SirFozzalot

This is what I've got:

2003 STi Type UK running about 325bhp.

The exhaust setup it was mapped with and is currently running with is:

Prodrive Sports Cat (same as PPP set-up) 2.5 inch
Prodrive De-Cat centre pipe (same as PPP set-up) 2.5 inch
Standard STi 2.5 inch rear pipe (with standard resonator)
Blitz NUR Spec S back box - 3.0 inch

I think I'm getting old and I'm starting to find the Blitz a bit tiresome so I'm thinking of taking off the Blitz NUR Spec S back-box and putting the original 2.5 inch STi back-box back on.

Will this **** it up? What sort of effect will this have on the car? Would it need mapping again due to the last section of pipe reducing to 2.5 inch from 3.0 inch?

matty4113

Nooooooooooooooooooooooooo, the blitz sounds amazing, I have the nur spec s and wanted a little more oomph so bought an H&S deresonated centre and absolutely love it.. With reference to a map tweak, I think it's always beneficial to have it tweaked but I dont think that changing the back box (which is right at the end of the system) will cause any problems.

SirFozzalot

That was my kind of thoughts on it but wasn't sure.

Anyone else with any input?

360ste

iTrader: (1)

The OE backbox will alter the performance of the car due to a increase in back pressure. Have you looked into fitting a bung in the tail pipe, as this will reduce the noise.
I have a APS 3.5 inch straight through system with a adjustable bung in the tail pipe when I close it down the car is a lot quieter but the performance is knocked down a level.

_Viktor

Have you thought about getting your current back box re-packed.

When I got my car the HnS was a little too loud for my liking (old also), so I ordered some Acousta-fil from thermal velocity, got my angle grinder, cut a window out, took out (what little was left) of the very old any sorry looking wadding, repacked with the accustafil.
took the back box down to a machine shop, which I had prevously checked could do stainless steel welding and they welded on a patch plate over the hole I had made.

sounds great now, just a gentle burble at idle and not at all annoying at 3500rpm cruising speed.


Vik

SirFozzalot

I've got a bung for it but I've never used it as I would need to drill a hole for the securing screw. I figured this would probably cause as much restriction as the STi box.