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My friend told me that if you use PVC Pipe as a CAI tubing, it can REALLY mess up your engine.. He says "When the PVC gets hot, it releases a chemical, and that chemical eats the piston rings". Sounds a little fishy.. I mean, a gas eating metal? a gas that can do that can come out of a COMMON used item?

Anyone else hear about this myth? I think this is a case for the "MythBusters"!
 

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Well, there are a lot of fumes from melting plastic im sure..but if they can deteriorate metal im not sure..
 

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I am no chemist by any means, but i would highly doubt it! For a plastic to give off a fume in order to melt the rings would have to be so dence it is almost impossible, but again i am no chemist! I wouldnt think so!
 

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Well, I have a gen 4 with a PLASTIC upper intake, so I doubt the claims of your buddy hold any water.

-DC
 

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Originally posted by duratecchie@Apr 30 2004, 12:01 AM
Well, I have a gen 4 with a PLASTIC upper intake, so I doubt the claims of your buddy hold any water.

-DC
That proves nothing, the intake on your engine is made for high temp's, many plastics arn't.

Research this first before you make any comments, guys; if you arn't sure, don't comment. Saying the wrong thing and making this guy think his engine is ok when he's really killing it is NOT good. Better safe than sorry.

The vast majority of places I'm seeing that even reference PVC plastics say that the fumes can be very detrimental to the engine; those places that don't reference this don't seem to have any knowledge of it whatsoever. The sites that do know about it say that ABS plastic is safer; I've read this many places before, so I think that if any plastic has to be close to the engine (ie, attached to the TB), then it should be that.

Btw, using PVC for things away from the engine (like attaching a CAI onto the maf) should be ok, as long as the PVC doesn't get to hot.
 

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Originally posted by biteableniles@Apr 30 2004, 01:33 AM
Btw, using PVC for things away from the engine (like attaching a CAI onto the maf) should be ok, as long as the PVC doesn't get to hot.
Thats what the original post was questioning.


The dude is using it for tubing, I highly doubt PVC would ever get hot enough to cause fumes.

Pay attention now. Engineering lesson, 101:

Thermoplastics - Any plastic that melts when it gets very hot.

We are talking very hot here, well over 500 degrees fahrenheit. Paper combusts at 451 degrees fahrenheit (a mighty good book, might I add). If you are saying that the temperature PVC tubing that is used in your engine bay for a CAI will reach 500 degrees fahrenheit and above, you must be living on mars.


No way, not gonna happen.

The concern his friend has is when PVC is heated and MELTS, it can release some pretty nasty compounds, as ALL plastics do. Most of the smoke related deaths in fires occur because of the plastics we use in our homes. PVC is a vinyl compound made of CHLORINATED products, meaning that if PVC is melted, chances are some form of chlorine is going to be released, as well as many other nasty and noxious by-products.

There you have it. I know I learned something in thermodynamics and injection molding classes.
 

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From what I'v heard, the PVC gets very brittle and is prone to cracking and breaking into pieces, especially with all the heat and vibration in the engine bay. If chunks of PVC are breaking off, then they're getting sucked into the intake because it's already past the filter.

Fat Tortoise, I thought you already had a CAI. Why are you trying to make another one?
 

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Durateccie, I specified and said attaching PVC directly to the TB (many intakes I've seen replace the accordion--normally those CAI's are all metal, though) could heat the PVC to a point where it could melt, which could cause many other problems, like dripping. A drop of PVC into your intake is NOT cool. (This may be extremist, of course.)

If i'm wrong, I'm wrong, though. The good majority of car websites that even mention the problem say that PVC isn't safe for near-engine intakes; this has to come from somewhere, although it could very well have started when someone with a turbo piped with PVC (easily high temperatures.) I'd still rather, in this situation, give bad advice that won't destroy his engine than "good" advice that would
It would probably be best to find someplace that has experimental testing on this--I looked everywhere, though, bar anywhere offline. Anyone got the goods?

PS, bah, my thermo class isn't untill next semester
 

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I don't believe your friend knows what he is talking about. I am a HVAC mechanic, and we use PVC to vent high efficiency furnaces, and hot steam blows through the PVC. Trust me, unless the PVC is melting, U don't have anything to worry about.

Adam
 

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Better yet, just use ABS plastic piping. :) Its a little more expensive, but it will not melt, and more durable.

Adam
 

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This debate rears it's head from time to time here. Here's the skinny.

PVC (Poly Vinyl Chlorate) decomposes into several chemicals when incinerated, most notably HCl vapor. HCl, as in Hydrocloric Acid. But a vapor. Now, no one knows the exact temperature at which this decomposition happens, since the documented tolerances tend to vary from source to source. DuPont (the defendant) says one thing, the plaintiffs say another. I tend to agree with the plaintiffs based on my own experimentation with PVC, but we'll save that discussion for another day.

Bottom line is this, and again, this is based on my own personal experience with PVC in a vehicular application:

Depending on the type and grade of PVC (yup, there are different types), there is a small chance that extremely high underhood temperatures can cause PVC not to incinerate, but to outgas small amounts of HCl vapor. Again, different PVC sources outgassed at different temperatures. Some as low as 130F, some didn't outgas at temps as high as 300F, which would never happen under your hood, unless your car caught fire. In which case I hope to hell you're watching said fire from a safe distance.

