highest compression to still run 93 octane
Tony Shephard has a 397 stroker with nitrous running 9's and when he's off the bottle he's running 93 octane with 12.8:1 compression. It's all about the tune honestly. I've seen as high as 13.5:1 compression and supposedly had NO issues. Just make sure the tune is right......Don't expect to advance your timing all the way as far as you can and expect not to get detonation or spark knock.
James
James
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+1 For Shell 93 octane....
I work for shell, and their gas is alot better than alot of the others....
But like I was saying earlier 12.8+ is safe. Don't be afraid of the compression issue, by going with lower compression your leaving power out on the table... Just my .02
James
I work for shell, and their gas is alot better than alot of the others....
But like I was saying earlier 12.8+ is safe. Don't be afraid of the compression issue, by going with lower compression your leaving power out on the table... Just my .02
James
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From: Decatur, TN (N-W of Athens)
Would it help to get it setup for E85 which is 105oc? I notice when I run around 65gas:35E85 I get more pep out of my car and it's just stock. There's a guy on here who's pretty knowledgable on E85, and since it's alcohol he's said you'll need to change over a few fuel components to account for this. Like fuel o-rings and I think even your fuel pump. Still though E85, 105oc and 30-80cents cheaper than even 87oc!
but yea its got almost 138k and it had 114k when i got it about a year and a half ago
and to everyone else thanks for the info. i want to run as high compression as i can on 93. cause that means more power!
and is the shell 93 really better than others? i usually go to hickory point or bp.
You really need to know what your dynamic compression ratio is. Your motor only sees the full static compression if your intake valve closes at bottom dead center or before.
If you have a late closing intake valve (as with a big race cam) your piston could be a 1/4 of the way up the bore before the intake valve closes and your engine only captures 3/4 of the cylinders volume, ie your 12:1 motor has the dynamic compression ratio of 9:1 motor.
If you have a late closing intake valve (as with a big race cam) your piston could be a 1/4 of the way up the bore before the intake valve closes and your engine only captures 3/4 of the cylinders volume, ie your 12:1 motor has the dynamic compression ratio of 9:1 motor.
