SecureS4

What is diameter of the pipes on the Milltek, not the tips, the actual pipes?

MachtigAvant (v3.0)

was it 2 3/4 or 2 1/2? I don't know.

SecureS4

I know most everyone on here says to get the Milltek but I wanted to do my own comparison of the two systems and determine if the Milltek is worth the extra Grand that has to be spent for it. From what I can tell, the APR full system advertises "In testing, a full APR exhaust produces gains of 25hp and 35lb-ft across most of the engine powerband." Whereas the Milltek advertises the downpipes...."When combined with the Milltek catback your S4 jumps by 40 lb-ft and 30hp at the wheels."
So I guess my question is, Should one pay an extra Grand for 5HP or should that money be spent on a hyperflow and some other go fast parts?

JDBlueAudiS4

then make your decision based on that, while there are no independent dynos of the APR/B&B System there are of the Miltek systems.

MachtigAvant (v3.0)

Some are louder then others, some have more power than others, some have larger tips than others, and some are cheaper than others. Of course, having a milltek system, I love my system and I would recommend it to anybody. Sure, it might be one of the most expensive sets on the market, but I believe there is a reason for it. Keep in mind, you bought an S4 over a 3.0 A4 for the same reason, you wanted the best. :-D

Seriously, a cat-back exhaust system is a cat-back exhaust system is a cat-back exhaust system. While I have not seen detailed dynos on ANY of the systems, I am sure they all give you certain gains. However, I can tell you that if you are planning on going with dp's, you are going to want to do your homework on the design just as much as the power increase. APR's exhaust is made by B&B. And while I really dig APR products, and I know it has only happened once, blown cats are not my thing, and that would make me very nervous about investing in a full system that is made by B&B. Not saying they don't make good exhausts, but I have not heard of a B6 S4 with a Milltek having bad cats.

If you are going to go the downpipe route, PLEASE make sure to do your homework on the design, manufacturing process, and materials used in the downpipes and cats in particular.

I read and did a ton of research on the milltek downpipes before I bought them. And yes, i was nervous at first. It's a gamble. Downpipes can potentially cause complications with warranties, because of emissions, cooking o2's, there are a number of reasons. I have not been able to find as detailed info on the manufacturing process of competitive cats other than Milltek. Milltek uses a very elaborate process of using a stainless steel alloy mixed with aluminum called Fecralloy. They band the steel strips (2 thousandths of an inch I believe) into cell counts of around 100-200 csi. Our stock cats have about 400-600 csi. Most aftermarket cats are near the 400 csi mark. Now you might be asking, wouldn't a lower csi count cause more complications with emissions? Yes, if you didn't use the best in emission control elements and manufacturing. Using certain previous earth metals and elements, the 200 csi count on our cats do as well as a job as the stock cats. Due to the chemical make up of the cats themselves. Having a 200 csi as opposed to a 600 csi will also yield quite an improvement in cross-flow.

Also, Milltek cats are made in europe. They are made to handle and cut through the very tough emission standards of european gas, which we know, has more impurities (sulfer, etc) then US grade gasoline. And these impurities will poison cats quicker then US gas. So, using a european cat WITH US gas is going to be quite effective when it comes to cutting emissions.

Above all, I want you to be happy with your choice. Whatever exhaust system you choose, just be sure to know what your getting. I did, and I have the peace of mind of knowing that I've got one of the best systems offered for our cars. I've been driving with them for a few thousand miles now and I have to say that the performance is addicting, the sound intoxicating, and the attention is welcomed. ;-) It really does sound mean. Take a ride in a Milltek full system and you'll be sold. Just be sure to check it with the bank before you go on your test drive. :-)

Just my $0.02, keep the change. ;-P

SecureS4

Thanks for spending the time to educate me on your exhaustive effors in research. I definitely appreciate it. I am really sold on the Milltek already (partly due to your 4th gear pull video) and just need that extra push to send me over the edge. I think I can consider that done. As for as the manufacturing process........I agree with you that Milltek does the best job. I think I am going to go with the cat-back system first and then get the downpipes. I think I owe it to the wife to give her only a mild heart attack at first. I will go with the downpipes later on and really give her the full blown cardiac arrest then.

Again, Thanks for the great information........I really appreciate it!

MachtigAvant (v3.0)

And great choice too. ;-)

Really, going with the milltek cat-back first is a great decision. Now for your next pitstop, are you going to go resonated or non-resonated? :-) I went with the resonated because I knew I was interested in the downpipes. GOing for the non-resonated full-back, in my mind, was going to be too loud. But from what I hear on the board, some really are digging the non-res full system. Good for them! I still think the resonated was perfect for my tastes.

Going with the cat-back first will give a boost in performance, and probably just as important, is going to give you the sound that the car should have from the factory. It will turn heads, and your going to love it. Once the (better?)-half gets used to the sound, then surprise her with the downpipes, which are mated perfectly for the cat-back system.

Of course, if there is anything else I can do to help, please just ask. Feel free to email me if you prefer.

SecureS4

I am not really concerned with the car being too loud. Frankly, around my area (plano, tx) all the punk kids have loud cars...............mostly mustangs, camaro's, trans am's, and plenty of junked out ricer's. I figure it will give em one hell of a shock to pull up next to this smooth black beast and hear a massive rumble when the light turns green and I walk away from them like they are standing still.
I actually had a nice run with a 2004 cobra stang last night and although he did walk from me from about midrange of third gear I took him nicely from a stand still with a very good launch.
Can't wait to get some more go fast goodies and make a run for my neighbors Z06 (will certainly be a losing battle but not near as bad as would be in stock form).

Thanks again!

MachtigAvant (v3.0)

Sounds like a plan! Can't wait to hear your impressions on it. Have fun with it!