EVAP removal and gas tank venting - a better solution.
06-08-2007, 09:29 PM
#21
Drifting
Thread Starter
On an unrelated note, I had no idea you could delete posts and that kind of made me think I was crazy when I just tried to respond to your deleted one. Anyway, what parts book were you referring to that didn't mention the valve? The FSM as well as the source you cited describes the EVAP relief valve.
06-08-2007, 09:31 PM
#22
Team Owner
Member Since: May 2002
Location: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
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Yeah but the problem is the parts book doesn't mention it anywhere, any year.
Unless this is it:
"EVAP EMIS INTER HOSE CONNECTOR (THREADS MUST BE COVERED W/TEFLON TAPE)"
Unless this is it:
"EVAP EMIS INTER HOSE CONNECTOR (THREADS MUST BE COVERED W/TEFLON TAPE)"
06-08-2007, 09:31 PM
#23
Team Owner
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What section? I didn't see it. My 85 page #s won't match up with yours of course. The source I cited is Autozone's website. I'd rather take investment advice from a homeless man.
Last edited by CentralCoaster; 06-08-2007 at 09:34 PM.
06-08-2007, 09:32 PM
#24
Drifting
Thread Starter
Oh I see, the first source was not corvette specific. Anyway, my 1996 FSM has an entire chapter about the EVAP system and it has a big description complete with pictures and cutaway views of this pressure release valve that serves as the only path for gases to reach the canister. Plus I saw it when I took the car apart, I mean it's there for sure.
Oh and like I said, very important, I'm only talking about late model C4's, so it may not exist on your car or be in your FSM or be in any parts books for your year. I have no idea when they introduced this valve, could have been as early as 1984 or as late as 1996, but my point is any cars with that valve should keep it instead of going to a vented cap.
We're both editing each of our replies like crazy so it's already confusing enough without posts being deleted. Ahhhhhhhhhhhhhhhhhhhhhhhh
Oh and like I said, very important, I'm only talking about late model C4's, so it may not exist on your car or be in your FSM or be in any parts books for your year. I have no idea when they introduced this valve, could have been as early as 1984 or as late as 1996, but my point is any cars with that valve should keep it instead of going to a vented cap.
We're both editing each of our replies like crazy so it's already confusing enough without posts being deleted. Ahhhhhhhhhhhhhhhhhhhhhhhh
Last edited by LouisvilleLT4; 06-08-2007 at 09:54 PM.
06-09-2007, 11:46 AM
#25
Race Director
So, the idea for older years without the valve would be to order the later year valve, install it, and delete the whole system. I really like the roll over protection part of this idea.
06-09-2007, 01:55 PM
#26
Le Mans Master
This relief valve exists right after the fuel tank and can simply remain
there with the rest of the EVAP gone. Not only would this serve to
vent the fuel tank when pressure builds up, but it would vent only
at such times, unlike a vented gas cap which constantly releases
smelly vapor. Using this valve, in order for fumes to be released they
must first build up to the same pressure that stock required before they
get passed through to where the canister is supposed to be. I think
this would work perfectly. Do you agree or do you see any problems
with this?
there with the rest of the EVAP gone. Not only would this serve to
vent the fuel tank when pressure builds up, but it would vent only
at such times, unlike a vented gas cap which constantly releases
smelly vapor. Using this valve, in order for fumes to be released they
must first build up to the same pressure that stock required before they
get passed through to where the canister is supposed to be. I think
this would work perfectly. Do you agree or do you see any problems
with this?
- Is the intent to vent directly at the valve (within the body enclosure
surrounding the tank) - Is fuel vapor heavier or lighter than air?
- Since the valve releases at higher pressures, what is the resulting
vapor's fuel/air ratio? Is this within the range in which ignition is possible?
outweigh the pros of reducing emissions of unburned hydrocarbons into
the atmosphere.
.
06-09-2007, 06:30 PM
#28
Drifting
Thread Starter
CentralCoaster, I'm not really sure what you're asking. I already told you that your year of corvette might not have this valve along the evap hose. My '96 does and that's the only year I can speak for.
outweigh the pros of reducing emissions of unburned hydrocarbons into
the atmosphere.
.
The intent is to route the valve to the outside edge of the body and pointing away so it can shoot the fumes away from the car. Fuel fumes are heavier than air and would tend to spread out along the ground. One could vent them out the top of the body through the fuel filler vent to eliminate the possibility of fume buildup within the body enclosure.
The pressure and risk of ignition is a good thing to consider and a good point, but if the fumes escape away from the car I don't think this will be unsafe. The fumes would dissipate very quickly from a non-enclosed starting point, even if a spark somehow does reach as unfortunate of a location as above your fuel filler. If a spark manages to get up there I would be awful uncomfortable with or without EVAP venting there, because that's a prime location for fuel spillage and whatnot, but I don't go around worrying about random sparks on top of my car.
