ok, iam getting ready to get a costom intake manifold that will replace the dynamic chamber. but I have a few questions first. There are a crap load of vaccume lines going everywhere. I need to get rid of any of them that connect to the dynamic chamber. personaly, I would like to get rid of all that vaccume hose lines that go everywhere on the driverside of the engine bay. anyway, on to my questions:

1. The vaccume spider that conncets onto all of the oil injector nozzels. is this thing really needed? if there were not any vaccume hoses on top of the oil injector nozzles would oil still get into the engine? so can i ditch the vacume spider and cap off the oil nozzels or not?

2. there are two vaccume hoses that conncet on the back of the dynamic chamber that conncet to the purge valve. what does the purge valve do? can I get rid of it?

3. the vaccume hose thats on the pressure regualtor on the secondary fuel rail. whats the vaccume hoses purpouse there? can i get rid of it??

bascily what can i get rid off?

car already has all of this removed: a/c, p/s, bac, bypass air contol valve, air pump, cold start, acv, charcoal canister.

the car has the TB mod done, so all the crap that was on the TB is gone. has RB headers, no cats (had a pipe to conncet the headers to the cat back made). apex N1 cat back. griffin rad, efan, 6 ports wired open (soon to be removed). the egr vavle will get ditched as soon as the gaskets for the intake mandifolds come.

i think thats about it. any suggestions or coments welcome!!

Jordon

 

oh, and i completly forgot to say its an 86gxl

 

what sort of custom intake are you going to use, the Dynamic chamber is worth about 10 HP to 12 HP so I am curious about why you are moding it

 

OK, item number 1. Yes, without the vacuum spider on it oil would still get into the engine. Lots and lots of it. The engine will suck oil worse than a boinger with completely shot intake valve guides. You see, the purpose of this line is to equalize pressure (in this case, vacuum, actually) on both sides of the oil injector, so only the oil metered is injected. If atmospheric pressure is on one side of the injector while 20 inches of vacuum is on the other, you have just created a mini vacuum cleaner. If you do this, Always carry a coupla' spare quarts of oil and a spare set of spark plugs!

Item number 2. The purge valve is Mazda's version of the PCV valve found on Boingers. Yes, you can remove it, but make sure the hose going from the oil fill tube to the Inlet Duct via a check valve is clear, otherwise you will find yourself with the oil dipstick mysteriously missing and lots of oil all over the driver's side of the engine!

Item number 3. This is the fuel injection equivalent of a power valve on a carb. When engine vacuum is high (like at idle and cruising), you have 28 psi pressure. At very low engine vacuum, you have 39 psi pressure (like when ya floor it!). Lower pressure, less fuel. If you remove the vacuum line, your gonna have your power valve "on" all the time. You'll be visiting the gas pump a lot more, and you may want to keep that spare set of plugs I mentioned earlier handy. Of course, you can correct all that with an APEXI FC or a Haltech ECU. Methinks the hose is a little cheaper, though....

Irv, Keith's dad

 

thank you sir!! you have helped me greatly

 

You seem to know a lot about how the vaccum lines and oil nipples work. Today I tested my oil nipples and one of them passes air both ways. My question is would this cause more oil to be sucked into the intake manifold. Could these malfunctioning oil nipples be causing my smoking? The smoke gets worse when at higher rpms when the vacuum pressure drops a bit. If you have any advice of things I should do while my manifold is off please go ahead. I want the smoking to stop.

Thanks in advace, Ed

 

can anyone answer these questions?

 

Hey Ed,
Maybe this could be a problem. In theory, there is an overlap between exhaust and intake ports being open, which would cause a vacuum leak. When this vacuum leak condition occurs, it may suck enough oil to cause smoking, but I do not know if this is indeed true in practice. I have not had an injector fail that way yet.

Irv, Keith's dad

 

Well I put everything back together and changing the oil nipple helped. Now I only smoke at around 5000 rpm's (big smoke cloud though). My mechanic friend thinks that maybe the vaccum pressure is low on the top side of the intake manifold which is allowing oil to be sucked into the bottom side of the mainfold.