Anyone know how much power is lost when using regular fuel vs premium in the 4.0 V6?

[j4x4ar3]

Originally Posted by armyoffoo

The Tacoma specifications acrobat file I downloaded from Toyota's website says the 2.7L recommended fuel is 87, and the 4.0L recommended fuel is 91 octane.

Recomended does not mean required. Scroll and look for my other post from USA Today. Recomended only means to get the full stated HP and Torque ratings you should use the recomended fuel.

[Darnefnet]

Originally Posted by j4x4ar3

Recomended does not mean required. Scroll and look for my other post from USA Today. Recomended only means to get the full stated HP and Torque ratings you should use the recomended fuel.

so it sounds what like what Toyota is saying is, Premium in the 2.7 will gain you nothing, the 4.0 it will give a little more HP.

[j4x4ar3]

Originally Posted by Darnefnet

so it sounds what like what Toyota is saying is, Premium in the 2.7 will gain you nothing, the 4.0 it will give a little more HP.

Close.. 2.7 premuim will get you nothing but in the 4.0 it will get you closer to the stated engine ratings... Can't get "more" than the spec using premium.

[lelandstanford]

Originally Posted by Darnefnet

9 HP at 5200 rpm

From actual dyno?

[lelandstanford]

Is premium 91 or 93?

[j4x4ar3]

Originally Posted by lelandstanford

Is premium 91 or 93?

Depends on what state you're in.... Premium used to be anything above 87. Here in California premium is 91 with mid-grade being 89.

I've heard that some states even have 85 octane as regular with some as high as 93. 87 octane is the minimum requirement for the Tacoma 6 cylinder.

[Splicer]

Originally Posted by lelandstanford

From actual dyno?

Ummm... he was being cute... or sarcastic... there is likely no data.

[Darnefnet]

Originally Posted by Splicer

Ummm... he was being cute... or sarcastic... there is likely no data.

Well the standards used for 2005 didnt specify 87 octane so Im sure Toyota dyno'ed with the recommended fuel. The new SAE standard required the engine to be tested with 87.

[toytacoma]

Originally Posted by j4x4ar3

Depends on what state you're in.... Premium used to be anything above 87. Here in California premium is 91 with mid-grade being 89.

I've heard that some states even have 85 octane as regular with some as high as 93. 87 octane is the minimum requirement for the Tacoma 6 cylinder.

Regions with higher elevations will give you a lower octane rating for your gasoline because of the lower air pressure. While most owner’s manuals recommend a minimum octane rating of 87 and most of the nation’s gas stations don’t offer anything less than 87, gas stations throughout Colorado sell 85. That’s because an 85 octane rating at high elevation (including Denver) is equal to an 87 rating in the Midwest, or other low-elevation regions.

Here's some information about octane at "How Stuff Works?

What does octane mean?

by Marshall Brain

If you've read How Car Engines Work, you know that almost all cars use four-stroke gasoline engines. One of the strokes is the compression stroke, where the engine compresses a cylinder-full of air and gas into a much smaller volume before igniting it with a spark plug. The amount of compression is called the compression ratio of the engine. A typical engine might have a compression ratio of 8-to-1. (See How Car Engines Work for details.)

The octane rating of gasoline tells you how much the fuel can be compressed before it spontaneously ignites. When gas ignites by compression rather than because of the spark from the spark plug, it causes knocking in the engine. Knocking can damage an engine, so it is not something you want to have happening. Lower-octane gas (like "regular" 87-octane gasoline) can handle the least amount of compression before igniting.

The compression ratio of your engine determines the octane rating of the gas you must use in the car. One way to increase the horsepower of an engine of a given displacement is to increase its compression ratio. So a "high-performance engine" has a higher compression ratio and requires higher-octane fuel. The advantage of a high compression ratio is that it gives your engine a higher horsepower rating for a given engine weight -- that is what makes the engine "high performance." The disadvantage is that the gasoline for your engine costs more.

The name "octane" comes from the following fact: When you take crude oil and "crack" it in a refinery, you end up getting hydrocarbon chains of different lengths. These different chain lengths can then be separated from each other and blended to form different fuels. For example, you may have heard of methane, propane and butane. All three of them are hydrocarbons. Methane has just a single carbon atom. Propane has three carbon atoms chained together. Butane has four carbon atoms chained together. Pentane has five, hexane has six, heptane has seven and octane has eight carbons chained together.

