Tom400CFI

It amazes me how confident you act for knowing so little.

The factory vented opti has an orifice between the manifold and the opti that massively restricts air flow into the intake. This orifice is way, WAY smaller than the hose that vents air from the intake snorkel to the Opti...so, the opti never actually has a measurable amount of "vacuum" in it. There is no "Suction", "sucking" water in, Cardo.

See that blue thing?





Get your facts right, learn some things, before you post horse ****. Could you do that for the forum please? Thanks.


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Tom400CFI

Hey Matt...at least he's consistent from thread to thread...topic to topic. There is only one troll in this thread. It's not Matt...It's not me. Not sure who the troll is? Easy; who posts the most fact, and the most help? Hint: It ain't Cardo.

Hey Cardo? Why don't you use your Smog pump for an "opti blower"? Isn't the fish pump 120v AC? IDK....but the smog pump is already in the car.

fake

I do not get it would GM design **** like this and sell me a $40,000 door stop? What is the best way to go when replacing the Opti?

cardo0

No suction! What an idiot! No suction means no flow If there was no suction then there would be no reason connect to the intake manifold. Your imagination engineering shows again you can't understand how a negative pressure system works let alone a positive pressure system.
Yes that orifice restriction will greatly reduce flow and negative pressure within the opti but claiming an unmeasurable amount of vacuum is stupidity. You share the same problem as your Motor Mouth confident that talks of a vacuum pump somewhere insisting soneone test for vacuum to verify his claims the opti has no restriction to the flow. He needs psychological help to. Or maybe physiological help also with his head stuck in his own restriction. Oh I think he proves he's the dump azz he's talking about. Claims he's an aknowledged expert too. What a kook!

MatthewMiller

If there's measurable negative pressure inside the opti as you claim, then measure it! Again, please prove me wrong. You're the one asserting the claim. Instead of calling people names and generally behaving like an ***, just prove your point.

ETA: You are stating that there must be negative pressure in the opti in order for air to flow through it: "No suction means no flow." Please note that neither Tom nor I said there is no suction anywhere. There is suction in the intake manifold and the port that the opti hose connects to. I'm sure there is suction up to the blue orifice he pointed out to you. But there is no suction in the opti itself. You're simply wrong about that. The only condition needed to move air through the opti is a pressure differential between the inside of the opti and some place downstream. The opti needs to have a higher absolute pressure than the vacuum source. As a matter of fact, the higher the pressure in the opti, the greater the rate of airflow will be! To the point, if you could create positive pressure in the opti (i.e. higher pressure than ambient), you would increase the airflow through it. That is literally how superchargers work!

If no suction in the opti really meant no flow, then the same would hold true for the intake manifold itself. And yet, the airflow through the intake manifold increases as the vacuum decreases. It's entirely possible for an intake manifold to have zero psig (i.e. no vacuum pressure), and for a naturally-aspirated engine that is when it will have its highest airflow at any given rpm. According to you, that's not possible. Even more possible, some people do crazy things like install a compressor upstream of the intake (aka "supercharger"), so that the intake experiences positive pressure! I guess you must believe that this causes the flow to reverse and shoot back out the air filter or something, LOL. The rest of us understand that positive pressure (you know, the opposite of vacuum) actually increases the pressure differential across the intake tract and therefore also increases the airflow.

Also, please quote any part of any post in any thread where I've claimed to be an acknowledged expert in anything related to cars or physics. One doesn't have to be an expert in anything to understand why the inside of a vented opti experiences no significant negative pressure. It's actually really damn simple to understand. In your last adventure in demonstrable ignorance, I did invite someone else who is an acknowledged expert and innovator to contribute to the thread. You'll remember him: he's the one who told you that you were completely wrong.

Tom400CFI

More nam-calling, huh? That's O.K. It's a common behavior from desperate people -and consistent with your other posts/threads. Excellent contributions, once again.

Now Cardo, earlier, you said this:
My car pulls nearly 18"Hg vacuum which is close to 9psi. I have a manifold vacuum gauge mounted on my dash. And I recall it's tee'd into the same port the opti uses
^The implication you were making was that the Opti housing has that amount of vacuum in it. That's how I interpreted it anyhow. If that's not what you were getting at...why even mention your manifold vacuum and the effective "PSI"? I don't see how you could possibly say or imply that, knowing about the restrictor that is inline, to the opti. I don't think that you were aware of that restrictor. I posted about it -even gave you a pic since I anticipated your denial of the restrictors existence...anyway, now you're nit-picking "negative pressure" that are so small, they would be un-observable on a typical vacuum gauge.

Let's put this worthless argument to rest; Cardo, "T" into your Opti Venting harness either between the restrictor and the opti, or the opti and the snorkel. Report back to us what your vacuum gauge reads.

Whatever the infinitesimal difference in pressure inside the opti vs. outside....it ain't enough to "suck water in", which was the whole premise of your "fish-tank-opti" idea.

Both premises, wrong. The thing is vented to atmosphere, through the air cleaner, so it's not under any meaningful amount of vacuum (easily provable with a "T'ed" in vacuum gauge), and the air is as clean as you'll get, under the hood of a 'Vette.

Let the name calling resume....


