KENSHIRO

iTrader: (2)

Hi guys just wondering if i will gain any increased airflow and throttle response by removing my resonator box at the moment i have a k&n 57i filter installed by the previous owner , and after being a honda owner i know how restrictive resonator boxes can be combined with aftermarket filter .

bob r

iTrader: (46)

I would say no.
With an induction kit, you should partition off the air filter from the hot engine bay and direct a cold air feed pipe from the inner wing to the filter.

360ste

iTrader: (1)

All that the resonator box will be doing in directing cold air from the front intake scoop onto the K&N. There used to be a pipe that replaced the resonator unit avaliable that connected the scoop direct to the airbox. If they are still avaliable you could use that or make up something to do the same job probably a lot cheaper. I took all of the intake system out when I fitted a FMIC which included a intake kit, still have not got round to putting a cold air feed pipe upto the filter yet.

corradoboy

Subaru intakes are very well designed and there is little to be gained from any aftermarket bolt-on products until you are over 350bhp or more. I/K's only really show benefits once you are running FMIC's and/or MAF-less set-ups. As hinted above, I/K's can actually reduce power due to drawing in hot and dirty engine bay air. Some older cars (98-00) also experienced MAF failure due to excessive vibration, and excess oil from the filter has caused issues in the past too. In tests by Harvey (Harvey Performance) he concluded that there is less than 2bhp to be had from drop-in panels, testing (IIRC) K&N, Green, OE paper, a foam one (not sure which) and the STi panel. The result was quite eye-opening, with the OE paper filter performing very well on both power and filtration, and the expensive (non-lifetime) STi item coming off quite badly, with a similar conclusion also in Scoobymag's similar tests. He also concluded that removing the resonator reduced performance as the airflow became turbulent, so it's better to leave it on. These tests were done on a classic on a rolling road over two consecutive days IIRC.

I removed the resonator on my 03 WRX PPP and thought it felt a tiny bit more urgent on spool-up. I enjoyed hearing the recirc DV on lift-off, albeit about half as loud as even the quietest VTA DV. I may have been imagining things, but I felt sure it ran slightly cooler in traffic with it drawing air from the O/S wing (with additional ventilation added).

KENSHIRO

iTrader: (2)

Thats that then cheers for the fast response

ScoobyNudge

iTrader: (4)

Agreed!

I have just removed my resonator on my 1999 turbo 2000 seems a bit laggy but nice sound it definatley needs a cold air feed directly fed Im gonna see what I can do with the orriginal snorkel ends cut off the snorkel and mated to a DIY sort of pipe to keep an OE fitment but less restriction

corradoboy

Be careful with direct ducting ! The resonator not only smoothes the air flow and quietens the intake, it also traps an amount of filth before getting to the filter, particularly water, dirty, oily, diesely water maybe. I remember one person on here opening up a fog light aperture and piping it straight into the air box. Within a few weeks his filter was overwhelmed with dirt which made its way through it and onto the MAF, killing that and risking meltdown. I sealed the air-box to the wing, and sealed all the holes from the engine bay. Then opened up vents in the fog surround and the undertray to get air in the wing, but not directly fed into the box so water and dirt mostly collected in the bottom of the wing.

will_wrx

Subaru spent time developing your airbox so it was efficient when it comes to noise, power, flow and keeping heat out.

Why go and ruin it?

Just bang an aftermarket filter in for a little more noise and performance, but still keeping the original airbox for its efficiency.