I have to run 20-30% nitro in my 3.3-4.6cc car engines, I'd not want a 20cc engine sucking that much nitro. Pure nitro is expensive! Car engines run 7-9min on 4oz, a 20cc 4C will suck 4oz in about 3.5 minutes. My Enyas run great on straight fuel 80/20, but have a wider needle on 5-10% nitro. 30% nitro probably burns 1.5-1.75oz/min. That's just too rich for my blood. No YS or Saitos for me. Ever.