Hey guys, Just wondering what would happen if you forced the VIAS actuator to stay open. Or should I say force the butterfly open which is actuated by the vias to stay open? Would there be any gains or losses?

 

zip tie or you can remove it permanently. I have mine zip tie'd as I have not had time to do the other way

 

ok, but are there any power gains? I have a second upper plenum and I have been thinking about just removing the butterfly completely, but if it isn't going to do anything its a big waste of time.

 

There would be losses, absolutely no gains.


http://forums.maxima.org/showpost.ph...40&postcount=6
Pay no attention to the lower squiggly green or blue curves.
Red and Blue lines = VIAS connected, VIAS not connected.



http://forums.maxima.org/showpost.ph...3&postcount=17

 

But isn't removing the valves part of the intake what SR20DEN modification to the manifold?

 

..


Unless you can prove my dynos wrong,

 

On a 5th Gen VQ35, here is good story for you:

http://forums.maxima.org/showthread.php?threadid=116808

On a 4th Gen VQ35, results are a bit different. Needless to say, results are very dependent on supporting modifications.

In my case:

Blue line: Stock with y-pipe and JWT ECU
Green: VIAS Open all the time
Red: VIAS Closed all the time

As you can tell, major difference, and my very own three stage VIAS. For optimal results, close from idle to 4000, open from 4000-5800, and close from 5800-7000.

 

Wouldnt you want it the other way Open from idle to 4000, closed 4000-5800, and then open from 5800-7000. It looks like the other way that you said is lower numbers.

 

No VTC's no care...

 

You don't need to force it to stay open. It's open by default and closes when vacuum is applied. If you want it to stay open just disconnect the vacuum hose from the actuator.

 

Theres only one single valve and a shelf between the upper and lower runners. I believe removing that shelf creates a plenum instead of separated sections therefore the gains are from there not from the actual VAIS removal. But then again it is a "secret" so to speak.... so I may only have it half right.

Can you elaborate on that, is that VTC related or something else?

 

I thought the butterfly was closed until around the 5k mark and then it opened up for more air flow. I was wondering what would happen if you had the full flow at under the 5k mark. So you are saying it is the other way around? That you have full flow until 5k at which the butterfly closes?

 

It's closed from 1800 - 3600 RPM.

LikeI said before no gains... hard to understand or you don't believe me?

 

I think you are confusing the VQ35 IM with the DE-K IM.

On this IM, the power valve is open up to 1800 rpm and again above 3600 rpm. It is closed between 1800 to 3600 rpm.

http://forums.maxima.org/showthread.php?t=496131

http://forums.maxima.org/showthread.php?t=488390

 

Deja vu, eh Puppetmaster?

 

ok, got it now. I didn't realize it was opened then closed then opened. I bought a second upper plenum so that I could port match and possibly ceramic coat and I noticed the power valve, but since it isn't hooked to vacuum it appears that it would stay closed until a significant vacuum occured, at which point it would seem to open. Thanks for the info.

 

This statement is as clear as mud.

What are you doing with the upper plenum? Port matching? Port matching to what? Did you mean extrude/honing?

If you are e/h then port maching the plenum wont do much, since you are making the plenum ports larger, therefore---> You will need to port match the lower IM and possibly even the heads.


Also, what will ceramic coating the plenum do The pleunum isn't subdued to extreme heat to the point where it would require any ceramic 'doings'. The only benfit would be smoother materiel, but that could be done by e/h, so in short, there wouldn't be any benfit, and of there is, please enligtnen me.

 

i am going to have headers installed and a custom b-pipe (with the extra o2 bungs) in the next few weeks. I want to ceramic coat the plenum on the outside for cosmetic reasons and the fact that it cools it down doesn't hurt. And yes I am planning on port matching the lower half as soon as the engine is stripped due to the fact that it is burning oil and the dealership is providing me with a new block under warranty. So when they strip it I will bring it to work, set it up on the mill and open up all the ports. And if I don't receive any gains from matching the ports I really don't care since it won't cost me anything to do it myself. But something tells me it will enhance the gains from the header installation, which will also cost me nothing because the nissan dealership I am going to has an awseome service manager. Why would I pay (what is it ?)700 + for extrude hone? I can polish everything on the inside myself at work....

 

Do you intend to flow test each port to make sure the flow is equal across all cylinders?

 

So true...

 

That's why he said it..