Nope, but as an engineer, I can tell you that it will only make a difference in your wallet and not your fuel tank

 

I've read some contradictory results on other forums for other cars.

Would really like to get some empirical data for this car.

Eph

 

you could try it. I think any improvements in efficiency would be minimal though.

 

Danny, I don't think a higher compression engine takes advantage of something in higher octane gas. My understanding:

Higher octane gas is primarly different in that it's harder to ignite. This is a requirement for higher compression engines where there is an increased likelyhood of glowing carbon deposits (or whatever) pre-igniting the fuel/air mixture before the sparkplug does (causing knocking or backfire).

Bottom line: if you don't have a high compression engine, and your owners manual recommends regular octane, and you're not experiencing pinging/knocking, higher octane fuel is a waste of money.

 

Well in my TCH I was getting some knock under load in hot weather. I switched to 89 octane and the engine feels livelier and I will only get an almost inaudible ping here and there (Toy manual states this is normal.) I think timing was greatly retarded with the 87, much less so using 89. Night and day. I ran a tank of 87 awhile ago and the engine clearly felt "dead". Couldn't wait to burn it off.

The manual recommends "at least" 87 octane - intesting way to put it.
12.5:1 compression ratio.

Not sure about the Nissan specs.

 

Different octanes might come from different sources as well, introducing more variables.

 

The NAH has a 9.6:1 ratio. That's the same as the conventional Nissan Altima and Toyota Camry engines. The TCH has a modified atkinson cycle engine which has a lower compression at slower speed and light load and then raises the compression under load - similar to what you described.

I don't see the advantage of this if you have to use a higher octane to eliminate the pinging. Are all TCH's like this or could you have a problem with carbon deposits or your timing might be off?

 

I just mean that it can unlock the potential of the higher octane gas into useful work.

 

Filled up with 93 on the tank I just started. After 100miles, I am seeing 49mpg+ on my car's gauge. This is about 3mpg than I saw on my last tank. Of course, it's too soon to know for sure. I'll report back when I get through the tank.

Eph