jonnyesse

i have a sti 6 and a welder who says he could cut an inspection panel into the top of the sti back box, then remove anything that was muffling the noise and finally weld up the inspection panel.
as it seems from posts that the main function of the backbox is sound and not performance related is this a good idea?
does anyone know the constuction of the backbox? can it be done?

raybotha

John , is it worth the hastle ? I found the pipe diameter going into the rear box also makes a difference . I personally found changing the rear silencer makes a difference . An Sti 6 rear silencer proves the above on my Sti 7 . Sti 6 box had bigger piping leading into silencer and inside too .
Just get a rear box , looks good , sounds good , goes better .

Ray

jonnyesse

cheers ray just an idea running in my head as if it didn't work then i would be getting a backbox anyway.
my theory to exhausts is that most performance gains occur through a catless downpipe,then catless midpipe with negligible gains via different backbox.
i believe a louder backbox gives the impression of more speed, everyone remembers their first cars(well mine anyway vw polo) and that occassional hole in the exhaust which gave that excitingly loud/ more power feeling.
hence the idea about trying to release more noise than the sti backbox and heck if it sounded **** it would just quicken me up ordering that hks big bore thingy

Floyd

iTrader: (9)

If the STi6 BB is the same as the STi5 BB then it won't flow as well as say, a PPP BB.

The STi5 BB has internal baffles and is not a straight through design. If the BB were opened up and some plumbing done then it would flow better but will probably be noisier.

F

raybotha

Floyd you right , its not a staright through unit (sti6) but the bigger piping leading to and inside that box makes a difference . A PPP does flow better .
I found you CAN feel the difference of a back box . eg. the boost comes in lower and spikes a little higher , and that you feel . Remember its not only foot flat that defines performance but throttle response and turbo spool , espescially when changing gears . But yes its the cats that give the most headaches . Once you've put a free flow on your Subaru , there's no going back . It feels the way the car was designed to go .

Enjoy .

Ray .