at what compression ratio is it necessary to switch from 87 octane gas?
I am building a mini me and the CR will be 10.1:1 and i was wondering if i could get away with using 87 or 89?

 

10:1 you'll probably want 92-93 octane for sure.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by evosol &raquo;</TD></TR><TR><TD CLASS="quote">10:1 you'll probably want 92-93 octane for sure. </TD></TR></TABLE>

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by zman &raquo;</TD></TR><TR><TD CLASS="quote">at what compression ratio is it necessary to switch from 87 octane gas?
I am building a mini me and the CR will be 10.1:1 and i was wondering if i could get away with using 87 or 89?</TD></TR></TABLE>
There are plenty of Honda engines that are close to 10:1 from the factory and call for nothing more than "regular". A few things can help deter detonation: polished piston tops and smooth combustion chamber edges, a step colder plugs, a few degrees base retard, a PCV system that doesn't recirculate thru the intake manifold, a cam with moderate overlap, which in effect bleeds off compression when then engine is running and lowers your dynamic compression...

but...

For peace of mind, i would just the good **** ; )

 

ahhh boourns. Its for my g/f's car (95 CX hatch) it already has a d15b7 and a S20 tranny. She doesn't really want to use 91 octane, but i might be able to convince her that its worth it.
What engine/tranny comes in the canadian 95 CX hatch?.....i thought that it was supposed to be the d15b8 1.5L 8 valve, but in the car she just bought from a lot a d15b7 1.5L 16 valve mated to a s20 tranny is in there.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by evosol &raquo;</TD></TR><TR><TD CLASS="quote">10:1 you'll probably want 92-93 octane for sure. </TD></TR></TABLE>