Anybody got one in there B5? Im thinking about going for one as a little upgrade to the standard k03. I know its not exactly much bigger but is nearly the same as a k04-15 in terms of output from what i can see. I know it will probably be hard to find one seccond hand but worth trying maybe.
Anybody running a K03-73?
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Yeah from the b6 quattro sport. With a few simple mods will pull a bit harder than at the moment.
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That was my thinking behind getting one. Just make it a little better. It's chipped at the mo so will need slightly more fueling for it but it's not exactly like going from standard to a huge turbo.
Geeky on audizine had this turbo and I am soon to fit one on mine. I have standard k03 tune and am going to try to bump the fuel up a bit by swapping injectors and fuel pressure.
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You cant just "bump the fuel up a bit"
The engine uses a MAF sensor, to measure the volume of air flowing into the engine, and bases the fuelling on these values.
If you up the fuel pressure or fit larger injectors alone, the ECU would notice the engines running rich, and trim all the extra fuel out by cutting back the injector opening time, resulting in either you being back exactly where you started, or with it popping a fault code because its reached the limits of its adjustment.
If you want more power, you need more airflow. If you want more airflow, the ECU needs to be mapped for it, because if it sees too much airflow then it will simply drop into limp mode expecting an fault has occurred.
The only way to fool it, is to fit a larger MAF housing. This in effect scales the airflow map by the % area increase of the new housing over the old one, and so long as its accompanied with matching injectors, will fuel more or less correctly and make more power.
As an example, switching from the stock 2.5" to a 3" MAF housing, is a 38% increase, so long as you couple the housing up with 38% larger fuel injectors, you'll end up with more or less 38% more power. It can make the engine a little prone to boost spikes though, so it may be worth installing a MBC in parallel with the N75 to act as an upper limit on the boost pressure.
The other issue is that if your ecu is already mapped, you'll be requesting 38% more power than the already mapped car, and you may well find a k03-073 cannot supply that much airflow.
The engine uses a MAF sensor, to measure the volume of air flowing into the engine, and bases the fuelling on these values.
If you up the fuel pressure or fit larger injectors alone, the ECU would notice the engines running rich, and trim all the extra fuel out by cutting back the injector opening time, resulting in either you being back exactly where you started, or with it popping a fault code because its reached the limits of its adjustment.
If you want more power, you need more airflow. If you want more airflow, the ECU needs to be mapped for it, because if it sees too much airflow then it will simply drop into limp mode expecting an fault has occurred.
The only way to fool it, is to fit a larger MAF housing. This in effect scales the airflow map by the % area increase of the new housing over the old one, and so long as its accompanied with matching injectors, will fuel more or less correctly and make more power.
As an example, switching from the stock 2.5" to a 3" MAF housing, is a 38% increase, so long as you couple the housing up with 38% larger fuel injectors, you'll end up with more or less 38% more power. It can make the engine a little prone to boost spikes though, so it may be worth installing a MBC in parallel with the N75 to act as an upper limit on the boost pressure.
The other issue is that if your ecu is already mapped, you'll be requesting 38% more power than the already mapped car, and you may well find a k03-073 cannot supply that much airflow.
At present my car is chipped so if i fitted this it would more than likely run less boost if everything was left as it is because the maf is getting the set volume of air at a lower pressure? I suppose it might make the car a bit better higher up the revs with it being a dlightly bigger turbo. With what byzan has done with bigger maf and injectors on a k03-73 and my car being chipped as well it would be interesting to see what boost it would run at.
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Yer, you'll probably find it will make more or less the same power, but use a bit less boost to do it. It might hold onto the power a bit better at the top end, as clearly we dont know the exact workings of the ECU and how it manages the boost pressure.
marks (byzan) car isnt on a k03-073, its on a k04-023 hybrid mongrel thing thats probably good for 280hp, hence the maf/injector mod works just fine, as his turbo is easily capable of running that power.
Perhaps if you ran the stock ECU and the maf/injector mod, the 073 might just about keep up?
marks (byzan) car isnt on a k03-073, its on a k04-023 hybrid mongrel thing thats probably good for 280hp, hence the maf/injector mod works just fine, as his turbo is easily capable of running that power.
Perhaps if you ran the stock ECU and the maf/injector mod, the 073 might just about keep up?
Yeah i know his is a fair bit bigger than the 73. Im just kind of thinking out loud. Kind of wish i had kept my standard ecu now to give it a go.
I can fool the oxy and temp sensor little to adjust the fuel trim. Im not taking a lot here anyway maybe less than 10% of what I already have. I just dont want to max the injector duty. I have not logged on VCDS yet to see what I am playing with.
