Optimal Fuel Grades for TTV6 (Gen 3 Engines)

Hello all,

I am interested in people's opinions on using fuel with a higher octane rating than the 87 recommended in the owner's manual.

From the little bit of reading I have done in the past it is my understanding that there is no benefits to burning a higher octane fuel than what's prescribed by the manufacturer, and that it may actually be disadvantageous. This is due the engine not running at a high enough compression ratio to burn the extra octane, thus potentially causing build up in the engine.

Interested to hear the thoughts and experiences of others. Myself, I was surprised(pleasently) to see that this new gen engine was designed to burn Reg. grade fuel.

 

Octane rating refers to the anti-knock additive. If the engine does not knock then the extra octane value provides little or no value. If the engine does knock, increase the octane rating......

 

Apparently the new tundra makes full power on 87, something that ford hasn't figured out with the 3.5 in the raptor.
I'll be running 87 in very high temps and high altitude. I suspect, like the raptor forums, that many will opt for 91/93 but it's designed to run on 87 so I won't toss any extra money at the tank

 

A bigger thing is ethanol free gas — unfortunately that’s usually sold as the highest octane.

this summer I experimented with that while towing in high heat and in the mountains and found about an 8% increase in fuel economy. But I don’t chalk that up to the 94 octane but the lack of ethanol.

 

Octane is not a substance in the gasoline, it’s a rating of resistance to premature combustion prior to desired ignition from the spark plug.

There is nothing to worry about using higher than called for octane rated fuel. No buildup is going to occur.

If it gives you a warm fuzzy to use higher octane fuel have at it, just don’t expect higher performance.

 

This isnt true. The engine can absolutely take advantage of octanes well beyond 93 if allowed.

Conversely it can also run on 87 without actually knocking. But it will have less power.

And full power is 63 less than the Raptor out if the same displacement. Why do you think that is?

if you put 93 in a regular F150 it makes nearly the same power as a raptor

The raptor is/was actually better equipped to run 87 octane than a regular F150 since it was only a 10:1 compression ratio instead on 10.5:1. You just wont make 450hp

 

Ultimately it comes down to what you are doing. If you are just casually driving to work, run 87. If you are towing a travel trailer through the rockies, there are seriously good reasons to run 91 or 93.

There is a threshold where octane becomes a determining factor in ignition timing. If you are mostly light on the throttle and not using a lot of boost you dont exceed the threshold and higher octane doesn’t do anything. If you are deeper into the throttle a lot(like towing or at the drag strip) you will exceed that threshold and additional octane will allow for additional power.

with the very high compression ratio and high boost these engines run, you could probably run 100+ octane before the engine actually reached peak timing at wot.

Also, one other consideration is that higher octane towing means you can make the required power/torque to pull the trailer with less boost. Less boost means lower exhaust backpressure and lower intake temps. Under heavy continuous loads, higher octane should help the truck pull consistently and more efficiently unless Toyota simply limited ignition timing.

 

https://www.caranddriver.com/features/a28565486/honda-cr-v-vs-bmw-m5-ford-f-150-dodge-charger/

mixed results.

 

FYI....Pure dino has different octane depending on your location/altitude. A bit bit different here in CO. I'm at 5470 ft before I head up to to mountains. I try to avoid any ethanol in my fuel. Worth the extra pennies....whether you have a 5.7L tunny or the new twin T v6. My 22 Frontier 3.8L v6 really likes pure dino.

 

It can be useful to run higher 91 or 93 when towing especially in warm environments. When towing, the engine is running more boost and making higher torque due to the heavier weight being pulled. Running 87 in this situation, the spark timing will be retarded due to the hotter air charge entering the engine in order to avoid knocking. 91/93 can allow a timing to advance vs 87 so more torque can be produced. Running 91/93 when unloaded won’t have any tangible benefits because Toyota uses torque request maps in their ECM control. This means that the engine produces the torque requested by the ECM and it won’t make more than requested. If Toyota says the engine was calibrated to run on 87, there won’t be much benefit from running 91 for example.

Finally, octane is a hydrocarbon chain. Gasoline contains octanes and heptanes, both hydrocarbon chains. What we call the octane rating is actually called AKI or anti-knock index. This AKI is calculated by taking the average of RON (research octane number) and MON (motor octane number). RON and MON are just two different test methods to measure the anti-knock properties of gasolines.

