ItzFilyO

U don't need the sound generator with the Takeda's open filter style, but u do need it with the closed filter like the K&N and stock cause they will be quiet without it. The Takeda will be loud and no need for another sound generator. K&N should've gone with that direction instead of just using the stock air box cause it's just the same as stock, plus u lose the sound.

jtrue28

DO NOT buy the K&N CAI. It was a complete waste of money.

Nobeanspls

I am thinking seriously about doing something with the intake. Can you peep down that opening under the filter and let me know what is down there? Is it open or filled with the brake cooling duct?

Nobeanspls

Looks like a 2013 AWD does not have a hole under the intake box. No way to do a better setup than stock.

Myxalplyx

By this logic, why don't you purchase a more restrictive air filter, to let less air in? Your engine would last much longer.....right?

Nobeanspls

Alright so I did some poking around near the stock airbox. What I discovered is that there is a nice gap under the headlights. This gap leads right into the fenderwell.

Interesingly, based upon the photos of the F-sport intake box I've seen online it seems this spot is where Lexus added an opening in the stock box for the F-sport intake.

My issue with the F-sport setup is that there is no snorkel into the space to ensure air is being drawn from the cooler fenderwell location. Secondly the bumper is blocked by the foglight area trim piece so there is no ram air effect anyway.

However, if assuming we were able to setup a snorkel and run it to the fog light area without the cover, then an additional ram air source would be available to the box at higher rpms. Combine this with the free flowing HKS or K&N filter and a smooth intake pipe and some actual gains may be realized beyond noise.

Also, because air takes the easiest path available and we are keeping the stock snorkel, the is no chance of sucking up water into the engine.

So to test my theory I need a second stock lower box portion. Anyone know where I can buy one without breaking the piggy bank?

GSTONY

I have a k&n on my car and I can tell you I did not feel no gains but the sound from the intake be screaming

jtrue28

The K&N intake system, or just a K&N drop in filter?

I can assure you that the car actually got quieter after installing the K&N CAI on my F-Sport, and other folks said the same. You are the only person I have seen that is claiming it made your car louder.

What I was hoping for was the sound that the K&N intake for the 3GS created. This however was not the case on the 4GS.

ItzFilyO

How can it be loud when it is a restricted (OEM-like) design minus the sound generator? Without the OEM sound generator or an open filter design like the Takeda that kit will be quieter than stock.

Myxalplyx

What is the square contraption to the upper left?

sonnyhood

Ive got the K&N filter replacement to my 3GS and its great.
Gives it a nice sound on high RPM, car breathes freeer.
Did notice bit more black marks around exhaust pipe, but have had new plugs since then and its perfect now.
I dont know how many of you have a GS450h but its a little shock when ppl read Hybrid at the red light, and at the green light they hear the rumble of the airbox as i take off, just enough noise to say dont F with me in traffic with your 2.0litre nissan or whatever
K&N well worth the money, i set my main to remind me every 5,000kms to clean it.
follow the instructions, dont go stupid with the K&N oil

http://www.knfilters.com/search/prod...x?prod=33-2220

ItzFilyO

Guys guys!!! 3GS and 4GS K&N are different. 4GS K&N kit uses stock parts, the only thing u change is the tubing and air filter, ur still keeping the stock box. This is a closed design, not open filter design like the 3GS, meaning u won't get any sound out of it. I wish K&N would go the 3GS route, I don't know what they're doing with the 4GS kit.

jtrue28

That's the top of the stock filter box. The part that "clamps" down after you check/change your air filter.

GregCanada

Not exactly. If the filter has a larger surface area that is not true.

Nobeanspls

K&N filters may allow a bit more particles in. I remember the best filter was the Apexi Power intake filter which both made power and was excellent in filtration when one website tested it against others.

If I were to go with the Takada, then I would replace the Takada's filter with an Apexi power filter.