GX470 Octane - Just some research is all-Talk among yourselves. (1 Viewer)

[hammerheadfistpunch]

So your saying that the computer will not make changes?

In 1984-86, a Mustang SVO had a little switch that would change timing if you couldn't find premium fuel and a noticeable difference in power. Back in the mid 80's, engine could be made to adapt to fuel grades, so I gotta believe that modern engine and computer system could make some changes.

The map will pull timing based on sensor input but it wont advance past base map. Tune for prumium and use regular gets you regular map performance. Tune for regular and use premium gets you regular map performance. Tune for premium and use premium gets you premium map performance.

The svo sounds like it had 2 maps stored. Modern engines also adjust for grade but they only asjust down from their base maps.

 

[GXO]

I have an 03, ran regular for a year. Ran mid for a year. Ran premium for a year. No difference at all.

 

[hammerheadfistpunch]

I have an 03, ran regular for a year. Ran mid for a year. Ran premium for a year. No difference at all.

It wouldn't make a difference on an 03, that was the single VVTi motor tuned for regular.

 

[thatcabledude]

I have never put anything other than 87 in my 2006.

No issues.

 

[hammerheadfistpunch]

I have never put anything other than 87 in my 2006.

No issues.

I dont anticipate you will ever notice a difference. I am a new GX owner and one of the thing that turned my wife off to many cars in the class was the premium fuel requirement...which, as it turns out, our 06 "requires". people have said it doesn't and that its the same motor as all other UZ's, I just wanted to dig in and see if I could add veracity to that claim. Turns out there are different tunes to the UZ, but I honestly don't think it will matter outside of towing heavy loads where a little more mid range punch could help.

 

[NMBruce]

So I was doing some reading today and found this;
"One thing that separates the GX 470 from other 120 SUVs like the 4Runner or FJ Cruiser is its standard 4.7-liter V8 engine. The 4.7 is available on the 4Runner, but the Lexus version (which calls for premium fuel) is rated to produce 263 hp (3 more hp than the 4Runner) and 323 lb.-ft. of torque (17 more lb.-ft. than the 4Runner); of course you can run 87-octane without grenading the engine, as it is designed to recalibrate to avoid knock, but Lexus does advise using 91. We reached out to Lexus to clarify exactly how these engines differ, and we were simply told the engine on the GX was calibrated to work with 91-octane to maximize power. That said, both the 4Runner and GX 470 4.7s feature the same 10.0:1 compression ratio, so pinning down exactly how Lexus squeezed out the extra performance is a riddle we didn’t completely solve."

this is from Off-Road.com. Luxury Off-Road: Why We’re Building a Lexus GX 470

 

[JLee]

So I was doing some reading today and found this;
"One thing that separates the GX 470 from other 120 SUVs like the 4Runner or FJ Cruiser is its standard 4.7-liter V8 engine. The 4.7 is available on the 4Runner, but the Lexus version (which calls for premium fuel) is rated to produce 263 hp (3 more hp than the 4Runner) and 323 lb.-ft. of torque (17 more lb.-ft. than the 4Runner); of course you can run 87-octane without grenading the engine, as it is designed to recalibrate to avoid knock, but Lexus does advise using 91. We reached out to Lexus to clarify exactly how these engines differ, and we were simply told the engine on the GX was calibrated to work with 91-octane to maximize power. That said, both the 4Runner and GX 470 4.7s feature the same 10.0:1 compression ratio, so pinning down exactly how Lexus squeezed out the extra performance is a riddle we didn’t completely solve."

this is from Off-Road.com. Luxury Off-Road: Why We’re Building a Lexus GX 470

Then look at the Tundra:

2005 (pre hp rating change):
282 hp and 325 lb·ft
2006 (post hp rating change):
271 hp and 313 lb·ft

I'm guessing the GX runs a little more timing to tweak the torque curve. I'd be curious to datalog a WOT pull through a couple of gears and compare ignition timing vs a 4Runner/Tundra.

 

[hammerheadfistpunch]

Then look at the Tundra:

2005 (pre hp rating change):
282 hp and 325 lb·ft
2006 (post hp rating change):
271 hp and 313 lb·ft

I'm guessing the GX runs a little more timing to tweak the torque curve. I'd be curious to datalog a WOT pull through a couple of gears and compare ignition timing vs a 4Runner/Tundra.

This, its just more advanced timing to beef up the torque curve which explains the paltry hp gain but moderate torque gain.

 

[jonshonda]

I run 87 when not towing. I run 91 when towing. I very rarely bury the skinny pedal when driving around town, but require all the power the V8 can muster when loaded up and towing our 5100lb camper.

 

[hammerheadfistpunch]

I run 87 when not towing. I run 91 when towing. I very rarely bury the skinny pedal when driving around town, but require all the power the V8 can muster when loaded up and towing our 5100lb camper.

Thats been my policy as well.

 

[stevezero]

i tend to get 30-50 more miles out of a tank of 93 eth than 87 eth fuel. i get an additional 30-50 miles out of a tank of 91 or 93 pure gas on top of the 93 eth. That would be mostly highway driving where i see the bigger gains. Locally, I use mostly Costco gas (which their 93 is within 10-15 cents a gallon of a regular station's 87).


