Is there an optimal air/fuel ratio for drag racing engines? While air/fuel ratio is important for fuel system management, there is no one optimum air/fuel ratio. These depend on engine type, fuel type, and engine modifications. Below are examples of some optimum air/fuel ratios for specific drag racing engine examples: engine induction fuel air/fuel ratio […]
… by Experience & Gut Feel Throughout the racing community, experience and gut feel are the most common methods for the selection of nozzle and jet size numbers for setup and tuning of mechanical fuel injection. It is a form of iteration or ‘connecting the dots’. Given enough time and expense, experience from good and […]
Throughout our publications, air intake and fuel delivery values are converted to a ‘uniform standard of units’. That is “pounds per revolution”. The tuning demands for weight of air and weight of fuel become easy to understand, record, and analyze with that numerical value. And easy to change in fine tuning increments with this simple […]
Quick news summary with different fuels: NA (normally aspirated):
E85 is examined as a racing fuel. E85 is a combination of ethanol and low octane gasoline. Some racers report more power from E85 than from methanol. On the other hand, when the Indy Car League converted from methanol to straight ethanol, dynamometer tests revealed a reduction in power after the conversion.
We made a full pass. Picked up 3 tenths of a second and about 7 MPH over 9% nitro. It was a rush. The engine is louder. And more radical. We are still making enough engine heat at idle to keep the oil dilution minimal. We are on our 16th pass on the same oil […]
We dropped the AFR to 3.2 The idle went up by 300 RPM over the 9% setup (with no idle adjustments).
With a small increase from 6% to 9% nitro, in preparation we dropped the AFR to from 3.7 to 3.4. As a result, we picked up a tenth of a second and about 4 MPH over 6% nitro.
Just a note about our test engine for this year. We put our blown alcohol engine back together for nitro testing this year.
Received this email from a knowledgeable racer: Crew of an A-Fuel car (nitro) Bought all your books. Excellent reading. However, my calculated AFR number gives unreal value. How can I make this applicable to nitro?