Hello all, I'm the proud new owner of my very own 10th AE! Unfortunately the motor is due for a rebuild or replacemant so I've been toying with the idea of switching to a s5 engine. I know to do this you must have a s5 ecu to run the engine. So at the risk of sounding like the noob I am I'll ask the following questions.
Are there more than just the two types of ecu's? (ie version changes throughout the years, not just s4 to s5)
And will it matter when doing a swap? (I don't think it will but I might as well ask)

Thanks,
~Brandon

 

switching to the S5 will just be ALOT of work for minimal gains...

if you want you could aways get the S5 bare block and bolt all the S4 stuff onto it...

 

What he said. If you can get a complete S5 engine, do so. Use the S5 block with the S4 front cover (for the OMP), and the S5 turbo and manifold. For everything else (including wiring and ECU) just re-use your S4 bits. A decent exhaust and intake will push you well past the stock S5's 200hp, just make sure you give it enough fuel.

 

Thanks guys, kinda what I figured from what i've read on the forum. I'll probably end up just buying another s4 block because it's a little cheaper. BTW I've also heard that the s4 engine is better for boost applications because of its lower compression, is this true?

 

if yer goin for BIG boost #'s then lower compression rotors are better but for street driving and better "all around" driving the S5 rotors are actually lighter by like .5 lbs