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Author Topic:   Ignition timing
r19v
Member
posted October 07, 2001 10:46 PM
How much total ignition timing advance do most of you use on a sbc on alcohol?


WILDphil
Member
posted October 07, 2001 10:58 PM
Most of the builders and people I've discussed with run in the range of 34-35 degrees. Some run as high as 37. Per some tech publications, once you get above 34 your upsetting balance between ignition timing cam timing. In addition, you'll have more difficulty starting a stalled hot engine. Everybody seems to have their own preferences due to how each builds their own equipment. Hope that gives you some ideas.


r19v
Member
posted October 08, 2001 09:23 PM
I thank both you guys for your replys. The reason I asked this question was that I read on a website, about alcohol as a racing fuel that to use 40 degrees plus timing advance and a minimum of 14:1 compression ratio. We are running 36 degrees advance and a 12.5:1 compression ratio. Is 14:1 a common compression ration to run with alcohol? Thanks


sdhnc29
Member
posted October 08, 2001 10:16 PM
Yes , 14:1 is very common . In fact , most of our alky engines are at 15.5:1 . Alcohol is an extremely slow burning fuel , thus , these engines thrive on compression . On average , a 23deg. engine likes to see 36deg. of timing . But you should run your engine on a chassis dyno or engine dyno to be sure . Piston dome , and combustion chamber design will greatly influence your ignition timing . On a dyno , you can see the affects of ignition timing , and find the exact place that your engine likes to run best . Hope this helps !


r19v
Member
posted October 08, 2001 11:21 PM
sdhnc, thanks for your reply and the sharing of your knowledge. Roger


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