Stock exhaust

[Ianxcom]

Hi. I am a new S4 owner and am looking to chip my car. I want that extra power but dont want the noise.
My question is, how big is the stock exhaust pipe diameter?

You see i am thinking of a chip plus piggies on a stock exhaust. I just dont know if it will be louder or if the turbo will still spool faster or the same being that it still has to squeeze through stock piping. if the piping is 2.25-2.5 that doesnt seem that bad.

[Ianxcom]

I edited my thread because my second question reguarded k04's with a chipped ecu on stage 1 tuning can be answered in the other thread.

[gointoscott]

stock pipes are 2 1/4 inches. I did my own piggies and have stock exhaust on my car. barely made a difference in sound. Still very quiet. I kind of wish it would have a little more of a growl.

I made a nice DIY for doing piggies. search for the ultimate diy for Piggies

[GunSupplier]

You see i am thinking of a chip plus piggies on a stock exhaust. I just dont know if it will be louder or if the turbo will still spool faster or the same being that it still has to squeeze through stock piping. if the piping is 2.25-2.5 that doesnt seem that bad.

You can do piggies on the stock exhaust. It'll still flow a hell of a lot better than not doing them. Have you seen pictures of what the pre-cats look like? http://www.audiworld.com/tech/eng75.shtml
I'm sure you can imagine how much of a restriction all that material is. Perhaps a bigger benefit of the piggies than just the easier and faster exhaust flow, is the fact that the massive heat generated from the turbos (which are placed literally RIGHT before that mesh-like pre-cat material) can escape way faster.

With the stock downpipes, the pre-cats create a "traffic jam" of heat in the pipe. The turbo then has to force out the heat it generates on its own AS WELL AS the heat that's starting to collect in the "low flow zone" before the pre-cat. This all leads to potentially shorter turbo life, as they consistently get hotter than they would without the ridiculously restrictive pre-cat.

Second question: If my k03's do crap out the k04 kit is quite expensive and runs higher boost. What is the performance like if i kept my chip programmed for stage 1 but with k04s. That way it will be only about 16lbs of boost but with more reliable turbos.

No, it makes perfect sense. There are people out there that do run their Stage I K03 chip on K04s, and they don't seem to have too many issues. The only thing is that they are, after all, different turbos, so the Stage I programs aren't going to be as fully dialed in as a proper K04 file would be. But, it has been done. You know, you don't HAVE to get a K04 "kit." You can just get K04 turbos + inlets/hardware (from places like VAST, Avalon, ECS, JHM, etc.) and bolt them on. That's what people call Stage 3-. Any of the tuners that burn their own chips will be able to make you a Stage 3- file that is adapted to K04s without fueling components, so the chip won't demand crazy high boost. You won't need any of the additional "expensive" fueling components, you can get those later.

Regarding the performance of a K04 car with a Stage I chip, it'll be pretty much identical to what you're used to with K03s. If you use the same chip, with the same amount of PSI, then you won't be seeing any power gains with the K04s. They will be MUCH more reliable, though, if you run them that conservatively.

Hope that helped a bit.

[Jung]

you could just get a scorpion exhaust or have a custom exhaust made for you with like 3 mufflers on it but have it 3"

[Ianxcom]

Thanks for the quick replies. The reason i would go k04 on stage 1 chip is i heard the turbos are more reliable (unless i can get rebuilt k03's or some other ballbearing turbo for cheap) and i dont want to take any chances on the stock rods with 20+ boost. Im just trying to prevent heartache in the future while getting more power.

I suppose i could get a 3" exhaust with 3 mufflers but that seems like it may cost quite a bit.

[Ianxcom]

oh and btw, smog checks are a big concern here in socal so that is also affecting my decision.

[Jung]

custom exhaust is way cheaper than ASP, AWE, APR, etc.. just get some magnaflows

[Ianxcom]

Do you mean 3 cats or 3 mufflers. Ive never heard of 3 mufflers before. Would that be more restrictive than the stock 2.25?

[Jung]

3 straight through mufflers. not cats. ive never heard of 3 mufflers either, but shit it might be pretty quiet. if theyre striaght through, they wont inhibit flow, but would still provide adequate sound dampening.

