My Octane observations

[omniphil]

I drive at least 70 miles a day so I fill up my tank every day. It gives me a chance to do some good testing fairly quickly.

Using premium gas with the thinking that it is somehow better or cleaner is just plain wrong. Using what your vehicle is designed for is the best approach for power and economy. Higher octane gas burns slower and actually hurts performance and gas mileage in an engine that isn't design around it. Some engines of course are design for premium gas and you want to use it that scenario. But a majority of vehicles are not, they are designed around 87 octane. Just check your owners manual and it will tell you. In general, you want to use the lowest octane gas that fulfills your vehicles requirement.

It would seem that the Blurs motor is designed around 92 octane in Taiwan. The gasoline is rated a different way over there. Their 92 octane is roughly equivalent to our 88 octane. Well, we don't have 88 octane, we have 87 and 89. After several tanks of 87 and then switching to 89 and then back to 87, I can tell you that there is a difference, I do alot of highway miles and there is a tiny bit more power as I am able to maintain a higher speed on the same roads. Its really going to depend on your gasoline vendor, they are going to be slightly different. Some brands 87 octane may well be close to 88 octane if your had it tested where as some others 87 might only be 86.8 for example. To be sure, I just started using 89 to make sure I was meeting the 88 octane requirement and I can say that it does perform better that the 87 I was using.

87 octane is close and its not going to hurt anything, and is a little bit cheaper, so I see that as a viable option if your not doing high speed commuting like I am. 92 octane is a tiny bit less performance wise too, but costs more, so that's not really a good choice in either case.

So in my opinion 89 octane is the gas you should be using for optimal performance.

[Rippinyarn]

Thanks omniphil! You have confirmed my results and I now routinely go for the "middle grade" fuel for the Blur. It seems much happier, and my idle is much more consistent (1500-1700 RPM) than it was on the "regular" grade.

Are you getting any of the engine over temperature warning lights on your commute? If you are, please tell us about it in that thread.

And in case anyone is wondering, I still love my Blur and it's frankly the best thing on the road

[omniphil]

Thanks omniphil! You have confirmed my results and I now routinely go for the "middle grade" fuel for the Blur. It seems much happier, and my idle is much more consistent (1500-1700 RPM) than it was on the "regular" grade.

Are you getting any of the engine over temperature warning lights on your commute? If you are, please tell us about it in that thread.

And in case anyone is wondering, I still love my Blur and it's frankly the best thing on the road

I have only got the overtemp light once during a top speed test down hill at 9000 rpms.

Since then I have added dr pulley lighter weights, switched to Mobil 1 engine oil and replaced the way over filled gear oil with the right amount of Lucas Gear Oil. I'm sure all of those thing help to make the engine work a tiny bit less and produce less heat. (I also replied to your heat thread too in more detail)