Ok, I'm getting pretty irked at watching my fuel gauge fall an eighth of a tank each way on my 15 mile commute. This is ridiculous, it's half highway, half city and I don't spend much time in traffic because I work 6:00 AM to 2:00 PM. I hear about people getting 25-30, but I seem to get maybe 15 mpg. I do not hot rid around and I keep the car at around 60 mph on the highway (3000-3200 rpms).

After I solved the clogged fuel tank problem, I started having issues with fuel smell. My west german pierberg pump was pushing too much fuel, so I installed an FPR, which did not really help. My carb bowls were overfilling and overflowing. So I switched to an old-style lower-pressure AC pump, and OEM Volvo Grose jets to stop the overflow. Still lost fuel out the bowls until I really readjusted the floats and valves as well as added a second top cover gasket.

No more leaking fuel, but my mileage is still lousy. I can't avoid running less-than optimum fuel. All we have around here is 87-91 octane which is not best for a 180 psi/cylinder B18B and I know that the stock timing spec (17-19 btc) is not quite right for modern fuel.

My idle is around 800 rpms, my mixture is on the lean side, I've never had too much trouble getting the carbs synchronized and mix-adjusted. Although I've lost some of my throttle adjustment due to the smooth butterflies I've installed.

My timing was at 20 btc. Today I adjusted it to 10-15 btc. I'm hoping that this will help somewhat.

So... given the fuel available here, what should I aiming for to get my timing to play nice with the "fuel." I realize that there are still many mileage variables, but I'm trying to address them one-by-one.

Any other ideas where my fuel is going? This is my daily-driver and the car I use to get to work to support my family, so I can't afford to be wasting all this gas.

Any ideas are appreciated, thanks.