Which Turbo? K03-058 or K04-023

[xs2man]

Hi guys.

Im gonna get a re-map done anyway, but I was having a random look around (as you do) and noticed two turbo's which might be nice.

I have a Standard 1998 1.8T Golf GTi (Mk4 obviously, 88k).  I'm getting a new cat-back exhaust anyway (Milltek or Blueflame?  Dunno yet which, advice here would also be appreciated, this is outwith the turbo budget), and a replacement panel filter (one of my freinds rallies and reackons this is the best way to go anyway).

The first is a K03-058 taken from a 30k 2003 A4 which is really affordable.  Will this just be a straight swap?

The other is a new K04 - 023 from an Audi TT (225BHP) but is new and would, realistcally, blow the budget out of all proportion (i.e. I'd have to wait for the re-map, possibly by up to 6 months as I'm still a student).

I could almost stretch the remap and K03 turbo and have been informed this replacement would give a slight improvment over keeping the original turbo.  The K04, however, will no doubt be a different animal, costing me so much I'll never manage to re-map at the same time, so will have to put off installing it even (will I?)  until about January (next student loan) when I will be able to afford the remap.

So, what would you guys do?  I'm in a dilema.  Realistically, I only really want about 200-220 BHP, but then, my mate has an 1997 A4 1.8T and is thinking of getting the same mods (before the turbo), and I really want to kick his ass.  But again, funds are tight, so if I'm required to get extra bits also to fit the K04 then I think the K03 will have to be the way forward.

Obviously, suspension and brakes are also on the cards, but this has top priority just now, as I don't take her on the track anyway, and this is really just for straight line power

[topher]

neither are a straight swap mate as far as i know. the k04 means new boost pipes, downpipe and oil lines.. you'd want new injectors too. if you lift the bonnet of an A4 you'll see the engine is the other way round.. not sure how much work would be involved in that swap.. but you know mk4 1.8T's run a k03 anyway ? might be a different housing but unless you've got an AGU its probably basically the same as you've already got.

[GazB]

Agreed with topher, if your gonna blow big money on changing the turbo then unless you go from a KO3 to KO3s which imo is not worth the effort, then go IHI

[xs2man]

Okay.  Can't afford the K04 then with all them extra parts needed.

I cant afford 2 grand and a half for the IHI conversion, so i'll not be doing that.  As for the K03, here is what I heard :

Dear Sir,

thank you for your interest in our products.

First of all, we don't produce any turbo that we call K03S. But I hope I can
answer your questions with the following explanations.

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.


And the K03 058 I could maybe get for less than 100 quid....

[topher]

borg warner never called it a K03s.. thats just what everyone "in the scene" refers to it as.

if you're determined to do it, like i said make sure it fits first.. coming from a longitudinal engine onto a transverse one.. the housing might be facing the wrong way.. ive never looked at one up close so i dont know.

but before you do that find out what your engine code is.. everything but AGU already has the k03s, and if you have AGU.. and the basic layout is the same.. the only thing you need is a modded turbo inlet pipe to get it to fit.. since the inlet flange on the turbo is a few mm bigger. you can either machine/mod a vw part (i have one ready to go sitting in my spare room) or use a silicone one.

you arent looking at much more power than you'd get anyway though.. the only reason i did the upgrade was because my k03 was knackered.

[xs2man]

Okay, maybe I'll just leave it then as its coming from an Audi. Every turbo I seen so far is for Audi's booo.  Especially wanted that K04 off the 225 bhp TT.  Never mind.

It was just my motor is coming up for 90k and this one had done only 30k plus apparently good for an extra 25 BHp (according to that letter anyway)

Oh well.