xdanny510x

Like the title says would it safe to run that much on 91?

HCI2000SS

iTrader: (2)

That's really pushing it IMO!

Rise of the Phoenix

iTrader: (27)

I agree. 93 would be okay with a spot on tune, but to me, that's pushing the limits of 91 octane.

427zm

iTrader: (9)

12:1 is perfectly fine! It's all about DCR, not static compression. Valve events brotha, open the intake valve earlier and longer, and you'll be fine. I'm running 12:1 in my 434, w/ a 235/251 114 cam, and we were still able to throw 30* of timing at it w/o detonation. Now, on 91, you'll want to back off the timing, but you'll be fine.

Rise of the Phoenix

iTrader: (27)

I stand corrected.

HCI2000SS

iTrader: (2)

Well that is true if he backs off the timing, but then you have to ask yourself is it really worth all that. I mean if I was putting all the time, effort, and money into a nice motor with 12:1 compression the last thing i'd want to do is limit the timing just so I could run 91 octane. That's just my opinion of course...

xdanny510x

How bout if i throw a mix of 100 into it

BSmiff

Then youre not doing what you initially asked about. If it is going to be a track car then it would probably be fine just putting 100 in there and running it that way. If this is a daily, you need to seriously consider your fuel choices. If youre going to be spraying the house down, go a point lower on compression and get a standalone with race gas.

Rise of the Phoenix

iTrader: (27)

Why not 93? Is it not available at all where you are at?

xdanny510x

Yea its about 10 miles away.. they sell 93 and 100 .. and this speed shop about 3 miles has containers of 100.

Rise of the Phoenix

iTrader: (27)

I see no reason to not run 93 then. You'll be much safer.