After all the speculation and debate on here about running the CCV into the exhaust and whether it's a good idea or not, I decided to test it for myself. I used a gauge setup that Gene sent me (thanks Gene), which he put together to test CCV pressures.

The bottom line is this: My CCV is no longer routed into my exhaust and it will stay that way.

Before I even start testing testing CCV pressures, I decided to see what, if any, pressure the exhaust routed hose might produce. So I unhooked the exhaust routed hose from the valve cover doghouse (temporarily routed my CCV down the side of the engine) and hooked the gauge to that hose, right where it would normally go to the doghouse. So, the gauge is now reading the direct pressure the exhaust routed hose would be exerting on the crankcase.

My findings showed that the exhaust routed hose would exert on average 10-15 inches of H2O, but I also noted readings as high as 20-25 inches of water. The gauge was pretty bouncy, but I could get a pretty decent idea of what was going on. There bouncing needle showed me that there are definate pulsations in the exhaust though. The needle would occasionally bounce to a slight vaccum for just a fraction of a second, then jump right back up to pressure. On average, there was pressure coming from the hose.

I haven't yet started to test CCV pressures of venting straight down versus to the back of the truck yet. I'm going to play around with locations of the end of the hose when routed toward the back of the truck before I start that testing, with an attempt to see if I can find an area of low pressure somewhere under the truck that might actually create a slight vaccum at the end of the hose. I'll keep you all posted.

 

Good info... thanks Jeremy.

 

Glad to see some #s finally. I kinda suspected that all along and never had any intention of routing mine to the exhaust. Of course now we will hear from those who will argue you have a poor design and therefore create backpressure. It never ends. Fortunately for me it never got started.

 

I expect that, and that's fine with me. I wanted to know how my setup performed and now I know. Sharing what I find is something that I'll always do with you all.

I've got pics of how mine is routed...the tube into the ehaust is at a 45* angle and has the properly angled tip on it as well. It's one of the crank case evac kits from Jegs actually. IIRC, after all the debate of the best way to route it so it might create a vaccum, mine is setup exactly like that.

 

So the less back pressure the better. I am going to do this tomorrow and I just wanted to know
Nick

 

My repeated cautions about not routing the CCV to the exhaust weren't based on speculation, but rather on measurements I took last April at Smokin! And guess what? If you hook your CCV hose back to your exhaust where you had it all this time, and then measure your CC pressure with the special oil cap I sent, you'll see even higher pressures than you're reporting here, because the CC pressure will add to the exhaust only pressure that you've reported! The gauge I sent probably isn't accurate enough for that. You need one of the big differential gauges like Tenn and I have, which can measure down to a few tenths of an inch H20 vacuum or pressure. The most I've seen at my intake due to RAM air dynamic pressure is about 3" H20 at 70 MPH, and that's at a stagnation point. There might be some locations around the truck to vent the CCV hose that have a slight vacuum due to aerodynamic effects, but I wouldn't expect to see more than about a 1" H20 vacuum at best.

Either Tenn or I can run a 1/4" hose from our cockpit gauge to various locations and check for lower pressure spots, or even spots with a slight vacuum. When I get around to it, I'll at least check the pressure where my CCV hose ends about mid way at the fuel tank.

 

Straight down the back of the block is how International does it. Of course I ran mine farther back because I don't particularly care for the smell. The smell varies with the type of oil you use though.

 

I suppose I could test some of that but I do not expect that much of a difference as long as the CCV has a clean shot out, at least a negligible one what with flow rate and all. The big issue is allowing the pressure to get out without a restriction.

 

How far back it you go
Nick

 

Mine dumps in front of the rear axle. It smokes/has good flow there. Curiously, there is no oil residue anywhere there.

 

I've been following the drama of the CCV into/not into the exhaust because I have done the CCV mod with the hose over the master cylinder and vented at the back of the cab on the driver's side. The smell and mist really stinks! There is a VERY slight oily coating on the end of the hose but no drips in the driveway.

I'm no Eugene (not even close) so I'm going to waste everybody's time and embrass myself with an idea I had.

Run the exhaust out in front of the rear wheel with or without a muffler. (I would go with the Walker BTM because I don't need any more noise) Run the CCV tube straight off the back of the doghouse, curving down to the frame rail on the passenger side. Routing this is a real pain. Enter the exhaust at the last bend before the end of the tailpipe. You could even extend the CCV tube right out to the end of the exhaust pipe.

This would certainly keep those nasty fumes out of the cab and out of any drive thru windows; the exhaust flow would help dissipate the CCV fumes. I would think that the exhaust would not create any back pressure using this approach? What do you guys think??

 

My CCV is routed from the doghouse with a gentle downward slope along the entire length of the hose, where it ends right under the driver's seat area of the frame.
It never drips.
The smell doesn't bother me, but my wife hates it. I turn it off at the drive through window.
Jeremy thank you for taking the time to post this information, I was going to plumb it into the exhaust some day, and now never will.

 

Mine runs through a catch canister full of stainless steel scrubbing pads and then back into the intake. It does a good job of removing the oil (I catch about a half pint every oil change) and no smells or problems with the hose freezing up.

 

Nice to know, i'm doing the CCV mod this weekend. Two questions, does oil build up in the bottom of the intercooler for not having a CCV mod ? should it be emptied/cleaned out when mod is done ?

 

Excellent question. I can't say that I've ever seen this issue addressed as even a potential concern, much less its potential for requiring corrective action.