Lexus IS Forum banner

1 - 8 of 8 Posts

·
Registered
Joined
·
21 Posts
Discussion Starter #1
I have the stock intake box and a factory filter, attached to an HKS intake tube. Stock otherwise, although I just ordered a Dezod green header.

Opening up the factory intake today, I noticed all these fins and ridges inside the air box, just downstream from the filter.

Has anyone ever tried to dremel these fins off, for straighter airflow through the filter? I'd guess they're either overengineered "structural stability members", and/or for sound dampening of the airstream, like the resonator chambers built into the stock intake tube.

I might try it, for the cost of a dremel bit it's worth a try for an externally invisible airflow mod.
 

·
Registered
Joined
·
586 Posts
I know the 3GSE engine Altezza can have problems when you port the fins in the box as it can effect the way the air flows through the MAF sensor, so i would imagine this may apply to the 2JZ as well.
 

·
Registered
Joined
·
21 Posts
Discussion Starter #3
Got any sources on that? I'd like to do some reading. I can't imagine it'd disrupt the airflow over the maf any more than an open element "cold" air intake.
 

·
Registered
Joined
·
675 Posts
Try it and let us know, take solid metrics before and after (AFM, fuel trim, mpg, ... readings across the load range, etc.)!
 

·
Registered
Joined
·
586 Posts
Got any sources on that? I'd like to do some reading. I can't imagine it'd disrupt the airflow over the maf any more than an open element "cold" air intake.
Sorry, i cant remember where i read it, maybe on one of the Altezza forums. I suspect the difference is the pod filters are round so there is no bias of the air on one side of the intake pipe, with the OEM its a rectangular box so the air can flow differently before the intake pipe creating a pressure difference.
 

·
Registered
Joined
·
21 Posts
Discussion Starter #6
So today I took the box out of the car, got it in my lap to really look at it, and I realized the "fins" for lack of a better word actually don't intrude into the plenum as far as I thought they did, and most of them are angled to kinda facilitate airflow towards the intake.

What I did notice that there were two areas that could be addressed: the transition from the round opening into the pre-fliter plenum, and the transition from the post-filter plenum to the round intake tube. Both these transitions were sharp, with hard angles where the round part of the plastic ended. So I took some fine sandpaper and hand-smoothed the radii to help the air move smoother across those transitions.

It's not much, probably really only good for a bit of throttle response and 0.1hp at the very peak of airflow, but it's something! I really like the design of the factory intake, I only wish it had straighter transitions. It's a great source of cool outside air.
 

·
Registered
Joined
·
21 Posts
Discussion Starter #7
Driving around today, didn't really notice a difference in throttle response. But above about half throttle, it seems like there's more intake growl than before.
 

·
Super Moderator
Joined
·
9,782 Posts
This has been done by many .... to eachs own adding snorkel to air box is one step above. And you’ll really like those headers.
 
1 - 8 of 8 Posts
Top