1GR 4.0 engine and premium fuel, anyone use it?

[Andy@AAV]

We all add weight and air/rolling resistance to our trucks and decrease the performance accordingly. The 4.0 engine produces more power on higher octane fuel and may help account for this. So, does anyone run the good (expensive) fuel? If so, do you notice better economy (MPG) or a real performance improvement from this?

For comparison I use 87 octane and get 16-17 around southern california with armor and 255-85 KM2's and only lack power on long grades or merging uphill on I5. I may try a few tanks of 93 to see if it makes a difference.

 

[Dave Bennett]

Been driving the 1GR-FE Taco since Feb '05 and tried hi-octane and regular. Not enough of a difference IMO to warrant the extra cost so I run regular and it's fine. YMMV.

 

[CA-RJ]

Where are you finding 93 in So Cal? Everything near me is 91 for premium.

 

[toyotech]

iirc, only the FJ recommends premium fuel. btw premium fuel is not consider good or better fuel. its just different octane rating

 

[Redline]

snip...

For comparison I use 87 octane and get 16-17 around southern california with armor and 255-85 KM2's and only lack power on long grades or merging uphill on I5. I may try a few tanks of 93 to see if it makes a difference.

I would say your fuel economy is very good for an armored truck with 255/85 tires. You must drive it well.

 

[1911]

Been using premium in mine since new; 130,000 miles on it now. With a 10:1 compression ratio (10.4:1 on later models) it needs premium to make its rated torque and hp. It will run fine with lesser-octane gas, but the ECM will just retard the timing and you'll get a little less power.

 

[keezer37]

Premium gas does not yield more energy.

I always run 89, runs fine. 87 made it knock a bit under strain.

The purpose of higher octane gas is to burn slower. To achieve this, premium gas goes through additional refining processes than standard gas. The cost of which is passed on to the consumer. The purpose of this slow burn is to compensates for higher cylinder pressures, higher cylinder pressure from a higher compression ratio or a build up of carbon in the cylinders. Phrased another way, it can be compressed more before it ignites. This is why lower octane gas pre-ignites or pre-detonates slamming the top of the pistons, causing a knock.



With this in mind, running gas that burns slower than is necessary for the pressure in the cylinders is a waste. I think and have thought so for some time that the whole gas mileage/improved performance claims of running gas your engine does not require is hokum. Hokum originated and perpetuated by those who would benefit from perpetuating these claims.

If they didn't call it "premium", would you buy it?

 

[Andy@AAV]

Where are you finding 93 in So Cal? Everything near me is 91 for premium.

Sorry, it is 91 and not 93. My manual states the use of "premium" fuel for maximum performance, and I do understand that switching to 110 from the airport won't help more . I was just curious if anyone had real world experience with using the extra 20 cents per gallon to help offset the extra weight and rolling resistance. Thanks for the replies!

 

[Ryanmb21]

I have run 91 since new, i like ~400 mile tanks and 20 mpg I get on road trips. There are posts somewhere with articles linked about the difference in MPG with the different fuels (not sure where they are, been years since I read them). Long story short, my take on these articles: (1) it takes the computer many many miles to 'process' the change in octane from 87-91 (so "trying a few" tanks will serve no purpose) and (2) the difference in MPG yielded a better MPG which outweighed the cost.

I can't find these posts, so I can't link them. I believe them to be true, I also note that many many people say "they tried a tank (or a few) and saw no difference" so they go back to the cheaper gas.

Where I live 91 is only about 5-6% more than the cost of 87, so if I get 5% more mpg I am happy. In my case 5% more MPG would be +/- 1 mile per gallon. In other words, if I get only 20 more miles out of my ~20 gallon tank then the cost is worth it. Another note, I commonly see people getting less than 15 MPG out of the very same motor, which is mainly due to larger tires and added weight but for me this would probably be unacceptable.

If I get 20 MPG it costs me about $18,050 in fuel to drive 100,000 miles (at $3.61 - the current cost of 91). If I only got 15 MPG it would cost me $24,060 or $6,017 more doll hairs.

 

[Redline]

snip... I commonly see people getting less than 15 MPG out of the very same motor, which is mainly due to larger tires and added weight but for me this would probably be unacceptable. snip...[/B]

That right there along with the driver and conditions make much of the difference.

 

[keating]

Keep in mind that the Dual VVT-i 1GR-FE in the FJC makes 254hp on 87 octane and is able to alter timing to take advantage of higher octane and make 285hp on 91 octane.

The 1GR-FE in the Tacoma has the "regular" VVT-i and makes 239hp on 87 octane with no adjustments, automatic or otherwise to make better use of higher octane.

In reality, the Taco engine is probably just factory detuned so as to not knock on 87, leaving some gains to be had with tuning.

With this in mind, running gas that burns slower than is necessary for the pressure in the cylinders is a waste. I think and have thought so for some time that the whole gas mileage/improved performance claims of running gas your engine does not require is hokum. Hokum originated and perpetuated by those who would benefit from perpetuating these claims.

 

[downhill]

Premium fuel does indeed make more power from this engine. 12 ft-lbs of torque at 300rpm lower. See the quote below from Wiki. I have heard other dyno tests show as much as 22 ft-lbs of gain. I do a lot of towing and mountain grades. I have felt the difference myself using the premium fuel. I also keep very close MPG numbers and my MPG with premium just about exactly offsets the extra cost. I am currently running non-ethanol 93 octane, but of course on the road I have to take what I can find.

quote from Wiki: The 1GR-FE is the 4.0 L (3956 cc) version, designed for longitudinal mounting in RWD and 4WD pickup applications. It has a 94 mm bore and a stroke of 95 mm. Output is 236 hp (176 kW) at 5200 rpm with 266 lb·ft (361 N·m) of torque at 4000 rpm on 87 octane, and 239 hp (178 kW) at 5200 rpm with 278 lb·ft (377 N·m) at 3700 rpm on 91 octane. This engine features Toyota's VVT-i, variable valve timing system on the intake cam and a compression ratio of 10.0:1.