B5 S4, About To Upgrade. Experts Step In
 

So, here is the deal. After a long debate of what to do with my Imola Yellow 01.5 S4, I have decided to upgrade. I am working with a local specialist and have decided to take the next steps.

My car currently has an RS4 Clutch, Flywheel. Aftermarket Downpipes, Borla Catback Exhaust. Stock boost, stock turbos.

We have decided that we are going to go extreme, and this is not going to be cheap either way. However, I am only going to do this one time. Here are the list of things that are going in, on top of all needed maintence items.

Upgraded throttle body boot. AWE intercoolers, RS4 Engine mounts, RS4 Transmission mount, AWE drivetrain stabilizer, VAST software, upgraded MAF, upgraded fueling, upgraded clutch, new fuel pump, all the good stuff that you could ever want to install on a car. You name it, it is going in. So, whats the deal you ask... Well here it is.

What turbos should I install. From what I was told, the KO4's from the RS6 can be modified to fit the B5. They claim to produce about 75 WHP more than K04's from the RS4. Or, I can use the K04's from an RS4. Well, here is my delima. The RS6 turbos will take quite a bit of exhaust work to match up with my aftermarket downpipes. I can get a set of stock downpipes and " Piggie " Them, or try to modify my aftermarket downpipes ( That could be difficult to do ). The second issue is that I searched the internet quite a bit, and sites like youtube show KO4 cars beating the K04 hybrids quite often. I know the hybrids produce 2-5 more lbs of boost, but I am just not sure.

I am looking for those who know, to chime in please. I am taking a ride in a local K04 Hybrid car on Monday. Hoping to have other imput before then.

Mike

If it comes down to choosing between a mild rs6 car or a full on K04 car id pick the k04 car. The little things that you might not have money for if you went with rs6's like motor/tranny/diff mounts really make a difference.

K04's are the standard. They were the first upgraded turbos to come out for the s4 but it has taken years to get were we are now as far as fueling & supporting mods. The first k04 cars certainly werent running 11's. A PJK04 kit (unmodified rs4 turbos) is the simplest and maybe cheapest solution.

The rs6 turbos arent called k04's just rs6 turbos. They fit on your stock manifolds no problem, the only exhaust modification should be welding a new flange on downpipes which isnt a big deal. I wouldnt run these on my car without new rods and a little head work to take advantage of the power

ER intercoolers are roughly the same price but larger than AWE's

034 motor and transmission mounts are much better than RS4, and not too expensive (get track density, there is a little vibration noise but its well worth the performance). The snub mount with cage, and Apikol Rear diff mount are also nice upgrades.

DTS is great, even better with the JHMotorsports mount for it.

As far as videos go results are skewed because of how well the cars are running, who tuned them, whose driving them, transmission, fuel pump & injectors, exhaust dumps, water/meth, race gas, lightweight wheels or gutted interior etc. Take a custom tuned k04 car and have the same person tune it with hybrids and it should make more power.

Thanks for your reply.

As for the motor, trans, and diff mounts. I will not go outside of stock. The car will never see a road course, and vibrations are not allowed. This is to make a quick winter beater.

As for the RS6 vs K04 all the supporting software will be included. The RS6 requires a different airbox, tune, injectors, fuel pump etc.... I would like to be one of the few who have it. However, I want to be a quick and powerful as possible.

Mike

I don't know how fast you want to go but a properly tuned ko4's can got into the mid to low 11's. Now for me thats plently fast enough. But If your talking about going even faster then the RS'6's are the way to go but with an extra 4-5 grand is the only way your going to make the RS6's usable bc motor work will have to be done in order to actually beable to run atleast 15psi with them. And as far as mounts 034motorsports.com they have some dam good mounts that are very comparable to stock if you buy street density or stiff as morning wood if you go with track density

jhjhjh

lol! Haha!

Ok. Thanks again for the imput. I really do not have a whole lot of experience with these cars. I like to drive them, and have always been a fan, but never went crazy like this.

I am supposed to go in an RS6 equipped car today. That should help me decide. However, I must say I am swaying towards K04's. Not only will it be less expensive, it sounds like they may provide all that I am looking for.

I will keep you all updated.

Mike

Unless your really want to go for it with Rods, Cams, RS4 Ypipe, Porting the heads and manifolds then the RS6's really arent worth it IMO. K04's have come far enough that its pretty easy for ANYONE to throw together a setup and make decent power. Even on piggie pipes and a bone stock motor. Its a much easier bolt on solution. Also

If i had RS6 turbos i would want to run full boost, water/meth, and perhaps racegas at times and with a stock motor i couldnt do this. If you turn down the boost and are making a safe ammount of power for our stock motor then a well build K04 car might still outrun you because the turbos are smaller, spool faster, are making comparable power and can better take advantage of the power they make.

Thats why i bought K04's instead of RS6's.

I have to agree that I think that is the way I am going to go. You really sound like you know your stuff...

I am going to go for a ride tomorrow. He could not make it to me today. Unless I see fit otherwise, I think that K04s are my answer. Plus I will be able to use my current downpipes. They will not work with the RS6 turbos. As my downpipes have two flanges one for the exhaust and one on the wastegate. They have a divorced exit.

Thanks again.

Mike

Hybrids are a waste of money and will hardly net you any gain because of the small turbine side.. RS6SS are under the k04 series and will net you 40-60hp over RS4 K04SS.