I run 93, except the last fillup (gas prices are getting waay expensive) I tried the 89, dunno if it was just me (perhaps going from 30degree days to 50degree weather) but I could of sworn I felt of loss of power.....
Theorically the higher octane will decrease the chance engine denotion at higher temps/rpm so your ECU will not retard timing (loss power.) Pretty much everyone I ever spoke about this always said they never noticed a difference between 87 & 93/4 going from cars whoms recommended octane was 87. So I don't know how much truth there is to this theory.
Gonna run 93 again next as see if Im just going crazy.
1996- BMW 328IS
<img src='http://img.photobucket.com/albums/v242/gws226/TEX/neverleanedsig.jpg' border='0' alt='user posted image' />
Performance: Zimmerman Cross Drilled Rotors-- PBR Deluxes-- Cosmos CAI---- Turner Pulley Kit--- Fan Delete mod---
Beauty: 18 polished M-Parallel replicas, Inpro Euros w/ Enchanced Angel eye kit, 20% tint
Clear corners/sidemarkers ---- Eurospec (Depos)
To do list:
UUC System U TDM- 3/05
M50 manifold converstion 3/05
off to the tuning shop for custom software 4/05
Cams/lightened flywheel, throttlebody........ well lets see what happens