Hopefully, there's somebody on this board with experience running higher compression on "pump" gas. I've read of a few tricks worth mentioning to withstand higher compression on cat-piss gas. We're really only talking about 93. It'll always get that. considering the ford zetec runs these things, it should work for ours. Those get away with 11:1 with less than this.
-shape a clover leaf combustion chamber, via creative welding and grinding. (almost-kinda sorta feasible)
-a smaller volume combustion chamber to lower the compression and increase quench. (???)
-wider cam lobe separation. It's something larger displacement engines like to make more torque at lower rpm. v8's run 106 on a tight cam. 112-114 is usually a good cruiser/RV cam. I've heard of closer to 102 being used for race engines. But, you can go as far out as 120 (HOT ROD '97)
-a cooler engine (excuse for a better radiator and cooling enhancements.
)
-thermal coatings, cryo-treating.
-oil spray piston mod.
-better breathing capability in the first place. Breathing mods alone can let you get away with running more compression, but not much more. (1/2 pt.-ish)
There's a lot of tricks to get this to work. All of this costs money, but what will I gain because of it? Now that the impreza is parked, I can ponder some of these finer details that are supposedly required for a good n/a engine to run really well. None of it's a black art, really. It IS about what you can pay for, and how much you can do yourself. Then pilot it, fix it when it breaks, trailer it occasionally, and basically cater to it
. There's plenty of opportunities to make it work, though.
-shape a clover leaf combustion chamber, via creative welding and grinding. (almost-kinda sorta feasible)
-a smaller volume combustion chamber to lower the compression and increase quench. (???)
-wider cam lobe separation. It's something larger displacement engines like to make more torque at lower rpm. v8's run 106 on a tight cam. 112-114 is usually a good cruiser/RV cam. I've heard of closer to 102 being used for race engines. But, you can go as far out as 120 (HOT ROD '97)
-a cooler engine (excuse for a better radiator and cooling enhancements.
-thermal coatings, cryo-treating.
-oil spray piston mod.
-better breathing capability in the first place. Breathing mods alone can let you get away with running more compression, but not much more. (1/2 pt.-ish)
There's a lot of tricks to get this to work. All of this costs money, but what will I gain because of it? Now that the impreza is parked, I can ponder some of these finer details that are supposedly required for a good n/a engine to run really well. None of it's a black art, really. It IS about what you can pay for, and how much you can do yourself. Then pilot it, fix it when it breaks, trailer it occasionally, and basically cater to it