Surprise re: V6 Engine

[TorontoMike]

Wikipedia has the following write-up about the v6 engine in the 5th Gen:
I bolded what was surprising to me: that the hp and torque figures are both pumped up with 91 octane gas. I had no idea....

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. An updated version of this engine features Dual VVT-i, increasing output to 254 hp (189 kW) and 270 lb·ft (366 N·m) on 87 octane and 285 hp (213 kW) and 289 lb·ft (392 N·m) on 91 octane. Inside, the 1GR uses a "taper-squish" combustion chamber design with matching pistons to improve anti-knocking and engine performance, while also improving intake and fuel efficiency. Toyota adopted a siamese-type intake port, which reduces the surface area of the port walls and prevents fuel from adhering to such walls. This engine has special cast-iron cylinder liners cast into the block, which are a spiny type to improve adhesion between the liner and cylinder block. With these special thin liners it is impossible to bore the block. In the event of cylinder wall damage (scoring, deep protrusions, etc.), the entire cylinder block must be replaced. For increased block rigidity, the 1GR also receives a high temperature plastic insulator/protector, which fills the empty space between the outer portion of the cylinders and block material common to open deck engines. For increased cooling efficiency, the 1GR employs water passages between the bores of the engine. There are two such passages for each bank for a total of four. This reduces cylinder hot-spotting and keeps combustion chamber temperatures more uniform.

 

[JB.]

:snacker:

 

[1engineer]

No suprises.

 

[TorontoMike]

Time and time again I have read reports that using higher octane gas in a new vehicle designed for 87 octane is a waste of money.

I bought off on that thinking on the assumption that the primary purpose of higher octane is to reduce knock when compression ratios are high.

Given all the computer management of today's engines (ability to re**** timing, primarily) I figured higher octane would make no difference at all, since nothing was knocking in the first place...

 

[TorontoMike]

Time and time again I have read reports that using higher octane gas in a new vehicle designed for 87 octane is a waste of money.

I bought off on that thinking on the assumption that the primary purpose of higher octane is to reduce knock when compression ratios are high.

Given all the computer management of today's engines (ability to re**** timing, primarily) I figured higher octane would make no difference at all, since nothing was knocking in the first place...

i love how they blanked out that word....political correctness at its finest.

 

[Stifler]

scrap the CAI and just run 91 :biggrin2:

 

[TorontoMike]

scrap the CAI and just run 91 :biggrin2:

I live in Canada where 91 is about $0.57 more per US gallon....that is on top of the $4.72 I paid per US gallon for 87 when I last filled up....keeping in mind that the Canadian dollar is currently worth more than the USD.

 

[Jayhawk5G]

I would like to see some dyno tests to back this up before I would ever consider switching to 91 octane...

I'm going to call BS right now that on a stock 5th gen, using 91 octane over 87 gives you a 31 hp increase.

 

[smallcandle]

But it is on the internet, so doesn't that automatically make it true? :biggrin2:

 

[Jayhawk5G]

But it is on the internet, so doesn't that automatically make it true? :biggrin2:

This just in, Don't waste your time/money waiting on a TRD Supercharger, just switch to 91 octane!

 

[StRanger7032]

It looks like the article is talking about the 1GR-FE engine in general, not referring to the tuning used in different vehicles. Could the 91 octane HP figure be from another vehicle, maybe not even one sold in the US? It says 254 HP on 87 octane, but ours are rated at 270 HP on 87. I recall when the latest generation of Tacoma first came out they were recommending 91 octane-one of the reasons I didn't buy one in 2007. The Tacoma 1GR-FE is now rated at 236 HP (lower compression ratio than 4R/FJ), but it now calls for 87 octane. Confusing...

 

[roadracer30]

It's entirely possible that the engine adjusts the ignition timing based on the fuel. My smart car can run on anything from 87+, but gets measurably better milage on 93 for this very reason. However, the milage increase is proportional to the increase in fuel cost, so it's nets out to no benefit.

I don't know if the toyota engine does this, but it's relatively common these days.

 

[Quentin]

While the Tacoma and the FJ/4Runner both have 1GRs, the Tacoma uses an older revision of the 1GR (built at TMMAL). The 4Runner, FJ, and Tundra all get the new 1GR with dual VVT. The same 1GR in the FJ makes 260hp while it makes 270hp in the 4Runner. That is probably the difference in tune, exhaust, etc. Rest assured that the Tacoma is a vastly different 1GR (completely different heads, cams, valvetrain, etc).

 

[homeyclaus]

I read that too, and understood it to mean that this is what the engine can be tuned to deliver, given the right map, exhaust, intake, and so on. Which depend on the country's emission standards and available fuel quality.

Standard engine management logic has always been to advance timing until your knock sensor starts sending signals, then back off. Then there is an advance curve based on rpms and throttle position, again subject to knock sensor feedback.

There is also O2 sensor input as well, which will affect mixture, with affects the propensity to knock.

On a fuel more resistant to knocking, timing will be more advanced. In general, that makes more power. Does that mean Wikipedia is correct? Not in the slightest, because we don't know how the min/max parameters or the rest of the mappings are set.

 

[Catchlight]

The show "Marketplace" on the CBC network here in Canada had an expert do extensive tests to determine whether premium fuel made vehicles run cleaner, get better mileage, or produce more power.

Their tests found that for vehicles whose manufacturers recommend 87 octane, going higher is a complete waste of money, and that some vehicles that call for high octane fuel run just fine on 87 octane.

They also found that gas attendants have been trained to recommend higher octane (higher profit) fuel whenever asked, and that a lot of consumers have been conditioned to believe that higher octane gas is better, even for their 87-rated vehicles.

Here's the short version of their findings:
Tip Sheet - Marketplace

 

[harper7]

Supposedly Toyota has adaptive ignition timing so if you run high octane fuel for a long time the engine will adapt ,advancing the spark ,resulting in higher efficiency, greater power and torque as well as reduced fuel consumption. I personally run regular and have not tried it.

Here is the Australian article,same 4.0 engine in the 4Runner's brother, the Prado and previously posted on the forum by JB...........Welcome to Land Cruiser Owners On Line

 

[Jayhawk5G]

The problem here isn't the concept of an ECU using sensor data to control things like timing, fuel, spark, etc. It's the idea that by simply switching from 87 octane, the computer is going to adjust tables radically enough to give you a 30hp increase by simply switching to 91 octane.

 

[N2GLOCK]

I had a 2011 Tacoma V6 before getting my 2012 T4R and I can tell you from personal experience that these engines run better on the higher octane fuels but I really only notice the difference when pulling my boat. The difference was especially noticeable when pulling up long hills.

 

[K O]

Supposedly Toyota has adaptive ignition timing so if you run high octane fuel for a long time the engine will adapt ,advancing the spark ,resulting in higher efficiency, greater power and torque as well as reduced fuel consumption. I personally run regular and have not tried it.

Here is the Australian article,same 4.0 engine in the 4Runner's brother, the Prado and previously posted on the forum by JB...........Welcome to Land Cruiser Owners On Line

Not that I'm going to start using Premium fuel, but if you cleared the ECU data wouldn't it adapt faster because it has no pre-existing data to average with?

 

[KodeRush]

Mine is 2011 Limited. I had a 7800km trip last summer, and we intentionally used 91# Shell V-Power for the entire trip. The trip was 98% highway, and the best I had is 12.9L/100km. I currently have had another 7000km on 87# Regular(usually from ESSO, Shell) for daily commute(70% highway), I now have 13.0L/100km. Consider more city driving now,I personally don't see any advantage for 91# in fuel economy.

I didn't try any towing though.