One doesn't simply replace stock turbos with "more reliable" KO4s using the orig ECU, ie, add'l goodies still req'd. Also, a aftermkt chip based on a KO3s will have to be updated/upgraded (with add'l goodies) for use with a replacement KO4 setup. Correct?

 

Yes you can run K04's with the stock ECU/chip. Yes there is improvement mid range and topend. Power is smooth, I feel,, they are even smoother than K03's.
Yes you can run K03 chipped software but it is not configured for the larger turbos. I would either run stock ECU or get the K04 program. Reason being , I have seen K04 turbos on K03 software and the boost levels were high. Car will be real fast even with the K03 ECU Chipped software but VAG it and see what levels your at. It may be fine.
To run O.CT RS4 K04's you need the Turbos, (comes with the needed parts to install), 5bar FPR and thats it, to get started. O.CT turbos are the real deal, different pitch vanes for quicker spool up, stronger shaft, housing is more heat resistant than the Audi RS4 K04's. Try Mr. Bob at Stratmosphere 1-866-533-1777. You can also email me at jjstuesser@sbcglobal.net if you have more questions.

 

The RS4 variety work best above 4500rpms. It will seem a bit soft at low rpms, and then all of a sudden you feel like somebody lit the afterburners;-) The custom tuned versions by Abt and OCT use a different blade pitch and in the case of Abt ( the ones I am most familiar with ), different shaft, bearings, etc. These give power from around 2500rpms, but will start to run out of breath around 5500rpms.

Stock software can be used with KO4s as Ming points out, but you'll be missing out on half the fun. Depending on whether you have a Tip or a stick, there are various torque levels you should stay within, if transmission life if important to you.

AMS is the North American Abt importer, or you can also contact one of their dealers like Achtuning who has a lot of KO4 experience.

10310-763-8000

 

Before embarking on your modding journey, you need to consider what you want from your car.

My desire was to retain the smoothness and drivability of the stock car while adding performance and reliability. I chose a tuner whose philosophy is aligned with mine.

You may want a 1/4 mile burner, or a smooth street machine. Your turbo choice as well as other equipment vital to their care and feeding will depend on your objectives.

I chose O.CT K-04's to replace some fried stock turbos. They have the same dimensions as the RS-4 units and offer different vaning, more heat resistant exhaust side housing, larger drive shaft, and other upgrades.

I did not want to lose any of the low end response of the stock engine, and also wanted a solid platform to build on. The early boost characteristics of these K-04's as well as the tuner's philosophy of smooth reliable power matched well with my needs so I went for it.

I ran these turbos with the stock ECU for several thousand miles, and agree with Ming -- smoother than stock. Also, the improvement in high end performance got me thinking about taking full advantage of the O.CT K-04's. I now have a pretty solid performer that delivers lots of smooth power!

I do not know if this setup would be right for you -- it all starts with you having a good understanding of what you want. That will help us all to help you!


Good luck! You are starting a fun journey!<ul><li><a href="http://www.stratmosphere.com/oct_a6.htm">This is a good place to start ---&gt;</a></li></ul>

 

Thanks to all for your great insight and perspectives.