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2L TFSI K03 or K04

9K views 8 replies 6 participants last post by  pitch3110 
#1 ·
Hello all,

i recently purchased the new facelift Audi A5 quattro with the 7speed double clutch S-tronic gearbox, putting out std 211hp and 350nm of torque.

I have already done an ecu reflash by IC chip tuning from Switzerland, performance is defentially a huge boost compared to std but not near what i want.

(Mind you i have a 2-ton truck pushing out 500hp and 1000nm of torque from a stupidly small 3.2L 4cyl turbo diesel)

so my question here, how much different is the K04 from the K03, has anyone tried to just modify the internals (shaft, bearings, turbine wheel and compressor wheel) of the K03 to be a K04? (as from my information, the housings and dimensions are the same but the internals are different. worst case you might need to mill the compressor housing and turbine housing to make it a little bigger to suit).

being a modification enthuasit i also want to ask, is the K04 really the best turbo upgrade out there? power levels of 350hp is good enough, i believe the s-tronic can handle 550nm of torque which puts the K04 in the safe area.

i am also a big fan of the IHI RHF55 turbocharger, borgwarner S200 series, mitsubishi TD05h-16g small, (same as the evo).

any insight would help alot thanks!
 
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#2 ·
Not plenty of information regarding turbo upgrades on this forum, but you may want to read this thread.

K04 puts you at around 270 - 280 whp range which should translate to about 350 hp. RAI has come out with a turbo upgrade capable of 300 - 330 whp.

Use the search. You may find what you're looking for.
 
#6 ·
It depends on your definition of "best turbo upgrade". If you're strictly after more power, then I'd follow some of the ideas on that other thread. As you noted, the K04 is the same size as our stock turbo. Going true "big turbo" with a custom tune will give you way more power than the K04 route. I use my car as a daily driver, and I chose the K04 for the long-term reliability factor.

The APR link Mizo provided is the same one I have, and the B8 A4/A5 and Q5 all use the same 2.0 TFSI longitudinal motors. The transverse mount is used on A3 and TT.

As far as differences, I went from stock to K04. It was a major improvement for me, and I have no regrets!
 
#7 ·
I believe the main issue is the transmission.

yes the engine can be built to withstand 500hp quite reliably however getting the double clutch 7 speed box to handle torque levels that exceed 600nm-700nm would need parts that as of yet i have not seen available for anyone.
 
#8 ·
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