DeWolf

Are the S3 pistons any different from a 91 S4? I have measured the 4.7 rods and they are the same length as the 5.0. Which is the better rod to use? The S4 rod is lighter that's for sure, but is it stronger than an early 80's 4.7 rod?

slate blue

S3 pistons are different and you’ll need to be careful with piston notches, early rods are the better rods and they can be lightened which is what I have done in the past.

DeWolf

My 4.7 pistons have no dish in them at all. They do have valve reliefs. The S4 pistons of course are dished with 4 valve reliefs. Does this make any difference in any way? Noob questions guys....sorry.

Strosek Ultra

DeWolf

What sort of power increase will the 5.0l bottom end produce. Bear in mind my car is a Euro spec 79 with the 240Hp motor.

karl ruiter

I'm not what you would search on...perhaps 16V Hybrid...but there is lots on data and probably dyno charts up here on this configuration. You would think that going from 4.5 to 5l would give you 10% (25ish hp), but think (based on the how much folks like this configuration) that something non linear happens and you end up with more.