The air mass meter does not need to know about this "lost" air as the throttles are closed at this point

 

Jeff TT

 

 

Jeff,

Not trying to cause arguments here but I'm with Andy on this one. The schematic clearly shows the recirc valves venting the opposite side of the MAF to the air filter. i.e. the already measured air is returned after the MAS, otherwise the air/fuel ratio will be incorrect next time the throttle is opened. This bit is probably irrelevent actually, because the fuel is probably sloshing around the cylinder or spat down the exhaust by then.

 

http://www.300zx.co.uk/tech/manual/manual/efec/009.gif

 

so thats why im getting shit mileage for my petrol.

 

Mmm will return with evidence very soon.

Jeff (god hope I am right now ! !)

Yup Duffers and Pingram are rite !

 

When you have BOV's you will run rich as the MAS has registered air that has now been blow off up some old bats Skirt !

 

Hense air that has already passed thru the MAS - if you vented it back in before the MAS that is when you would have trouble ....

 

Still im sure you will agree that running rich for a very small ammount of time is not the end of the world !

 

 

 

------------------

Z ya

 

Nico91TT

 

 

God is coming ...and he dont have stock turbos . . .

I bow to the might of Nico, seems after a relook I f???ed up see told ya I need spec`s!!! Andy D & Andy P your right!

 

Jeff TT

you guys are putting me off buying bovs,

ive had a look at the hks site and they do a recirc valve thats made for increased boost.do you guys recon that this could sort out our goose honk sound then (cheaper 2 than buying bovs only 150 for a pair)

bovs dont sound the best solution to zeds as the recircs sound a much better idea!