Just seen a 3IS intake pipe and it's slightly different. Our 2IS pipe has some kind of square box shape thing attached near the ventilation connection from the engine block. And in the 3IS intake there seems to be something different. I read that it's some kind of sound generator. Question is, is this sound as good as the sound from a F Sport metal intake? and is the 3IS intake pipe direct fit on the 2IS?

 

My understanding of those reservoirs is that they're there to increase the effective volume of the tube without reducing air velocity past the MAF. The increased volume is desirable under high-load situations with the throttle plate wide open, behaving as an air capacitor of sorts, artificially increasing the plenum volume between the MAF and intake valves.

If it has anything to do with sound, it'll muffle induction sound, as it's releasing perpendicularly to the air flow, which would stall out any outgoing induction energy. I replaced my OEM air tube with a 16" long piece of 3" aluminum tube with a 30-degree bend in the middle, and about 4" cut off the TB side. The MAF responds marginally quicker to throttle inputs than OEM, but under load, it's noticeably louder from the front of the vehicle. MAF signal doesn't seem to be negatively affected, but I haven't changed engine air demands yet.

 

https://www.clublexus.com/forums/is-...l#post10726057

 

So the 3is pipe has some sort of sound generator incorporated into it's design then? I currently have a drilled lower airbox and a joe z intake pipe which gives a good sound. But wondering if the 3is pipe with the modified lower airbox will sound better than the Joe z pipe? Any ideas?

 

What you're hearing with yours is mainly the drilled out lower intake box. IIRC, the straight pipe design like the JoeZ and F-Sprot can actually be a bit quieter than the stock tube. The sound generator on the 3IS and 4GS intake pipes a bit more noise into the cabin, and you can hear it outside as well mainly into the 3k+ RPM range. I don't know if it gives any minor HP increases like the F-Sport and JoeZ claim, probably not though.

I've got a 4GS intake with the sound generator on mine and I like it. Should note the 4GS and 3IS are the same intake so you buy whichever one is cheaper. iirc, not all 3IS's have the sound generator (I want to say it's standard on F-Sports, and may have become standard across the lineup sometime after it's original release), so if it's something you plan on buying, make sure it has it.

 

How do you tell if it has a sound generator? Which bit is the sound generator itself? Can you show me a 3is pipe with and without sound generator so I can make sure I'm looking at the right one

 

3IS w/ sound generator: https://www.ebay.com/itm/LEXUS-IS350...Condition=3000

3IS w/o sound generator: https://www.ebay.com/itm/2015-LEXUS-...Condition=3000

2IS stock tube: https://www.ebay.com/itm/2006-2015-L...Condition=3000

 

If you have an IS250 the intake must have the Letter "B" near the throttle body side.

The IS350 has the Letter "A" near that area as well.

 

Looking at that pic, what's at the other end of that sound generator trumpet like pipe? is it an open hole pipe? will that not cause a vaccum leak?

 

It's a diaphragm:
https://www.clublexus.com/forums/is-...generator.html

 

Interesting.

Kinda makes me wanna take it to the absurd and figure out what kind of passive radiator (from the speaker building world) could be driven from the signal and build it as a 4th order bandpass. Probably make it sound like an exhaust header leak.

Y'know, like those exhaust whistles, or a duck call on the blowoff.

 

Will drilling a hole and custom welding a pipe to the side of the Joe Z pipe and then attaching this sound generator work? That way it's like best of both worlds, the performance improvement of Joe Z and the sound of the Sound Generator

 

I don't see why it wouldn't.

My absurdist idea is really just that, but using bigger, less resonant materials.

 

Here you go for the F Sport trim. Just look at the correct one, and color you need. IS350/IS250 the pipe diameters are different.

https://hpsperformanceproducts.com/p...-blue-27-569bl