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Tuning problem

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Hello everyone,

Recently i have tuned a turbocharged 1FE-ZE engine which had 725cc injector dynamics injectors (which should hold up to atleast 600whp) and 1 intank aeromotive fuel pump ( new ) and 2 outter welbro fuel pumps. The engine is running on an motec m84 ecu and i have set the map compensation table for fuel that it should compensate for 100 for every 1 bar boost or 100 map ( this usally works perfect ).

The problem is that when i tunned the engine everything was fine until boost 0.8 bar afterwards when i increase the boost the engine keeps on going leen so i have to increase the fuel by the ecu manager fuel table and when i do so the injector duty cycle goes up more than 85%, while the engine only has 540whp. Also i checked the fuel pressure, it is set to 5 bar when i go wot the pressure holds for sometime then it starts dropping to almost 4.3 bar of fuel pressure when boost comes. So what could be the problem?!


Just going off your post...

ID725 = 600whp

85% from 600 whp = 510whp

You at 85% duty cycle = 540whp

If you think about if, that's well within your calculation :)

And in regards to your fuel pressure - sounds like your fuel pump is having problems keeping up with the requested pressure, however at 4.3bar the ID725 still flows a lot since it's rated 715cc@3bar... My guess would be a stronger fuel pump and you will be able to push it a bit more.

Your fuel pressure should increase in a linear fashion with boost pressure to maintain a consistent differential fuel pressure. If your base fuel pressure for example is 5 bar, you should see fuel pressure increase to 6 bar when you have 1 bar of boost. If the fuel pressure fails to rise, or begins to drop off, this would normally indicate that your fuel system/fuel pumps can't keep up.

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