I was just wondering what exactly gives the S5 TII engines 20 more HP than the S4 TII engines. Is it just higher compression rotors or a different block...what the difference?

 

higher compression rotors, larger turbo ports, different a/r ratios, no twin scroll system to add resistance in the manifold. boost levels are set at a higher spec and the wastegate is larger.

 

Search Noob!!! it is in the Sticky on the top of this section....did u read those before you posted?

 

yes I did do a search...thats how I found out about the higher compression rotors and such...but there was so much mixed info that I wasn't sure what was viable...thanks Karack

 

np


and don't be fooled by the stock numbers, modded both are comparable to each other but with some minor differences in spooling characteristics and power curves. the lower compression S4 rotors offer more room to play with boost while the S5s have a little less buffer room in this area.


i'm planning on taking off my twin scroll system this weekend, porting out the turbo inlet ports and porting the wastegate. i am kind of anxious to see how it affects the power curve and spooling characteristics.

 

so an S4 motor isnt totally out classed by the S5...they both have their own strengths and weaknesses...ithats cool...so I guess I WANT an S4 motor since I will most certainly need that "buffer room"...ok things are comlpetely cleared up now...thanks so much