Topic: DIY d-series catch can, now with SLASH CUT (Read 37332 times)

danz · « **on:** March 07, 2009, 06:45:43 PM »

Last motor went from crank pressure (i think) so i wanted to come up with a better PCV solution than i tried previously.

these pictures should be self explanitory...

the catch can is made from some 2.5" exhaust, with 1/2" OD tube nipples and a 1" OD tube nipple for the filter.

the black box has a 1/2" OD tube welded in it so its not being restrictive anymore. (inlet is 1").

Run the two 1/2 inch hoses from the black box to the catch can, and run another 1/2 inch from the VC vent to the can. I think i might have a local shop weld in a 1/2" nipple on the VC so I can vent it some more, and add another to the catch can.

All in all it cost me about $35 including hose and filter. "This price also includes 2 pints of RickP's blood." ROFL!!! hahah. didnt see that at first.

and OMG... props from JD.

Quote from: Joseph Davis;1051343

Good to see some solid grassroots DIY, props.

ratcityrex · « **Reply #1 on:** March 07, 2009, 07:07:48 PM »

so when you are in vac how dose the intake tube on the vc get air in if its being sucked out by the exhaust? Wouldnt they be fighting eachother? Im getting ready to build my can and im doing a slash cut also, bit Im trying to figure out how to set up the breather on my vc. $:-\$

danz · « **Reply #2 on:** March 07, 2009, 11:11:11 PM »

how about you tell me why you want your valve cover to suck air in ()

CSaddict · « **Reply #3 on:** March 07, 2009, 11:26:57 PM »

V8 guys have been doing that for years. Great rendition of a classic!! Nice work.

danz · « **Reply #4 on:** March 08, 2009, 12:09:37 AM »

true.. those v8 bastards do everything first.. :yes:

only down side of my setup is the gas velocity is rather low at that point in the exhaust track.. not like after the collector on an NA 4:1 header, which is usually where the v8 crowd install their slash cut.

but it will works good at high rpm which is when it matters most.

if i ever get off my ass and find a cheap (or free) vacuum gauge ill find out what kinda vac it really pulls.

t_cel_t · « **Reply #5 on:** March 08, 2009, 02:52:13 PM »

Quote from: ratcityrex on March 07, 2009, 07:07:48 PM

so when you are in vac how dose the intake tube on the vc get air in if its being sucked out by the exhaust? Wouldnt they be fighting eachother? Im getting ready to build my can and im doing a slash cut also, bit Im trying to figure out how to set up the breather on my vc. $:-\$

google venturi effect

d112crzy · « **Reply #6 on:** March 08, 2009, 02:58:30 PM »

Maybe weld a fitting onto a 3/4" or whatever size needed so it fits where the o2 sensor goes(on the dp).

Awesome can though.

What I've always wondered is what that black box does? Us F/H owners don't have that on our cars. Is it an empty box that hooks up to the back of the block and the valve cover?

ratcityrex · « **Reply #7 on:** March 08, 2009, 03:08:37 PM »

Quote from: d112crzy on March 08, 2009, 02:58:30 PM

Maybe weld a fitting onto a 3/4" or whatever size needed so it fits where the o2 sensor goes(on the dp).

Awesome can though.

What I've always wondered is what that black box does? Us F/H owners don't have that on our cars. Is it an empty box that hooks up to the back of the block and the valve cover?

Bolts to the block and alowes crank case pressure to go out therw there and to a tube that has a pcv valve attached to it where it then goes to the intake manifold and sucks the blowby out.

d112crzy · « **Reply #8 on:** March 08, 2009, 03:20:52 PM »

AHh, ok. I thought it went to the valve cover. Our shit goes from IM directly to the valve cover.

ratcityrex · « **Reply #9 on:** March 08, 2009, 03:27:11 PM »

Same idea, it just goes from the back of the block instead of the valve cover.

snarf · « **Reply #10 on:** March 09, 2009, 12:26:41 AM »

2.5" exhaust genius why the hell didn't I think of this. I'm going to build one of these but without the black box. I'm curious to see how much oil it collects.

