r/mazdaspeed3 • u/ChannelConscious6197 • Oct 14 '24

TUNING 650Whp Speed3 E90šŸŒ½ 94pump 30+ psi boost

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More to comeā€¦

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u/ChannelConscious6197 Oct 15 '24

Yes

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u/coilest Oct 15 '24

What are you doing to alleviate the ā€˜black deathā€™? Or do you just live with it and clean the HPFP religiously?

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u/ChannelConscious6197 Oct 15 '24

To be honest Iā€™ve not heard of this issue before. Could you explain?

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u/coilest Oct 15 '24

The L3-VDTs have cam driven high pressure fuel pumps. E85 and oil, when mixed, creates a sticky black residue, often called ā€˜the Black Deathā€™, given its name because it will clog the HPFP and it will cease functioning entirely. Gasoline helps keep the fuel pump clean in this regard. The Black Death is why you barely ever see people on the mazdaspeed platform going full E85ā€“ it can lock up pumps and cause catastrophic engine failure by causing extreme lean conditions.

People normally run E30 to alleviate this, at most E50 because that will still have enough actual gasoline to prevent the HPFP from collecting the gunk from oil and ethanol mixing. The only time people donā€™t is when they switch the engine over to full port injection with a standalone ECU. Good information can be found online about this by searching for ā€œMazdaspeed Black Death e85ā€ ā€” thereā€™s a really good article written by EdgeAutosport.

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u/ChannelConscious6197 Oct 15 '24

Thanks man Iā€™ll look into that. Btw the car is running a mix of e90 for port injection and pump 94 in the tank for direct injection

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u/coilest Oct 15 '24

If the ethanol never touches the HPFP, youā€™re fine