I just fitted a Prodrive backbox (the WRSport one from Subaru with the oval tailpipe) to my unmodified WRX MY03 wagon but it's too noisy for my liking.

Anybody got any ideas for a back box which is less restrictive (a remap is on the horizon) than standard BUT hardly any noisier? I like a subtle car which doesn't advertise its presence.

Any (sensible) suggestions please

Francis K

 

hiya,i think your the first guy who wanted less noise than the prodrive boxes make!
imho if its gona flow better your going to have more noise,but do you not think thats what the scoobs are all about"part of the whole experience"

 

I must be getting old but I don't want people on the street turning round to see what the noise is like a chav Corsa driver.

 

I've got the same set up ( 03 WRX Wagon ) with the prodrive rear box , I don't find it too noisy , but yes it does take a little getting used to . I think the problem is to do with it being A wagon ,I think you get more noise back in the cabin than in the saloon due to the big empty box effect .It might be worth sticking with it for a while and see if you can get used to it , especially if you want to remap it soon .

Dave

 

i cant hear a thing with my prodrive bb ? or is it just me

 

Prodrive BB is about as quiet as they get, and are slightly restrictive TBH.

 

You can make it quieter by fitting some equal length headers to the car, but will lose the famous scooby burble

 

Will you do a P.X for a std my04 STI back box ..done 2k.
Nice and quiet.

 

You will get used to your Prodrive backbox, and a wagon seems much louder as mentioned above. The other big advantage is it looks standard and probably doesn't attract as much attention as a 4" monster. "Modified vehicle, officer, not me..etc, etc".

 

Good try thedrill! When it comes off you will get the chance to buy it on Scoobynet or on Ebay!

Francis K

 

You could have a look at Remus systems. They used to be (on classics) quieter than standard but with reasonable flow.

 

No harm in trying...LOL.

 

try a magnex 6x4 oval thats what i have on my 94L wagon but its to quit for me but still looks good and sounds great..

 

prodrive backbox too loud - first time I've heard that one.

you'd hate my car.

 

Interesting thread as I've just had the same Prodrive backbox put on my standard 01 WRX wagon and I also was a little shocked by the noise - I was expecting something a LOT quieter. I've had it on for over a week now and just about used to it though. At first I was tempted to change it back! Personal preference for me is a quiet exhaust though the scooby burble does sound very good. It's just that I'm sure I've read on this board that it was supposed to be the same volumn level under 4k revs and then it gets more vocal but I'd say it is as its noisest when sitting stationary (still very conscious of it at traffic lights or sitting in queues).

I've noticed a nice increase in driveability though (also had a panel filter change) and as I'm looking at a full decat and remap next year sometime I've no real option but to get used to the noise increase and at least this way I'm more used to it before the increase then.

Richard.

 

And give the neighbours time to get used to it too

 

TOO LOUD = TOO OLD

 

Why not put a standard twin pipe on?

 

Thanks for the advice guys - standard box goes back on in the short term.

Francis K

 

Franics matey - still surprised you find the PPP back box too loud, it's bearly a whisper compared with some of the other kit out there. I'd really stick with it and get used to it if I were you.

If you really don't like it audible I'd give H&S a ring... they can do a nice looking 3.5" back box, and I believe they have some flexibility for making it very quiet if you ask for it custom like that.

The standard back box was the first thing I replaced on mine - dreadfully restrictive - hope your not rolling around on that for too long.

 

Francis,
PMd you.

Nick

 

Francis,

Been there, tried that. I've posted before about exhaust noise and while I agree to a certain extent with another's comment, "Too loud = Too old", as an oldie myself, I also just don't appreciate noisy exhausts.
I do appreciate the Impreza burble but looking at other high performance cars, you very seldom see "quality makes" fitted with noisy exhausts.

The original twin-pipe back box is quite capable of passing an appreciable higher flow rate without losing more than about 3/4 bhp compared to more noisy backboxes so I would tend to stick with the original backbox but go ahead with the re-map and even, like my own car, have a full de-cat system fitted.
The de-cat and the re-map is what really "ups" the power and my own classic wagon is now producing about 265bhp with standard backbox.
This "stealth" approach is the way to go to ensure you're not classed as boy-racer and an added benefit is that any attention from "boys in blue" is minimised.
p.s. If you think your present set-up is too noisy, just wait until you hear the exhaust after a full de-cat with your backbox----makes motorway speeds intolerable.

 

:Hmmm,

In process of buying a WRX 2001 with a"WR" exhaust with an oval tailpipe.

Is this made by Prodrive or is there an other "WR" on the exhaust scene ??

 

IMHO the backbox is not particularly restrictive. It's everything in front of it that restricts. So, decats and standard STi box should keep things quiet but give you the power gains from the remap.

 

IMHO most of the 'drone' noise penetrates the cabin simply because the ineffectual sound insulation wasn't designed for anything louder than the OEM pea-shooter. Worse in a wagon or a Forester due to the open deck.

In mine I simply added some Dynamat Extreme to the floor and the spare-wheel well, and some old felt carpet underlay wadded into the vent area. (The vent is probably different on different models - the key point is that a huge amount of exhaust noise bounces off the road and comes straight back into the cabin.)

This reduces the motorway drone considerably. The vent is partly to allow the air pressure to dissipate if the airbags go off, there is one each side, so you are reducing the safety margin if the air bags deploy if you block one.