I highlighted compression ratio because that's the item I'm most up in the air about right now. I'm working on a new build with some peculiar goals that I think are interesting... a step beyond the thinking that goes into most race motors.
Design restriction: When *not* under boost, the motor must run with only 93 pump gas. During this time, which I'll call "regular driving," I absolutely want to maximize gas mileage potential. For compression ratio, this means up. With no boost, we'd be talking a good 10.5:1. But then there's boost.... I want capability of 30mpg from this thing... the car's lightweight and the ECU can do whatever I want to make it meet this, but 8.0:1 would probably make it impossible however I look at it.
Design restriction: When under boost, the motor can be aided by a second fuel system. I'm willing to have the intake modified to hold a whole second set of fuel rails and big port injectors (40lbs?), which would simply have a 0% duty cycle during normal driving, but controlled sequentially as a second cooperative fuel system (I'm using an ECU no one's seen before, the capability is there to run twin port sequential fuel systems and sequential port nitrous all at once). Under boost, I want to maximize power. This means more boost (not that simple I know, but still, it means more boost in general). The fuel choice in the second fuel system must not kill my wideband O2 sensors!!
My heads flow 320+cfm at the lift I'm going with on the intake side, 225+cfm on the exhaust side (I mis-wrote the numbers on the exhaust so I don't know the specific numbers
). The block and bottom end can handle anything I throw at it that won't knock. Turbo is an AirWerks S88, and my target output levels on 93+alky is four figures at the ground, so call it a 1200bhp target.
Another consideration: what stroke should I go with? Less stroke = less cubes, but more allowable RPM which means more HP at lower TQ. It also means I don't have to dish the pistons as much. More stroke = more cubes, more torque, more dish, etc. Block is a GM LSX block on a 4.125" bore. Crank can have any stroke really in order to meet my goals. So far I've really looked at a 3.750" (401cid) or 4.00" (427cid).
So let's talk compression ratio and stroke with these design goals in mind. Should be fun and different
I've done lots of searching on different forums, so I'm really looking for actual numbers people would suggest and why they chose them to maximize BOTH gas mileage and power.
Design restriction: When *not* under boost, the motor must run with only 93 pump gas. During this time, which I'll call "regular driving," I absolutely want to maximize gas mileage potential. For compression ratio, this means up. With no boost, we'd be talking a good 10.5:1. But then there's boost.... I want capability of 30mpg from this thing... the car's lightweight and the ECU can do whatever I want to make it meet this, but 8.0:1 would probably make it impossible however I look at it.
Design restriction: When under boost, the motor can be aided by a second fuel system. I'm willing to have the intake modified to hold a whole second set of fuel rails and big port injectors (40lbs?), which would simply have a 0% duty cycle during normal driving, but controlled sequentially as a second cooperative fuel system (I'm using an ECU no one's seen before, the capability is there to run twin port sequential fuel systems and sequential port nitrous all at once). Under boost, I want to maximize power. This means more boost (not that simple I know, but still, it means more boost in general). The fuel choice in the second fuel system must not kill my wideband O2 sensors!!
My heads flow 320+cfm at the lift I'm going with on the intake side, 225+cfm on the exhaust side (I mis-wrote the numbers on the exhaust so I don't know the specific numbers
). The block and bottom end can handle anything I throw at it that won't knock. Turbo is an AirWerks S88, and my target output levels on 93+alky is four figures at the ground, so call it a 1200bhp target.Another consideration: what stroke should I go with? Less stroke = less cubes, but more allowable RPM which means more HP at lower TQ. It also means I don't have to dish the pistons as much. More stroke = more cubes, more torque, more dish, etc. Block is a GM LSX block on a 4.125" bore. Crank can have any stroke really in order to meet my goals. So far I've really looked at a 3.750" (401cid) or 4.00" (427cid).
So let's talk compression ratio and stroke with these design goals in mind. Should be fun and different
I've done lots of searching on different forums, so I'm really looking for actual numbers people would suggest and why they chose them to maximize BOTH gas mileage and power.
I knew leaded race gas was bad and methanol is corrosive, just checking that the corrosiveness is only pre-combustion.