 

Also gasoline is mostly octane…

 

I appreciate everyone's input and discussion!

I think what I am taking away from this is that I will be using Reg (87) grade with the exception of the couple times a year I am towing a camp trailer, at which time I will run at least Premium (91-93)

 

Yes. Unless your fuel prices are super close like mine, its usually not worth it. My 91 octane is only 15 cents more than 88 so i just run the 91 every tank.

 

The engine closest related to the iForce in that article picked up 20 WHP, dropped 0.6 seconds 0-60, and dropped half a second in the quarter mile switching to 93 octane.

 

All of my experience is with port injection, and GDI is a different animal. My understanding is that the fuel is sprayed into the combustion chamber at just the right time, and because of that you can get away with running lower octane fuel.

I can confirm that when towing heavy 10k+ with a fully loaded truck, 87 octane works well with no knock or other issues.

 

So I actually live in Canada and my wife has Native Status meaning if I buy gas on a reservation (there are several near by) she gets around a 15-25 cent per litre discount. It doesn't make them the same price but really closes the gap.

My only concern is that the "Res gas" or "Native gas" gets a bad wrap around here. Some people claim its lower quality. I have a hard time believing this as gasoline is a regulated product. However I also don't want to put watered down (as some people claim) fuel in my truck

 

I'm sceptical that "Res gas" is watered down and most likely comes from the same refinery as everyone else's fuel. Does Res gas have additives? That could make a difference in cost too. I recall seeing various taxes on fuel when driving thru Canada on my way to Anchorage. The Res prolly has less taxes applied to fuel sales. I'm purely speculating of course.

 

You are exactly right. I suspect it is more of a placebo effect than anything. The research I have done on the topic indicates that it MAY have less detergent additives than some other brands.

 

15 to 25 cents savings is pretty good all things considered.

 

Absolutely it is! Especially when you're buying 100+ litres at a time

 

Heck, it might be better gas! Best to take advantage of your wife's native status when you can. Are there other things you can save on when buying on the Res besides fuel? Groceries?

 

The biggest discount we get is not paying HST(13% tax) on vehicle purchases,which is HUGE.

Other than that anyone with Native Status can save the 8% portion of HST on most retail purchases.

We don't live on a reservation but I believe if you live and work on reservation you aren't required to pay income tax.

 

13% is huge. That 8% retail savings ain't bad either.

 

As per Toyota 389hp on 87 octane.

 

Direct injection is huge but one thing that this engine has that many other truck engines dont is turbos. That effectively gives it a variable compression ratio. The pressure in the cylinder when you are at 15 psi of boost is equivalent to a 21:1 compression ratio naturally aspirated motor, but at 0 psi its 10.5:1

If the PCM detects that the fuel in the tank is lower octane, not only can it pull timing but it may reduce boost to reduce cylinder pressures to better cope with the lower octane rating.

A non-turbo motor can only run between vacuum and ambient pressure. If they set the compression ratio so high that it needs 91+ octane, there is nothing they can do to back off the air load to reduce knock.

 

Another consideration that may be important to you is detergent additives. From what I have seen, Shell and Exxon’s highest octane fuels contain more than the minimum required amounts (at least according to their advertising). Still probably cheaper to put in a bottle of (insert your favorite) additive every several thousand miles if you feel it may be beneficial. YMMV.

 

Oh trust me I have pondered exactly this lol. In the manual Toyota recommends fuel that meets a detergent standard (can't recall the term they use) in my area they say she'll is the only retailer that meets this standard.

Not specific to the Tundra though, they recommend it for all Toyotas

 

TopTier? Any name brand should carry it. Whether or not it matters is a different story.

https://en.wikipedia.org/wiki/Top_Tier_Detergent_Gasoline

I do know that the few times I have filled up at Maverick my vehicles drive noticably crappier. I have also had similar happen once or twice with Sinclair but typically they are good. I stick to Chevron and Exxon normally since we have one of each in town, but Shell is good too if I am traveling. A lot of times P66 is the only thing around in the rural areas on UT, WY, etc and its always done decently.

 

All high compression engine will benefit with higher octane

 

On the same topic, there's something to said about "mid-grade gas". If it's not used very often at that station, you run the risk of getting pretty old lousy gas. (I'm pretty sure I had that recently when I tried mid-grade at my local station.)

I guess I'm saying either use bottom grade, or premium, whatever those numbers are for you.