I'm shelving this project as well as the LGX ported tb and LFX ported intake manifold. I just don't have the time to devote to them right now, and won't any time soon.

Sorry guys.


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Since our buddy Jason has defected to the turbo 4 camp, if it would be wonderful if the filler epoxy material could be listed so some of us could try a diy pass at our neglected intake manifold.

Also the odd 'silencer' protrusion in the intake manifold exists in the intake air bridge before the maf sensor. I assumed it helped straighten the air flow. Has anyone removed this other protrusion without negative effect?

The only sensor that I know of in the LGX intake manifold is the MAP sensor, The MAF sensor is in the tubular section of the airbox lid. Removing the protrusions will not effect MAF sensor operation.

I use a Polyurethane filler material. It's been working for years with no failure or ill effects from gasoline/oil getting on it. There are several different brands out there that are readily available to the everyday consumer. It's absolutely possible to do it yourself but have patience and think about what you are doing. It's really a pain in the ass with the filler on the LGX intake.

I will say that just by removing the huricane generator (protrusions) I saw about a 10% airflow increase. I had planned on trying an intake with just the protrusions removed on the dyno, between the bone stock intake, and fully ported intake just to see what kind of difference it made.


That said, I currently have 1 brand new LGX intake manifold I'd let go of if anyone is interested and would like to try their hand on a spare intake manifold... But I have a feeling the only way anyone is going to want it is if I port it...

Yea, I was referring to the one in the tubular section by the filter box since you had said you'd been removing the ones at the intake manifold since working on the lfx and had no problems. I didn't want to cause an issue with bad readings if the thing served some kind of air straightening purpose on the maf side.

Looks like i'll be cutting those off then.

Nice friday evening project.

I removed the silencers or whatever they are from the intake manifold.

Easiest way I could think of was to melt them off since I didn't have any snips small and strong enough to clip them.

Driving around I can't really say there has been any change in performance or sound. I need to find a nice non-traffic-y time on a 60mph road (there are some nearby) to go 0-60 and compare to my current record of 5.4 seconds. Honestly I can't judge any sound effects removing them may have had because my mrt v1 exhaust completely drowns out any kind of intake whistling that may be occurring.

I did notice that the K&N dropin that has about 5k miles on them now was decently dirty and so i swappped in my other K&N dropin. I'd recommend replacing (cleaning) cotton gauze filters twice as often as your paper ones as the benefits of the flow-rate diminish exponentially as the filter becomes dirty vs the linear flow rate effect of paper filters.

I have not yet tried filling in the intake manifold.

lemme know a price, will see what I can do this week.

Uh you do know that they are cleanable and reusable right? That's an expensive replacement on a consistent basis...just sayin....
Unless you just have 2, clean one and keep until the next replacement??

I have two so I dont have to rush the cleaning and drying process to avoid downtime driving.

Helps that I got one free.

Jason, would you be willing to port that last one?

This sounds like a fun project, has anybody else worked on this? Does anybody have the part# ??

if anybody is interested:

ACDELCO 12674143 {#12645755} GM Original Equipment

So does anyone know where we can purchase a ported manifold?


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jacofab is the guy that did them on the gen5 v6, so i dunno if there is that much of a demand. I really want one, and I've got some experience with aluminum manifolds so I ordered a stock one yesterday.

We'll see how much room for improvement there is and worth doing for the community or possibly post a DIY for a mild port job

apparently the trick is filling the thing, not really porting it (for the most part) ...to remove the cavities that cause turbulence and slow air flow down.

Not a simple feet.