1 Topic by pbcrazy (edited by pbcrazy 2015-02-18 18:06:03)

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Topic: Will ABS survive engine bay?

I'm considering designing/printing a catch can for my Audi. A catch can basically sits in the engine bay and intercepts oil vapor that would otherwise go into the intake tract (not exactly ideal). I'm really not sure if it would hold up though. If I put the catch can on my heat shielded side, the exterior wouldn't see temps over 150*F, But the oil vapor would still be quite hot (not sure I could give a fair estimate, but easily 200+*F). Would the oil melt/destroy the plastic catch can?

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2 Reply by browning54213

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Re: Will ABS survive engine bay?

I thought about this as well, but I don't recommend it since you are boosted. When coming out of boost you can sometimes have gas vapors get into the intake and catch can, which could lead to the can being chemicaly melted. If you were just doing a braket or something under the hood I would have no problem using abs, but for something that could have a negative effect on your motor if it were to fail i say nay...

3 Reply by pbcrazy (edited by pbcrazy 2015-02-18 18:19:05)

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Re: Will ABS survive engine bay?

It would be on the PCV system, so no gas vapors should enter. That being said, you are right about boosting and it will always be under some pretty serious vacuum pressures, and should a piece of the plastic break off my turbo would be gone. Other alternative is delete the connection to my intake, and just have the catch can vent to the air. No vacuum, and if it does fail no big deal. I just think it would be a pretty cool piece (not to mention legit cans are $150+)

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4 Reply by carl_m1968

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Re: Will ABS survive engine bay?

It is almost impossible to make a ABS print that is air tight. They will always have microscopic holes and gaps between the layers. So if you need a part that can hold up to pressure or vacuum then printing it would not be a viable option. ABS reaches a glass transition stage around 110C. That is the temp at which it become deformable. That would be around 230F so you may be getting really close to dangerous temps for ABS.

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5 Reply by jnadke (edited by jnadke 2015-02-18 19:21:27)

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Re: Will ABS survive engine bay?

carl_m1968 wrote:

It is almost impossible to make a ABS print that is air tight. They will always have microscopic holes and gaps between the layers. So if you need a part that can hold up to pressure or vacuum then printing it would not be a viable option. ABS reaches a glass transition stage around 110C. That is the temp at which it become deformable. That would be around 230F so you may be getting really close to dangerous temps for ABS.

Vapor smoothing does a pretty good job of filling in gaps.  I printed a water-proof flower vase yesterday.  I vapor smoothed it for 2 hours.  No leaks (and it didn't smooth it out completely, still has a semi-gloss w/ texture).

Now, water proof and airtight are 2 different things, but it's worth experimenting.  Vapor smoothing a part for longer usually makes a solid surface.



For some real pressure, you can epoxy coat it.  Here's a study showing how well epoxy coated parts handled in a pressure vessel test.

http://utwired.engr.utexas.edu/lff/symp … ireles.pdf

They did experiment with Minwax Sanding Sealer in that paper too, it performed well.  Probably cheaper than Epoxy Coating.



TL;DR:  Coated parts can easily withstand 20-40 PSI.

6 Reply by browning54213

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Re: Will ABS survive engine bay?

pbcrazy wrote:

It would be on the PCV system, so no gas vapors should enter. That being said, you are right about boosting and it will always be under some pretty serious vacuum pressures, and should a piece of the plastic break off my turbo would be gone. Other alternative is delete the connection to my intake, and just have the catch can vent to the air. No vacuum, and if it does fail no big deal. I just think it would be a pretty cool piece (not to mention legit cans are $150+)


You are correct sorry forgot that you turbo guys have alot more between your pcv bungs than us s/c guys. Any way a vented catch can will not work because without vacuum your pvc will never open. And on top of that you would be drawing unfiltered air through there which is no good either (unless of course you are one of those big turbo nuts who dont run filters #nofilter lol).

7 Reply by pbcrazy

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Re: Will ABS survive engine bay?

browning54213 wrote:

You are correct sorry forgot that you turbo guys have alot more between your pcv bungs than us s/c guys. Any way a vented catch can will not work because without vacuum your pvc will never open. And on top of that you would be drawing unfiltered air through there which is no good either (unless of course you are one of those big turbo nuts who dont run filters #nofilter lol).

PVC won't need vacuum attached to it. Many people actually just take a hose and run the pcv directly to the ground (I personally do not wish to dumb nasty oil on the ground), it's a somewhat sealed system with a check valve on the intake manifold. And yes I run a filter, my turbo's not that big lol.

I probably won't even bother with this project, just way to many ifs

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8 Reply by browning54213

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Re: Will ABS survive engine bay?

pbcrazy wrote:
browning54213 wrote:

You are correct sorry forgot that you turbo guys have alot more between your pcv bungs than us s/c guys. Any way a vented catch can will not work because without vacuum your pvc will never open. And on top of that you would be drawing unfiltered air through there which is no good either (unless of course you are one of those big turbo nuts who dont run filters #nofilter lol).

PVC won't need vacuum attached to it. Many people actually just take a hose and run the pcv directly to the ground (I personally do not wish to dumb nasty oil on the ground), it's a somewhat sealed system with a check valve on the intake manifold. And yes I run a filter, my turbo's not that big lol.

I probably won't even bother with this project, just way to many ifs

Sorry to hear that your abandoning the project.

PCV valves do require vacuum to operate though. Trust me I'm an engineer lol.