View Full Version : This resonator thing

2nd August 2000, 21:44
Can someone who's actually done it please describe in minute detail the process of removing the resonator in my air box (my00).
If it makes a big difference when removed why do they fit it in the first place?

3rd August 2000, 00:08

On a my99/00;
* remove wheel and front splash guard under wheel-arch/front bumper
* remove supporting bracket between engine-tub & inner wing (2 nuts; one fiddly!)
* remove big black & performance sapping "gourd-like" thing (2 nuts) - this is the resonator!
* remove the black plastic piece now flapping in the engine bay
* put the support bracket back in & refit splash guard

Is that enough detail?

The resonator is there purely to reduce the noise of the engine.


[This message has been edited by DaveW (edited 03 August 2000).]

3rd August 2000, 02:01

Is that the same location on a MY93 WRX and can you just bin it without any life threating effects.

Muddy http://bbs.22b.com/ubb/smile.gif

3rd August 2000, 17:28

I know someone with a MY93 and the above instructions worked for them.

As for bining it, its up to you but you might want to keep it for when you come to sell and the buyer wants a quieter car http://bbs.22b.com/ubb/wink.gif


PS: What time do you call that to be posting here. I thought I was bad http://bbs.22b.com/ubb/biggrin.gif

[This message has been edited by DaveW (edited 03 August 2000).]

3rd August 2000, 17:54
Thanks Dave nice clear instructions, i think I'll give it a go.
Just one other question, have you got any top tips for getting the fasteners out that hold the wheelarch liner on. They look like they might self desruct if I so much as show them a screwdriver!

Swiss Steve
3rd August 2000, 19:35
I did a couple weeks back. Can't say I noticed any performance increase but a couple other guys said the turbo spools up a bit quicker, and should give a little extra power due to colder air being drawn from under wheel arch rather than in engine bay.
Most noticable difference is noise. You hear all intake sucking and blow off when change gear. Below 3000 and on light throttle around town you down hear intake roar...
Its not so intrusive that it drives you mad. If you ever had a normally aspirated car with a K&N (like my Mk 2 '76 Mexico) you'll recognise the intake noise.

With regard to the splash guards, you really do only need to remove the smaller front one.

Remove the standard intake scoop from the front panel in the engine bay (one bolt) and just pull it off the resonator inlet, (protrudes through inner wing panel) & replace bolt in front panel.
There's 2 nuts (10mm I think) on the inner wing panel, one just in front of the main filter box & other slightly lower down. Remove with 10mm ring spanner or small ratchet. The top one is one of the resonator nuts the other for the support bracket. The bracket has to be re-fitted as it has the retaining hole for the clip which reconnects the upper & lower splash guards.

Most of the plastic clips, you just push the centre round part in a little. You have to 'tickle' some of them out gently as they can be a little caked with dirt behind, so you need to shake that loose. I used a flat blade screwdriver to gently ease them out.
There's also a couple of metal cross head screws to remove.
There's several different sizes of plastic clips. Keep them in the right order for correct re-fitting. The biggest one is under the front spoiler to join to the lower splash guard. Trickiest clip was the small one holding the splash guard to the inner lip of the actual arch in the wing. It has a cross head slot for screwdriver but the threads were slipping. Unlike the other clips which you push in the center - I guessed with this having a crosshead srew slot it needs to come OUT - so I had to push at it from inside the inner wing by putting my hand down through the opening left by removing the front air scoop off the front panel. (Careful - it's pointy - so can't use yr finger). I think I did this to be able get at the other bolt holding the outer end of the support bracket (10mm open ended spanner).
There's another bolt holding resonator on, underneath - so it's time to get on your back and think of England.
Resonator box just pulls out - once all bolts are removed - it just pushes onto filter box inlet in same way as front air scoop pushes onto resonator inlet.

Only thing that concerned me a bit was water splashing in and getting into some of the electrical connectors under there... but it looked pretty clean, probably indicating no intruding water.
After refitting splash guard, I notice there was an extra hole in the lower one which could be blocked off to prevent water getting.

As per Haynes, refitting is reversal of dismantling.

Enjoy the noises.
It sounds like the Delfino Feroce when Tiff was reviewing it on Top Gear.

3rd August 2000, 22:47

I'm on Holiday so no work the next day, a nice lie in for me. http://bbs.22b.com/ubb/smile.gif


4th August 2000, 17:11

Mmmm holidays, I've heard about those, its where you don't go to work isn't it. Must try one one day and see what it's like http://bbs.22b.com/ubb/wink.gif


PS Lucky sod http://bbs.22b.com/ubb/smile.gif and I hope you like the turbo and wastgate noises.

4th August 2000, 17:58

It's nice this holiday lark "he he he". http://bbs.22b.com/ubb/smile.gif
Anyway i have just completed surgery this afternoon on my pride and joy. Removed Resonator which was a piece of cake, the only hard bit was putting the lower plastic shield back on!!.
I only took it out for 5min, didn't notice any change though. However now that I know what I have just taken out I can appreciate that the Air filter will get alot more unrestricted air. Exactly what is the black box with two pipes supposed to do, after looking at it it looks a bit pointless other than stopping water getting into the filter directly.
Don't seem to be hearing any more noise though, should I be?

Cheers Dave for getting me through that tough operation.


4th August 2000, 20:52

Glad everything went OK.

Try driving with the windows down and see if you can hear it.

Do you have a standard air filter?

Reason I ask is this could be the reason why you can't hear the turbo whistle and wastegate whoosh. I've got an ITG which may be letting more of the sound out. My mate with the WRX93 has a K+N.


4th August 2000, 22:43

Getting a HKS Superflow Thingy-me-bob next week so hopefully I'll hear the turbo whistle and wastegate woosh (with the window down).