I did a 2400 mile trip towing our 1500 lb teardrop, and averaged 14mpg for the trip. That was pretty good considering we did it going over and thru the east coast mountains at 70-75mph the whole trip. I noticed a marked difference in mileage when i used 87 vs 93 eth or 91 pure. To the point where i put my daughter to use searchin puregas.org for stations to fill up at.

I dont wring out my engine, but dont baby it all the time either.

 

[hammerheadfistpunch]

i tend to get 30-50 more miles out of a tank of 93 eth than 87 eth fuel. i get an additional 30-50 miles out of a tank of 91 or 93 pure gas on top of the 93 eth. That would be mostly highway driving where i see the bigger gains. Locally, I use mostly Costco gas (which their 93 is within 10-15 cents a gallon of a regular station's 87).


I did a 2400 mile trip towing our 1500 lb teardrop, and averaged 14mpg for the trip. That was pretty good considering we did it going over and thru the east coast mountains at 70-75mph the whole trip. I noticed a marked difference in mileage when i used 87 vs 93 eth or 91 pure. To the point where i put my daughter to use searchin puregas.org for stations to fill up at.

I dont wring out my engine, but dont baby it all the time either.

My experience mirrors yours re: pure gas. It makes a huge difference on mileage. I haven't seen a difference in octane between e10

 

[larsdennert]

I have the VVti motor and definitely tell the difference in 89 and 91 octane, but only when towing. I'm sure 87 or 85 would lead to more spark retard and be more noticeable. That being said, the motor runs on any fuel.

I SC'd my 3.4l 3rd Gen 4Runner. Not running 91 in that motor was rather hazardous and unpleasant.

 

[half k cruiser]

The 1GR-FE in the 4runners and Tacomas will adjust to different octane levels. They even have a different HP/TQ rating based on whether you run them on 87 or 91 octane. However, here's the kicker, its about 15hp and even less torque. It also doesn't state where in the powerband you will see that 5% difference in HP/TQ. I would also wager that the only place you will notice a 5% hp increase on a 5,000lb vehicle, is in your mind.

Now as for whether or not you get a mpg increase in 87 vs 91 or ethanol vs non ethanol, I have no idea. I have always suspected you would get better MPG with non-ethanol, but I've never done any back to back testing on it. I would be curious if anyone has ever done an actual test in controlled conditions where the only thing that was changed is the octane and ethanol ratings.

 

[hammerheadfistpunch]

The 1GR-FE in the 4runners and Tacomas will adjust to different octane levels. They even have a different HP/TQ rating based on whether you run them on 87 or 91 octane. However, here's the kicker, its about 15hp and even less torque. It also doesn't state where in the powerband you will see that 5% difference in HP/TQ. I would also wager that the only place you will notice a 5% hp increase on a 5,000lb vehicle, is in your mind.

Now as for whether or not you get a mpg increase in 87 vs 91 or ethanol vs non ethanol, I have no idea. I have always suspected you would get better MPG with non-ethanol, but I've never done any back to back testing on it. I would be curious if anyone has ever done an actual test in controlled conditions where the only thing that was changed is the octane and ethanol ratings.

I've done lots of my own personal testing on this topic (ethanol vs pure gas) and I can tell you that it makes a difference. Try it on the 80,it REALLY likes it. I went from 13.5 to 15.8 mpg. Its not rocket surgery, E10 has less energy available to burn so you have to burn more of it. Worst program ever.

 

[Toyo8696]

08 4R 4.7 here. Having owned Several Toyota's with the 4.7s I can say without any doubt the 4.7 runs better on 93 Octane. I have always produced better mileage, better /smoother acceleration. I work on a large amount of Toyota's with the shop I have. I know them pretty well.
The only 2 differences that I can discover to which increase hp between Toyota and Lexus how the ECM is hard coded and the exhaust. However, the 4R and GX are so damn close mechanically.
Theee are just my thoughts. Yours of course will vary.

 

[hammerheadfistpunch]

08 4R 4.7 here. Having owned Several Toyota's with the 4.7s I can say without any doubt the 4.7 runs better on 93 Octane. I have always produced better mileage, better /smoother acceleration. I work on a large amount of Toyota's with the shop I have. I know them pretty well.
The only 2 differences that I can discover to which increase hp between Toyota and Lexus how the ECM is hard coded and the exhaust. However, the 4R and GX are so damn close mechanically.
Theee are just my thoughts. Yours of course will vary.

Yeah, I haven't noticed a big difference 91 to 85 (Utah) but I can tell a little difference in smoothness and response. I did a 1500 mile trip to so cal and back recently and I kept premium in it the whole time and my mileage wasn't any better, but it sure ran like a champ at sea level.

 

[Dustin Keeler]

I have a 2004 and have been running the 87 since I got it (2.5 months ago). I have been having slight hiccups during heavy acceleration. I switched to 91 to compare in my ride and it has eliminated that hiccup (could be coincidence but it is noticeable). I don't see any difference anywhere else though. I would be stoked if I saw a little more MPGs but wouldn't we all?

 

[hammerheadfistpunch]

Another interesting bit of data on this.

 

[GXO]

I've noticed better power and mileage in the winter with premium. Altitude is best with regular, and summer with midgrade. Been a few years like this and it seems consistent.