Opti Venting With MAF on Pressure Side?

Hey guys,

I did search the board first and came up with most people suggesting to run the fresh-air side of the opti to the intake of the blower/turbo. The problem that I see is that I run the MAF on the pressure side. So if vacuum is placed before the MAF, the motor is actually sucking un-metered air. Essentially a vacuum leak. Is this correct?

How do the FI people run the 'fresh air' side of the opti?


Thanks!
-Scott.

I am running mine between the filter and the inlet side of the compressor without any problems.
Chas

Chas,

Do you run the hose before of after the MAF?

Thanks,
Scott.

Scott, run the hose on the suck side of the turbo... between the air filter and the MAF (assume the MAF is on the suck side). You want the MAF to see the air.

Hey Jon,

My MAF is on the pressure side so I can only run the hose pre-MAF (inlet side). I guess maybe you could run the hose post MAF on the pressure side with a oneway valve??

Just so I'm clear, if your pulling vacuum for something it has to be with metered air (after MAF). Please confirm.


Thanks again,
Scott.

Hey Jon,

My MAF is on the pressure side so I can only run the hose pre-MAF (inlet side). I guess maybe you could run the hose post MAF on the pressure side with a oneway valve??

Just so I'm clear, if your pulling vacuum for something it has to be with metered air (after MAF). Please confirm.


Thanks again,
Scott.


Scott, there is some confusion.

Lets break it down like this... any air that you want the ECU to recognize needs to go in before the MAF.

Now, on a boosted motor, the only way to have vacuum all the time (like for the opti) is to route it to the inlet side of the compressor (because its always sucking in).

This also lets the MAf recognize the air being dumped in because the MAF is way downstream fro the vacuum line.

Ahh, I think I'm with you now. I believe you are saying to use the turbo inlet as the vacuum source/signal.

Currently I am using the engine manifold as the signal and it is sucking in unmetered air = bad.

See image of current and proposed:

http://i296.photobucket.com/albums/mm187/boosted-lt1/Opti.jpg

-Scott.

Ahh, I think I'm with you now. I believe you are saying to use the turbo inlet as the vacuum source/signal.

Currently I am using the engine manifold as the signal and it is sucking in unmetered air = bad.

See image of current and proposed:

http://i296.photobucket.com/albums/mm187/boosted-lt1/Opti.jpg

-Scott.


You got it bro! The proposed drawing is what you want!

Pictures are worth a thousands words ;)

I guess I could run a small air filter at the end of line #1 shown. I'm thinking a small foam filter used on an RC nitro engine.


Thanks!!

-Scott.