K03-73 (B6 190bhp) turbo upgrade

[SteVR]

Hi guys, well I have just purchased a k03-73 turbo for the a4. The car at the moment engine wise is standard apart from a remap (unknown from the previous owner) and a bosch 710N valve.
What would you guys recomend I need to partner the new turbo? probably looking to purchase a silicone TIP (anyone got one knocking about??) will the fuel injectors be up to the job?? its a 2000 APU lump, I could be wrong but didnt these have higher flow rate injectors than the earlier AEB lumps??

 

[jcb]

don't think so (could be wrong)
as for upgrades what is your MAP running at now?
personally I think pushing more hot air through a stock SMIC is an issue.
The TIP is a nice bit of rubber bling to add but I can't seeing it freeing up a massive amount of power.
decent hot and cold side pipe work sound like your best options.
CAT delete, 3" downpipe, 2.75" exhaust, FMIC in that order if it was me

 

[SteVR]

MAP spikes to 16psi, holds 13/14psi. I have a 2.5" bore scorpion exhaust sat in the garage so thats sorted. I am not looking for massive power somewhere near 220-230bhp with 220-240lb/ft.
I am a bit skeptical on the TIP if its not needed I wont, I am only interested in "must haves" as I am building it on a tight budget. Front mounted Intercooler and a sports cat may come at a latter date.

 

[aragorn]

I suspect your running very close to the limits of the stock MAF and injectors at 220-230hp

You could look to change to a 3" MAF housing and use larger injectors, and infact if you were to run the standard ecu (not the mapped one) with this setup, you'd probably make around 210hp without even remapping it (although your ignition timing wouldnt be quite right). You'd then need a custom map to extract the maximum from the setup.

If you find marks hybrid turbo thread, you'll see that 3" MAF and Vauxhall LET injectors with a 3bar FPR are almost a perfect match, and will give you approx +38% power. Unfortunately if you tried to run them along with your existing map i suspect you'd be trying to push around 260-270hp thru that turbo, which would end in tears!

 

[SteVR]

Thanks for the reply. Ideally I would just like to bolt the K03-73 in and run on the current chipped map. Would this be possible or not a wise move with regards to running lean? I cant really afford to have it remaped again. Would a MBC set to a more friendly boost level help get round the issue??

 

[aragorn]

If you did that, you'd simply get exactly the same amount of power you have now. You'd need a custom remap to get the most from the new turbo, and there seems little point going for a custom map with the stock MAF and injectors to me.

My point was more that seen as your on a budget, you could fit the MAF and injectors, and using the standard map you could have around 210hp, until you get a custom map lined up.

 

[SteVR]

But seeing as the current turbo is only a lowly k03-005 would the k03-073 not yeild slightly more gains on the remapped ecu due to the larger inlet and exhaust turbines? (my knowledge of FI engines is limited as you may have gathered )

 

[aragorn]

Your APU engine should have a K03-029 at the moment?

Anyway, because the way the ECU is programmed, it would just turn the boost down to ensure the MAF reading (and therefore the power) remains the same.

 

[SteVR]

Ok that makes sense. Well it should have a 029 but its had a rebuilt turbo by essex turbos and is only a 005.

 

[slappy_dunbar]

Ok that makes sense. Well it should have a 029 but its had a rebuilt turbo by essex turbos and is only a 005.

You will see a nice improvement then. The -005 is god-awful tiny. The K03-073 shares its compressor wheel with the K04, so you should see a bit of a drop in combustion air temperatures. Your timing might improve as a result.