not 100% here but I think the 2 piece NurSpec R narrows to 2.5" at the flange

 

Why 3"? ....... 2.5" is good for 400bhp+

Why do you want loud OP? ..... know this is a personal preference, but big exhausts on underpowered cars sound ****e! By getting the bore right for the power your making (and no bigger) you get the lovely raspy tone! By sticking a 1000bhp capable exhaust on a 250bhp 2.0 its just going to sound asbo and youll never get through noise testing for any events if you so fancied at some point.

For most people, if you've sourced your friendly mot centre, a 2.5" turbo back straight through H&S is all the exhaust anyone should ever need.

 

It's not the fact I'm chasing big noise, I want some noise yes, but I'm not going for 3" for noise, I was going for 3" because of better flow ?

Thanks for feedback

 

Can anyone second that or ?
If the 3" doesn't narrow to 2.5 then I don't mind going with the 2.5 instead tbh

Thanks

 

as already stated.. 2.5 is all you really need.. go for the NurSpec S its the 2.5" backbox only.. other than that there are plenty out there that sound well.. Afterburner Vortex looks and sounds excellent, just youtube a few and see which you like.

few of my old boxes

Afterburner



NurSpec



Genome

 

You should only be buying once, I have seen no proof that your better sticking to a 2.5" system. The more gas you can flow the better on a turbo charged vehicle, I run a full 3" turbo back with Apexi sports cat and Cobra cat back system with no resonators and 3.5" tail pipe. Sounds amazing and not too loud and has definitely made a nice performance gain as the engine can move allot more air!

 

why only once? whats wrong with variety?

 

Misconception here being that bigger bore means better flow .... not the case!

Maximising gas speed in an exhaust is really important to the shape of the torque curve (more so on NA granted, but the same theory applies to FI to a lesser extent).

A uniform bore with no nasty shoulders as the tube diameters change is all your after and in which case, all other things being equal, youd get a better flow and a slightly lower rev point for peak torque with a 2.5 over a 3.

3" exhausts only become a requirement when the 2.5" starts to limit the gas flow, which you need to be knocking on the door of 500hp+ for this to come into play.... and with regard to exhaust note and tone, the point at which an exhaust is just big enough for the power the engines making (and no bigger) is always the point at which the note is nicest/cleanest/raspiest etc.

Unless for whatever reason you just hate your neighbours and want them to hate subarus, in which case fill your boots with the lariest 3" backbox you can find .... just be honest to yourself and admit your doing it just for the "noise", and in no way for the "bit of performance" bit. :-)

 

I'll happily go for a 2.5 instead of 3, honestly. I agree I do want some noise yes, However I do also want what's best for the car. If 2.5 and 3 literally make zero difference to the car I'll go with the 2.5 just to make things a simple fit tbh

 

Correct, its proven in the venturi effect, larger bore pipes cause pressure drops and slower moving air or fluid.

Harvey did tests on how exhaust dimensions directly effected bhp/torque and spool up and also proved this.

ive recently read in an old post on here that Harvey found that a 2.75" diameter exhaust could support 600bhp

 

@Powerwrx , if you have the money then sure fill your garage up with different exhausts for every day of the week when the mood takes you. I like to choose carefully after research and current mod path and purchase one exhaust system that's fit for purpose and not risk wasting money buying all different exhausts for the same car.

 

its not a case of having money to buy as many as you want, and hardly any money would be wasted if you buy and sell on, telling someone to choose only once is pointless because not many will stick with the same system throughout.. people like change wether it be exhaust, wheels or whatever. you buy a computer game,play it and get bored do you buy another or stick with the same one because it was the one you wanted initially I cant see it.

 

http://pages.ebay.com/link/?nav=item.view&alt=web&id=350927164757

Just want to check before I buy this, from what I can see it will, but can anyone confirm that this will fit into my Wrx air filter box ? Or will I need to buy a Sti box ? Not sure if this filter is bigger or not but the description says it should fit in my wrx

Thanks

 

http://www.scoobyparts.com/sti-parts...sti-air-filter

here you go mate

 

Thanks a lot, really appreciated

 

no problem mate, please don't expect to put it in though and notice any difference, it may help a touch if you decide to go down the exhaust and remap route but on its own it wont do much.. there are a few decent filters out there, Green, Cosworth to name a couple

 

Yeah I'm going with the nur spec exhaust, decat back, walbro fuel pump 255, this panel filter and getting Duncan from race dynamix to remap

Thanks

 

Have been thinking about one of these for my classic.. but in 2.5" with a H&S sportscat and a resonated cobra centre section.. no idea what it would sound like though!

 

should see a good return then mate

 

Just to let you all know where im up to. I've ordered my blitz exhaust, along with panel filter and fuel pump. Ordered them from scoobyparts.

Unfortunately won't be getting exhaust till mid March, other bits should be here before then. However scoobyparts did give me a discount though which I thought was quite nice of them.

I've also messaged race dynamix to let them know what's going on so I can get my remap done hopefully towards end of March

Thanks
Chris

 

Received my bits and pieces now. Filter and exhaust fitted. Looking to fit the fuel pump on my next day off.

Just wanted to ask if anyone has had any problems fitting there exhausts ? Connecting the back box to centre pipe was perfect, however fitting my centre pipe to the decat was a real struggle.

The decat was on the car when I bought it, it had the standard centre pipe still attached to it and a prodrive back box and that fitting was quite snug. While fitting this new centre back to the decat though I snapped one bolt and bent another, had to go to a local shop to purchase some new bolts. It's fitted not so bad now, there's a complete seal, I've felt to see if there's any blowing and there isn't, just wondering if anyone had any sort of issues like this ?

On a good note, next is fuel pump and map :-)

 

Hahaha, the old "i want a loud exhaust" thread again.

Well so did i a few years back and proceeded to fit a hayward and scott 3inch open mouth downpipe and full mated 3 inch true blitz nur spec r system to my RB5. Loud?? I used to set off every car and shop alarm on the main street if i blipped the throttle at all in the local town, and as for the antilag....

Its comming off very soon and im fitting a full new Miltek system which suits me better nowadays, the blitz is far too boy racerish for me now!! Yes the noise is entertaining for a while, but you soon get bored with it and it does nothing but attract attention from the police etc which soon becomes annoying.

It will be for sale very soon if anyone is interested in the full system with hayward and scott downpipe give me a PM

Kevin