Translator

Guys, I was searching for some videos of the 427 Convertible on Youtube, and found a video that struck me as odd. Please check out the video below. It shows an air silencer on the air intake for this LS7, which is the same that is used for the LS3's. The Z06's do not have the silencer. I searched other videos of the 427 convertible with engine shots, and they too appeared NOT to have the silencer, except for the one in this video. What gives? Installed by mistake at the factory?

X25

Interesting. So other 427s don't have it? I wonder if someone installed LS3 air intake for some reason.

Translator

^^^ I have NEVER seen an air silencer on an LS7. That car appears brand new though. According to other 427 videos that show the engine compartment, I did not see it.

Translator

No one knows the answer to this question? I looked at some pictures in the 427 Registry thread as well, and lone and behold, some also have the silencers installed while others do not.

RichieRichZ06

That is weird because the GM Electronic Parts Catalog only shows one air intake for all the LS7 cars. It clearly shows the silencer on all LS3 models, but not an any LS7 engines.

Jawnathin

I saw one of those for the first time the other day on a 2012 GS with the hood popped. Was curious as to what it was. Any function to it?

Translator

Richie, yes indeed that is totally strange But the picture clearly shows the silencer in the LS7 of that particular 427 in the video, which is brand new. I also searched the 427 owner's thread on this site, and found another picture of one there that also had the silencer. Most do NOT have it though, but for one reason or another, some do. I wonder why though, that is the question?

Translator

In my personal opinion, GM put this on the LS3's to restrict the power output of the engine, so it did not get too close to influence LS7 sales. It does quiet the air charge a bit, thus it being a "silencer".

Translator

For this reason, aftermarket CAI's make more of a difference on the LS3, when compared to the LS7, as all aftermarket units obviously eliminate the use of the silencer.

JWingo

Air silencer does not add or subtract air flow. It is a damping device. Ambient air pressure which is exposed to air filter element determines CFM.

Translator

I am not an engineer, but I was under the impression that the silencer diminshes air flow (CFM's) and velocity. The air is entering the silencer, prior to entering the throttle body, thus the path is not direct. Thus, the LS7 (except for a few as noted on this thread possibly by mistake) and the LS9 do not use the silencer. I will let others shim in on this, but the purpose of the thread is not for this discussion, so in order not to highjack the topic, it is best not to enter into it.