Not another Octane Battle But—

Hello agsin,
I see what gas to use on the new Tundras comes up a lot and many have diff opinions and there is a lot of egos hurt and bro science answers…it seems.

I’m going to mention one thing and this is a fact not just talking with no knowledge.
I was a ASE certified tech for Ford for 15 years then quit because I’m also a Fireman and hated working 2 jobs.
Anyway in my time the way most of the computers worked on cars and trucks is that the computer will advance timing to get the most performance while driving and when it senses detonation it will then back the timing off in degrees until the ping stops.

If the new Toyota is set up in similar fashion (I don’t know if it is) then running premium fuel will without a doubt make more power. No one can argue this fact.
Again I don’t know how the new system works but there are knock sensors on the new trucks witch tells me there probably working in similar fashion.
Detonation kills performance and can hurt any motor and it’s more dangerous on any forced induction set up!

I may be wasting my money. Maybe a Toyota tech can chime in here. But I use premium. It’s my choice because I want the most power and I’m in Texas. With the heat here I don’t want my motor retarding timing due to it being so hot out and having detonation under load!
Again let’s not turn this into who’s right who’s wrong.
This is common sense if the new ECU works in this way. Again I don’t have this info!
Either way I luv my truck and I was a Ford guy!
Take care!

 

Thanks for the info. Totally agree with both of you. I heard it’s as much as 100 hp increase lol KIDDING! I’m sure it’s not much just personal preference and because we’re I live in summer it can be over 100 degrees for several months. Then we turn our A/Cs on and that motor is working to stay cool and make peak power when we demand it

 

Agreed. I have seen this reported from several sources. Watching my vehicle data reporting to my head unit via iDatalink, I get more timing advance running 87 than I did 85 (high altitude so 85 is ‘regular’ and 87 or 89 is ‘midgrade’).

My truck absolutely runs better on higher octane fuel and makes more power under the curve - especially lugging around 2k rpm - than lower octane fuels. I doubt it makes any more top end power, and I have yet to see as much on dyno runs, but low to mid band power are definitely improved vs low octane fuels.

 

@Jinkx - OT, coming from the ford 3.5EB world, any insights on the new Toyota 3.5TT? I assume that you purchased a new tundra over f150 eco boost for a reason.. care to share?

 

It doesn’t increase power. It just allows the computer to not pull as much timing as it would on lower octane so therefore it’s not losing power.

 

So you guys who are running 93+, is it because you're towing and hauling heavy all the time? How much power do you really need rolling down the freeway empty?

 

IME, it’s not about total power, but power under the curve - meaning, the truck will hold a gear longer cruising under load without downshifting. This is the case with or without a trailer. More timing advance gives the expanding gasses more time to act on the piston and makes more power. To much advance at low speed is like throwing a stick in to bicycle spokes; bad things happen. Higher octane helps this.

So, ya, it doesn’t add power per se. But compared to lower octane fuels, you can extract more power per rotation of the engine instead of limiting that power potential due to pre-detonation.

 

I'm just thinking about the fact that premium is at least 85 cents a gallon more here than regular and wondering if and when it might be useful for me to run it.

 

IF you are spending more for Premium then wouldn't it be better to get NON Ethanol?
In my area, Since the beginning of Dec. Mid and Premium is actually cheaper than Regular by a penny. Not sure how long this will happen, but numerous stations are doing the same thing.

 

The only non ethanol here is premium (91).

 

To answer a few ? Here. Running premium will benefit anytime that the computer has to retard timing. Toyota rates the power of our motors 389 if I remember correctly. So for the guys running premium the can get that 389.

The trucks running 87 will experience less when under load,excessive ambient temps outside or towing. Again all three of these make it easier for detonation to happen.

So why do I run premium? Because I want my full 389 hp and I want it no matter if I’m towing or just jumping on the freeway. I don’t mind paying the extra that’s to make sure I’m getting the full potential of my truck. That’s just me. You can’t go wrong running 87. Just don’t expect the same power as with 93 if the computer is advancing timing. More timing means more power until detonation sets in. Premium is an insurance policy plus I’m a ex drag racer I want the most power my motor can make. To each it’s own. For the average person with a daily driven truck not towing 87 will be just fine for most.
Just not for me
Great info here thank you

 

what classifies as "excessive ambient temperatures"?

here in southern AZ, there are many months where ambient is > 100F, especially on the highways.

 

Have no idea but triple degree temp figs I would never consider normal.

 

How do you get pre-ignition in a direct-injection engine?

 

Direct injection is just how fuel enters directly into the cylinder. Has nothing to do with ignition timing. Hope that helps.

 

Anyone else?

 

Wow this is interesting. Makes sense. For the ethanol questions here: Ethanol has less energy per volume than regular gasoline so non ethanol usually produces better gas mileage and or generators run longer. Project Farm on YT has a few videos showing this difference.

 

I assume you are asking about how a vehicle can have pre-ignition with direct injection…?

Direct Injection gasoline motors still inject the fuel into the cylinder well before combustion occurs. This is mostly done to eliminate fuel vapors outside of the combustion chambers for emissions purposes with the added benefit of more precise fuel metering for each combustion cycle.

This is unlike modern diesel vehicles that control combustion via the timing, duration, and number of injections during a compression-ignition cycle. Due to the high compression and heat of diesel motors, the fuel combusts just after or concurrent to an injection event.

Both gasoline and diesel direct injection systems evolved to remove the air/fuel mixture from the intake and keep it (mostly) in the combustion chamber. But the gasoline is not injected into the cylinder to create the combustion event as diesel is. Due to it being more volatile with a faster spreading flame, gasoline still needs time to mix with the incoming air, so it is injected before the spark plug fires. Timing is still controlled and advanced/retarded by the computer firing a spark plug, independent of the injection timing. Fire the plug too early with lower octane fuel and you get knock, just like any other injection system, be it multi port, throttle body, or carb.

 

Correct but you can still have detonation due to too much advance.

 

Yes but advance with timing has nothing to do with the fuel injection totally two diff things going on at diff times in the cylinder and that’s 100% controlled by the computer.
I think some are confused by fuel injection and ignition timing. Try not to over complicate it. It’s Totally two diff things happening at diff times with each cylinder.

 

To keep this simple
The more timing the computer adds in any engine the higher octane fuel you will need. More timing in any engine will make more power until detonation occurs. How do you stop detonation and allow your engine to makes the most possible power you run 93 over 87 octane so the computer can add more timing, you keep your cylinders cool or take away oxygen hence higher altitude areas run less octane fuels…
With ethanol or without it doesn’t matter it’s still works the same way.
This conversation is simply why I run 93. Direct injection or how much Ethanol doesn’t matter for what I’m talking about.
Take any gas with or without ethanol or with a carburetor or direct fuel injection. The motor will make more power with 93 over 87 because due to the computer always trying to advance timing to make the more horsepower and torque. It’s more pronounced with ours because of the turbos over naturally aspirated engine…
Again just trying to keep this in simple terms and not over complicate it.

 

You and I are agreeing. There’s also injection timing to consider as well.