Atticus · « **Reply #11 on:** March 09, 2009, 01:23:16 AM »

Quote from: danz on March 08, 2009, 12:09:37 AM

if i ever get off my ass and find a cheap (or free) vacuum gauge ill find out what kinda vac it really pulls.

you lazy fuck..... I told you you can borrow my extra one to test it

TTC · « **Reply #12 on:** March 09, 2009, 10:35:37 AM »

MS paint your routing im curious

trevor72 · « **Reply #13 on:** March 09, 2009, 01:30:35 PM »

mother fucker, exactly what i have planned for mine, right down the the moroso knock off breather and one way valve. (same kem parts as what's on the stang) Cept mine will hopefully be square and alum.

ps good work

brine04 · « **Reply #14 on:** March 10, 2009, 02:02:45 PM »

anyone have a part number or link for that one way valve?

ratcityrex · « **Reply #15 on:** March 10, 2009, 02:37:33 PM »

Quote from: brine04 on March 10, 2009, 02:02:45 PM

anyone have a part number or link for that one way valve?

You can get them off any gm car from the mid 80's on. Normaly they fit in your pocket pretty well when you go to the wrecking yard

1Fast68 · « **Reply #16 on:** March 10, 2009, 03:16:02 PM »

Quote from: CSaddict on March 07, 2009, 11:26:57 PM

V8 guys have been doing that for years. Great rendition of a classic!! Nice work.

:yes: Evac systems are Pretty common in the V8 world, only issue is they aren't recommended for cars with restrictive mufflers/exhaust as they can actually create more harm then help.

My collectors have the bungs welded in for Evac tubes but I have kept them capped off as I felt my mufflers are too restrictive. I will use them when i put my new bullet muffs on.

danz · « **Reply #17 on:** March 12, 2009, 02:14:53 AM »

Quote from: brine04 on March 10, 2009, 02:02:45 PM

anyone have a part number or link for that one way valve?

michigan_soler · « **Reply #18 on:** March 13, 2009, 06:18:50 PM »

http://store.summitracing.com/partdetail.asp?autofilter=1&part=SUM-120108&N=700+115&autoview=sku

thats the summit kit... 35 bucks is pretty good deal.

Towdogg · « **Reply #19 on:** March 13, 2009, 09:43:54 PM »

This is Good shit!

I need to do 1 also..

Emperor · « **Reply #20 on:** March 17, 2009, 12:09:32 PM »

WTF explain the intake cover
or is it a hose???

HiProfile · « **Reply #21 on:** March 18, 2009, 01:59:46 AM »

THose are breathers, very common on older cars. The one you see is basicly an enclosed filter which can have a tube hooked to the outlet. I think I'll be doing this before summer, my car currently just has a vent on the VC.

If you have a very restrictive exhaust, you can still do a slashcut, but you'd want an extra check valve vented to atmosphere. It would go between the breather and the slashcut check valve. In case the exhaust backpressure overcomes the suction from the slashcut (albeit unlikely), it would still allow crankcase pressure out.

Aero · « **Reply #22 on:** March 20, 2009, 12:31:28 AM »

I would love to see a measurement of vacuum from the exhaust through a pull. One of the guys here in town did it on his spirit R/T.

stealthiskey · « **Reply #23 on:** March 20, 2009, 01:03:17 AM »

If the can has a filter on the top, won't most of the gas pulled from the slash cut come from the fresh air through the filter rather than the crankcase?

,proportional to the ratio of opening diameters on the filter and inlet tube (O vs o)

Unless blowby mass is greater than vacuum mass, so that the remaining mass would vent to atmospheric pressure at (14.7 psi absolute)

Hook a vac gauge to the can and see if you pull more vac with the filter, or with that opening blocked.

92CXyD · « **Reply #24 on:** March 20, 2009, 09:40:01 AM »

Yeah remember the balance mass flow equations M1=M2 from fluid dynamics.

In other words you can not pull more gases out the slash cut than you can have gases going in to the catch can. ;D

ratcityrex · « **Reply #25 on:** March 20, 2009, 01:33:18 PM »

If you look at the pics where its on the car, He dosent have the filter on the catch can anymore. He went to a baffeled valve cover breather off of a V8 stlye

danz · « **Reply #26 on:** March 20, 2009, 08:24:41 PM »

Quote from: ratcityrex on March 20, 2009, 01:33:18 PM

If you look at the pics where its on the car, He dosent have the filter on the catch can anymore. He went to a baffeled valve cover breather off of a V8 stlye

yup.. cabin doesnt stink like poison anymore either.

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Author Topic: DIY d-series catch can, now with SLASH CUT (Read 37332 times)