Quote:
Originally Posted by EgoFG
I fully agree with the concept.
A few years back, I had a very regular driving routine (5 days to the office return, no weekends, half of the time 70-80kmph, half stop/start).
During this time I did some ECONOMY testing on my EFII I6.
I was rigorous, I always ran the car to 50km left on the trip meter, I always ignored the first tank after swapping fuel, and always ran the test for at least 3 tanks.
I found 91 -> 95 -> 98 was all worth the extra money, using Caltex. Then I started using different brands. I found Caltex=BP, but Shell 98 was no better than 95 from Caltex or BP
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What car did you have, I find compression and volume efficiency comes into play with the fuel used, not to mention how the car is driven or what loads the engine is under.
I drove to work over the same road a lot and used the cruse control and conduct the test from one point to another at the same speeds, windy days aside noted but average economy was noted with all fuels, E10 when it first came out was real crappy in my stock VY SS manual as it lacked power under 2200rpm but then a improved E10 came out from Shell and it was really good.
I remember Shell had a 98 octane in the beginning and then changed that brew later, but when that 98 came out and I would tune my bikes I had to jet them to it or they could be out of tune running that stuff.
The best fuel economy I got out of my SS was the same on all fuels E10 or 91, 95, 98 at best of 8.2L/100 but with air-con on E10 failed, so when the engine was under more stress the E10 did not cut it for economy. 9.2L/100 on 91 octane and 9.6L/100 on E10 I think it was average with car-con on. and this was all with Shell fuel, I did not use any of the Caltex types.
I had a stock New 1999 179kw V8 VS ute and I had to run that on 95 octane in summer or the bugger was gutless if you got up it, the knock sensor would cut in and retard the spark timing that bad that a V6 could hose it off, on 91 you could over take once and that was it, try that again with the next car coming and you lost 40kw for sure.
In the colder months it was ok to drive taking it easy with 91 and back in the day I would only use 95 because the fuel economy worked out the same price wise, it was 4c more a L and my mates dads 1997 V8 LTD he was one for working out the figures and he said such was the same he worked out with his, so he only use 95 as well.
It would be good to have a button to press to show if the engines is retarding the timing come up on screen when the mapping drops out of true mode, the Gen 3 can drop out anywhere from 2 deg to 4, 6, 8, 10, 12 deg and some just go straight back to 12 deg directly, so if the driver was informed of such then one could have a better handle on if it was crappy fuel directly and make a informed change, in stead of being ignorant of the fact what's going on with the engine, not to mention chewing less fuel and less pollution and all.