DAVEB

iTrader: (133)

The Nissan parts catalog calls it an "Adapter, Intake", so it's not much help. The part # is 14040-2Y900.

spirilis

iTrader: (2)

I'm not sure if my VIAS is working properly... I'm aware of all the Mother of all VIAS threads, and I'm not sure if mine's really doing it. I don't feel much extra kick after 5K RPM. So at some point I may want to at least remove the vacuum tank/Power Valve assembly and inspect everything. Plus Cutlr7 said he noticed some weird stuff deposited on the front of the plenum one time at a meet... I might wanna check to see if anything's leaking.

I'm not doing it anytime soon, 'cause it sure does sound like a P.I.T.A. but sometime I should check it out...

spirilis

iTrader: (2)

Nice. Sounds useless to me

IceY2K1

iTrader: (3)

You know...that makes sense.

Looking at the Throttle Body, I felt it appeared to be made for more then just the Maxima and I'm not talking about only the I30. I felt this, since the TB mounting holes for the IAC valve has TWO opposite sets of holes to be "clocked" either direction PLUS on the back side, there are TWO predrilled holes(you can see in the pics above where the gasket loops around them).

This intake adapter, not only shields/forces the IACV bypass air, but it *COVERS* these two predrilled holes. They don't have threads, but why in the hell they are there, I don't know, besides mabye they're used on another intake manifold from another car.

I'm going to remove mine, since if it was an EGR or IACV "adapter", I'd be concerned about longterm effects. Honestly, the only drawback I can see is some slight turbulance from the bottom opening into the intake manifold area where the EGR port comes into. However, I'd say that's going to be a minimal loss compared to the restriction this thing makes.

IceY2K1

iTrader: (3)

Also, you know an EASY way to know if this makes a POSITIVE difference would be for someone with an Apexi S-AFC or boost/vacuum guage to remove it and see if the Air Flow % increases or Vacuum Hg decreases(increases more negative?).

sloppymax

iTrader: (8)

go to the black box and unplug the vias line. plug it up and run it over 5k to see if there is a difference. if there is no difference then something is wrong. on the box, unplug the one on the far left if you are cali spec and if you are fed then its the only vacuum coming from the box.

spirilis

iTrader: (2)

I see you don't know too much about the VIAS

Unplugging the left line shouldn't make a difference regardless. It is the FRESH AIR SUPPLY for the Power Valve for when the VIAS is turned OFF (<5200RPM). Removing it just changes the fresh air supply to the engine bay, rather than the intake resonator between the MAF and TB. Heck when I bought the car, it came with that hose disconnected for some odd reason.

I have manually activated the VIAS before by using a vacuum pump hooked up to that line, and I did notice some kind of difference, mainly a loss of low-end torque. I also notice the Power Valve actuator does move if I rev it up past 5200 RPM with no load on the engine.

However, I don't seem to feel the benefit in real WOT driving under load. I'm curious as to maybe whether the Vacuum Check Valve for the vacuum tank is sticking, thus the VIAS works in all situations except when I actually need it, with the engine under load and the vacuum at minimum. If the Vacuum Check Valve were to stick open, then the VIAS would turn on but very little vacuum would reach the Power Valve, thus making it not activate.

NewLoveI30

Is there a quick way to see if the VIAS is working? Is there really supposed to be a big difference after 5200RPM?

Galo

Alex...please post results & observations when u do this....I trust your butt dyno since u and I were dead nuts equal in our appreciation of the timing advance to 17 degrees way back over a year ago so by all means, keep us posted...

BTW, the TB diameter on our Maxes = 60mm, which is why a few months ago I was dreaming about installing the TB from the Pathfinder version of the same engine which was 70mm

Regime

iTrader: (2)

Ok gentlemen,
I spent the good part of this morning doing and testing (mostly testing) this mod.
First off, this is extremely easy to to. Took me all of 5 minutes to pull the TB off and remove the restrictor plate, this also included a bit of cleaning. You mileage may vary on this.

First off I tested the car to get a baseline with my G-tech. Now before I hear all sorts of rantings on how this is not an accurate testing instrument, let me just say that mine has never been more than 2hp off of my actual dyno figures, on ANY of my cars, and I do have quite a few.
I put down an autotragicly 186hp averaged 5 runs togather...before the mod.

So after removing the plate and checking for any leaks that I might be able to feel or hear, I did another 5 runs. within 15mins of the last runs. I got an average of 189hp.

