i know that the s4 13bt has less power than s5 13bt. it's because of the boost and compression ratio right? but does a s4 have the same potential as the s5? since like the rotors are more durable on the s5? thanks.

 

I've heard that you can run more boost on an upgraded S4 engine, since it has lower compression to start with, but I'm not 100% on that one, could be wrong.

 

yes, you can run more boost on an S4 engine because of the lower compression

 

Yeah more boost, like maybe a tiny bit more when you start getting into the really high boost area.. ->25PSI

<-25PSI i'm quite sure you'd want to go with the high compression...

Lower compression hides dodgy tunning well..

 

but if i wanted to upgrade, then just get the higher compression rotors? what if i wanted at 300rwhp or less?

 

Personally i'd use S4 N/A rotors, or even S5 N/A rotors to get 300rwhp..

N/A rotors, ported engine, properly sized turbo that doesn't need to run an insane ammount of boost.

Personally thats what i'd do... You could reach the 300hp goal many different ways.

One thing to remember is the higher compression engines once boosted need much more careful tunning and as cool as possible inlet air.

 

Highcompession is same power with less boost, More power with same boost
More power when your off boost

go highcompression if your budget allows it, im going with 9.7:1 rotors if i ever get ahold of a set

-Jacob

 

reason i dont wanna stay NA and port motors is cause of smog. but is it hard to get to 250rwhp s5 NA?

 

full bridgeported n/a? look up the judge ito 6 port bridge on nopistons


also the s5 engine has better doweling... it will do better @ HP above 450... but you really need to be redoweling after that anyways. I guess you could get away with not doweling... but I wouldn't chance it. I really don't see myself wanting much over 450 anyways.

 

I was actually talking about a ported turbo motor before in my last post.
Not trying to suggest you stay N/A.

 

oh, hehe, ok.

well, i have a s5 gxl right now, it's just that, the swap seems to cost too much right now.