Octane and timing tips?
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Joined: Oct 2014
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Octane and timing tips?
I need some tips for what timing to set and what octane to run on my build. I have no clue what horsepower Im making as it has not been on a dyno yet, but a wild guess would be around 500.
I have a 327CID engine with 72cc heads and a Weiand 144 supercharger making about 6psi of boost.
Hydraulic flat tappet camshaft and roller rocker with 1.6 ratio.
Custom made headers.
The compression ratio of the engine in 9.3:1 and with the boost it makes around 12.5/13:1.
MSD Ignition system with a mechanical advanced distributor which puts of +22 on total timing. I've set my idle timing at 10 degrees advanced now, and Im running at 98 octane (european standards). Im wondering if I should go even higher on the octane, and if so, should I also retard my timing even more?
I have a 327CID engine with 72cc heads and a Weiand 144 supercharger making about 6psi of boost.
Hydraulic flat tappet camshaft and roller rocker with 1.6 ratio.
Custom made headers.
The compression ratio of the engine in 9.3:1 and with the boost it makes around 12.5/13:1.
MSD Ignition system with a mechanical advanced distributor which puts of +22 on total timing. I've set my idle timing at 10 degrees advanced now, and Im running at 98 octane (european standards). Im wondering if I should go even higher on the octane, and if so, should I also retard my timing even more?
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Thread Starter
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Joined: Oct 2014
Posts: 73
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Thanks for the tips.
The engine is buildt by myself. I will read that MelWff. It was a lot of info, but much can never be enough
During my rebuild this winter I've experienced that whatever you do, consequences comes a long side with it
The engine is buildt by myself. I will read that MelWff. It was a lot of info, but much can never be enough
During my rebuild this winter I've experienced that whatever you do, consequences comes a long side with it
Drifting
Joined: Oct 2012
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From: Medina Ohio
If I'm reading correctly that you are at 32 degrees all in, then it is too much timing. I am not familiar with what your 98 octane correlates to in US standards, but I assume around 91 octane.
9.3:1 is a bit high for compression with the blower. Stock pulleys with the 144 on a 350 should put you around 5 psi. With the 327 you might be more like 6-7+ psi.
I would recommend around 28 degrees of total timing.
9.3:1 is a bit high for compression with the blower. Stock pulleys with the 144 on a 350 should put you around 5 psi. With the 327 you might be more like 6-7+ psi.
I would recommend around 28 degrees of total timing.
Last edited by Ibanez540r; Jul 14, 2015 at 09:14 PM.
