another ethanol problem

[Tcoat]

Originally Posted by alan.chalkley

All of the cars have knocking/pinging issues on 91 and e10 fuel.
Most of the cars are 2005 models or newer.
The one i usually drive has done 352000kms and some have done 600000+kms.
We also have new ones , ( that have replaced "damaged write offs" that are rested upside down on their roof).

OK at those miles they are just plain worn out. The E10 has nothing to do with it.

[WolfpackS2k]

I believe that Australia rates their octane differently than is done in N America (US at least). So I think his 91 fuel is equivalent to 87, or "regular" in the US. And 98 is equivalent to our "premium" 93. If you're getting engine knock, switch to a higher octane fuel. It's not uncommon for engines with very high mileage to form carbon deposits within. These deposits can cause hot spots that cause pre-detonation, AKA knock. A fuel with more octane has more ignition resistance. Should side-step the problem.

[alan.chalkley]

Originally Posted by WolfpackS2k

I believe that Australia rates their octane differently than is done in N America (US at least). So I think his 91 fuel is equivalent to 87, or "regular" in the US. And 98 is equivalent to our "premium" 93. If you're getting engine knock, switch to a higher octane fuel. It's not uncommon for engines with very high mileage to form carbon deposits within. These deposits can cause hot spots that cause pre-detonation, AKA knock. A fuel with more octane has more ignition resistance. Should side-step the problem.

Yes , this could well be the answer to the problems , but the bean counters cannot see reality apart from the $/litre on the fuel account and the $$ per new cars.
So we just top up with 91or e10 fuel after most shifts and put up with pinging/knocking/rattling engine noises.