My initial thoughts are that the intake growl is *slightly* louder, the revs come on more quickly, reving in neutral, and you can use less *slightly* pedal effort to get the car accelerating. Also my autotragic is a DOG off the line, but this definatly made an improvment there, the car is not bogging *as* much as it was.

*NOTE* some of this improvement could have been from cleaning the backside (I had recently cleaned the frontside) of the TB and the first 6 inches of the manifold.

Again your mileage may vary, this was just my experience this morning. I'll let you all know anything more that comes up including any change in my gas mileage, which I suspect will go up a bit, if I can just stay off the damn right pedal

sloppymax

iTrader: (8)

[QUOTE=spirilis]I see you don't know too much about the VIAS

put a little rubber cap on the end. this causes it to have no vacuum. i ran mine capped off and past 5200, it was a dog up top. then i reconnected the line from the box to the stock resonator and all the pull was back. diagnosis-vias not broken.

IceY2K1

iTrader: (3)

J/K...you must have me confused with someone else Galo, since I haven't advanced my timing.

I don't even trust my own butt dyno, however if it's as easy as Regime is saying, why not.

I'm planning to dyno in the near future, so I *MAY* try and see what happens on the dyno, however a small change like this probably won't show.

***We need someone with a boost/vacuum gauge to test this at idle and see what difference it makes.***

I was trying to come up with an adapter plate like the 4th gens use for the Pathy TB, however my fear is our ECU will freak out from the TPS sensor/TB diameter change.

I wonder how similar/disimilar the two are.

spirilis

iTrader: (2)

OBD-II Scantool reading the MAF reading wouldn't help too much would it? (it'll give a MAF reading, but the samplerate is rather slow so getting a consistent series of samples for direct comparison is difficult)

---

Nevermind, you're talking about idle. Either way a MAF reading may not give much, since the ECU is supposed to adjust the IACV to compensate so that engine RPMs stay within a certain amount, and I'd assume the MAF reading wouldn't change much if the ECU's doing its job.

What would a vacuum gauge on the intake plenum show, in the event that the restrictor plate (obligatory NASCAR reference) actually does restrict significantly? Would it even make that big of a difference at idle?

IceY2K1

iTrader: (3)

Good point~!

I'll have to think about this. I wonder if a voltmeter would measure the signal to the IACV stepper motor.

IceY2K1

iTrader: (3)

What if you help an RPM above idle?

That should work.

spirilis

iTrader: (2)

Ideally I'd want to see MAF reading comparisons under a certain amount of load, at a certain RPM...
That's why it's tricky and difficult. Maybe I could do it by driving the car, recording MAF reading, Calculated Load Value and RPM... probably Throttle Position too.

Because the problem is, if I maintain a condition identical in load and RPM after removing the restrictor, and am able to *maintain* it for a few seconds while the OBD-II scantool records data, I seriously doubt the MAF reading will be any different. What should be different is how much throttle it takes to achieve this... (right?)

IceY2K1

iTrader: (3)

Hmmmnnn.......

That last part might work.

IceY2K1

iTrader: (3)

The calculated load would go down and the MAF gm/sec or whatever would go up, however I'm not sure how consistent those are and I doubt a small change like this would be noticeable.

If I log those on my OBD scanner, I can plot them vs. each other in Excel.

twist

Just removed the adapter, here are some pics.

Regime

iTrader: (2)

Another interesting "bonus" for all the ricers out there....
this mod in conjuction with my Injen intake now "whistles" about 10x more than betore. I know alot of you ricers out there are spending big $$$ for the "turbo-spool up" whistler insert...here's your chance to have it for free

I think I will be chopping off the egr tube flush with the manifold tract very soon, as I *think* most of the sound is coming off that.

IceY2K1

iTrader: (3)

Auuuugh ****...I hope you're right.

I couldn't stand that whistling sound, so I put my stock airbox back on.

Hey, at least we know we're getting more air, right?

djPlayboy

i want to see some more pics and a good write up

Regime

iTrader: (2)

well on a good note, almost all the whistling is down under 3k which I am almost never at

spirilis

iTrader: (2)

Shoot, I wouldn't mind a little whistling, I'm using the stock airbox w/ K&N filter (no scoop though)... that sounds /<-r4d y0h

twist

djPlayboy, there is a writeup in my homepage, there are 2 instruction pics and there are pics of the adapter.

twist

Results of the adapter removed. From what i can tell the accelaration is a bit better. Dont know about the gas mileage, hard to keep off the right foot. But IMO i think its running a bit better.

irish44j

iTrader: (38)

we need to find out who the guy who designed the VQ was and give him a call .....among other questions would be the one that asks "if that plate is not helping anything, only hurting, why is it there..."

