LaserK04

Would an S4 with K04 turbos installed run satisfactorily with stock software? I have to wonder if the chip tuners could get the RS4 code and work from there to develop something. I'm just curious if it has ever even been attempted. With the rate that turbos are failing on S4's I see the opportunity to get K04's or some variation installed "relatively" inexpensively. I know that going to a GT25 or something similar to APR stage 3 would be best, but that's astronomical amounts of $$. I'm confident that if I supplied the turbos there is a dealer out there who would be more than happy to install them if I blew my current turbos. I doubt most dealers would even touch this, but there are some who would not think twice......

Derick - DFW

As the motor uses different heads, compression etc. I couldnt imagine that someone like APR couldn't remapp fuel curves and boost to maximize the use of KO4's.( I think Neuspeed already has this?) As far as stock programming you will see little or no gain as the whole purpose is to run more boost = more power. So using the stock program would run stock boost = same power.

LaserK04

Well, as far as K04's and the stock chip, that's my goal. To have it run like stock. Smooth, and (relatively) slow. I was more concerned that the car may stutter or hiccup with different turbos, or that any other parameters would be thrown off. Basically, my question was primarily to ensure that the car will still run fine on stock software and K04's until someone can get the tuning right.

But you have to start somewhere, and I think that testing the RS4 fueling, timing, and boost maps might be a good starting point to at least begin to explore the capabilities of the K04's and then tweak from there. I would think that even though there are some internal mods to the RS4, it would be close enough to get things up and running.

My only concern with K04's would be additional lag. I know that tuned properly that is not an issue on the 1.8T, so the tuners should be able to get similar results with the S4. I mention this because I had heard a lot about lag on the RS4.

I've seen lots of talk about exhausts and downpipes and people loosing low end torque on the S4. That's total bull. The reason it "feels" weaker is because you don't get a sudden tidal wave of boost that you get from a stock car. SlvrBullet and I did some testing with his road dyno. Here are some preliminary results: http://photos.yahoo.com/pearlwhites4

As you can see, the car with downpipes has far more torque (even with stock chip) at low revs that the car with stock exhaust. That's why I'm thinking that K04's with some aftermarket downpipes and exhaust will not really have much of an increase in lag with proper chip tuning.<ul><li><a href="http://photos.yahoo.com/pearlwhites4">Road dyno graphs of S4's</a></li></ul>