Downpipe effects on exhaust note?

[mistral cytz]

I ordered a resonated Fast Intentions catback for my 2007 S4 last week and will eventually be upgrading to 2.5" catted downpipes from my current piggie pipes. I have heard multiple videos and in person an S4 with catted FI downpipes mated to a resonated FI catback and have decided it's exactly the sound and volume I'm aiming for.

If current funds would permit I would have ordered the catted FI downpipes along with my resonated catback last week through JHM but I just can't spend the additional $1500 + shipping and duty to get the full system right now.

So my question is, are all 2.5" downpipes going to effect the tone and volume of the cars exhaust relatively the same with my Fast Intentions catback? I'm looking at Milltek or Trexturk downpipes for MUCH cheaper and although I'd still need to have cats welded in, the price difference is huge!

It just seems like the catback is where all the various muffler chambers and pipe bends produce the most variance in exhaust sound between all the different catback brands and that the downpipes are relatively the same in shape and bends to fit where they are and seem to not really vary between say Milltek and Fast Intentions in appearance?

If I'm wrong, please correct me as I'd rather go for the FI downpipes sound quality that I've heard, but again do downpipes really effect the tone of exhaust note and volume between different brands, or are all 2.5" catted downpipes mated to my Fast Intentions catback going to sound very similar or the same?

Thanks.

[dolphin B6 S4]

catback only: Too quiet…
Fi catback with cat less downpipes: seems loud for the first week and then realize it's still not loud enough!

For volume reference here is a video of me vs a catback only 350z..

https://www.youtube.com/watch?v=sx9rRfQpSDk

[mistral cytz]

catback only: Too quiet…
Fi catback with cat less downpipes: seems loud for the first week and then realize it's still not loud enough!

For volume reference here is a video of me vs a catback only 350z..

https://www.youtube.com/watch?v=sx9rRfQpSDk

Your car sounds awesome and yes I know the catback on its own won't be enough for me either although I'll be running piggies with it initially. But I'm looking for answers to my original question. Do downpipes really effect the tone of exhaust note and volume between different brands, or are all 2.5" catted downpipes mated to my Fast Intentions catback going to sound very similar or the same?

[Datadatum]

I recently installed a JHM 2.75" DP, combined with my stock CB. RS4 fitment.

The difference in sound is a deeper sound ONLY at high volumetric flow (i.e., when it is floored). It is a bit louder, and definitely deeper. A full sound. I would relate it to when you get really good speakers and you can listen to them at much louder volume, because the sound is crisp and complete...

[dolphin B6 S4]

He wants to know if different brands of downpipes sound any different. I would assume that they all sound pretty similar granted the placement of the cats and size of the tubing is the same. Trexturk, milltek, and FI downpipes mated to an FI catback all sound a little different on youtube though

[mistral cytz]

He wants to know if different brands of downpipes sound any different. I would assume that they all sound pretty similar granted the placement of the cats and size of the tubing is the same. Trexturk, milltek, and FI downpipes mated to an FI catback all sound a little different on youtube though

Hmm yeah I didn't know if the difference in sound between all those downpipes with the sane Catback was related to different audio qualities and recordings but I'll listen to some more to see. I'm happy with the sound that my soon to arrive Catback will make with the matching FI downpipes, but if I can pair the FI Catback up to trexturk for half the price and get the same sound or nearly the same why not?

[dparm]

Everyone's bends will be virtually identical, and the tubing IDs should be virtually the same. I suspect that they'll all sound identical unless someone is using some sort of tubing with thicker walls or weird angles (unlikely due to cost and space constraints).

As soon as you move to resonated ones, that's when things start changing. Of course, the primary cat converters will affect the sound too.

[mistral cytz]

Talked with Fast Intentions today and they said that most 2.5" downpipes with 300 cell cats are going to sound identical with their Xpipe catback exhaust. The only options I know for downpipes on the B6/7 S4 are Milltek, APR, FI and of course Trexturk. Does anyone know of any other companies that make 2.5" downpipes that can come catted and aren't super expensive?

[Bruno_s4]

Talked with Fast Intentions today and they said that most 2.5" downpipes with 300 cell cats are going to sound identical with their Xpipe catback exhaust. The only options I know for downpipes on the B6/7 S4 are Milltek, APR, FI and of course Trexturk. Does anyone know of any other companies that make 2.5" downpipes that can come catted and aren't super expensive?

Avoid the ebay ones if you don't want leaks from what I've read.

[mistral cytz]

Avoid the ebay ones if you don't want leaks from what I've read.

I'm thinking trexturks Bruno. But I would still need cats welded in..

[Blackstallion]

I'm thinking trexturks Bruno. But I would still need cats welded in..

I may have milltek ones still lying around at my parents place. They were for a tip which fit 6mt. If I still have them I'll let you know

[mistral cytz]

I may have milltek ones still lying around at my parents place. They were for a tip which fit 6mt. If I still have them I'll let you know

Thanks but I've read that millteks neck down to 2.25 briefly and have the cats located very high up in the downpipes causing the same heat soak problem as the OEM?

[s4ski]

Some other options, but not necessarily good ones. Labree being one, but also necks down from what I understand, not sure what pricing is. B&B is less money, but will not connect up with other brand catbacks - would require some fabrication for fitting, and necks down. In short, I think you are best off saving up for the FI catted DPs.

[mistral cytz]

Some other options, but not necessarily good ones. Labree being one, but also necks down from what I understand, not sure what pricing is. B&B is less money, but will not connect up with other brand catbacks - would require some fabrication for fitting, and necks down. In short, I think you are best off saving up for the FI catted DPs.

Yeah, I've basically decided to just save for the FI.

[Jake@JHM]

Can't go wrong with the FI DPs. They fit perfect, hold up to the test of time, and have been proven time and time again to improve performance!

[mistral cytz]

Can't go wrong with the FI DPs. They fit perfect, hold up to the test of time, and have been proven time and time again to improve performance!

Jake,

Any rough idea as to how many miles the Cats on the FI downpipes last?

Also any update on the FI Catback I ordered last week as far as build/shipping time? I don't even feel like driving my car until I get it installed now! :(

[Jake@JHM]

Same status as last time!

We haven't had a cat fail because of old age. Only mechanical issues such as bank swapped o2 sensors etc..

[mistral cytz]

Same status as last time!

We haven't had a cat fail because of old age. Only mechanical issues such as bank swapped o2 sensors etc..

Okay good to know. Will you be releasing the new adapter clamp for the 2.5" downpipes to stock size cb neck down on your website soon?

I know a few other guys that would be interested in ordering the FI Catback in full 2.5" with these clamps so they can have the option to order the FI downpipes through JHM later on and not have to deal with the cost and hassle of modifying a necked down exhaust to fit the downpipes later.

[Guitarmageddon]

This thread has constantly been bumped to the top, and I click it everytime....hoping there are sound clips

Disappointment....