[Rated S]

Piggie Pipes and Exhuast along with anything turbo related won't matter in Socal. I have Full Stage 3 w/ Piggies and I pass no problem.

[Ianxcom]

Piggie Pipes and Exhuast along with anything turbo related won't matter in Socal. I have Full Stage 3 w/ Piggies and I pass no problem.

Well that's good to hear.


So another question. How do the s4 stock internals hold up to 16lbs of boost from a chip.

[Rated S]

Well that's good to hear.


So another question. How do the s4 stock internals hold up to 16lbs of boost from a chip.

Internals can hold like something up to 500whp iirc.

[Jung]

Well that's good to hear.


So another question. How do the s4 stock internals hold up to 16lbs of boost from a chip.

yeah man.. stock internals are great. our motors are made to take boost, no worries unless you're going to be running a high boost big turbo setup

[Ianxcom]

Wow. I had no idea. Thats impressive.

What is the amount of hp/boost stock fueling can handle?

I ask because i only really want to run 15-18 lbs of boost. and get around 320-340fwhp and 360-370 tq.

[Jung]

sorry to say but you'll never see 320-340 whp on 15-18lbs w/ k03s...
stock fueling can handle like what.. 350whp, but you'll need bigger turbos (ie k04s, rs6, etc etc)

[Ianxcom]

nooo. i meant fwhp. whp measurements are too crazy for me. =P

So i take it i can just bolt up k04s and get it custom chipped for 20lbs and be ok on stock fuel then?

And by upgraded fuel is that just bigger injectors and stronger fuel pump or is there more to it?

[JackalS4]

nooo. i meant fwhp. whp measurements are too crazy for me. =P

Assuming you mean "flywheel horsepower", then you should hit those numbers (320hp/360tq+) with just a GIAC chip, possibly adding a catback and/or downpipes to seal the deal - stage 2(+)!

[BITRBO]

haha. sorry, not to be a dick but the title of your thread should've been: "Stock exhaust, and everything else about these cars..."

seriously though, you obviously need to do a little more homework. check out this FAQ sticky atleast once and I bet a lot of your questions will be answered: http://www.audizine.com/forum/showthread.php?t=128295

...the search feature will also help you with anything not answered in the FAQ sticky.

GL and welcome aboard!

[Ianxcom]

Thanks and i dont take in personal. I did look at the FAQ and did learn alot. I did a bit of HW and was going to talk about everything but i noticed another recent thread which i decided i would take the other question to so i edited my thread. Someone addressed my question so i guess thats how it got started.

[BITRBO]

no prob. I know I spent my first couple months on AZ, AW, and AF just lurking around and reading FAQ's and people's posts... that helped a bunch.

Not sure if you finally got answers to your last questions, but usually people get what is called "fueling" or "custom tune" when getting ko4's (or other turbo larger than stock). You can run ko4's w/o this "fueling" (as many people do b/c it's expensive), and just run on an OTS chip but you won't get the full potential of the xtra flow/boost provided by the larger turbo; IIRC you might even have to get your chip "tweaked" too. This is called "Stage -3", instead of the regular "Stage 3".

With these cars you'll also find many people using WHP or AWHP more often than BHP or crank-HP... You can search on typical drive-train loss percentages to make your own conversion, but I think for our cars it's about 22-23% (+/- 1-2% depending on who you ask).

hope that helps.

[Ianxcom]

Yes that helped a lot thank you. I have been doing alot of thinking and i think i will just go the GIAC (still need to do chip research but i hear this is most 'aggressive') and piggies. Other upgrades will be pending stock failure.

[S.Line.Power]

stock pipes are 2 1/4 inches. I did my own piggies and have stock exhaust on my car. barely made a difference in sound. Still very quiet. I kind of wish it would have a little more of a growl.

I made a nice DIY for doing piggies. search for the ultimate diy for Piggies

cut out the resonator. i did this and it sounds great at wot and stock at everything else and with the piggies you can hear the turbos through the tailpipe at idle ;)

[O 16581 72452 5]

3 straight through mufflers. not cats. ive never heard of 3 mufflers either, but shit it might be pretty quiet. if theyre striaght through, they wont inhibit flow, but would still provide adequate sound dampening.

