Fix for collapsed vacuum line due to FI?

I would try to find a thinwall plastic tube to shove through the existing hose. I know on my Whipple set up they have you do this. I really had to lube it up to get the tube shoved in, but it's for the same problem you are experiencing.

When I installed the air/oil seperator, I swithed those out for steel braided lines. I'm not 100% happy with the fittings at each end and have a machinist friend that is going to make some custom fittings for me. The fittings work fine, they're just not the fit and finish that I like to have. The braided lines certainly won't collapse.

jay07 said:

Who sells that type of thing? I'm not even sure where to look.

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The plastic liner is out of the stock tube.

Yes, the stock tube. Do you still have it? If not, I'm sure someone out there has one that was taken off.

anthony05gt said:

Yes, the stock tube. Do you still have it? If not, I'm sure someone out there has one that was taken off.

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I think I still have mine - PM me your details if you want it.

jay07 said:

I might still have part of it, but it's not long enough. It has to run from the valve cover hole all the way back to the back of the firewall. Is there any place I can buy plastic tubing like that?

I did discover that a 3/8 I.D copper pipe fits nicely though (although a bit snug).

Right now I haven't done anything yet because I'm debating getting an air/oil separator . Although for that I would still need to reinforce the hoses.

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The copper should work just fine, especially if it's a snug fit.

jay07 said:

Right now I haven't done anything yet because I'm debating getting an air/oil separator . Although for that I would still need to reinforce the hoses.

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According to JDM you shouldn't use a oil separator and just a breather.

NastyStang113 said:

According to JDM you shouldn't use a oil separator and just a breather.

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What's their explanation?

klaw said:

What's their explanation?

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Brad Barnett's forum is down for some reason so I can't find it.

NastyStang113 said:

Brad Barnett's forum is down for some reason so I can't find it.

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Found the explanation:

Originally Posted by JDM's owner
There is no right or wrong with oil seperators. We just choose not to use them because to make it work properly you have to have a sealed system. What I mean by sealed system is no breather caps or any other evacuation device hooked to the engine. Some of the oil buildup in the supercharged cars is from reversion on decel. These motors are extremely tight and on hard decel you can pull 30 inches of vaccuum, which will allow oil to be sucked back through the guides. With a sealed system that will still occur. With an oil breather cap, that will not occur. If a car is running enough power, say 500whp+, we will stick a breather cap on it. This helps two things. 1 is to control the oil being sucked through the guides on a hard decel and 2 pressure or boost that seeps past the rings will get blown out the breather cap. Once oil goes past the guides, it actually goes back up through the intake tract and gets sucked up into the supercharger. On a sealed system, under hard accel, as soon as you shut the throttle body, the motor is going to do everything it can to pull air from somewhere. The path of least resistance is the crankcase - it will pull it past the rings, from the PCV system, and even from the rear main seal - with the breather cap, you're giving it a path of least resistance. It is useless to use an oil breather cap and an oil seperator device because the oil seperator device only works properly on a sealed system. We just chose to use a breather cap so that when the motor needs to pull air, it does it from the atmosphere instead.

We have run tests here on the dyno that shows an oil breather cap cuts nearly 80% of the oil ingestion on a high horsepower supercharged vehicle.

Hope this helps,
Jim @ JDM