I have a couple of ideas burning in my head but need to solve an issue before i can go ahead with this. Im looking at putting ram air onto my newer 2000 truck but have some concern about the PCV system and the arguments both against and for it. I'm not looking to open another can of worms here so be nice will ya!


I recently tested for vacuum between the air filter (clean filter) and the turbo and got 0.5 hg of vacuum under full acceleration. Now i would like to put on ram air but wouldn't that put a positive pressure on the turbo and instead of vacuum on the crankcase i'd get a positive pressure if i left the PCV hooked up, should the PCV be re-routed to the exhaust to pull vacuum or just let it breath eg. dual breathers? How can i keep the vacuum on the crankcase as it was designed?

CanadianRigger,


Here (http://www.autospeed.com/cms/article.html?&A=0652) is an interesting article about negative boost. The subject of the article is an Audi A4, but I think the concept applies across the board. You might have to poke around to find parts 1,2 and 3.


Enjoy.

CR


Be more specific about your testing methods on the intake. I'm curious. Paper filter, WOT, Boost pressures, etc...


I've been waiting to finish my WMI so I can test my EVAC set-up with a vacuum gauge. I was also going to test vacuum on the inlet hose to the turbo.


Another good reason(I think), to re-route crankcase into exhaust so you can pressurize intake side of turbo. Although a CDR should prevent pressurization of crankcase from Ram-Air effect. But once intake side of turbo is under positive pressure, CDR will not work properly and create a positive pressure in crankcase from rotating assembly.

Billman,


How about using a fitting like you used on your exhaust and putting it at a 45 to the post turbo intake charge. Would the boost blow back up that angle cut and check valve? I wonder?

My test was pretty much not too scientific. Had a paper filter (OEM) and it was clean. Removed the CDR tube from the inlet and fitted the inlet with a bushing to a hose and ran the gauge in the cab, needle moved to the negative slightly on light throttle to show some vacuum there but went to 0.5~ on heavy acceleration. Boost levels are only factory with no faking in the system so i'd imagine they're pretty low.


I don't thing the CDR will prevent the crankcase from getting pressurized, i have 2 of em and they both can be blown through in either direction, doesn't it just regulate the vacuum by opening farther with a harder draw on it?

CR - My mistake then on the CDR. I'll have to check it out more. I'm curious to the vacuum readings on the inlet with a full load and a bunch of boost(15+).


QM - Finally got WMI done. Started truck for first time in weeks. With Single Breather and nipple/check valve on exhaust downpipe. While idling, I found 1psi on hose. I couldn't believe it. I figured I had a bad check valve(which I did check before install) and it was pressurizing gauge. Wrong. 1psi on gauge was coming from crankcase.


Tomorrow I will take it for a good ride and monitor vacuum...If any. I'm beginning to have my doubts. JD keeps saying there's pressure in 'Them Down Pipes'. Maybe after 60 something years, he's learned a thing or two.


As far as putting that nipple set-up post-turbo intake side, May as well keep the CDR the way GM designed it.


On Edit: Boost should not pressurize crankcase if checkvalve does its job.Edited by: Billman

Seems like a check-valve would be self-defeating - how would crankcase ventilate at pressure-rise down-stream?


Compared to a low-compression gasoline engine, the 6.5 has virtually no blow-by.


Purpose of the CDR is to limit amount of vacuum in the crankcase, not prevent blow-by and other vapors from entering intake system.


The minimal applied vacuum allows Baro to "pressurize" the crank main seals, preventing oil seepage.


Too much vacuum would allow Baro to force any- and every- thing in the environment in thru the seals.


A well-maintained Diesel engine can make several hundred thousand miles without a drip from the crank, if Baro pressure is slightly greater than crankcase pressure.


With crankcase open to the intake system, little pressure can develop.


Again, Diesel fuel is a light oil - how can combined crankcase vapors thru that small tube seriously and detrimentally offset the amount of fresh air coming thru that large air box?


Only instances I've heard of were of engine surging - gaining speed - from too much crankcase vapor, possibly from using non-Diesel spec oil.


Even turbo-spec'ed passenger vehicle oil does not meet Diesel oil requirements - gasoline engine oil will vaporize quicker than Diesel oil.


More vapor - not more blow-by.


(synthetic oils are another story, wheatdude......)


p.s. - the engine will run better on the cool air at the front of the vehicle than the hot air that just passed thru the ac condensor and engine coolant heat exchanger (radiator).


Just make sure that driving snow and rain do not have such an easy path thru the intake ducting.http://www.dieselplace.com/forum/smileys/Cool.gif


Edited by: gmctd

HEY - autospeed is charging for that article! Bastages. Perhaps I should check my links before I post.


Summary - smooth out the insides of the airbox, make sure there are no rough transitions, leave the MAF screen where it is (if equipped), and use a good flowing element. Basic stuff, but what made the article interesting was their testing methodology - present a hypothesis, design a test, examine data, draw a conclusion (all while minimizing type I and II errors)!

i have started to come up with some ideas for my intake. k+n filter, k+n precharger, no airbox, 90 degree pvc elbow, probably 4 in diameter, and hook that into the existing rubber intake. my goal is to fix the flattened part of the rubber intake.

Eliminating that scrunched-up duct should be a big improvement for the '96 up inlet system.


Mine's '95 derived, and relatively wide open, so I was astonished to see that on Turbine Doc's '98 truck.


Even with that, his truck is a 'hauler', but it will set the DP flag - that little 'dirty air filter' thingy in the duct - at times.

i saw at napa that there are two different sizes of the round air filter for my 97. one is bigger than the one that fits my truck. i wish k+n had a bigger filter, but at least they have the hose clamp hook up that the napa filters don't.

August seems to be love bug season and my truck is coated right now in bug guts. I was looking at one of those fart pipe cars with the 10" tall airscoop on the hood and I started wondering how you could keep the air filter clean with all the bugs in the air this time of the year, short of garaging it.


I might have to rig an aluminum screen before the filter.

QM: 98.95% of those fart pipe cars don't actually BREATHE through their hood scoop - they are just there to look good and increase drag.

This one did. The filter lay just below hood level and parallel to the hood's surface. The scoop was more of an air dam and the lowest point in the dam was the filter.


At ten inches tall, it was bigger than anything I'd want. I'd say four inches of scoop should do it with all the air your displacing up from infront of the hood, it should be easy to redirect at the nose of the hood. A raked angle on the hood itself wouldn't hurt. Say 4-5" of lift at the rear.

Eliminating that scrunched-up duct should be a big improvement for the '96 up inlet system.
Can someone post a pic on the "scunched-up duct". So I know what exactly to remove.

August seems to be love bug season and my truck is coated right now in bug guts. I was looking at one of those fart pipe cars with the 10" tall airscoop on the hood and I started wondering how you could keep the air filter clean with all the bugs in the air this time of the year, short of garaging it.
I might have to rig an aluminum screen before the filter.
Panty hose, new of course, over the filter. Thats what alot of people do for the ram air intakes they put on their Caprice's and Impala SS's.
Never know it might work here too