I run straight 50W oil. I'm OK.Stupid. You're diluting the oil & washing the oil film off the cylinders.I have a Trans Am that gets 8-10 MPG. Drive it as often as weather permits.
Carb mixture set about as rich as I can make it w/o fouling the plugs or setting the exhaust on fire.
Needless to say there is no catalytic converter or any other emissions BS anywhere on the vehicle.
Goes like hell though.
Indeed - pretty good!My wife has a Grand National that gets 18-22MPG, she drives it regularly. (Summer, she's frequently on her motorcycle.) It's set to run as lean as EGT's and driveability allows for mileage...it also puts >700HP down at the wheels and runs mid-10's in the 1/4 mile, through full exhaust with catalyst. Not bad for two tons and a little V6!