Pressurized fuel releasing from the car does indeed sound pretty scary, but it's not even 1 PSI of pressure, and all things considered I don't think this would change the amount of risk appreciably as long as one puts a little thought into where their fumes are aimed beforehand.
All that aside, I'm not even addressing your comment about the environment because nowhere did I endorse that other people should remove EVAP, and this discussion is for people who already have. Read the thread prior to getting all righteous.
- Is the intent to vent directly at the valve (within the body enclosure
surrounding the tank) - Is fuel vapor heavier or lighter than air?
- Since the valve releases at higher pressures, what is the resulting
vapor's fuel/air ratio? Is this within the range in which ignition is possible?
outweigh the pros of reducing emissions of unburned hydrocarbons into
the atmosphere.
.
The pressure and risk of ignition is a good thing to consider and a good point, but if the fumes escape away from the car I don't think this will be unsafe. The fumes would dissipate very quickly from a non-enclosed starting point, even if a spark somehow does reach as unfortunate of a location as above your fuel filler. If a spark manages to get up there I would be awful uncomfortable with or without EVAP venting there, because that's a prime location for fuel spillage and whatnot, but I don't go around worrying about random sparks on top of my car.
Pressurized fuel releasing from the car does indeed sound pretty scary, but it's not even 1 PSI of pressure, and all things considered I don't think this would change the amount of risk appreciably as long as one puts a little thought into where their fumes are aimed beforehand.
All that aside, I'm not even addressing your comment about the environment because nowhere did I endorse that other people should remove EVAP, and this discussion is for people who already have. Read the thread prior to getting all righteous.
Last edited by LouisvilleLT4; 06-09-2007 at 09:35 PM.
06-09-2007, 08:58 PM
#29
Race Director
With enviro. impact, from what I remember there is a vent in the canister to. Also I mentioned above that the cap is tested in an emissions test. In this county anyways. Many places do not test the cap or have tests at all. Also track cars vent the fumes. Many cars sit around doing nothing at all, those type of cars would be venting. Yes? From what I am reading here, a car that is driven and has a working cap, would not be venting. My car that is mostly a track car and sits around jacked up most of the time, would be venting.
I really like the enviroment, I don't see how my car could do better though, I could start it up once in awhile so it doesn't vent but that makes fumes to.
So it seems with deleting the system that removing everything is fine and you do not need a vented cap. But, if your cap became plugged there would be no backup system to prevent tank deformation.
I really like the enviroment, I don't see how my car could do better though, I could start it up once in awhile so it doesn't vent but that makes fumes to.
So it seems with deleting the system that removing everything is fine and you do not need a vented cap. But, if your cap became plugged there would be no backup system to prevent tank deformation.
06-09-2007, 09:31 PM
#30
Drifting
Thread Starter
A few posts ago CentralCoaster said that the evap system doesn't hold vacuum from the tank (that is, it allows air to be blown in). We're not plugging that line with this method, so there would still be vacuum release.
06-10-2007, 09:53 AM
#31
Le Mans Master
'the following discussion is for people who already have' removed
their EVAP?
Your comments throughout look future tense to me ...
#01 - I think this would work perfectly.
#05 - just looking at it all is what made me convinced that this will work.
#18 - If you keep the relief valve in place instead, I think this problem would be avoided.
and so on.#05 - just looking at it all is what made me convinced that this will work.
#18 - If you keep the relief valve in place instead, I think this problem would be avoided.
Nor is there any disclaimer stating you don't endorse others performing
this mod. Or stating why you are interested in it, yourself, aside from
a remark well down to the effect that:
Originally Posted by LouisvilleLT4
the canister itself surprisingly only weighs 2 pounds in the later models
and is honestly not worth the huge process of removing the rear
bumper to get at it. I removed it anyway, not only for weight reduction
but because I suspected vacuum leaks from the EVAP hoses.
and is honestly not worth the huge process of removing the rear
bumper to get at it. I removed it anyway, not only for weight reduction
but because I suspected vacuum leaks from the EVAP hoses.
Let me put it this way: I've had my vette for one year now and it's been
down for probably 9 months out of that year. As soon as I get it fixed
and back on the road again it is staying there for as long as possible.
I cherish the times when my Corvette is on the road; although I like to
talk about future mods and weight reduction, I find when I get behind
the wheel that it drives just fine stock and that it's more than fun
enough the way it is. If you get the car and you're unhappy with the
way it drives, by all means start wrenching on it but don't fix what isn't
broken.
down for probably 9 months out of that year. As soon as I get it fixed
and back on the road again it is staying there for as long as possible.
