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Kugelfischer timing


CG901

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Hoping to tap into the expertise here.  I would like help to set up a mechanical fuel pump sprocket orientation to correspond with TDC.  Yes, it was correct when I disassembled it but it was moved during storage.  The guidance from BMW Motorsport is 189deg OT change.  This is the german translation.  

How can I determine the position of injector piston #1 when #1 cylinder is at TDC?  

 

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You can take the plug out of the top of the pump and actually see the #1 piston.  You can find TDC for that piston which would be the END of the fuel discharge stroke.  I have not played with the M12 engines but moving the timing on the Gp2 CSL injection systems makes little or no change if you are talking about 1-3 teeth on the pulley.  There was a small change in drivability (on and off the throttle) but not significant HP change on the dyno.  I have not tried playing with the pump timing on the M49 Gp5 car.  

1970 1602 (purchased 12/1974)

1974 2002 Turbo

1988 M5

1986 Euro 325iC

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Preyupy, thanks for this advice.  Will check the piston position in the pump.  Given it’s the M12/13 Turbo, getting this right will likely make a big difference in performance.  I don’t have a dyno so engine has to go back into the car to get a start.  

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The good thing about the mechanical FI system is the end of the discharge is always at the same crankshaft position regardless of engine speed or throttle setting.  The discharge event starts sooner as the delivery volume increases.  I would suspect that you would want the fuel delivered to each port just before the intake valve starts to open.  This makes sure that it does not get blown back into the plenum and puddle somewhere.  

1970 1602 (purchased 12/1974)

1974 2002 Turbo

1988 M5

1986 Euro 325iC

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Preyupy, thank you.  Makes good sense.  

I am waiting for the BMW guys in Munich to clarify the specs in the manual which seem to specify a static setting for the pump pulley.  The german translation applied to technical literature is inaccurate!  

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I am running the Gp2 3.5 CSL with the Schnitzer slide valve injection.  I have the pump set so the injection event STARTS at 90 degrees BTDC on the intake stroke, this is at wide open throttle.  This makes sure that the fuel has been completely delivered by the time the intake valves are open and the piston starts down the intake stroke.  Any sooner and the fuel will puddle too much at lower engine speeds and throttle settings with the slide valve throttles.  

1970 1602 (purchased 12/1974)

1974 2002 Turbo

1988 M5

1986 Euro 325iC

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So did you set the 90 degs BTDC  based on  dyno work, is this the static setting recommended for your engine?  

 

I am not sure what the 189 degs OT from BMW Motorsport means yet!  

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I have not seen that timing information used before and I'm not sure how to interpret it.  I have tried to advance and retard the injection timing by 18 and 32 degrees, crankshaft (1 and 2 teeth on the pump drive).  Advancing it did not change HP or torque, retarding it 18 made no difference but 32 degrees it did lean the mixture and cost me about 10 hp.  It seems to drive and run at low speeds better at the 90 deg advance than at 108 or 122 so that is where I have left it.  

 

I would say the only way to really know with your engine is to get it running on the dyno and try different settings.  90 degrees is a safe starting point I would think. 

1970 1602 (purchased 12/1974)

1974 2002 Turbo

1988 M5

1986 Euro 325iC

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