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WhiteC1

Tom400CFI and MathewMiller, My hat is off to you gentlemen! I'm not sure I could display such a level of restraint when faced with the insult-laden rants of a fool... I'm a Mechanical Engineer working with oil pumps (testing, development, etc) and realize like you (and most people) that pressure, or vacuum, is only created by restriction to flow. Oil pumps don't produce pressure, they produce flow (volume). If you want more oil pressure in your engine, without changing any internal clearances (i.e. restrictions), you get a high VOLUME oil pump, and up goes your pressure at a given RPM. Or, you use higher viscosity oil, which is harder to squeeze past the clearances. It's the restriction to flow that creates pressure. I know you already know this.

The simple tests you suggest would certainly convince almost anyone of how the system works. The orifice in the vent line is very small, so the engine won't have to deal with a massive vacuum leak (if it was hooked directly to the Optispark port without the orifice). Thus, the high vacuum exists on the ENGINE side of the orifice, with only a small flow of air (at atmospheric pressure) being drawn through it. The resulting small volume of air being pulled through the Opti is enough to do its job, but certainly not enough to create any negative pressure inside the Opti, unless the fresh air port was completely blocked.

I suspect I'll get dragged over the coals by you know who for not understanding the World we live in, but I'll take that chance. I've got your backs, even though you don't need it!

Regards,
John

SJW

Correct. And there have been a few reported instances of folks accidentally choking off the fresh-air inlet side of this vent system (pinching the hose), and finding that the pressure differential that then develops has distorted the cap to the point that the rotor makes contact and is destroyed. In a properly-functioning OEM opti vent system, the opti housing interior should be at the same pressure (very close to atmospheric) as the air in the intake bellows where the inlet line connects.

Live well,

SJW

MatthewMiller

Sigh...Our boy hasn't given up on this yet, despite all of physics and mechanical engineer who works with flow systems for a living all telling him he's wrong. From another thread we get the following:
Of course, Warren has no idea what heated argument cardo is talking about. And he had no idea what cardo was trying to prove. cardo doesn't understand that Warren is not measuring vacuum with full open flow through the opti and a tee fitting to the gauge. He's measuring with no flow using the gauge at the end of the line instead of the opti. That is, the gauge is a closed termination of the vacuum line. And of course it will see engine vacuum under those conditions! The orifice size doesn't even matter when there's no airflow! I think "cardo doesn't understand" could easily summarize this whole thread.

cardo, I don't expect you to believe me, but I have an OEM opti sitting on the shelf. I took out my trusty Mityvac and connected it to the opti's suction port. No matter how hard/fast I pulled the lever, I could not register any vacuum reading at all. Why? Because of course the air is flowing freely through the opti, just as it does when it's installed on the car.

Tom400CFI

Yikes. That is unbelievably misguided.

It's weird to me how some folks who post on forums are so resistant to learning. Here, Cardo0 could learn a thing. I've seen it many times and I don't "get it". One time I had a forum member vehemently argue with me that the roof is not part of the structure of the car. Vehemently. I posted a couple pages from Corvette from the inside where Dave McLellan himself, talked about the roof as a structural element and cited frame frequencies with the roof on vs. off. This person felt berated. Why? They just learned a thing! One guy quite the forums b/c he didn't want to learn how a fuel pump works on a C4. WTF? It's more important to be right or win, than it is to learn a thing? Crazy.


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MatthewMiller

Unfortunately, this isn't limited just to webernet forums...

cardo0

Just to keep this thread alive here's a U tube video of the vacuum - 10"Hg - at the air duct side (across the opti):
Yes it not actual because it's not tee'd and instead dead headed but everyone can see there is plenty of vacuum on the other side of the orifice restriction.

More to follow.

MatthewMiller

If it's "dead-headed" (i.e. the gauge itself is terminating the airflow) so that there is no airflow, then of course it will pull vacuum! As WhiteC1 (a mechanical engineer who works with pumps for a living) told us earlier in the thread, "It's the restriction to flow that creates pressure." But there's no restriction to flow through the Optispark distributor ("meaningful" in the context of the teeny orifice restrictor between the vacuum source and the Opti), so there's also no measurable vacuum. I guess you still don't understand.

Tom400CFI

Dude...you don't "get it". And "beating a dead horse" is a good emoticon for your post. Also, do they have a "You can lead a horse to water..." emoticon?

mixalive

Does anyone have the part number for the vacuum restrictor? I don't think my MSD unit has a restrictor in the vent line.

MatthewMiller

I don't know the OE number, but Eckler's has the full set of hoses and restrictor. If you have the restrictor in place, it should be on the side of the intake manifold, in line with the hose near the vacuum port it connects to.

ETA: It looks like the revised p/n for the 1996 version of the vacuum harness is 12556174. Not sure if 1995 would be different - not sure why it would be, but ya never know.

jmgtp

Tom400CFI

I wonder what happened with this? I mean, I know what happened, if testing continued. But we never saw the "more to follow" part. (?)

This might be worth a watch, for someone....






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cardo0

Incompetent would include those that are to lazy to measure the vacuum for themselves. Or just too plain incompetent to measure this themselves!

Tom400CFI

Incompetent and lazy are different characteristics. Look 'em up. But I get what you're trying to say. My question then, is; are you going to measure it the proper way? Or aren't you?

And for the rest of our entertainment value, when are you going to hook up a 110v fish tank pump to your opti?


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