Couple of Exhaust Questions

[NeedMoreSpin]

Hi all!
 
I\'m looking to make some changes to the exhaust system of my FD and was hoping a few of you guys could help me out with a couple of questions! I\'ve had a search on this board and couldn\'t really see anything close to what I\'m after but I did find a really good write up of the dynamics of swapping from a 3" to 4" system!
 
I\'ve currently got a stock cat (Jap import if it makes any odds?), stock downpipe as far as I know and an aftermarket (Blitz Nur Spec R) catback. I\'m looking to replace the stock cat with a silenced midpipe and I\'m wondering what the stock bore size is so that I can make sure my replacement midpipe has the right bore size and flanges to fit the downpipe and catback. I\'m sure that\'s an easy question for someone out there! :Hammer If I go this route, I may also consider having it wrapped, I hear that can reduce the noise slightly although I can\'t really see any heat benefits once past the downpipe? Has anyone done any/all of this and feel it was worth it or would I just be better off getting a high-flow cat?
 
I\'m guessing replacing a stock cat with a silenced midpipe wouldn\'t really reduce the noise so I\'ll be looking at changing the exhaust by the summer too as the Blitz is a touch too loud... whilst it doesn\'t bother me directly, I do feel bad for the neighbours when I fire her up, a lot of the curtains and blinds start twitching when I do. :WaveBye Not the kind of attention I really want! :3Confused Also while cruising it does tend to drone. Has anyone got a particular combination or setup that they feel is surprisingly quiet without being too restrictive? I\'m certainly not looking to drop down the power for less noise, infact in the future I\'m considering going single turbo route but I really don\'t want it to be unnecessarily loud.
 
PS - This is with the removable bung IN on the Blitz... I\'ve never tried removing it, I dread to imagine how that\'d sound for the neighbours.
 
All feedback appreciated guys! Thank you.

[m1tch]

Before you remove the cat have you got a power FC attached?

[NeedMoreSpin]

Yep, car came with one on a base map for a street ported engine on non-seq twins. Will be getting any exhaust work done at the same time as a remap.

That\'s partly why I want to get as much info upfront as possible as I\'m looking to take all the bits with me and having the whole lot fitted at once and then remapped to save on costs.

[Ricco_04]

Standard size is 2.5"

You can bolt up a 3" to your system if you want though.

I have a 2.5" silenced mid and when I swapped it around with the car there was no noise difference on idle and I couldnt really hear a difference on throttle - that one I got in stainless from Pip @ WGT.  A few people dont want them because they are " only 2.5" " and people usually go for 3" or above - so you can find them around 2nd hand for a reasonable price (stainless).  Just an option, if you are going to have it made, I would go with 3" silenced.

I have also read on here that the rear silencer seems to make more of a difference than the mid pipe in terms of noise level.

[NeedMoreSpin]

That\'s exactly the kind of info I was looking for Ricco_04, thank you.
 
I\'m a bit unclear on how I\'d bolt up a 3" system though, do you mean the whole system, i.e. replace the downpipe, midpipe and catback with a 3" system or just the mid pipe if the catback is the same bore or bigger?
 
I\'m also concerned now that perhaps I was wrong and my cat isn\'t stock... the Blitz Nur Spec R is 80mm (3 1/4" - O/D or I/D?), I wouldn\'t have thought a stock cat with 2.5" bore would have flanges to fit to a 3 1/4" catback?
 
I seem to just be further confusing myself here :rollin.

[jayra]

3" straight through HKS full system, not to loud, or maybe Im just deaf already lol!

[NeedMoreSpin]

That\'s my end game plan too jayra, I want to get a full system that\'s not too loud but without it being too limiting on the flow. I\'m just really not sure where to start... I guess going for a full system as you have would be the easiest in terms of getting it right but I wouldn\'t really get the opportunity to hear it running before it\'s fitted and it\'d probably be the most expensive route to go also... I\'d rather buy the bits as they come up on the forums here but without knowing what\'d bolt on to what I have now, I don\'t want to take the plunge yet.
 
I think I really need to get under there and have a look at the bore and flange sizes so I can do this properly.
 
I\'ll look into the HKS system, thanks for the recommendation. :cheers

[Ricco_04]

You can leave the stock downpipe in but I would be tempted to change it for a 3" then a 3" midpipe with a silencer and a decent catback - if you do it all in one go then it saves on getting the map altered again so will save you some ££ in dyno time.

[NeedMoreSpin]

Thanks very much for the input so far guys, I\'ve taken your advice... I\'ve started collecting some bits from the forums here, got a 3" HKS Downpipe heading my way and an unbranded 3" silenced midpipe too shortly! I\'ve not decided on the catback yet, thinking HKS Hi-Power but I need to keep my eyes open in the For Sale section.
 
I\'ve been looking into the turbo to downpipe gasket and I\'ve been reading that people have had issues with graphite/non-OEM quality replacements due to heat and pressure? OEM gaskets are also hella\' expensive, so I was wondering if anyone else had come up against the same situation when replacing their downpipe and if so, what they did about it? Should I just bite the bullet and fork out for an OEM one? I was considering posting up in the wanted section but thought I\'d get some opinions first, I might just be reading horror stories and the graphite ones are perfectly adequate?
 
Just to be clear, I\'m talking about this one:
 
http://www.pineappleracing.com/oem93-95fdturbotodownpipeexhaustgasket.aspx
 
Cheers again guys for the advice so far!

[philiwily]

I just used my old one, it never gave
me any trouble.