KA Head Z24 Block Once more for giggles

[datzenmike]

Not quicker starts except in bad weather, more reliable starts. My '78 L20B would fire on less than one turn, one bump of the starter. Can't argue about the mileage from EFI.... they have constant feedback from O₂ sensors and constantly adjusted air fuel. I mean how can you compete with that?  

[frankendat]

50 minutes ago, datzenmike said:

Not quicker starts except in bad weather, more reliable starts. My '78 L20B would fire on less than one turn, one bump of the starter. Can't argue about the mileage from EFI.... they have constant feedback from O₂ sensors and constantly adjusted air fuel. I mean how can you compete with that?  

 

I drove my 620 L20B for six months without a starter. Parked it facing out, never facing uphill and never parallel with someone in front of me. Pushed a couple of steps, jumped in, popped the clutch and go....

I believe the mileage would be better with EFI but how much better?

 

[Stoffregen Motorsports]

13 hours ago, frankendat said:

 

I believe the mileage would be better with EFI but how much better?

 

Well, as Mike said, you really can't beat an O2 sensor.

 

You also said "all things being equal". Thing is, they are not equal. The self tuning capabilities of most EFI systems is the reason for the lob-sided argument. Yes, there are tuners out there that can get ridiculous mileage out of carbureted engines, but that's also not an equal argument. Are you one of these guys? Probably not.

 

To stop beating around the bush and give a hypothetical answer to a hypothetical question, you're probably looking at 5-10% better mileage with EFI. But mileage isn't the only reason EFI is better.

[datzenmike]

Any driver can get better than 10% increased gas mileage by changing how you drive, however an EFI is tireless and does this for you, ALL the time and even better. On trips only, I get high 20s and even just into the 30s (per US gal) with my 710 wagon 5 speed 4.11 gears.

[frankendat]

3 hours ago, Stoffregen Motorsports said:

Well, as Mike said, you really can't beat an O2 sensor.

 

You also said "all things being equal". Thing is, they are not equal. The self tuning capabilities of most EFI systems is the reason for the lob-sided argument. Yes, there are tuners out there that can get ridiculous mileage out of carbureted engines, but that's also not an equal argument. Are you one of these guys? Probably not.

 

To stop beating around the bush and give a hypothetical answer to a hypothetical question, you're probably looking at 5-10% better mileage with EFI. But mileage isn't the only reason EFI is better.

Thank you Stoffregen Motorsports, You're right on both counts, the first that I'm not one of those guys and the second that I was seeking a hypothetical answer. As for all things being equal, I was only speaking of averages e.g. two vehicles of same age, same wear, same driver, same parts, with the exception that one is mechanically fed by carburetor and one is computer fed by EFI and to narrow it down further, the engine in both vehicles is a Z24 and the EFI is taken from a KA (applied to a Z24 to create a Z24E) If I understand correctly, then it is your educated opinion, that the Z24E will achieve a maximum of 10% (between 2 and 3 additional mpg) increased efficiency.