I cherish the times when my Corvette is on the road; although I like to
talk about future mods and weight reduction, I find when I get behind
the wheel that it drives just fine stock and that it's more than fun
enough the way it is. If you get the car and you're unhappy with the
way it drives, by all means start wrenching on it but don't fix what isn't
broken.
a reasonable question. It has virtually no impact on performance, is
essentially weightless and, as an incidental matter, keeping it intact
helps buy more time for us here in the fish bowl we all share.
If you suspect a vacuum leak, a little time with a Mityvac might confirm
or disprove this diagnosis. In the event your suspicions are founded,
some new hose or sealant would restore the EVAP system and you'd be
on to the next project.
Instead, now you've begun to pull parts, perform research and perhaps
wonder whether the pilot light in the unit heater in the garage is going
to become a hazard once you are finished.
I gather that at this point in your project, you are committed to
finishing the removal/disabling of the evaporative system. Knowing
what you know now, if someone posts Monday that they think they
have a problem with their system that sounds similar to the symptoms
you first experienced - what would you advise them to do?
.
06-10-2007, 10:13 AM
#32
Drifting
Thread Starter
Pardonnez-moi: approximately where in the thread does it say
'the following discussion is for people who already have' removed
their EVAP?
Your comments throughout look future tense to me ...
Nor is there any disclaimer stating you don't endorse others performing
this mod. Or stating why you are interested in it, yourself, aside from
a remark well down to the effect that:
Now, for a member who's had this to say about ownership:
Asking why it is necessary to remove the C4 Evaporative system seems
a reasonable question. It has virtually no impact on performance, is
essentially weightless and, as an incidental matter, keeping it intact
helps buy more time for us here in the fish bowl we all share.
If you suspect a vacuum leak, a little time with a Mityvac might confirm
or disprove this diagnosis. In the event your suspicions are founded,
some new hose or sealant would restore the EVAP system and you'd be
on to the next project.
Instead, now you've begun to pull parts, perform research and perhaps
wonder whether the pilot light in the unit heater in the garage is going
to become a hazard once you are finished.
I gather that at this point in your project, you are committed to
finishing the removal/disabling of the evaporative system. Knowing
what you know now, if someone posts Monday that they think they
have a problem with their system that sounds similar to the symptoms
you first experienced - what would you advise them to do?
.
'the following discussion is for people who already have' removed
their EVAP?
Your comments throughout look future tense to me ...
#01 - I think this would work perfectly.
#05 - just looking at it all is what made me convinced that this will work.
#18 - If you keep the relief valve in place instead, I think this problem would be avoided.
and so on.#05 - just looking at it all is what made me convinced that this will work.
#18 - If you keep the relief valve in place instead, I think this problem would be avoided.
Nor is there any disclaimer stating you don't endorse others performing
this mod. Or stating why you are interested in it, yourself, aside from
a remark well down to the effect that:
Now, for a member who's had this to say about ownership:
Asking why it is necessary to remove the C4 Evaporative system seems
a reasonable question. It has virtually no impact on performance, is
essentially weightless and, as an incidental matter, keeping it intact
helps buy more time for us here in the fish bowl we all share.
If you suspect a vacuum leak, a little time with a Mityvac might confirm
or disprove this diagnosis. In the event your suspicions are founded,
some new hose or sealant would restore the EVAP system and you'd be
on to the next project.
Instead, now you've begun to pull parts, perform research and perhaps
wonder whether the pilot light in the unit heater in the garage is going
to become a hazard once you are finished.
I gather that at this point in your project, you are committed to
finishing the removal/disabling of the evaporative system. Knowing
what you know now, if someone posts Monday that they think they
have a problem with their system that sounds similar to the symptoms
you first experienced - what would you advise them to do?
.
The only thing that's future tense here for me is routing the hose. Everything else is long gone. What's done is done and you should stay the hell out of my thread if you have nothing to say but irrelevant personal attacks against anyone and everyone who is running without EVAP. What you're doing is called being an internet troll; no one is trying to attack or defend the EVAP system except for you, at the expense of this otherwise enlightening discussion.
06-10-2007, 11:12 AM
#33
Team Owner
Member Since: Jan 2006
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I'd advise them to stay the hell away from this. That back bumper was a bitch to remove and I wouldn't do it again for something so insignificant as EVAP.
The only thing that's future tense here for me is routing the hose. Everything else is long gone. What's done is done and you should stay the hell out of my thread if you have nothing to say but irrelevant personal attacks against anyone and everyone who is running without EVAP. What you're doing is called being an internet troll; no one is trying to attack or defend the EVAP system except for you, at the expense of this otherwise enlightening discussion.
The only thing that's future tense here for me is routing the hose. Everything else is long gone. What's done is done and you should stay the hell out of my thread if you have nothing to say but irrelevant personal attacks against anyone and everyone who is running without EVAP. What you're doing is called being an internet troll; no one is trying to attack or defend the EVAP system except for you, at the expense of this otherwise enlightening discussion.
