Premium Fuel Injectors + Premium Fuel = Better Performance?

One thing I've rarely seen considered in the premium 91 vs regular 87 debate is the type of fuel injectors and their performance versus stock Densos. I've noticed a material uptick in pep and response, ease of towing, etc. when my Densos were upgraded with heavy duty Densos and I started running 91. Only notice decreased fuel economy when I demand response, which is often. The 5VZ might just like premium depending on quality of the fuel.

For the most part, all season tires show the best road noise to fuel economy and combined power in our weekend driving.

 

The thing is, is that the ECU is designed and programmed for 87, not 91. I would think that means it's best fuel trim setups are for 87. Yes, you can put in different injectors, or other parts, but as long as the ECU is stock, or OEM, they won't make all that great a difference.

Just my thoughts. Probably wrong...
Pat☺

 

higher octane will not give you any more power. higher octane fuels are for engines with higher compression 87 octane fuel ignites faster than a 91-octane fuel by increasing the octane in fuel it increases the amount of heat it takes to ignite the fuel this is to keep the higher compression engines from detonating the fuel b4 the piston reaches top dead center causing engine knock that will destroy an engine. Thats why race cars with 11 to 1 compression run High octane fuel like 105 or higher.

 

So I think I’ve only got a few thousand miles on the new injectors. Non Denso. I guess I do have a lot more power especially in the lower rpm range. More torque I guess. But I only run high test. It gets sluggish with low test. My Z28 is 11.5/1 compression and it runs pump gas fine.

 

Higher octane only makes more power because it can withstand higher compression in the engines designed to use it.

The 5vz isn’t one of those engines. At the very least you’d have to put a different tune on it (assuming the engine can even make that sort of compression). Some modern engines can adjust for octane automatically, but these 4runners were discontinued long before that was a thing.

New injectors can atomize the fuel better leading to a more complete combustion. But that has nothing to do with fuel octane. Even replacing the old stock ones with brand new ones can make a difference. This is what you’re noticing.

Putting anything above 87 octane in a stock 4runner is a waste like feeding Kobe beef to a mutt.

 

Nope

 

i've never understood the difference between"octane rating" and "research octane number". this is what it says in my owners manual so i've always used premium gas. probably a waste of money, but never had any issues!

 

Research octane number is a standard of measurement that we use to measure fuel octane, like how Celsius is a unit of measurement for temperature.

Research Octane Number (RON) used everywhere but the US. The US uses Motor Octane Number (MON). The rating you see at the pump is Pump Octane Number (PON), which is the average between RON and MON. Because of this people often incorrectly believe that US fuel is lower quality than Europe, it's the same the number at the pump is lower because we use a different system.