chairman

Or just a new RS4..

AofC_RR

Probably would have been cheaper and less labor intensive, and you'd still have a working S5 engine for later.

RI A6

This engine has been charge optimized for direct injection using the latest in computational fluid dynamics design techniques. If you alter the flow pattern, you can change the combustion chamber efficiency, and you can deposit an excess of fuel on the cylinder walls.

There are no changes in the bottom end of the RS4 engine. The block was built to handle lots of power.

Be careful about the ECU. Dual ECU's were needed to keep up with all the engine management calculations at 8250 rpm. One ECU per bank.

Your compression ratio is already 12.5:1. Why would you want to reduce it, unless you are going to supercharge?

CanuckRS4

It would be easier to drop and RS4 engine in there...what you say you are doing is impossible.

kompressor_S5

maybe i should supercharge it then, i figured 420hp out of an s5 motor could be done .But maybe not

kompressor_S5

have you seen the inside of a rotocast head port? I hear ya but this motor is far from F1

kompressor_S5

or broken wallet

Shoe

You are basically going to have a completely different engine with aftermarket parts, unless you know the owner of the dealer I don't seem them honoring your warranty if your engine blows.

This is a big ambitious endeavor. Personally, I would do a full exhaust, headers, tune and you should be around 375-380hp. If you have a company do some custom cams you should be nearing 410hp which seems like a lot less trouble then redoing the entire engine.

Another thought is your time frame for this project. There is a good chance the RS5 will be out by end of 09 or mid 2010. If this project takes over a year you are better off waiting then having the S5 out of commission for such a long time. This is only from a practical standpoint, I bet it would be a fun project.

RI A6

I suspect that they considered the surface roughness of the ports when they did their optimization, and may even count on it to create the flow that they need. Charge flow in DI combustions chambers is tricky.

As I understand it, all of the Audi FSI engines were optimized in conjunction with a company in Germany that specializes in CFD. This is one of the reasons Audi is able to reliably run 12.5:1 compression ratio.

However, your project will definitely be interesting!

Europa

... its high-RPM operation. From what I know about the motor, it's just simply not going work the way you want it to (if at all) without its complex brain. So you probably can't just wing-it with some homebrew ECU.

Plus, it's highly likely that it won't be a simple part-for-part swap; just because the block is the same, SO many of the specs could be different:

- bearing diameters (on the crank... which has a dual-mass vibration dampening system, vs. on on the existing S5 motor).
- clearances for things like sump, etc.

Also, don't forget the massive changes to the overall architecture of the car. It's not your standard longitudinal quattro front diff; the diff offsets the bell housing, which is bisected by the halfshafts and drives two clutches bla bla bla... it's *so* different. So while the block *looks* like it'll accomodate everything... it might not.

Nevertheless, I don't mean to be discouraging; I'd love to see you succeed in this project. So, if you do proceed, good luck!