In the instances where the outgassing occurred, the amount of vapor wasn't significant enough to cause combustion chambers to melt or anything. In fact, it was just barely measurable. However, prolonged exposure to these vapors could very well cause permanent damage to your engine. How long would it take? No idea. All I know is that the vapor can be produced under certain condiitions, and isn't exactly a noble gas.

IMHO, to be safe, I'd use ABS plastic to avoid any issues, since it doesn't outgas any caustic vapors when heated or incinerated.
 

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Originally posted by Racer X@May 2 2004, 11:25 PM
This debate rears it's head from time to time here. Here's the skinny.

PVC (Poly Vinyl Chlorate) decomposes into several chemicals when incinerated, most notably HCl vapor. HCl, as in Hydrocloric Acid. But a vapor. Now, no one knows the exact temperature at which this decomposition happens, since the documented tolerances tend to vary from source to source. DuPont (the defendant) says one thing, the plaintiffs say another. I tend to agree with the plaintiffs based on my own experimentation with PVC, but we'll save that discussion for another day.

Bottom line is this, and again, this is based on my own personal experience with PVC in a vehicular application:

Depending on the type and grade of PVC (yup, there are different types), there is a small chance that extremely high underhood temperatures can cause PVC not to incinerate, but to outgas small amounts of HCl vapor. Again, different PVC sources outgassed at different temperatures. Some as low as 130F, some didn't outgas at temps as high as 300F, which would never happen under your hood, unless your car caught fire. In which case I hope to hell you're watching said fire from a safe distance.

In the instances where the outgassing occurred, the amount of vapor wasn't significant enough to cause combustion chambers to melt or anything. In fact, it was just barely measurable. However, prolonged exposure to these vapors could very well cause permanent damage to your engine. How long would it take? No idea. All I know is that the vapor can be produced under certain condiitions, and isn't exactly a noble gas.

IMHO, to be safe, I'd use ABS plastic to avoid any issues, since it doesn't outgas any caustic vapors when heated or incinerated.
I'm sorry, but don't you mean, "Polyvinyl chloride"?
 

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When melted, PVC also releases chlorine gas. Chlorine is a corrosive, so that could be what has led to the rumor about this. AFAIK, unless you were litterally burning the PVC pipe, there would be a very negligible amount of Chlorine gas released. However, if enough gas were released, it could potentially eat away at the metal innards of your engine, however, it would probably be over the course of tens of thousands of miles, under normal operating conditions.

JR
 

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Originally posted by afi292+May 3 2004, 10:04 AM--><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (afi292 @ May 3 2004, 10:04 AM)</td></tr><tr><td id='QUOTE'> <!--QuoteBegin-Racer X@May 2 2004, 11:25 PM
This debate rears it's head from time to time here.  Here's the skinny.

PVC (Poly Vinyl Chlorate) decomposes into several chemicals when incinerated, most notably HCl vapor.  HCl, as in Hydrocloric Acid.  But a vapor.  Now, no one knows the exact temperature at which this decomposition happens, since the documented tolerances tend to vary from source to source.  DuPont (the defendant) says one thing, the plaintiffs say another.  I tend to agree with the plaintiffs based on my own experimentation with PVC, but we'll save that discussion for another day.

Bottom line is this, and again, this is based on my own personal experience with PVC in a vehicular application:

Depending on the type and grade of PVC (yup, there are different types), there is a small chance that extremely high underhood temperatures can cause PVC not to incinerate, but to outgas small amounts of HCl vapor.  Again, different PVC sources outgassed at different temperatures.  Some as low as 130F, some didn't outgas at temps as high as 300F, which would never happen under your hood, unless your car caught fire.  In which case I hope to hell you're watching said fire from a safe distance.

In the instances where the outgassing occurred, the amount of vapor wasn't significant enough to cause combustion chambers to melt or anything.  In fact, it was just barely measurable.  However, prolonged exposure to these vapors could very well cause permanent damage to your engine.  How long would it take?  No idea.  All I know is that the vapor can be produced under certain condiitions, and isn't exactly a noble gas.

IMHO, to be safe, I'd use ABS plastic to avoid any issues, since it doesn't outgas any caustic vapors when heated or incinerated.
I'm sorry, but don't you mean, "Polyvinyl chloride"? [/b][/quote]
Yeah, I did. Sorry, it was late.
 

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An engine would probably have to consume the entire amount of decomposing chemicals at one time to do any damage. Which would mean the intake would be a pile of dust.

I wouldn't worry about it, there is a much worse chance of engine damage from acid by not changing your oil at the proper intervals.
 

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My friend told me that if you use PVC Pipe as a CAI tubing, it can REALLY mess up your engine.. He says "When the PVC gets hot, it releases a chemical, and that chemical eats the piston rings". Sounds a little fishy.. I mean, a gas eating metal? a gas that can do that can come out of a COMMON used item?

Anyone else hear about this myth? I think this is a case for the "MythBusters"!
I've had PVC tubing coming from my throttle body,& then attached a flexi pipe to it to get the bends for it to reach the bumper on my 02 Corolla (Had it for about a year before I sold the car & it was fine,in fact the gains were noticeable - even the guy I sold it to kept the piping) .. As a matter of fact it was a mechanic who told me about this cheap mod (he had it on his 4age 16v GLI)
 
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