2GR-FKS (3.5L) detailed layout

The guy I replied to said he was using 91 because old timers said it burned cleaner. I then explained due to the same detergent package being used there not going to be a difference in how clean it burns. Now that I think about it though, that's not completely true. 91 requires more compression and advanced timing to properly burn which means that there's a higher chance of unburnt fuel exiting the exhaust. So in an engine designed for 87, you have a lower quality burn using 91. Does that make sense?

 

I thought the truck is tuned for 87 but can change the timing for higher octanes if needed.

 

87 is the recommended fuel octane rating in the United States. We calculate octane ratings differently. The 91 is the RON (think of Europe and other areas) which is not used in the US, we use AKI which is (R+M)/2. If you get any better fuel economy from premium it's due to the fact that there is no ethanol in your fuel. I believe that varies by state though.

 

I run 87 in my truck

 

I had a 1997 V-6 4-Runner that loved 87 Octane back in 1997. In 1999 I bought a 1999 Camry that would knock/ping/ding with 87 and ran fine with 89 or 93.

I have also seen 2000 and newer engines that have been torn down and those that ran 93 when it wasn't recommended had much more carbon build up.

So moral of this story is... My Tacoma runs fine on 87 octane but my mileage stinks..... wait that didn't help or prove anything

 

Mileage stinks Try running a tank of 89 and see if your mileage picks up any. Maybe your personal situation where your truck is driven and the type of fuel your running there is a ping condition and the computer is sensing engine knock backing down the timing. Wont know unless you try. All over this country there are various blends of gas and who knows what your truck does or doesn't like. You want the fuel that will give you the most efficiency with the lowest octane rating. Different brands, alcohol content or winter /summer blends can all make a difference if your trying to eek out the most mileage.

I have found on my truck that isn't even broken in yet running around town in sport mode, 5th gear, ect off seems to help with the mileage. I haven't done any long freeway drives yet.

 

I've heard someone else mention that, but I haven't seen anything from Toyota actually confirming it. The inverse is obviously true with knock sensors and how it will retard timing to prevent damage. I don't think an engine is going to increase timing until it knocks and then back off.

 

If it were me i'd be running whatever the manual says which is regular. If you are putting in anything rated higher you are just throwing away money in my opinion. I would also buy from any retailer who has top tier gasoline. http://www.toptiergas.com/retailers/

My manual for my jeep says to run regular and putting anything higher is not recommended. It will provide no benefit over high quality regular gasoline, and in some circumstances may result in poorer performance.

Moral of the story, the manual is your friend.

 

What about for an automatic?

 

Oh my god not the stupid octane debate again... The octane rating is the fuels knock resistance rating. That's what it stands for not how clean it is, not more mpgs or power it will give you, it's how knock rsistant the fuel is.

 

What?

No kidding. I'm just reading what came out of my owners manual.

 

Thanks for the link.

Interesting tidbits, beyond what has been posted already:

• Oversquare design (bore > stroke)
• Oil jets to cool bottom of pistons
• Polymer cam covers
• Exhaust runners cast into the head
• 2900 psi from the high-pressure mechanical fuel pump driven off the camshaft

I hope the oil cooler doesn't rely on a few rubber gaskets to keep the coolant separate from the oil.

 

Did you pump her?

 

What? That's exactly what happens. Too much heat and you have auto ignition. I'm not sure where you think I'm wrong. Higher octane resists more heat before detention. If you run your engine in shitty hot conditions while towing in a low RPM you'll increase the chances of detention due to sub optimal engine operating conditions.

 

Long battery life?

 

Stability refers to oxidation and deterioration of its octane rating.

What you're describing is knock resistance.

 

Fair enough, I used wrong terms.