Cheap alternative to premium?

A

AJB0009

Joined
Feb 6, 2020
Messages
390
Location
Charlotte, NC
I have typically always run premium in my little Tacoma (4 cyl, 4 speed auto), as it needs all of the help that it can get.
I either run Exxon or Shell premium. It is a noticeable difference when I do. With the cruise on and you start going up even the slightest hill, it will downshift. Sometimes it will shift from 4th to 3rd, then to 2nd in a very short period of time, turning about 5,500 RPM's. If I run premium, it downshifts much less.
But, given our current situation with fuel prices, it is just not affordable for our budget any longer.
Just curious if anyone has figured out, is there a decent octane booster or something of the like that you can put in regular unleaded and in the end would cost less than premium with the same results?
 
AJB0009 said:
I have typically always run premium in my little Tacoma (4 cyl, 4 speed auto), as it needs all of the help that it can get.
I either run Exxon or Shell premium. It is a noticeable difference when I do. With the cruise on and you start going up even the slightest hill, it will downshift. Sometimes it will shift from 4th to 3rd, then to 2nd in a very short period of time, turning about 5,500 RPM's. If I run premium, it downshifts much less.
But, given our current situation with fuel prices, it is just not affordable for our budget any longer.
Just curious if anyone has figured out, is there a decent octane booster or something of the like that you can put in regular unleaded and in the end would cost less than premium with the same results?
Click to expand...
I really can't conceive of how the octane rating of the fuel would directly correlate to your ad hoc "hill test". But nevertheless...

Raising the octane level of gasoline is always expensive, whether it is by increasing the concentration of more highly branched hydrocarbons or by an additive such as toluene or EtOH. Unfortunately there is no free lunch here.
 
Well - there is actually several, but it may not necessarily be the greatest idea. MMT was mentioned, and that has nasty habit of fouling up spark plugs as well as messing with catalytic converter function. Tetraethyl lead is an incredibly effective octane booster, but I think most people understand the problems that go beyond just catalytic converters.

It's not cheap, but many have used small proportions of toluene. And of course the easiest, but somewhat risky, which is fuel ethanol. There's probably no cheaper octane booster than that, but then again, problems.
 
Premium is slower burning and less volatile than regular. Try regular and if your engine does not ping or detonate, you don't need premium. Premium will not make your engine run better either. Some believe it does and I think it's all in their head.
 
AJB0009 said:
I have typically always run premium in my little Tacoma (4 cyl, 4 speed auto), as it needs all of the help that it can get.
I either run Exxon or Shell premium. It is a noticeable difference when I do. With the cruise on and you start going up even the slightest hill, it will downshift. Sometimes it will shift from 4th to 3rd, then to 2nd in a very short period of time, turning about 5,500 RPM's. If I run premium, it downshifts much less.
But, given our current situation with fuel prices, it is just not affordable for our budget any longer.
Just curious if anyone has figured out, is there a decent octane booster or something of the like that you can put in regular unleaded and in the end would cost less than premium with the same results?
Click to expand...
Got a 2009 Toyota Tacoma in the family. 2.7L/Auto/2WD. My father got it in 2011 with 23k miles. Currently in 2022 it's at ~75k miles.
On couple long trips (Charlotte-Greensboro and back, 5 times per week for 3 weeks back in 2014-ish) I noticed better fuel efficiency with 89. Tried 87/89/93. 87 provided sluggishness and increased amount of downshifts, like you noted too. 89/93 decreased amount of downshifts required to drive the same highway commute, and increased Fuel Efficiency just a little. Overall the truck just felt less stressed. Almost like going from 25PSI in the tires to 40PSI. Given the price VS benefit ratio, in my case 89 was the most efficient option.
Don't forget that thousands of owners rack up millions of miles on these just fine on normal 87. Like this 1.5 million mile Tacoma. My dad's is the same, but red in color.
Best MPG I ever got on that truck was 28MPG. Cruise Control @65MPH, night time with zero traffic, 38PSI in stock size tires, and 65F ambient temp.
 
Last edited:
I'm surprised at the responses most of you are giving...

Modern engines constantly push timing to increase efficiency and torque output for a given engine RPM. Transmissions are programmed to hold on to a gear as long as possible before downshifting again to increase fuel efficiency.

Just because an engine is DESIGNED to run on RUG doesn't mean it can't see slightly more efficient operating conditions, or increased power from using premium. It just means that it can attain its performance targets for power and economy using RUG.

