I am currently running a full de cat and prodrive back box but still have the original resonated section in,Although the sound is nice and deep I would not say its really got the burble. I also find it can be a little droning on motorways.Do you reckon changing the resonated section for a straight through piece? or will that make it even worse in the cabin of the car, Anybody had the same problem, the car is a 2.5 litre STIso I'm only really interested with 2.5l cheers Gonzo.

 

hi mate i to have the 2.5 sti my car has the ppp but i have had it remapped by JGM , i still have the ppp sports cat but i have taken out the centre resonater combined with a ninja 2 back box and it sounds fantastic and still pretty quiet in the cabin , hope this helps mate.

 

Hi mate I thought that the 2005 2.5l PPP STI onward keeps the standard cat in the down pipe and removes the under panel cat (2nd).
Did you try the car with the resonated section in before the map ? mine is also mapped by JGM.

 

Get rid of the centre silenced section Will rev more freely and sound better inside and outside of the car

 

Really now that's the sort of answer im looking for. have you had similar experience ? will it need a map tweak? I looked at one from Cobra exhaust they do one with a small silencer I was wondering if that would tick all the right boxes or maybe just go with the straight through one

 

Done it to both my new ages, OEM centre to H&S straight through. Don't waste your time, just get a straight through pipe. The prodrive box won't give you anymore noise unless you do, and even then it isn't going to be miraculous. It will however, rev more freely and feel less lumpy on the accelerator and inside the cabin. No remap just enjoy. Price wise about £100 tops. H&S run groups buys so would be worth a look or even a phone call to Ian at H&S to get a snet price.

 

yes the resonator box was in before the remap as that is how the car came but a remap wont make any difference to the noise will it, just take the resonater box out and try it you can allways put it back in, i didnt go for decat as i cant be bothered changing for mot reasons and it might only make 1 or 2 bhp difference so not worth the hastle , just my opinion though mate.

 

greatgonzo, Replacing the center section with a straight through pipe, assuming your 2.5 litre impreza is still running the unequal length headers, you'll find the scooby burble would be slightly more pronounced, will make your droning noise slightly louder and will increase BHP minimally (will not need another remap).
--Steve.

 

Agree it will be noisier but how will it allow the engine to rev more freely?

 

not to sure about running more freely but no you wont need another remap, the resonator box is not that restrictive its just there to make it a little quieter , take it OUT you will love it mate.

 

I think im going to get one and give it a go
I just dont want any more droning in the cabin area of the car,I don't mind the level going up out side of the car. hopefully it will change the note of the exhaust and help stop it droning.

 

The drone may be because you have took the cat out, as i said before i didnt as i cant be bothered messing about for the mot.