compression ratio vs octane
What gearing/convertor/clutch does the car have? You dont want to clean the plugs and then look at them. Just pop a few new ones in and drive it as you normally would for a couple miles, then look at them. If you see small blue or black spherical deposits, or any metallic looking material, you're detonating or pinging whether you can hear it or not. I can get 94 Octane super at Sunoco gas stations in CT... You may need that. But you can also tailor the vacuum advance and mechanical advance so it doesnt come in as fast if the convertor is tight and gearing is high. You also may need to carefully tune the carb to work with those curves too. Pinging will almost always be much louder than rockers, detonation you may never hear anyway.
I have a 4 speed with 3.23 gearing but shorty tires/wheels at 24" so it runs
at 2500 rpm at 55 mph and my timing is all in at 2500 @ -34.
I have a wideband afr in the car and have been tuning 2 different carbs.
The 3310 750 and a 670 street avenger. The 670 wants to run lean no matter what and the 750 likes to run fat. I've been changing jets and secondary springs to keep wot about 12 on both carbs but the 670 cruises
at 15.5-16 and the 750 at 13.5
If I understand detonation somewhat, the fatter mixture helps reduce that
correct?
I have my initial timing set down to -16, the car runs better all the way up
at -20 but I thought I'd keep it at 16 until I can be certain it's not detonating.
I have a race track about 10 miles away and just outside it a BP station sells 110 octane fuel, but I'd rather not have to run there to mix gas all
the time. A few local stations sell 93 octane and I'd like to stay with that.
Octane boosters pretty much do nothing correct?
Thanks for your help!
