experimenting with timing
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grasshopper
- Posts: 206
- Joined: Wed Aug 13, 2014 10:25 pm
- Your car is a: 1976 Fiat Spider
experimenting with timing
Hi all. I am in the middle of a restoration. I have my new engine running. 1800cc,Faza 35/75 cams,,high comp pistons,dual idf carbs. My timing is set at 10deg btdc. I am trying to dial in the carbs and am wondering if my timing should be even more advanced to lets say 15deg ? If so,how do I do it ?
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sptcoupe
- Posts: 987
- Joined: Tue Mar 17, 2009 9:25 pm
- Your car is a: 1972 124 Sport Coupe
Re: experimenting with timing
IDF's love advance when you have the CR and longer duration cams to go with them.
10-12 degrees BTDC is enough, but it depends on the octane of available gas, condition of the engine, etc.
Just dial in what you can without causing it detonate. 10 degrees BTDC is safe for most engines. On my coupe I have a 10:1:1 CR, and with 93 octane pump gas I can run 12 degrees with no detonation. In this Houston summer heat or if I'm planning on tracking it I run it at 10 BTDC, unless I am running 100 octane race gas. But I never go above 12 BTDC.
Total advance should be 34-36 degrees, and it should be all in around 3100-3200 rpms.
If you can program your advance curve, I have posted somewhere in these forums the factory ABARTH ignition curve that was used on 1800s with a similar build.
10-12 degrees BTDC is enough, but it depends on the octane of available gas, condition of the engine, etc.
Just dial in what you can without causing it detonate. 10 degrees BTDC is safe for most engines. On my coupe I have a 10:1:1 CR, and with 93 octane pump gas I can run 12 degrees with no detonation. In this Houston summer heat or if I'm planning on tracking it I run it at 10 BTDC, unless I am running 100 octane race gas. But I never go above 12 BTDC.
Total advance should be 34-36 degrees, and it should be all in around 3100-3200 rpms.
If you can program your advance curve, I have posted somewhere in these forums the factory ABARTH ignition curve that was used on 1800s with a similar build.