Cheers Muddy.

4th August 2000, 23:00
Just add my 2 cents worth..

I followed Dave's instructions a couple of weeks ago and removed the resonator with no problems - Cheers Dave

I found that there was a deeper note to the exhaust and I could hear the dump valve hissing (even with a standard air filter). Since then I've had a Magnex back box fitted and it has a great sound. What I did find was that it was very 'boomy' inside the car. Now because I use my car for the daily commute, this was becoming a bit intrusive, so I have actually refitted the resonator.

There is still a nice note from the Magnex backbox - just not so noticable at lower revs. So I guess it is really personal choice.

One other thing I did try was putting a piece of flexible aluminium tube where the resonator used to be. The idea being to draw air in from the front of the car and direct it onto the air filter (similar to K&N induction kit - certainly cheaper) - this seemed to work quite well.


5th August 2000, 18:25

I haven't really driven the car since I removed the resonator just a jaunt along a road. I'll give it a good blast next week when I get it serviced and when I go to Donnigton on Friday(just spectating Can't afford it!!!).I've got a janspeed S1 exhaust from downpipe and I didn't notice any different sounds,It's a quiet exhaust in the 1st place.
Good idea about the pipe I'm planning on doing some thing along the same lines i.e; funnel made to fit hole to force air into engine bay(sounds good don't know if I can pull it off though).This is for when I add my new Induction kit that I'm getting next week. http://bbs.22b.com/ubb/smile.gif http://bbs.22b.com/ubb/smile.gif http://bbs.22b.com/ubb/smile.gif

Mudy http://bbs.22b.com/ubb/smile.gif http://bbs.22b.com/ubb/smile.gif

5th August 2000, 19:04

I bought the aluminium tubing from Halfords. I secured it inside the front wing with a couple of plastic 'zippy' ties, either side of the support bracket (the one you have to remove to get at the resonator). It is very easy to shape and very light, so there souldn't be a problem with it moving or falling off.

Good luck

5th August 2000, 21:15
Why remove it at all ?

fit a blitz cone/K&N/pipercross etc. The resonator can stay in place!

6th August 2000, 00:11

If you remove the resonator, you can put a larger Dia. pipe or modified tubing(or something like that)in it's place so it has got a direct flow from front of bumper to the wing, then to filter. Obviously bi-passing the small Dia pipes that go in and out of a plastic box, which i believe is a much more restricted air flow.

Just my Thoughts anyway!


Muddy. http://bbs.22b.com/ubb/smile.gif http://bbs.22b.com/ubb/smile.gif

6th August 2000, 08:40
Hi Guys,
took my resonator off yesterday and apart from chewing up one of the plastic clips and losing another one it all went smoothly!
Haven't noticed any extra power but it definately makes some entertaining noises even with the windows up! (Muddy- you going deef or something? http://bbs.22b.com/ubb/wink.gif )
I might try the flexible pipe route or just block off the gaping hole in the wing where the intake used to be.
Anyone got any ideas for uses for redundant resonators? (actually I'm keeping it in case I get tired of all the swooshing)

6th August 2000, 09:10
Hello all,
If you have removed the resonator from a MY99/00 car, it might be a good idea to remove the triangular orange plastic wedge from the right hand side of the front wing, underneath the indicator, and block off the hole in the inner wing were the intake pipe used to pass through. Then the cold air can get into the cavity created underneath the front wing by the plastic arch guard. That is what I have done on mine and my friends MY99's. Purely on a aesthetic front, it may be a good idea to remove the left hand side orange wedge also, to leave the car looking balanced. The volume of air that would pass naturally into the effectively 'sealed box' behind the arch guard, through the small slots in the orange wedges, and the small voids here and there, are probably insufficient to allow effective breathing of the engine.

PS Lee,
Why do it? Its free, and took me 20 minutes per car to do. Thats cheap BHP increase.

Cheers MTR

7th August 2000, 12:43
Well I can't understand members comments that they have found no performance gain .When the resonator is removed - including the little orange wedge as recommended by MTR
and when combined with a K&N filter + bleed valve giving 17psi boost - thanks Lee performance is substantially improved.
My Rex now pulls in top gear from 2000 rpm!
Bloody Great!

7th August 2000, 16:53
I considered doing this, but was advised by a v.reputable source that the resonator prevents oil/water/duckling feathers http://bbs.22b.com/ubb/frown.gif etc. permeating the filter, causing similar problems to oil impregnated filters further down the line.

Anyone checked their filter after continued abscence of resonator?

7th August 2000, 18:58

I'm not one to divert a conversation BUT, This bleed valve you have fitted. Where did you get the info to fit it. Was it Lee's website or another source?.
More info on this would be appreciated. http://bbs.22b.com/ubb/smile.gif

Lee- if it is your website is there any more info i need to fit one?. Will the descriptions apply to a MY93 wrx?. Can a Dweeb(me) fit one easily?.

PeterA- Inner plastic shield should offer enough protection to stop filter sucking in ducks etc. Where is the oil coming from!!!
I can appreciate water getting in, but not alot unless you plan on driving through 4ft deep puddles.

Muddy. http://bbs.22b.com/ubb/smile.gif http://bbs.22b.com/ubb/smile.gif http://bbs.22b.com/ubb/smile.gif

8th August 2000, 01:30
Muddy - Take a look at this web site for relevant info on the bleed valve mod.

8th August 2000, 05:48


for more detail - certainly without the resonator you need to increase the cleaning frequency. After 5'000k's there were a few flies and bits of debris in there.

But if your splash guards are in place correctly, nothing too large can get through! My main concern is one of water ingress through the orange vent under the indicator - but several checks since I removed the resonator has revealed no problems....so far!