Unexpected power boost

I've had my truck 3 years and not replaced the battery because it never gave me one problem or indicated it was weak. But 2 autoparts stores checked it and said it was "bad" and needed replacement. So I bought a new Diehard 27F (710 CCA, 885 CA, 165 Minute Reserve Capacity, slightly better than OE) yesterday, letting Advance Auto install it. Right out of the parking lot I could tell the engine ran better.
I have been running regular unleaded in the truck and only occasionally put some premium in the tank, never noticing any difference in the way it ran. (I just learned that Toyota recommended premium for this 4.0 V6) But I'd gotten a great deal on premium and filled up the half empty tank with it the day before. And now with a new battery, the butt-dyno told me it had a noticeable improvement in its performance. Apparently the old battery was delivering insufficient power to the coils, even though it seemed to run great. It now runs even better.

 

Placebo effect my friend.

 

The engine control unit has done a reset because the battery had been disconnected.

 

Feel free to run the premium.
But the only reason it is recommend is to get the "actual" full hp rating of the engine.
There isn't a big difference between 87 and 91. I belive it was like 7 hp more?

The 4.0 is a pig. It eats everything.
Don't fear 87. Run it as you please.
It won't hurt anything at all.

 

yep. Stop wasting your money on premium. Run 87 as the owners manual states, @RA77

Unless you have a supercharger, then you actually need premium.

Also, the battery replacement wouldn’t improve your performance. If it does, your alternator is failing.

 

My car always runs a little faster after I wash it.

 

Mine only runs faster with Nike brand tires.

 

I thought this only applied to the Dual VVTi 1GRFE?

 

Pretty sure the HP rating went up around 2011. That's when they added the 91 octane suggestion in the owners manual.

I'd have to go and look.

 

I did some searching and you are correct that the single VVTi 1GRFE can gain a smidge more hp/tq with 91. Like 2hp and 7tq which seems like a wash given the price difference though lol.

 

FWIW, OP has an 07'

Research number and octane number are NOT the same.

Now I know why OP said 91'.

• 87 AKI = 91 RON
• 91 AKI = 93 RON
• 93 AKI = 98 RON
• 100 AKI = 104 RON
• 104 AKI = 108 RON

 

Or OP lives at elevation…and still meant premium.

 

How can V-Power Nitro not hop up a V6?

 

It even sounds faster.

 

I should say I wasn’t poking fun at @JasonLee

Just at Shell marketing.

 

Yes! It's got Electrolytes!

 

Thats ONLY for Prius's and the likes

 

This.

I notice the same every time if I disconnect the battery or use the erase function on my obd scan tool.

 

It may be a placebo effect, but I feel like my truck is just a touch peppier when I run 89 versus 87. I don't notice a difference between 89 and premium, though.
It's butt dyno, so I may be imagining it, but I swear it accelerates a little better.

I run 87 most of the time.