Having just got an 09 WRX, only thing that's missing is the noise - Subaru have stuck a massive silencer on it (I guess to make it really quiet & appeal to normal, boring people) - but I'd like to move the Prodrive exhaust from my 03 Blobeye WRX to it, get that boxer burble back a little.

I can physically do the work, but the question is will the slight reduction in back pressure cause problems for the mapping? I understand if it's not mapped for that back pressure it might affect fuel economy but are there any other problems? I'll leave the cat & resonator stock, it's literally the last few feet & silencer I'll swap out.

Obviously if I had zillions to spend I'd pay a company to do the whole job incl mapping (actually I'd prob just get an STI to start with!), but I don't so am looking for answers that don't involve ££lots please!

 

I fitted seat covers and had to remap.

 

I looked in to doing the same thing on my 08 hatch, but was told by the garage it would not fit, or would cost too much to get it to fit so I bought a prodrive back box to fit , I may be wrong but I don't think you will get the same noise unless you buy a full system for example Cobra at about £600
This is what I was advised at the time ,so that's what I am currently saving for ,no remap needed either
i am sure some one with more knowledge may have a different view

 

fat-thomas - lol! How much did a remap cost roughly?

Yeah it won't fit for a straight swap, I'll need to weld the stainless a little to refit the 90 degree bends, bit of an effort but that sound's like heroin so probably worth the effort! It won't sound exactly the same but you can tell that 2.5 flat four is making the same sounds it's just getting muffled so much.

That's cool about the Cobra not needing a remap - that's a great system and definitely tempting. If I was minted I'd do the same.

I might ask in the scooby shop down the road about the remapping thing on the reduced back pressure, will update this thread if I get anywhere

 

if your keeping the cats in then you won't see much of a difference from a mapping point of view. The resonator being in/out is normally a very tiny difference in wastegate duty so the ECU should be fit to compensate for it on the standard settings.

 

Very helpful - thanks. Exactly what I was hoping.

Am I right in thinking the 3rd generation resonator in this case does quite a big job in removing the flat four burble? As in just swapping the muffler might not be enough to restore the 2nd generation prodrive WRX burble, and I might need to ditch the resonator too... assuming it's those sound waves that were the top of the list that the engineers tried to remove.

Might be I get the muffler swapped and find the sound restored how I want tbh, I'll post some videos here when I get going with the project

 

you can switch from the giant backbox for a traditional sized box and then remove the resonator (just replace that section with some straight pipe if you can weld) and you should get a good bit more sound out of it without sounding too rash (depends on the box you stick on of course)