I'm as interested as any of you in this "mod" but am a bit apprehensive....I mean, why would they put the thing there if it didn't serve any 'positive' purpose....hey if removing it adds 3 hp Nissan could have claimed 225 hp not 222

On a related note, where does that extra supposed few HP come from on the AE?

Regime

iTrader: (2)

My car is an AE and I had it there.
I would guess it is to stop crud from the EGR and IACV systems from blowing back up the intake tract to the MAF. Also probably some sort of emissions thing to limit incoming airflow. I have seen all sorts of flow reducing equipment on all sorts of cars.
For example there is a reduction pipe on the early 90's 460's in the Ford F250's that when replaced with a larger pipe gains 10hp and 4ft/lb at the wheels.

MaximaVQ97

iTrader: (4)

i just "hacked" my EGR tube down about 1 1/2 inches!!! it took a little while, me and my g/fs brother did it, heres what i think of it ... right away my autotragic seemed to accelerate better!! although this could be due to the 57 degree weather outside.. i will take pictures tomarrow morning... and write a better folllow up

-Anthony

IceY2K1

iTrader: (3)

Cool....also HOW you did it please.

I'm SOOOoooo itching to do this...must wait till dyno...must wait till dyno.

Regime

iTrader: (2)

You'll be OK Ice, You'll survive. It isn't THAT impressive of a gain.
But then again, free HP is always good HP.
And you might want to get some GoldBond Powder for that itch.

IceY2K1

iTrader: (3)

I know it's NOT going to be dramatic , but I'd guess it would be similar to an UDP?

Anyways, it's NOT that I think 3hp is going to be noticeable, just that I want to rip it open and check it out. Any fear of that seal leaking or needing to be replaced?

You ready to stop by TS?

Regime

iTrader: (2)

I'd say that it is very similar to the UDP improvements.
The seal looked fine, then again I am not exactly sure how I could test this peice for leaks.

Anytime that TS is ready I am. Haven't heard anything about Larrio's though?

IceY2K1

iTrader: (3)

I'm pretty sure you'd have a stumbling idle/rough engine if it was leaking, but it's probably cheap so I could throw in a new one at the same time. Just being ****.

You got email.

Regime

iTrader: (2)

I would Highly doubt you will need a new gasket.

thanks for the email ice

ChromeSE5

iTrader: (3)

To be safe though, can i put that gasket maker stuff on the TB?

IceY2K1

iTrader: (3)

I don't see why not.

I'd just probably put the bead on the OUTside of the gasket on the IM side. The TB side is just flat.

Max_Gator

What - nobody reads my VIAS threads????

http://forums.maxima.org/showthread....5&pagenumber=4

Anyway . . . yes there is a VERY big difference - say 25 whp!

FYI, even if you take off the intake manifold you can't see the variable runners because they are inside the composite manifold. When Nissan replaced mine, I tried to see inside but couldn't. They wouldn't give me the manifold to cut open to see what was wrong inside.

To test to see if your vias APPEARS to be working, you need to look under the black box. There you will see an L shaped piece of metal sticking out. That is the actuator and runs through the manifold. When the VIAS is activated, it will flip up (or down I don't recall). To test, position yourself so you can see that piece and then just rev the engine with the throttle cable in the engine bay until it flips - or until you hit fuel cut. If it doen't flip, it doesn't work.

Even if it flips the VIAS may not be working - but that is fairly rare.

You can disable the vias very easily for comparison while driving. Find the black box and look for a connector below it. If you detach this connector, the VIAS will not actuate. You can test it by doing the above procedure. This is in large part how I proved to Nissan my VIAS was broken even though it appeared to be working.

In other words, there is a switch you can throw on your car to turn off about 25 hp!

Max_Gator

This sounds like an interesting mod!

Not sure I understand enough about how the IACV works to add anything to the discussion but . . . is it possible to test at WOT? Would that take the IACV out of the equation and just allow you to determine if more air is flowing past the MAF?

IceY2K1

iTrader: (3)

Max_Gator,

I thought someone already said the Mother of all VIAS threads, I assumed yours.

As to the IACV, I'm just grabbing at straws here. I know the MAF voltage would change, however the ECU will compensate with the IACV opening less. Anything other then idle would get around that, but how do you get consistent readings is the problem. It needs to be dyno'd, but the gain is probably so small unless you did before/after/before and got consistent differences it would just look like dyno variation or heating up of the tires/fluids. I'm not saying it wouldn't show, it's just hard unless you know how to eliminate as many variables as possible.

*cough*you*cough*