It turns out that heptane handles compression very poorly. Compress it just a little and it ignites spontaneously. Octane handles compression very well -- you can compress it a lot and nothing happens. Eighty-seven-octane gasoline is gasoline that contains 87-percent octane and 13-percent heptane (or some other combination of fuels that has the same performance of the 87/13 combination of octane/heptane). It spontaneously ignites at a given compression level, and can only be used in engines that do not exceed that compression ratio.

During WWI, it was discovered that you can add a chemical called tetraethyl lead (TEL) to gasoline and significantly improve its octane rating above the octane/heptane combination. Cheaper grades of gasoline could be made usable by adding TEL. This led to the widespread use of "ethyl" or "leaded" gasoline. Unfortunately, the side effects of adding lead to gasoline are:

Lead clogs a catalytic converter and renders it inoperable within minutes.
The Earth became covered in a thin layer of lead, and lead is toxic to many living things (including humans).
When lead was banned, gasoline got more expensive because refineries could not boost the octane ratings of cheaper grades any more. Airplanes are still allowed to use leaded gasoline (known as AvGas), and octane ratings of 100 or more are commonly used in super-high-performance piston airplane engines. In the case of AvGas, 100 is the gasoline's performance rating, not the percentage of actual octane in the gas. The addition of TEL boosts the compression level of the gasoline -- it doesn't add more octane.
Currently engineers are trying to develop airplane engines that can use unleaded gasoline. Jet engines burn kerosene, by the way.



http://auto.howstuffworks.com/question90.htm

[Splicer]

Originally Posted by Darnefnet

The new SAE standard required the engine to be tested with 87.

Well, I had not heard that... is that verifiable? What I have read (possibly in R&T) is that the new SAE standards simply require that all dyno testing [for HP ratings] be performed with all accessories (power steering pump, alternator, water pump etc.) in place when the engine is tested -- in effect, the engine must be equipped exactly as it will be when the vehicle is sold.

In the past, engines could be tested with or without accessories, so the ratings were skewed. The new requirements allow more equitable comparisons.

[Darnefnet]

Originally Posted by Splicer

Well, I had not heard that... is that verifiable? What I have read (possibly in R&T) is that the new SAE standards simply require that all dyno testing [for HP ratings] be performed with all accessories (power steering pump, alternator, water pump etc.) in place when the engine is tested -- in effect, the engine must be equipped exactly as it will be when the vehicle is sold.

In the past, engines could be tested with or without accessories, so the ratings were skewed. The new requirements allow more equitable comparisons.

I think you might be thinking of the PRE 1972 standards where it was basically a bare engine on a dyno, after 1972 they had to test with exhaust, aire cleaner and assesories, not the ac, but water pump, alternator etc. Another thing added with J1349 was that all engines are to be tested at the same ambient temp and humidity.

[Splicer]

No, I'm referring to a change in the ratings method beginning in the 2006 model year. If I run across it, I'll post the info.

Edit: This is not where I first found it, but it seems to be what I was thinking of -- from Wikipedia:

SAE-certified horsepower

In 2005, the Society of Automotive Engineers introduced a new test procedure (J2723) for engine horsepower and torque. The procedure eliminates some of the areas of flexibility in power measurement, and requires an independent observer present when engines are measured. The test is voluntary, but engines completing it can be advertised as "SAE-certified".

Many manufacturers began switching to the new rating immediately, often with surprising results. The rated output of Cadillac's supercharger Northstar V8 jumped from 440 hp (328 kW) to 469 hp (350 kW) under the new tests, while the rating for Toyota's Camry 3.0 L 1MZ-FE V6 fell from 210 hp (157 kW) to 190 hp (142 kW). The first engine certified under the new program was the 7.0 L LS7 used in the 2006 Chevrolet Corvette Z06. Certified power rose slightly from 500 hp (373 kW) to 505 hp (377 kW).

[lelandstanford]

Originally Posted by Darnefnet

Well the standards used for 2005 didnt specify 87 octane so Im sure Toyota dyno'ed with the recommended fuel. The new SAE standard required the engine to be tested with 87.

Are you certain of this?

I thought the only requirement is advertised output and fuel grade used.

Is it even possible to run 87 with high HP engines like Enzo or CL65?

[Splicer]

^^ I'd sure like to see some verification. On the face of it, it just doesn't make sense to me.
And as you say, some engines require premium fuel.

[briq4]

I'm new to the forum and looking to purchase a Tacoma 4x4 Access cab with the v-6 and manual 6-speed. The fuel "requirement" is confusing to me, nowhere on Toyota's site does it say what is required, When going to fueleconomy.gov they say that all the tacoma models use regular.

yet on here, several people say it requires premium. Does anyone actually have the manual and can say definitly what it says for the 07 Tacoma with the v-6?

Thanks in advance.