Plumbing LS3 PCV w/ ITBs
Thread Starter
Teching In
Joined: Jan 2010
Posts: 36
Likes: 0
Plumbing LS3 PCV w/ ITBs I have an LS3 with ITBs. For the PCV ports on the engine - specifically the "snout" that comes out of the valley cover and the nipple on the passenger valve cover - can I just run hoses from them to a catch can, or am I suppose to do something else?
if i recall right, the last time I plumbed an LS the valley cover port went to a fitting on the intake manifold around the MAP and the valve cover port went to a fitting on the intake tube just after the MAF; of course neither exist here.
if i recall right, the last time I plumbed an LS the valley cover port went to a fitting on the intake manifold around the MAP and the valve cover port went to a fitting on the intake tube just after the MAF; of course neither exist here.
if they go to a common plenum then you plumb like any other pcv system.
if they are individual runners complete to the head you will either need to plumb a common 'log' connecting each runner to create a common vacuum point OR have to have an open vent to a catch can with a possible option FROM catch can to open header vacuum check system.
if they are individual runners complete to the head you will either need to plumb a common 'log' connecting each runner to create a common vacuum point OR have to have an open vent to a catch can with a possible option FROM catch can to open header vacuum check system.
Staging Lane
Joined: Oct 2015
Posts: 86
Likes: 0
I have an LS3 with ITBs. For the PCV ports on the engine - specifically the "snout" that comes out of the valley cover and the nipple on the passenger valve cover - can I just run hoses from them to a catch can, or am I suppose to do something else?
if i recall right, the last time I plumbed an LS the valley cover port went to a fitting on the intake manifold around the MAP and the valve cover port went to a fitting on the intake tube just after the MAF; of course neither exist here.
if i recall right, the last time I plumbed an LS the valley cover port went to a fitting on the intake manifold around the MAP and the valve cover port went to a fitting on the intake tube just after the MAF; of course neither exist here.
IRTBs or ITB (Individual runner throttle bodies, or individual throttle bodies)
Single throttle body per cylinder. Great for response/high rpm, not sure how fun tuning/syncing modern ones on a v8 would be, but motorcycles have used them for a long time. The Bmw e90 M3 uses Itb's on its v8, and sings.
http://www.bimmerboost.com/images/im..._teaser3-1.jpg
Here's a photo of one with ITB's with a joined plenum (one per bank) on an LS, as well.
https://levelxmotorsports.files.word...gine.jpg?w=474
Single throttle body per cylinder. Great for response/high rpm, not sure how fun tuning/syncing modern ones on a v8 would be, but motorcycles have used them for a long time. The Bmw e90 M3 uses Itb's on its v8, and sings.
http://www.bimmerboost.com/images/im..._teaser3-1.jpg
Here's a photo of one with ITB's with a joined plenum (one per bank) on an LS, as well.
https://levelxmotorsports.files.word...gine.jpg?w=474
Last edited by msmnick; Oct 26, 2015 at 09:13 PM.
TECH Junkie
Joined: Dec 2005
Posts: 3,092
Likes: 11
Post 2 has it right if you want to run a PVC system. You would have to drill a port on each ITB below the throttle plate to in order to get the vacuum from each cylinder. Then as stated join them all together and make one PVC hose so to speak. Myself I would run a catch can.
Regarding the valve cover I would run that to fresh air through a filter attached to the valve cover.
Regarding the valve cover I would run that to fresh air through a filter attached to the valve cover.
Thread Starter
Teching In
Joined: Jan 2010
Posts: 36
Likes: 0
I'm back to revisiting this question and I'm totally lost.
I have my oem intake manifold installed and I have the passenger valve cover running to a fitting on the intake tube behind the MAF and the valley cover snout running to the port on the throttle body.
I am going to install my ITBs now. I will run the passenger valve cover to a vented catch can.
However, i'm not sure what to do about the valley cover snout. From my readings it seems there are 2 possibilities:
*run it to another vented catch can
*the ITBs have a common vacuum log (that the MAP reads from) that also has a port at the end where you can draw vacuum for HVAC, power brakes/etc...; do I want to run the valley cover snout to this port?
I have my oem intake manifold installed and I have the passenger valve cover running to a fitting on the intake tube behind the MAF and the valley cover snout running to the port on the throttle body.
I am going to install my ITBs now. I will run the passenger valve cover to a vented catch can.
However, i'm not sure what to do about the valley cover snout. From my readings it seems there are 2 possibilities:
*run it to another vented catch can
*the ITBs have a common vacuum log (that the MAP reads from) that also has a port at the end where you can draw vacuum for HVAC, power brakes/etc...; do I want to run the valley cover snout to this port?
Trending Topics
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine
Verdad Gallardo
7 Most Reliable High-Performance Engines GM Has Ever Built
Verdad Gallardo
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin
Verdad Gallardo
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
I've salivated over ITBs for a while now and run it through my head a few times. Running to the vacuum log seems obvious(and correct) but I worry about the volume of airflow available there. Without a common intake plenum to draw (a lot of?) vacuum, I would consider running a restrictor in the PCV line so you don't starve your other accys of vacuum. Perhaps I am being overly paranoid. I haven't had my hands on a complete setup yet to see how the vacuum log is configured so this is a theoretical risk.