LSx454 with ITB Catch Can Help
Thread Starter
Staging Lane
Joined: Oct 2011
Posts: 90
Likes: 2
From: Adelaide, Australia
LSx454 with ITB Catch Can Help Hello all. I have an LSx454 fitted to my car, and it uses a Jenvey ITB intake set up. The car is a semi show car, used to only run a few thousand miles per year. I do drive it without air cleaners and know that's not ideal filtration wise but i just live with that and change the oil frequently.
I want to connect up a catch can, and have bought an Elite Engineering one to replace the one on there now which doesnt seem to work very well. I have a vacuum port tapped into each of the intake runners, and they go back to a manifold block, which is where I also tap into for the MAP sensor.
So my question is how do I connect the catch can, given there are the three ports, one on each rocker cover and also the valley?
As I understand it I can take the ports from each rocker cover to a tee, then those to the catch can and then the can to the manifold block?
Where should I take the valley cover port too, as i understand I would normally take that to the air cleaner, but that's not possible on my ITB set up.
This is my engine set up now;
I want to connect up a catch can, and have bought an Elite Engineering one to replace the one on there now which doesnt seem to work very well. I have a vacuum port tapped into each of the intake runners, and they go back to a manifold block, which is where I also tap into for the MAP sensor.
So my question is how do I connect the catch can, given there are the three ports, one on each rocker cover and also the valley?
As I understand it I can take the ports from each rocker cover to a tee, then those to the catch can and then the can to the manifold block?
Where should I take the valley cover port too, as i understand I would normally take that to the air cleaner, but that's not possible on my ITB set up.
This is my engine set up now;
Three port cans are generally meant for FI setups. With yours I'd probably say that a vacuum pump might be best. At WOT you really have no way of plumbing the can back into the intake. At part throttle the same issue exists. Usually you'd use the engine vacuum to pull gases from the block into the can. You cannot do this without more or less defeating the benefit of the ITB's. Tying any of the cylinders to each other defeats the ITB's perks(at least with a block big enough to matter for a catch can) and also creates an imbalance to what air quality the cylinders see.
Really the best thing would be to use a vacuum pump to pull the crank gases through the can and leave the ITB's exactly as they came from jenvey.
Really the best thing would be to use a vacuum pump to pull the crank gases through the can and leave the ITB's exactly as they came from jenvey.
TECH Addict
Joined: Jul 2013
Posts: 2,189
Likes: 123
From: Portland, Oregon
A vacuum pump would absolutely be best for an ITB setup, unless you have the individual stacks going into shared plenums for the catch can. The BMW S54 (I think) has a shared plenum for its ITB's and can run a closed loop emissions system, and can also use a catch can in a conventional manner. To run the ITB stacks open, like you have them on your beautiful engine in the picture, you really would want a vacuum pump.
Thread Starter
Staging Lane
Joined: Oct 2011
Posts: 90
Likes: 2
From: Adelaide, Australia
Yea thanks, I have actually read a little about vacuum pumps and came to a similar conclusion, I also like the potential performance gain it gives. But as I understand it there isn't much point in going to one unless you strip the motor and fit a new set of piston rings to take advantage of it? At this stage stripping the motor is a step too far.
I did have this crazy idea of perhaps making up a tube that sat at the end of one of the trumpets plumbed to the valley port. But take the two rocker covers to the catch can and small vacuum manifold block i have already via a non return valve. Then the normal driving I think the two rocker covers would do enough but I was thinking then at wot at least the pressure in the crankcase would bleed and be drawn into the trumpet? I know its not ideal, but it is a streeter so truthfully it doesn't spend much more than the occasional short burst at wot.
Any thoughts on that or is it a dumb idea?
I did have this crazy idea of perhaps making up a tube that sat at the end of one of the trumpets plumbed to the valley port. But take the two rocker covers to the catch can and small vacuum manifold block i have already via a non return valve. Then the normal driving I think the two rocker covers would do enough but I was thinking then at wot at least the pressure in the crankcase would bleed and be drawn into the trumpet? I know its not ideal, but it is a streeter so truthfully it doesn't spend much more than the occasional short burst at wot.
Any thoughts on that or is it a dumb idea?
Last edited by VRSenator065; Aug 9, 2016 at 08:13 PM.
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Verdad Gallardo I don't think it adds to the look of the motor if you are running it off of the idler pulley. I had to move a lot around to get mine to fit and still be able to pull the battery out. If the battery is rear mounted that would help.
Thread Starter
Staging Lane
Joined: Oct 2011
Posts: 90
Likes: 2
From: Adelaide, Australia
Just an update on this. So the system I came up with is a semi legal hybrid idea. I have the vents off each rocker cover going to an Elite Engineering catch can, through a non return valve to the vacuum manifold block. But I also have mounted a traditional vented catch can out of site underneath the fender, this is plumbed via a non return valve to the larger vent port in the valley. The idea is for general driving the closed loop Elite can does the job. But under hard acceleration the crankcase can vent via the regular vented can. So far so good, seems to work well.
11 Second Club
Joined: Mar 2012
Posts: 1,541
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From: South Florida
Just wondering. What got in the way of the battery?
Teching In
Joined: Feb 2022
Posts: 2
Likes: 0
Hello VRSenator065 -- I realize this is an older thread but I've recently embarked on a '72 Corvette restomod project. I'm looking at the LSX-454 crate engine (as you most likely know the '72 vette was available new w/either a 350 (base) or optional 454), and I definitely want to put an ITB set up on it. After a few days searching the interwebs you are the only one I've found that's paired the two. I'm curious how it's gone in the intervening ~6 years. How is the performance? Do you still have the car? How did the Jenvey set up work with the LSX-454?
Best Regards,
-jjd57
Best Regards,
-jjd57
