OK, a little background on me. I've been a 3S enthusiast for several years, to the point where I can now tear down and rebuild a turbo Stealth or 3000GT without any problem at all.

There are all sorts of mods for those cars as well, the first of which being upgraded turbos and the MANY variations we have of them, which is where I come with this question for some experienced techs out there.

My family is growing, I need a 4-door car, but I refuse to give up the fun of driving, hence my purchase this month of a 2000 or 2001 S4 (have it narrowed down to 3 cars, whoever has the best price at the end wins, all things being equal, but I digress...)

I'm looking at the K04 turbos and the ONLY thing I can tell that's different from the K03 is the compressor wheel. Is that correct?

The housing appears to be the same, the bearings, shafts, exhaust turbine,,, everything. Am I missing something?

I ask because I see availability for the K04 compressor wheels and I wonder why not take the K03 stock turbo, disassemble, rebuild with K04 compresor wheel, take to shop to balance, then have upgraded turbos for $200 each instead of $1,000?

What am I missing here? Or are most of the forum users more enthusiasts than tinkerers...?

 

if you think a k04 compressor wheel just slapps right into a k03 your crazy.And saying you know about turbo cars and not know that the compressor wheel to compressor housing clearence tolerance... basically a ko4 wheel would be touching a k03 housing

sorry don't mean to sound like a dick

 

Heh heh... that's OK, I'm used to people who assume the worst and jump my sh*t BEFORE asking more about my background.

For the record, there are SOME compressor wheels that are upgrades that DO slide directly into the original compressor housing. In the TD04 world, clipped wheels are an upgrade with an approximate increase of 10-15% in output and they WILL fit into the factory 9b exhaust housings. The 13g wheels sometimes fit, sometimes they won't and they have to be machined. THAT was the point of ASKING, not just STATING it could be done,,,

In other circumstances (which I'm not altogether certain is the case HERE because I don't know YOUR background), the compressor wheel CANNOT fit into the stock housing, and the housing has to be machined (which is NOT a problem, almost EVERY major city has a class A machine shop in some back corner of an alley somewhere - you just gotta ask around, Nashville has this one guy who was a Navy metallurgist and has his own shop with every piece of equipment he'd need to build an entire engine from scratch, but it's in a little hole in the wall and you'd never know he was there except by reputation alone).

So, again, even if the compressor housing has to be machined (costs about $60 bucks each), plus the compressor wheels at $50 each, plus the rebuild kit at $90 bucks, plus the balancing by a local turbo shop for $75 each, you're looking at $275 each just in parts and labor to convert these over.

Is there someone who knows FOR AN ESTABLISHED FACT because THEY'VE ALREADY TRIED IT, that this can't be done this way? Please list specifically what you've tried and why it didn't work.

Thanks,

p.s. On the 3s forums we have an "advanced tech" section that this would fall into. I don't see it here, or am I missing something there, too?

 

well.. while i will say you are above my expertise.. but from a business stand point it seems somewhat of a silly question to me. you are basically asking ... at least from what i can gather... if it would be cheaper to have buy the pieces seperately and have them put together and installed.. i will say that will always be a cheaper route but you need expertise and knowledge of wahts going on and connections as you said... That is the advantage of retailers that sell "prepackaged" goods is they are doing the work and marking up the product.

so i guess what im saying is if youre willing to do the leg work and research im sure that you are absoultely correct and could get yourself a deal.

 

Oh, I'm talking about doing the rebuild work myself.

The only 2 things I would have done is the housings bored as required (don't have the equipment OR the expertise to do it myself), and have the turbos balanced (again, lack of equipment and expertise).

Rebuilding a turbo is EXTREMELY easy, just time-consuming. Takes me almost a day to tear two turbos down, clean all the associated parts, inspect for excessive wear on non-replaced components, then reassemble.

I'm thinking from a business standpoint somewhat as well. If the output of a converted K03/K04 turbo is similar to or even matches a stock K04 turbo (especially if you clipped the K04 compressor blade before installing) and I can do the conversions for under $300 each, I could sell a SET of rebuilt upgraded turbos WITH a warranty for $1,000 and make a decent little profit for my time. $400 bucks a day isn't shabby...

Make it even a better deal by getting a group buy or a large order with discount for the ECU changes and other stage 3 mods, and you could make this kit HALF the price of the existing Stage 3 upgrade, save the community a ton of cash they can invest elsewhere, and make a tidy little income for yourself on the side.

Just curious to know whether there are any tech heads on this forum who have tried this before. Like I said, my previous platform (3s) has been around since the early 90's and just about everything has been tried, experimented with, LOTS of tech-heads on our board...

 

Perhaps talk with the owner of buehn engineering. http://www.buehnengineering.com/ If you search on audiworld you will find his name and I think/know he knows a TON about this.

 

Welcome to Audi, you can't rebuild crap, it needs to be replaced.

The K04 is much bigger on bot hot & cold side, the housing is also bigger.
K03's & K04's are not interchangeable. Some people do change the compressor side to
the RS6 turbo, or do K04/k16 hybrid.

These Turbo's are NOT like Garetts, where you can pick your trim & install in a few
hours. If that was the case, you would see a lot more variants in turbo's. Just about all the
kits are a modified K03 or K04, being clearances, balanced, or Hybrid.

Also the turbo does not come apart like more other turbo's. There just totally different,
don't forget it has a internal wastage.

Working on the car will be nothing like the Mitsu. The engine needs to be pulled to change
the turbo's there no room any where in the engine bay. That's the main reason there are not
a bunch of other kits out there. The 2.7t just doesn't have any room.

Before you say you want to do K04's look into things first. Audi's are so much more expensive it's
not even funny. The electronics are way above Mitsu, parts, including go-fast stuff is much
more costly. DP's alone will run you $1500, and take hours to install.

A full STGIII K04 setup from a stock car, you are looking at about $10,000 in parts. So a search, as this
has been talked about over & over again.

 

Thanks for the info, that's more the kind of information I was looking for.

I DID do a search, and didn't come up with anything SPECIFICALLY talking about modifying the K03 housings to accept the K04 wheels. I've seen the clipped/pollished thing talked about ad nauseum though...

Yeah, I was wondering about that, although now that I'm in my 30's, I'm thinking Stage 1 chip with downpipe and catbacks with the DV's and intake mods would be about as far as I'd need to go. Just got to thinking on a tangent yesterday about these turbos and thought I'd pop the question out there.

Dont' really need to be doing sprints with the baby in the back seat (which is why I'm getting out of 3s - gotta have those 4 doors). I'm sure he'd love it though...

Again, thanks for the more specific info!

Rich

 

love that youre thinking out of the box though... thats good to hear.