ok, so my turbos are starting to wease under load and im slowly losing power, now ive heard of a few different options, there are the RS6 turbos which is supposed to grant me alot more whp but they are much bigger turbos, so i would think the spool up time would kill. then there is the traditional K04s which im leaning toward,cause its known and safe, but ive been told that the T3/T4 would be good, they're cheaper and ive heard would net more horse. any ideas?

 

I don't have a definitive answer for you about the T3/T4. It doesn't seem to be too popular around here. The RS6 turbos allow for 500+ wheel horsepower, which the K04s can't achieve. The two concerns with going much bigger than K04s are: 1) Non-existant turbo lag with K04s turns into a pretty significant delay with RS6 turbos [the 2.7 simply doesn't displace enough exhaust to spool the RS6 turbos fast enough] and 2) The RS6 turbos have enough flow capability to potentially produce more power than the stock motor can safely handle. You might have to replace some internal parts to avoid eventually damaging the motor.

As long as the T3/T4 physically fits, you could get it to work with a custom one-off tune and you'd have to custom fabricate the manifolds from scratch. There are some S4s running around with Garrett GT series turbos, so I don't see why a T3/T4 setup wouldn't work if you can get it to fit and run.

I apologize for not being more specific, but T3/T4 setups just aren't popular at all for the S4s. I'm assuming it's simply because there is a significant amount of custom fabrication and placement that needs to be done to get them to fit properly. None of the kit makers (AWE, APR, VAST, MTM) seem to be using T3/T4s either, so getting software and hardware for the turbos would be a bit of a challenge.

The K04s are always a safe bet. There's tons of kits and tuning out there available for them and they are proven. K04/K16 hybrids are somewhat popular as a sort of step between K04s and RS6 turbos because they use the K04 housing (meaning an easy fit to the factory manifolds) while providing significant power over plain vanilla K04s.

 

I'm sure there is a thread discussing this already but I thought I'd ask here becuase it is semi-related.

What is the expected lifespan of K04's vs. K03's? Everyone knows that K03's are flaky and can give up the ghost anywhere after 50k. But, how do the K04's age? anyone have 75k or more on a set of K04's?

Thanks Guys!

 

Come on people

 

You cant really answer that question..there jsut too many variables..all i can tell you is that the k04's are much stronger and more reliable... Its rare that ive seen a blown k04..

 

People do blow K04's but more from poor installs, not replacing clogged oil lines, and trying to push them too far. There was also a "bad batch" made this fall and a bunch of people blew their k04's within 4 or 5000 miles. If you do an OTS stage 3 kit it should be good for a LONG time, there are people who are putting some miles on the kits. If you custom tune for max power (above 400 whp) youll probably shorten the life a little.

And you can use any turbocharger your little heart desires if you have the knowledge and experience to fabricate your own inlet pipes, manifold solution, deal with waste gates, and it might even be easier at that point to so a stand alone ECU and completely tune it from the ground up. Me personally i dont even have a lift, ill be doing my stage 3 install on jackstands, so this is a little past my abilitys. Also unless your making at least GT power whats the point? And what makes them better than existing garrett and tial kits?

There is someone on the other forums who is doing just this but with Mitsubishi turbos. (Mitsu turbos are very popular, used on alot of applications, and have a very good reputation) Its going to be a sweet 1-off custom s4.

If you have the money and can afford to try something new and be unique than do it, but for the rest of us who are trying to spend less than $25,000 and finish in 6 months its just not an option.

Another point: Spool time on rs6's and GTs is longer than K04 but its not like its going to kill you. Its really only a couple hundred RPM's with RS6's and in the coming months as tuning and hardware is refined it will likely become less and the difference wont be as noticable. People have been putting the "k04's spool faster" arguement out there for a while and its really a moot point. PSI isnt everything, bigger turbos dont have to work as hard and at the same PSI they can flow more CFM of cooler air. The GT or RS6 car will walk the k04 car, WAY more top end. Iv also mentioned this in some other threads, If your sinking $15,000+ into a big turbo kit alone and trying to creat 5-600 HP please spend the few thousand extra to increase the displacement and beef up the motor internals. Youll appreciate it, and if you have a built 3.0L with GT25's lag will not be an issue. K04 cars will scream in terror and blow their turbos out of fear

"600+whpTwin Gt turbo audi S4 V.s 440whp ko4 S4 The race is to prove that a well built GT S4 should spool fast enough that a ko4 car can't pull away...cost the ko4 guy 1000 to find that out"

Keep in mind theyre running the same Boost, and that the GT is NOT making 600 whp at the boost it is set at in the races

http://videos.streetfire.net/video/6...4-T_113175.htm

 

I think i want GT turbos now....