Im working on gutting my 00VI, and just doing a bit of research and trying to figure out exactly what can and should be done. I took the VIAS and the other end cap off, stuck a flash light in, and took some pics. As of now, I am baffled as to actually how this thing works. From looking at the outside I had my ideas about what actually went on inside the 00VI, but now I am just flat confused.







The third picture explains it best. The "tube" is where the power rod sits. The squares on the left are the ports that go into the LIM. The "roof" of the tube is where the upper runners go, meaning, the runners from the outside of the 00VI go "over" the power rod. The area to the right is called the surge tank per the FSM. Picture 2 is a shot of the inside of the surge tank.From what I can tell, it has no intakes, meaning it simply stores air until its needed (power rod opens). On the right, there is that "wall" where the runners come out the top of; it looks like that wall simply separates the surge tank and the runners from the TB.

Two things I am thinking at the moment:

1) If you remove the power rod, you're losing top end. Why? Because as I said before, it looks like the surge tank only holds air, with the power rod out, you hit the gas, the surge tank air gets used up fast, and it doesnt get "replenished" until you let off again.

2) If you knock out the "wall" between the surge tank and the runners, you could essentially have a dual runner design.


Someone correct me if I am wrong on this, please.

 

Subscribed.

 

actually, i believe you have that backwards. the long runners give you better low end. the power rod kind of bypasses the runners and allows a larger mass of air to be, more or less, dumped into the LIM. by removing the power rod, your low end will suffer greatly. at least, that's how i understand it.

PS: neither the 00vi or the MEVI have actual dual runners, just that valve to unrestrict air at higher RPMs.

EDIT: besides, why would you want to gut an 00vi???

 

Yes, longer runners give you more power at low rpms, because of the large amount of air ready to be sucked in at a rapid rate. The same is done here. That surge tank is essentially the "large amount of air ready to be sucked in at a rapid rate". With the rod in, that air gets sucked in at 5K rpms, then once that "reserve" is gone, its gone. With the rod out, that air gets sucked in at 1500 rpms, and once its gone, its gone. Then, you dont have that "reserve" above 5K rpms.

Yes, I am aware that neither of them have dual runners. However the potential is here, possibly, to have a dual runner setup.

Why? More power.

 

I know someone has done this. IIRC the low end was $hitty. Maybe krrz350 or krismax i cant remeber

 

Dandymax.

 

Referring to the removing of the power rod, or gutting the 00VI? Dan removed the power rod, I think, didnt know he gutted any more than that.

 

That's cuz he didn't. He just removed the rod.

 

Oh ok I thought it was him.

 

Arent there old dynos showing that top end HP is gained with no power rod? I know for boosted guys no power rod = more peak and more power towards redline, and also as everyone knows removing the rod hurts low/mid range power, I dont think its worth it. Now if rev limiter was extended then thats another story and will probably be better with no rod.

 

True especially if you're cammed and running a relatively aggressive tune with headers/exhaust/etc...

 

There's no "loss" or "replenishment" of air. It doesn't operate on some kind of air storage principle. Airflow within the intake manifold is never static. That chamber is used to shorten the distance the pressure wave coming off the intake valve has to travel as it heads back to the intake port. When it's timed just right the returning wave can shove extra air through the port. Dynamic supercharging.

 

Okay, I got the first part, and I think I grasp the second part. So what youre saying is, the valve doesnt actually "open up" another set of runners (which, for some reason is what I thought it did, dont ask me why), but it essentially keeps the pressure wave created by the valves closing from affecting the movement/velocity of the airflow through the runners, correct?

Now; obviously its all theoretical, but if that wall separating the "surge tank" and the runners was removed, and the rod was kept in (and activated), would there be possible yields? Or even if the rod was removed. I guess, would a "dual runner" design produce any benefits over the existing 00VI?

 

you've kinda got it but you're still off a little. here's why:

long runners give you better low end because they allow an increase in air velocity. when you're in the lower RPM range there is a vacuum pulling air through the runners.

now when you get higher in the RPM range, even though the air is moving quickly through the runners, it's still not enough to satisfy the engines needs and is essentially choking the motor. this is why the USIM drops off around 5600 RPM.

the 00vi (and MEVI) on the other hand have valves that open at a certain RPM and bypass about half of the runner;s length. this allows the engine to suck in as much air as it needs because the now half length runners are not as restrictive.

basic rule, long runners = good low end, short runners = good high end.

 

don't worry about that, it's a common mistake since the 00VI/MEVI are referred to as Variable Intakes even though they are not a true dual runner design.

 

The runners aren't bypassed because the distance from the plenum to the intake port remains the same. The air has to come from somewhere. Dynamic supercharging is the means.

 

Any intake manifold that alters its geometry to optimize volumetric efficiency at different engine speeds can be considered a "VI".

 

perhaps bypass was the wrong word. but the power rod valves do open up an entirely new path for air to travel, correct? and in that way allow a larger mass of air to be delivered to the intake ports than would otherwise be possible?

 

granted. but when i imagine a VI system, i imagine a dual runner setup not the 00vi design. i would venture that this is the case for most people.

but it's better that you correct me with more precise detailing than i inadvertently misinform him.

 

No sir. What you described would be a dual runner manifold. The path in the 00VI/MEVI remains the same; the surge tank has no inlet, only an outlet. In other words, air enters and exits the surge tank at the same point. The surge tank gives air that the engine can't use (bounced off the intake valve) a much shorter distance to travel before it is bounced back toward the intake valve to help shove in air that is already traveling down the runners (that travel over the tank). This effect is RPM dependent and varying the distance from the intake valve to the surge tank determines the RPM range where it works. Intake valve closing ABDC also affects this.

 

Wow that makes sense. Lets say the 00vi was converted to a dual runner design, by removing the wall from the surge tank and runners. Obviously, the dynamic supercharging would lose its effect, as there really is nothing for the pressure wave to bounce off of. But would the increase in air flow through the "lower runner" (what used to be the surge tank) compensate for the loss?

 

with this information, and another look at my 00vi, i actually understand exactly how it works now. totally blew away all my preconceptions but i get it, lol.

i too am now wondering the performance/efficiency differences of a dual runner design vs the dynamic supercharging effect created by the 00vi.

nismology, if the 00vi has advantage over dual runners, would that have something to do with engine displacement or because the vq design uses a relatively short stroke?

 

Same with NA, Dan removed his because he races his car and with the extended limiter and also he launched at high rpms. This mod I will play with, but being auto, not racing as much and a daily driver may hurt. But overall I could potentially re-gain the lost low-end with other mods. It's just something for me to play around with.

 

Only thing I would do to the 00vi is make those square ports bigger