Using premium can certainly allow the engine ECU to push timing a bit more in lower engine speeds with larger throttle openings before knocking occurs (where the knock sensor would pull timing using RUG). This might allow the car to continue up the hill at a given speed with a certain throttle setting without downshifting using premium. Using RUG at the similar condition may have caused slight knock, which will cause the engine ECU to pull timing, causing the throttle position to increase to maintain the same torque output, causing you to now hit the mark where the transmission thinks it needs to downshift.

I too have noticed similar experiences when pulling trailers. The engine will hold a gear longer when using premium on slight grades. You do have to be very in tune with your vehicle to notice this.

While I don't advocate this...use a OBDII monitor and watch the knock retard during a tank of RUG, and a tank of premium, and report back.
 
DriveHard said:
I'm surprised at the responses most of you are giving...

Modern engines constantly push timing to increase efficiency and torque output for a given engine RPM. Transmissions are programmed to hold on to a gear as long as possible before downshifting again to increase fuel efficiency.

Just because an engine is DESIGNED to run on RUG doesn't mean it can't see slightly more efficient operating conditions, or increased power from using premium. It just means that it can attain its performance targets for power and economy using RUG.

Using premium can certainly allow the engine ECU to push timing a bit more in lower engine speeds with larger throttle openings before knocking occurs (where the knock sensor would pull timing using RUG). This might allow the car to continue up the hill at a given speed with a certain throttle setting without downshifting using premium. Using RUG at the similar condition may have caused slight knock, which will cause the engine ECU to pull timing, causing the throttle position to increase to maintain the same torque output, causing you to now hit the mark where the transmission thinks it needs to downshift.

I too have noticed similar experiences when pulling trailers. The engine will hold a gear longer when using premium on slight grades. You do have to be very in tune with your vehicle to notice this.

While I don't advocate this...use a OBDII monitor and watch the knock retard during a tank of RUG, and a tank of premium, and report back.
Click to expand...

It really depends on the car. May two decades ago it was "premium recommended" with some cars, while others said "premium only" even though the owner's manual might say that regular was OK with reduced performance.

Still - a lot of cars these days recommend even 93 AKI. I have no idea where to find anything similar other than specialty gas stations that blend in unleaded race gas.
 
Lubener said:
Premium is slower burning and less volatile than regular. Try regular and if your engine does not ping or detonate, you don't need premium. Premium will not make your engine run better either. Some believe it does and I think it's all in their head.
Click to expand...

It doesn't necessarily have to burn slower. The only requirement (other than meeting any reformulated fuel standards for emissions) is about resisting preignition and detonation. Unleaded race gas has an extremely high octane rating and burns faster. However, the concerns with race gas go way beyond just octane rating.

dsportmag.com

Fuel 101: Race Gas, Octane, and Alternative Fuels Explained

Want to go fast? Come find all the answers to the fuel to use in your race car. We break down the differences so you can make the right choice at the track.
dsportmag.com dsportmag.com
You may have heard the following: “don’t use too high of an octane fuel or you will lose power.” This is a half-truth. Having a fuel with too high of an octane will not cause your engine to lose power. The problem is that the popular components used to make the octane of a fuel higher slows the burn rate and a fuel with a burn rate that is too slow can result in an engine power loss. Of course, that is just typically what happens and it does not hold true for all fuels. As an example, VP Racing Fuels worked with the Scranton Brothers and their turbocharged Pro Class Celica throughout the 2002 season to develop a new fuel blend. This blend was designed to provide 120+ motor octane with the quickest burn rate possible. The result was the VP Import blend which produced six percent more power in the Celica than VP Racing C16.​
 
Dave9 said:
If you want better fuel economy, turn your cruise control off, then go slower up hills and faster down them.
Click to expand...

Even this SUX! Diminishing returns hits ya hard! Up always is sucking energy while down is giving energy, just at a much smaller % than the hill takes away!
 
Dave9 said:
If you want better fuel economy, turn your cruise control off, then go slower up hills and faster down them.
Click to expand...
Had a flashback from High School days after reading this... High School Driver's Ed teacher gave us penalty points if we did that^. She never allowed us to go slower uphills. What she taught and forced us to do is accelerate slightly above speed limit going down the hill (or on straight road before hitting the said uphill) and let that momentum take the car over the next hill while using little to no gas pedal. So that average speed is never below speed limit and doesn't slow anyone else down, while vehicle doesn't have to stress itself through extra shifting and higher RPMs. The Driver Ed vehicle was a Buick Park Avenue, but her personal vehicle was a 3 cylinder Geo Metro. Needless to say she was a bit of a hypermiler, so her hill driving technique likely came from that.
 
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