phantom meneSS

Ive read alot about what DCR guys are chasing with 91 octane (typically 8.4 give or take), what DCR would you advise with 94 octane?

Matt.

brad8266

iTrader: (23)

8.5...

LETHL_SS

iTrader: (21)

you can go 8.75 with ~93 octane

GOaT Cheese

I personally run 9.03 on 91. It has alot to do with the overlap of the camshaft. If your overlap is too much, your midrange scavenging sends the cylinder pressure through orbit. On my set up at 9.03 DCR, I have very little overlap, so my midrange cylinder pressure doesn't screw me, but I have gobs of torque under 4000 rpm. (610 @3500 to be exact). Also my engine idles like a John Deere tractor due to the early IVC event. My dynamic stroke is 3.32" from a static stroke of 4.00, and a static compression ratio of 11.31:1. It does detonate a little if the coolant temp gets above 190 or so, but I don't let that happen.

phantom meneSS

Ok great, we have 94 everywhere (our RON 98 = your PON 94) and will not have a problem sourcing that anytime, the engine statistic's are as follows:

406ci LS2
AFR 225's
248/252-108 LSA/108 ICL
SCR - 11.76
DCR - 8.84
Quench - 0.035"
Overlap - 34.4 @ 0.050

Guess i am pretty happy with the figures, now just gotta finish putting it together and see what numbers it lays down.

slow trap

iTrader: (22)

that sounds like a sweet setup and should lay down some decent numbers.i think you will be o.k with that 8.84 dcr.i had alittle over 9.0 also and ran 93 on a h/c setup but different combos has different cylinder fill and spark tolerance.i say you'll be o.k.

98SS1LWEE

iTrader: (25)

so, mine is 7.67, is 93 octane bad for my engine? should i find something else?

brad8266

iTrader: (23)

7.67 is low compression, which means that you are less likely to detonate. 93 is fine for ya.