expert advice

[raedareeg]

hi
i need advice and opinion for 2 matters
1-we have Nissan,sunny, with 1.6 l, 2011, gasoline engine mec Hitachi ecu sh cpu,i need to change octane from 95 to 89,can it be done by obd2 or jtag?
2-same thing for hyundai sonata and elantra,sim2k ecu.2.0l,2010
and how that affects fuel economy,
ps:very bad pinging sound.
thanks for help

[ominimicu]

i am no expert, but changing to lower octane..will reduce combustion power, it may detonate earlier as higher octane resists more compression, and fuel economy get bad but will compensate by the fact that 89 is cheaper.


i gues the only problem could be earlier detonation, although it is the spark that controls detonation...maybe advancing the spark timing will solve your issue

[smokey08]

i am no expert, but changing to lower octane..will reduce combustion power, it may detonate earlier as higher octane resists more compression, and fuel economy get bad but will compensate by the fact that 89 is cheaper.


i gues the only problem could be earlier detonation, although it is the spark that controls detonation...maybe advancing the spark timing will solve your issue

I think you mean retarding the spark timing. This will noticeably reduce the power output of the engine.

[raedareeg]

the fact is octan 95 is ...in a way...not available,the important issue is economy.can we have it?

[ominimicu]

you will get less km with the 89, but it s cheaper..so in a way it compensates.