Found a k03 Turbo available on a local CL post. It has 5304 10150 95b stamped on the compressor cover

Looks like it's a K03, but could be k04 compressor housing, and he claims it's from a 2k1 a4. Can someone help me with a positive ID? What I am looking for is one of the "Sport" or "k03s" that are cited below as the "post-2000-further-developed units cited below" I have a APR chip coming and will want to have a newer turbo soon, when I combine this with a 4.0 FPR, I think I am done with my stage one engine mods.

here's a breakdown of turbo's from a rebuilder from another VW forum:

<<All the following turbos have the same installation dimensions and
thermodynamical performance. The differences are only in the actuator that
opens the turbine bypass valve:
K03-011 (5303 988 0011) 150 hp, 65 N actuator
K03-026 180 hp, 85 N actuator
K03-035 180 hp, 85 N actuator
K03-044 150 hp, 65 N actuator
K03-045 156 hp (Ibiza Cupra), 85 N actuator with 2 ports
K03-049 150 hp (Sharan/Alhambra), 65 N actuator
The 180 hp versions have an actuator with a higher opening force due to the
higher exhaust gas pressure (which is a consequence of the higher boost
pressure). Otherwise the valve would be pushed open by the exhaust gas
pressure.

The following turbos are a further development (since 2000) and have an
improved and slightly larger compressor while using the same turbine (still
with the same installation dimensions):
K03-052 180 hp, 85 N actuator
K03-053 150 hp, 85 N actuator
K03-058 150 hp/180 hp, 85 N actuator

Consequentially, putting a 180 hp turbo on a 150 hp engine will not bring
about any change in performance, but putting on a K03-052/053/058 instead of
the older versions will bring a slight improvement in engine efficiency.
Additionally, with re-mapping the ECU you can achieve about 215 hp without
danger of overspeeding the turbo. With the older turbos, 195 hp is the
limit.

With the K04 that's also commonly used (5304 950 0001) the power output
should not be more than 220 hp. That means, changing a K03-052/053/058
against a K04 does not make a lot of sense.>>

So, if you can please tell me more about turbo specifically, I'd be appreciative.

 

There is no reason to add a 4 bar FPR to your setup just because you put in a new turbo.

 

Well, I guess that depends on the Turbo, don't it??? For me, this increased fuel pressure is cheap insurance. I am not planning on boosting past 1 bar ever, but if it ever does happen to lean out for any reason whatsoever, I want to feel safe.

Any help with the Turbo question? Can anyone decode the above table from the turbo tuners?

 

No. It depends on the tune. If your not changing chips/tunes then you dont need to change the FPR. Our cars have a MAF to tell the ecu when more air is getting to the engine. The 2001+ A4 uses a wide band 02 so the ecu tries to hit a set AFR.


BTW where do you live? Because all of the A4's in North American came with a 4 bar FPR stock, so you might already be running a 4 bar.

 

But I AM changing chips, and this comes down to years of experience racing Porsche turbo motors. As far as tuning is concerned, I would consider changing the fuel pressure, turbo or boost as tuning a motor.

Now my grocery getter is a 1999.5 1.8TQ, I want my wife to have reliability and myself to have some power. I live in the Pacific Northwest, and I will have to check to see if it is 4.0 bar stock. I'd be shocked if it was, but I've been wrong about such details before.

Any one on here have any more info on this turbo?

 

Stock is 4 bar. You are talking about going from a k03 to a k03s. Wether you are going from a k03 to a k03s or from a k03s to a k03, you don't need a different tune. The APR tune was designed with the use of the stock 4 bar fpr. Why are you so worried about it leaning out? I think the k04 compressor housing is identical to the k03.

 

Changing to what chip? The tuner is going to tune for a set of injectors/FPR combo, changing the fuel pressure just changes the AFR at WOT while the ecu adjusts for idle/PT.


All A4 1.8t's from 97-2001 came with a 4 bar FPR stock, only the transverse cars from VW/Audi came with a FPR with a lower pressure rating.

I have been in the A4 game for 9 years, racing A4's for 8 years and was sponsored by GIAC for 5 years.

There is very little difference between the K03 found in the 96-99.5, 2000 and the 2001+. The main difference is that the newer K03 got a slightly more aggressive compressor wheel and a 4mm shaft in place of a 3mm found on the ndbw years.

 

In my original post, it says APR chip. I think with the semantics of a "tune" you are referring to the specific chip tuning, which I should have caught on to earlier... just your semantics vs mine. That's ok.

Thanks for identifying my 4 bar FPR, now I know I need a 5 bar to get where I want to go. Why do I want to not worry about leaning out? Here's the deal: I like to have the peace of mind that I am not going to blow a head gasket, melt a piston crown or nuke a ring landing while at full boost, that's why I want it. Listen guys, this is not about making a small turbo change, this is about running higher levels of boost than stock and advancing the ignition timing... heating the chamber up. I want it to run slightly rich at WOT. I think this is a pretty good safety precaution for any turbo car running over stock boost, one that I used in building 993tt's that made over 600bhp or an average 944 turbo pushing just 300. It's simply not gonna hurt. At worst, Mike correctly identified that my computer trims the fuel slightly or I lose a slight bit of my fuel economy. It's not gonna kill mine or your grandma. Be at peace.

But in the end, I just want some help identifying a turbo. Can anyone provide a source for identifying a 5304 10150 95b, or a table listing all the K03/K04's by model year?

That would sure be a help.

 

the stock fpr already recalculates for the added boost. thats the whole reason FOR an fpr. the apr tune uses a 4 bar fpr and is completely safe. running it richer is pointless unless you want to get less power out of the setup. you won't even scratch the forged mahle pistons inside your engine. there are guys pushing over 700hp on those babies. and there are thousands of guys out there running chipped setups on the stock fpr w/ 0 problems. 1 guy on this site has done so for the last 100k+ miles. but if you want to be ****, for no reason, be my guest.

 

Just call Borg Warner about the number on turbo. IF you just want to be safe (not needed but what the hell) you can buy an adjustable FPR at ECStuning or wherever that will reach over 5 bar.