Turbo change on BEX

[Vothir]

Hello there guys the time has come for my old stock turbo to be changed and a friend of mine has a spare k04-015..So i wanted to ask do i need to change anything else or it's a plug n play mod..? It's an A4 1.8T BEX QUATTRO 2003,it's mapped with the current turbo probably i am going to have to remap the ecu but do i need to take care of anything else? Thanks in advance

[Ozone510]

Should be plug and play.

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[drifthero11]

Like above it should be plug and play hardware wise. For me personally I would recommend a remap and tt injectors, besides that you should be good.

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[Vothir]

Like above it should be plug and play hardware wise. For me personally I would recommend a remap and tt injectors, besides that you should be good.

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Do you recommend injectors and remap performance wise or to be on the safe side ,i am asking because i don't want to get more power right now at least for the next month cause my wife is going into labour anytime and i can't spend more right now on the car..Can i change injectors after sometime or it's a risk?

Thank you both for the fast reply

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[Ozone510]

You def need a remap, injectors or not. It won't be expensive and I have a set of injectors I'll be selling next week. 386CC OEM TT injectors for a good off the shelf tune. I wouldn't add this turbo to your car until you secure funds for: remap, injectors, and a larger MAF. Also highly recommend a larger intercooler, but it's technically not required. Do not do things in staggered order, you'll spend more money in the long run and break shit. Ask me how I know.

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[Vothir]

Ok then i am going to postpone till i have funds for all things i need..Thanks again

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[grayjay]

You def need a remap, injectors or not. ]

There is nothing so different about the KO4 that it would cause any troubles running with a stock ECU that was tuned for a K03. The ECU will still read the MAF and pressure and take care of fuel and wastegate control exactly as with a stock KO3 turbo. You will not get any significant performance increase from the K04 since the ECU's wastegate control will keep it operating at same stock boost and power level but it should still run fine. Boost would just not start until slightly higher RPM due to the larger turbo. Huge limitation here is the small stock injectors as they cannot supply enough fuel to sustain boost level higher than stock above around 5000rpm so you really cannot take advantage of the higher air flow capacity of the K04 until you can also supply increased fuel to match. Changing the injector hardware will definitely require tuning of the ECU to compensate for increased fuel delivered per squirt. Learn to DIY tune/flash ECU with tunerpro and nefmoto or else pay other to tune it for you.

[Vothir]

I just didn't think that it would make such a change since BEX comes with k03s (k03-073) which has the same compressor as k04 only the body is 42/46 mm instead of the 40/45 of stock

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[Cybersombosis]

That is what Grayjay is saying. Putting the K04 in now without tuning is fine as a direct replacement for the K03. No need to wait for tuning and injectors before you install the turbo. Once you decide to spend more money on tuning , injectors and supporting mods, the bulk of the work is already done as the turbo is already installed.