hi,if i was to fit a decat downpipe and leave the oe centre section(with cat/resonator or whatever it is?) with a 2.5" h&s backbox(original scooby sport design) will it make it any louder than leaving the oe downpipe in place?(i do realise it needs remapping.)
car is a 98 v4 sti type r.
thanks.

 

anyone?

 

Don't quite understand what your saying.
So you've got a backbox fitted now and you want to know if your car will be any louder if you fit a downpipe, is that right ??

 

Hi matey which backbox you have now fitted at moment?
If you have fitted standard peashooter,will be louder...


Jura

 

got the h&s backbox already fitted,want to leave the oe mid section and replace downpipe.

 

May I ask why you want to keep the standard middle section ??

 

to keep it as quiet as possible.

 

On my last Scoob I had a catback system fitted first as I didn't have enough moolah for a full decat. It sounded nice and throaty as the centre section was 3" but tapered to 2.5" for the backbox and downpipe. When I had the downpipe changed it was definitely a lot louder and the turbo spooled up more quickly.

With an OE centre section (which has a resonator NOT a cat) it will still be louder than it is now but certainly not unbearable with a decat downpipe.

 

So you want best power gains but retain the quietness, yea ??

 

yes mate,just want to know if it will be louder.

 

Yes it will.

 

alot louder? even with the resonator in?(centre section)

 

Yes it will be louder.
Searching for easy power means fitting a less restrictive exhaust system, which in turn means it going to be louder. It just can't be helped.
You have a few options though, for instance, on my car I have a complete 3" system including back box, middle section and downnpipe coupled with a GT spec manifold and up-pipe.
The manifold is from Lateral and exhaust is from Milltek. Very good power gains but without all the noise. Nice subtle rumble. Louder than standard but by no means LOUD.
If you can afford it, that's the route you should take.

 

It will sound like this

Louder yes but not in a bad way. The classic silencer isn't really that great at reducing noise, the main offender to noise is the back box and the downpipe which will also up the ante

http://www.youtube.com/watch?v=_Zgh3A1ouOw

104.8db with 3"dp, 2.5" H&S centre pipe and H&S Scoobysport back box

 

thanks,would a sports cat downpipe be quieter than the decat downpipe?

 

anyone?

 

sports cat will be quiter cos you shouldn't have the pops and bangs with a cat still in there.
here is a vid of mine with cats in place:
ClickMe!
and here is a vid after fitting decat down pipe and remap
ClickMe!

 

Recent H&S group buy in the group-buy forum area (funnily enough) ~ Ian offered to add a silencer into the centrepipe section for an extra £60 (I think) - didn't think it would make any serious impact to the flow.

 

the centre silencer does naff all for noise reduction.i had a std centre section and a 'powerflow' backbox and it was loud enough to be heard about 2 streets away. replaced with a straight thru centre section and a standard STI backbox - car is now really really quiet in comparison so as said above all noise reduction is in the backbox. thats in a 99 classic