Thread: What Octane Petrol for 4L V8

Yeah sure , of course they would add 10% ethanol to 98 and then sell it 15 cents cheaper.
Good business for a very short time.

Regards Philip A

Originally Posted by PhilipA

Yeah sure , of course they would add 10% ethanol to 98 and then sell it 15 cents cheaper.
Good business for a very short time.

Regards Philip A

I did not say they added it to the 98, it is added to 91 blend it increases the Ron and not the MON, I just checked and there is several ways to calculate the octane rating.
I haven't read enough on it I was only going on what I was told

I did not say they added it to the 98, it is added to 91 blend it increases the Ron and not the MON, I just checked and there is several ways to calculate the octane rating.
I haven't read enough on it I was only going on what I was told

Ethanol is 109 octane . While it is not straight line 10% will increase RON by about 2 points RON.

Australia uses RON so 91 is 91 RON .
From Wikipaedia

In most countries, including Australia and all of those in Europe, the "headline" octane rating shown on the pump is the RON, but in Canada, the United States and some other countries, like Brazil, the headline number is the average of the RON and the MON

Quote from Choicehttp://www.choice.com.au/reviews-and-tests/transport/cars/fuel/biofuels-and-e10/page/e10-at-the-bowser.aspx

Standard unleaded petrol is classified as “91 RON” (with RON standing for “research octane number”), which is the resistance rating for that fuel. E10 is never lower than 91 RON, but can be slightly higher at 93 RON or 94 RON, depending on how the ethanol is blended into the petrol.

So IMHO do not try and run a High compression D2A on E10.
Regards Philip A

Originally Posted by PhilipA

So IMHO do not try and run a High compression D2A on E10.

I run my D2a (CR9.38:1) on E10 all the time (in fact for the last 5 years) and no problems.

Regards
Andrew

I run my D2a (CR9.38:1) on E10 all the time (in fact for the last 5 years) and no problems.

That's great but in your case you will pick up power and economy by using 98 as the Motronic ECU will adapt by advancing the timing .

I guess it's a judgement or calculation whether the gains are worth it to you.

Regards Philip A

We tow a large 24' van with our Disco 2 (V8), the van weighs 2.5t and we have been doing laps since 2006. Our observations are when towing, 95 octane is the go you get about a 15% km gain (over using 91 oct). Running around the suburbs 91 octane and or using 95 isn't really noticeable.
However when on the east coast we use the 95 oct E fuel which is generally priced a little better than normal 91.

I had a low compression V8 D2. Always ran 91 unleaded. Never ran any better on 95 or 98. Never ran any worse either.

Thank you to all who have contributed to this thread, the responses are quite diverse.

Given that my D2a is a high compression 9.38:1 I think i'll stick with 95 octane rating for now, run that for a few months, monitor the running and economy and then try the 91 octane to see if there is any noticeable difference.

Having run higher octane fuel in my subaru I tend to agree that the higher cost of the fuel is benefited by better fuel economy L/100km's but we'll have to see how this pans out with the Disco.

cheers
Mark