Sti Quad Tip Muffler question

[Jiyujin]

Hey all,

I've tried searching the forum but could not find any information on my question.
I was wondering if there are any internal differences between the Sti quad tip mufflers to standard single tip mufflers say on a GT, apart from the obvious single / dual tips.
Sound/tone, performance...?

Thanks in advance.

[Shaheenis]

I made the change - first mod.

Definately better sound - deeper. Not 100% sure but I don't see why the muffler itself would be any different, it looks the same. The twin outlets may provide more flow but you are probably limited by the inlet size which is less than 2 inches per muffler but then you look at the size of the exhaust wheel and wastegate port on your turbo and I think you covered . With aftermarket dump pipe only they sound great under throttle.

[peadya100]

It's a much debated topic this one. Some people say there's a sound difference, others swear there's no difference. Personally I thought the sti libs had a slightly growler sound than the spec b, but I might be imagining it.

[alexeiwoody]

It's the same muffler internally. Not the best for power (very restrictive above 230kw/big turbo etc) but nice and quiet otherwise (compared to straight through muffs/tcp/open varex).

[Robbks]

it's not teh same internally,
I's got two outlets and as such has two exit-pipes which run the length of the muffler from the front chamber and out the back
this does allow a slightly louder note and changes the mufflers resonances slightly

[alexeiwoody]

Bruce had his PostFl Sti quads' internals 'scanned' by some bloke in the know and the verdict was they have the same internal structure (perhaps bar the extra pipe? the inlet and the muff still being the stock size and both muffs having the same packing/no. of chambers) as the stock Gt muffs. They do sound slightly different, agreed...

If the OP is after more performance or sound, IMO the Sti quads aren't different enough to spend the $. It's still a very OEM muff.

[THE SpecB]

I believe the STi quads are different internally as the sound between stock GTB mufflers is noticeable in sound and depth.

I don't think by just adding dual tips would make this occur.

[Shaheenis]

For me it was worth the money spent for both sound and looks, I wasn't expecting more performance. Given 80%+ of the members are running less than 200kws the performance shouldn't be a concern for stock mufflers. What I will say is there is definately a deeper note, no question but not a boxer rumble as such. It just sounds like a really nice factory exhaust if that makes sense which is what I wanted. If you want people to hear you coming, this is not the exhaust. My next door neighbour actually commented on how nice the car sounded after I replaced the factory GTB muffs for the STI ones and he didn't even know I changed them. He said 'have you done something to the exhaust?'

[ferret89]

For me it was worth the money spent for both sound and looks, I wasn't expecting more performance. Given 80%+ of the members are running less than 200kws the performance shouldn't be a concern for stock mufflers. What I will say is there is definately a deeper note, no question but not a boxer rumble as such. It just sounds like a really nice factory exhaust if that makes sense which is what I wanted. If you want people to hear you coming, this is not the exhaust. My next door neighbour actually commented on how nice the car sounded after I replaced the factory GTB muffs for the STI ones and he didn't even know I changed them. He said 'have you done something to the exhaust?'

I like them, quiet enough to go unnoticed in city traffic or on highway but growl a bit when stepping on it

Keen to see how it changes when I throw the stock dump out

[Manaz]

There was a massive sound difference when I swapped from the stock Spec.B mufflers and the STI mufflers on my car (with a 3" turbo-back exhaust in front of them). Much deeper, massive improvement in boxer rumble. In fact, they're so loud I'm considering a resonator/muffler in the mid-pipe to pull them back a bit - the stock mufflers made the whole system sound barely any different to stock.

[Jiyujin]

Thanks for all the feedback guys! Just contemplating which would suit my car without going over board and losing performance and being drowned out.
Cheers!