BMW 2002 FAQ

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[quote="JK"]Tommy, I've always run 39 deg. advance with 105-110 octane race fuel. 40 would be max. 
Please post all of your injection specifications and maybe someone can help. What's the pump, air metering devise, is it pulse injection, what's the ECU etc. etc.

Some more ideas:
I would look at your pressure at the injector. That seems low for the atomization you need that close to the valve. Modern systems are WAY higher than that at the fuel rail, and at high RPM you need it atomized or it won't fully burn. Also your spray duration may need some tuning and/or advancing. Your fuel pump may also be falling behind during maximum volume demand..you can put two in series. Your volume may be correct but a higher pressure at the injector will have better atomization.

borrowed from rceng.com

[b]"Our fuel pump dyno can test many different types of electric fuel pumps.  We can adjust the voltage to gauge what differences they would have on flow vs. pressure.  We usually start the test at 35 PSIG and end at about 110PSIG. Many in tank pumps have an internal bleed off, or pop off valve, that limits maximum pressure, and usually operates in the 60 to 70 PSIG range. This test tells you exactly what the Horsepower value, or limit of your pump is.

If you are increasing the horsepower of your engine by 30%, - your fuel pump may not be capable of delivering enough fuel to support the desired horsepower increase.

Example: If you have a pump that supports 200 BHP, Natural Aspirated, it will have to produce at least 100 Lbs. of fuel Per/Hr at system pressure. (Break Specific Fuel Consummation of .50 is considered normal for NA engines.) At the target Horsepower of 260 BHP the pump will have to produce at least 130 Lbs. of fuel Per/Hr ,at your system pressure, to meet your requirements, and may not be able to provide this additional fuel.

Our test will tell you exactly what horsepower your pump will support from 35 PSIG to maximum pump PSIG."
[/b]
also

[b]http://www.geocities.com/MotorCity/Pit/9975/dataBySubject/EFImods.html[/b]

Think about the combustion process. at high RPM you have milliseconds to light the fuel on fire before full compression. The higher octane fuels need more advance because the burn is slower. The advance also guarantees a thourough burn peaking just before full compression creating the most power.

I'm no guru, I'm just coming up with ideas that I would try if I where in your shoes.[/quote]

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