fstr n u

What is the most common exhaust swap done amongst the members on this forum with the 4.2L 8 Cylinder version of the S4's? And are people doing the full catback system or just mufflers?

I love the sound of my new S4 but it's so darned muffled you can barely hear it inside or out....but I don't want to get into a system that drones on the highway or is too intrusive and annoying.

wooglin4

I run Neuspeed from the down-pipes to the muffler. Non-resonated. The sound is perfect.

ESSSFOUR

I'm running Milltek from the cat back. I am happy with it for the most part there is the odd time where I want it louder but i'm glad its not for a every driver. My wife even like the sound she says its sounds more refined then your typical loud v8 rumble. Check youtube for vids there is ton of them.

fstr n u

What and where are the downpipes on this car? Are people referring to the exhaust manifold/header? Otherwise we are just talking about catback systems....right?

Most cars have off the bottom of the engine block an exhaust manifold (or pair of), leading into a collector, running through 1-2 catalytic converters straight through to one or two mufflers and then out through the tips.

mikeh

PM SAKIMANO for advise

mikeh

Did you ever decide on which exhaust option to go with? If you did what was the deciding factor?

fstr n u

I had gone with a Borla muffler setup and removed the resonator. It was perhaps a little loud for most drivers but i could tell the sound from the V8 would be worth it to enjoy. Boy was i right. I would drive around in a lower gear than necessary just to hear that sound of the 4.2 V8.

Why did i choose Borla over another manufacturer? Many of the pre-made kits i saw for sale utilize Borla mufflers for their inherent ability to deepen sound somewhat. If you are simply looking at adding a little more bark to your car, keep the resonator on and go with the Borla muffler. There was (with the automatic) a little drone somewhere in the 1500rpm vicinity if i recall properly, wasn't bad, just there.

I actually sold my S4 6 months after buying it and dumping a whole bunch of money into it. Nice car, i had decided to get my wife something a little different and something had to go.

Your other options for a deep sounding exhaust would be Bassani or Corsa (would likely sound wicked on these cars).

sakimano

***I know you've already modded/sold your car, but for the forum's sake, I'll spew out a bunch of info I've gathered over the past few years***

Get a 2.5" catback with an x-pipe crossover for best results.

Fast Intentions works very well, and they offer both a resonated and non-resonated version. Non-res is a bit louder. Both sound great.

You should also do a 'full' exhaust. See below for more.



we have intake manifold (big grey thing ) then leading to AWFUL exhaust headers. Those then lead to the downpipes, which have 2 cats on each side...a precat and a main cat (catalytic converter). Then the cat-back connects to the downpipes and runs out the *** end of the car.

intake manifold - a restriction to top end power (high rpm power). JHM offers a revised intake manifold for $950 that will add about 15whp. The stock one isn't terrible, and preserves some torque for drive feel, but the revised one is AWESOME

exhaust headers - stock are CRAP. JHM offers longtube equal length headers for about $2500. Expensive. and a big job (engine pull)...but they also replace the downpipes so that's a financial bonus. They add about 30-40 WHP and about 50-60 WTQ.

downpipes - stock are CRAP . They are 2.125" wide, very restrictive, and have 2 cats on each DP. The pre-cats are right up by the engine (inches from the headers), and they are there for startup emissions. After 30 seconds their job is done, but the rest of the time they're stifling your engine keeping WAY too much heat in. many people GUT the precat material, and experience a 15-20whp power bump. Excellent mod, because it's basically free (you can DIY this if you're pretty sharp). An even better option is a 2.5" catless downpipe (i.e. Fast Intentions), but tough to pass emissions with that here in Ontario.

catback - stock is CRAP. It is 2.125"...and is crimped to like 1/2" in one spot. It has mufflers and resonators to keep it quiet. It has NO crossover. All around it's a poor design for power, but is good for a quiet OEM application. Ditch it pronto.

Basically you have a few good options for exhaust mods:

1. piggies (gutted precats in OEM downpipes) + 2.5" x-pipe catback: good for sound...good for power (about 15-20whp and more torque). Good all around. Don't *** up though by buying a 2.25" catback (APR, Milltek). Don't buy 2.5" catback without an x-pipe (Stasis). Feels like a new car with the piggies. Without them piggies mod, the aftermarket catback will do almost zero power wise. It's just for sound at that point. Piggies are either free (DIY) or about $450 to do a core exhange with JHM or VAST. Catback (Fast Intentions for example) is about $1200-1400.

2. aftermarket 2.5" downpipes + 2.5" xpipe catback - this is a great way to go. You'll pick up solid power (about 20-30whp and more torque), solid sound and will really feel like your car has been transformed.

3. JHM headers + 2.5" xpipe catback - the best exhaust available for our car. This will add 40-50whp and 60-70 wtq. Friends with this setup ABSOLUTELY PASTE stock S4s. They run 1/4 miles in the 12s...and the car sounds EPIC. They run pretty close/equal to weaker stage III B5 S4 (yes...stage III) for example AWE or APR stage III B5 cars. Expensive though. Expect to pay $2750 for headers...$1200 for catback, and about 1500+ for installation.

I recommend doing one of those modification strings before getting your car tuned. 90% of the tunes out there are basically a little timing thrown at the car...throttle manipulation to trick you into thinking you're going quicker...and that's about it! I'll boldly include REVO, APR, GIAC on that list. ASP may kill your car, so avoid at all costs.

JHM on the other hand has written a tune that attacks the entire spectrum of engine management, but they won't sell you it unless you also have at least piggies + catback at the minimum. this is because the tune is written for a freer flowing exhaust. the other tunes...are not. They're cookie cutter.

JHM sounds like a company I work at thanks to my rabid fanboyism in this (and other) post. I don't. Reality is though they're the only company who is making great products for our car. This is backed up with the fastest B6/7 quartermile times list. While you may not be a 1/4 mile fan, it's a fantastic timed acceleration run that is standardized pretty much everywhere. I believe 10 of the top 13 cars on the list are JHM modified. All of the fastest cars are JHM tuned. It's not a mistake or accident.

jhmotorsports.com

fstr n u

Sorry for chiming in here. When i was researching exhaust systems, There are 2 main companies that offer complete exhaust setups for the B6 S4. The one company utilizes a Borla muffler setup with a larger diameter exhaust diameter than stock. I had a shop locally do up a custom build using almost an identical setup. I loved the way it sounded and having had the resonator removed, if you don't enjoy the "louder' setup all the time, stick with a resonated setup. These cars sound absolutely fantastic with a modified exhaust.

mikeh

JHM sounds like a company I work at thanks to my rabid fanboyism in this (and other) post. I don't. Reality is though they're the only company who is making great products for our car. This is backed up with the fastest B6/7 quartermile times list. While you may not be a 1/4 mile fan, it's a fantastic timed acceleration run that is standardized pretty much everywhere. I believe 10 of the top 13 cars on the list are JHM modified. All of the fastest cars are JHM tuned. It's not a mistake or accident.

jhmotorsports.com[/QUOTE]

Great write up SAK.....hopefully people pay attention.

Thanks