1FZ and higher octane fuel technical discussion... (1 Viewer)

[Formulaonehd]

Thought i might bring this thread slightly back to life but only because i proved myself wrong.

I have been experimenting with the higher octane in fuel to see if there are any major changes. These debates often arise here in Aus with long distances traveled in the country between fuel stops.
I can honestly say that higher octane fuel does equate to increased mileage. I cant give an exact number just yet as there are other variables still to factor in. Interestingly my economy dropped after replacing spark plugs and leads. NGK with correct gap (very odd)

Got back onto higher octane (95) drove the same and definite increase in mileage over several tanks of observation.

Was getting around 16-18L/100kms am now getting consistent 14L/100kms (sorry not sure in miles)

Happy with this and this was achieved before spark and leads changed.

 

[fz1boxer]

mine does run better on 90 ethanol free than on 87 with corn likker in it.
but can't tell a difference between the ethanol free 87 and 90 octane that is available around here.
no technical evaluation to back it up but i did check my bronco which gets about the same mileage as my LC.
when running 87 and corn likker i would get consistent 9.5-10 mpg,when running ethanol free 87 or 90 it went up to almost 11.5.

 

[Formulaonehd]

Yeh it's definitely better, nothing to make you jump up and hit your head in the roof but worth the extra coin as it still amounts to saving money in the long run
There was a big debate here about how far they could go on the main tank and sub tank . Some were boasting 800kms (500 miles) to a tank which is pretty decent. I think they were running ur vortex 98 octane which is about 10-15c per litre more expensive than base 91.
I remember my Nissan turbo charged vehicles from the 90s needed to run on this 98 octane or they would ping like crazy and blow smoke

 

[ericbirk]

Thought i might bring this thread slightly back to life but only because i proved myself wrong.

I have been experimenting with the higher octane in fuel to see if there are any major changes. These debates often arise here in Aus with long distances traveled in the country between fuel stops.
I can honestly say that higher octane fuel does equate to increased mileage. I cant give an exact number just yet as there are other variables still to factor in. Interestingly my economy dropped after replacing spark plugs and leads. NGK with correct gap (very odd)

Got back onto higher octane (95) drove the same and definite increase in mileage over several tanks of observation.

Was getting around 16-18L/100kms am now getting consistent 14L/100kms (sorry not sure in miles)

Happy with this and this was achieved before spark and leads changed.

Wow thats pretty impressive actually. I cant get any better than 20l/100km!!!

 

[hammerheadfistpunch]

This has been an interesting thread to revisit. I recently went through something really similar regarding the 2UZ-FE in the 120 thread. (spoiler, there is a DEFINED difference in octane performance in the Lexus versions of that engine with dual VVT-i) My person experience with the 1fz goes like this:

1. regular gas works great in Utah all times of the year without knocking
2. I use premium towing in the heat and it does help with my mileage and power
3. the truck idles and runs substantially better without corn in the tank

Outside of that I think its all conjecture.

Truthfully I think the major benefit to running premium in high demand situations has less to do with engine design and more to do with hot spots from 300k miles of carbon buildup.

 

[Blade 80LC]

Was getting around 16-18L/100kms am now getting consistent 14L/100kms (sorry not sure in miles)

Happy with this and this was achieved before spark and leads changed.

‪l/100km to mpg‬‏ - بحث Google‏
...Was 13.1 - 14.7 mpg and now 16.8

 

[Blade 80LC]

Checking the fuel economy of one fuel vs. another should be pretty simple for anyone who commutes with their truck and usually buys low octane fuel. (If you normally buy premium fuel to reduce pinging, you may not care to try low octane just to see if the fuel per mile is cheaper.) I used to commute in a Blazer (now ride a train to work) and very consistently got 9.5 - 10.5 mpg on my commute days. Same trip day after day. On weekends my mileage varied significant depending on how I was driving. If you commute in your truck, try one fuel for a week, then the other fuel for a week. If the results show any improvement, perhaps try a longer test. Give the computer a chance to run it's tests with the different fuels. My brother once told me after tracking his fuel for months, that he was certain that mid-grade fuel gave him 10% better fuel mileage than low octane. High octane gave him no further boost. That may have just been for his particular vehicle at the time. He now only buys low octane for his Land Cruiser.

My current driving varies enough that some tanks give me 15+ mpg, but most are closer to 10-11; so my changing fuel is not likely to show a statistically valid change. I'd be interested in results from someone with more consistent numbers. I hadn't thought about a computer with knock sensors changing timing or fuel delivery rates to impact mileage. I could not see how higher octane fuel could even theoretically give better fuel economy, since the octane is just a knock reducer, not an energy booster.

 

[Formulaonehd]

Yeh it's very relevant to revisit this. Some people just throw their hands up and admit defeat with the fz fuel economy

Turbo FZ apparently is the way to go plus you get better mileage . Run higher octane as well which is cheaper in the long run aswell.

Has anyone experienced rediculous consumption driving into a pretty strong head wind ? I had to turn around head home and swap cars (the Mitsubishi turbo diesel) to drive 800kms the other day as the 80 used a quarter of a tank of fuel to only cover 60 odd miles... Enough to make you cry I couldnt believe it drank so much

 

[COYS]

My stock 1997 with 250k miles was knocking accelerating from a stop on a regular basis. I could definitely hear it climbing up my indoor parking garage.

Just today filled it up with CA premium gas iirc 91 octane for the first time. Ran 87 octane for as long as I’ve owned it.

Knocking is pretty much nil from the limited miles and temps I’ve driven around since.

Will continue to monitor when driving in the hotter 80 degree mid day temps around LA metro.

 

[scottryana]

If this is the case, you might have a crazy amount of build up on top of the pistons. I would buy a cheap borescope that connects to your cellphone, pull the spark plugs and take a look. If it is buildup causing detonation you might just be able to clean things instead of doing a new engine.

My stock 1997 with 250k miles was knocking accelerating from a stop on a regular basis. I could definitely hear it climbing up my indoor parking garage.

Just today filled it up with CA premium gas iirc 91 octane for the first time. Ran 87 octane for as long as I’ve owned it.

Knocking is pretty much nil from the limited miles and temps I’ve driven around since.

Will continue to monitor when driving in the hotter 80 degree mid day temps around LA metro.