My Thermal R&D Exhaust for my 3.0 had 3 straight through mufflers per pipe (6 in total). It was close to stock quiet, 3" pipe with 3 straight through mufflers would be an awesome power boost to a turbo car while retaining nearly stock sound.

The turbo acts as a pretty good muffler also.

[Jung]

pretty good muffler if you're deaf.
ever heard an s4 without an exhaust? not exactly quiet

[GunSupplier]

pretty good muffler if you're deaf.
ever heard an s4 without an exhaust? not exactly quiet

I'm not sure you understand what he meant. He was just pointing out that the turbo acts as a sound muffler in general, which is true. He wasn't telling the OP to run open downpipes because it would miraculously be "quiet."

He was just stating that a turbo car with exhaust will always be quieter than an N/A car with that same exhaust, because of the muffling effects of a turbocharger.

[Ianxcom]

I forgot about this thread I made.

I have a friend who put an ASP 3" DP on his stage 1 car with stock exhaust. I now have an APR chip and was thinking of getting piggies because mated with a stock exhaust system i would think the gains are minimal if any when comparing the two. Both relieve the backpressure directly after the turbo and end up going out the same diameter in the end.

Thoughts?

[MacDaddy]

pretty good muffler if you're deaf.
ever heard an s4 without an exhaust? not exactly quiet

not really loud either. Some engines you can damage your hearing if you rev them up without an exhaust. S4 won't do that. (i'm refering to a S4 engine with the downpipes in place and the cat-back removed)

[OneSickSedan]

I have piggies with stock exhaust. Still quiet as hell almost like stock. But you will definitely notice a difference in performance. Especially how quick the turbos start spooling. Torque comes in way faster. I'm probably gonna get a SSAC catback mated with my piggies for a little more performance and sound. You should find SSAC catbacks for under $200. Good luck.

[Ianxcom]

Thats good to hear cuz i dont really want any noise at all.

[JackalS4]

Thats good to hear cuz i dont really want any noise at all.

"I don't want any attention."



Sorry, had to (The Jackal).

[NogaroWonda00]

yeah just to add a bit more knowledge to you, stage 3 cars run 20+psi easy (ie WITH fueling) and the reason everyone does all the upgrades at one time is due to the fact that it costs around 500 bucks just to get the motor pulled, so while you have it out why not do the intercoolers, waterpump, timing belt, clutch and turbos.

I really dont understand your reason for not wanting a louder exhaust lol, I HAD cat back on my car when i first bought it and you could hardly even tell it had it.

PS on AWE's site they say 460fw hp for their stage 3 kit

[mrpeterparker]

Thats good to hear cuz i dont really want any noise at all.

save a LOT of money and buy a tesla roadster =)

[lucajS4]

gut the down pipes take out the middle resantor keep stock muffler or change it sounds perfect not loud at all thats what i did i got a wole exhuast system but didnt put it in yet

[Ianxcom]

I really dont understand your reason for not wanting a louder exhaust

I had a honda with a loud ass exhaust for years. Just done with it. I chose this car for luxury and speed. Plus Im getting older and dont want to draw attension to myself

take out the middle resantor

never thought about this. Will consider it only if it makes a noticable difference. Since exhaust only adds like 5-10hp anyways i didnt wanna mess with it.

[NogaroWonda00]

okay dont get me wrong but a s4 will never sound like a honda. think of it like this, noisy fart canned honda isnt liked much, but a clean exhaust on a s4 makes people cum in their pants!

my car is pretty loud lol but i have had more people than i can count tell me the shit sounds sweet, doesnt mean its not luxurious, i guess my point is, the exhaust is a big part of the picture when your talking about power, if its not big your turbos dont spool nearly as fast, and if you do plan on throwing k04s in there its making them not work as good as it could be, but its your car your choice.

[NogaroWonda00]

I had a honda with a loud ass exhaust for years. Just done with it. I chose this car for luxury and speed. Plus Im getting older and dont want to draw attension to myself



never thought about this. Will consider it only if it makes a noticable difference. Since exhaust only adds like 5-10hp anyways i didnt wanna mess with it.

5-10hp, man dp's on a stage 3 have a 50whp gain!