Anyone switched to 87 octane?

DWAM

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Hello!

With these great gas prices we are experiencing! Has anyone switched to 87 octane from 89. I haven’t yet. I will next fill up! I never thought I would! But this is getting ridiculous!
Take care,
Matt
I've only ever burned 87 in my 2020. Works fine, never a knock.
 

Dusty

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I started using Sunoco 89 octane last summer when I was pulling the tractor more frequently. It was then I noticed that the engine idled more smoothly, in fact, the idle was almost imperceptible. So I continued using it through the winter.

Lately, there's about a 50-60 cent difference between 87 and 89 at Sunoco, so the last few tanks have been 87. I can now notice the idle again. My steady passenger says its psychological, she can't feel anything. She could be right since humans can trigger a believe based purely on psychological predisposition. However, my last tank was some off-brand 87 and half way through the tank I started realizing a notchy response in the accelerator. Doesn't do it all the time, but it's there.

So far with only three tanks I cannot see any impact to gas mileage.

Regards,
Dusty
2019 Ram 1500 Billet Silver Quad Cab 2WD, 5.7 Hemi, 8HP75, 3.21 axle, 33-gallon fuel tank, factory dual exhaust, 18” wheels. Build date: 3 June 2018. Now at 69778 miles
 

62Blazer

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I'll go ahead and throw in my $0.005 worth on the topic.
The first thing I will say is that I worked for 12 years as an automotive test engineer specializing in fuel economy testing. Manufacturers of complete vehicles down to some crazy "as seen on TV" aerodynamic bolt on or snake oil would hire our company to perform industry certified fuel economy testing. There are several industry standards from enclosed dyno cell cycles to over the road testing based on the SAE recommended practices. I am in no way trying to say I'm the foremost expert in fuel economy testing, nor trying to say anybody else posting about this is wrong. However I will say that nobody I have ever seen on one of these posts is even close to performing what would be considered a certified or industry recognized fuel economy test. Again, not saying anybody is wrong and they can draw their own conclusions on what they have done and make decisions based on what they have done but no manufacturer, big investor, etc... who use that data to make a business decision.
I have a '16 Power Wagon with the 6.4 and have done a couple of "studies" between 87 and 89 octane. Always ran at least 3-4 tanks of either octane in a row. Have never noticed any "seat of the pants" power or performance difference, and there was no obvious fuel economy difference that I could tell....at least not obvious enough to justify spending the extra money for 89 octane. Yes, I agree with previous posts saying that the ECM may be pulling timing out of the engine with the lower octane which would lead to reduced power....you don't know unless you are monitoring the data. But keep in mind you are rarely ever using the full power of the engine. The horsepower rating of the engine is the maximum power it can achieve, and not what you are using the vast majority of the time. It doesn't matter that the engine is rated at 410 HP because it doesn't take anywhere close to the much power to cruise down the freeway at 70 mph.
But hey, if people want to spend their money on 89 octane I don't have any problem with it.
 

bcbouy

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i'm still filling up with marked 91 octane because it's the same price as mid grade and has no ethanol.it goes in everything i own with an internal combustion engine.i just filled my deck boat and 2 5 gal.jerry cans this morning.$300. ouch.and the boat still had a 1/4 tank before filling it.
 
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ExpressRules

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I thank 62Blazer for his logical and well thought out post regarding if 87 vs 89 makes any real difference in power and fuel mileage. As you might realize at this point I'm 100% in agreement with him.

Seat of the pants feeling is no way to determine the mileage and power claims. Example I can provide is that about four years ago I owned a C4 1991 Corvette with L98 engine. That year the L98 made 245 hp and had low end torque that was fantastic. Two years ago I sold it so I could buy a C4 1995 Vette and that year had the LT1 engine that made 300 hp.

Although I know from all the specs and tests all confirmed that the 95 was faster in all test, my ass was telling me the 91 seemed faster. The low end torque curve of the 91 made it feel faster even though I knew better. Seat of the pants can fool us every time.
 

HEMIMANN

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I'll go ahead and throw in my $0.005 worth on the topic.
The first thing I will say is that I worked for 12 years as an automotive test engineer specializing in fuel economy testing. Manufacturers of complete vehicles down to some crazy "as seen on TV" aerodynamic bolt on or snake oil would hire our company to perform industry certified fuel economy testing. There are several industry standards from enclosed dyno cell cycles to over the road testing based on the SAE recommended practices. I am in no way trying to say I'm the foremost expert in fuel economy testing, nor trying to say anybody else posting about this is wrong. However I will say that nobody I have ever seen on one of these posts is even close to performing what would be considered a certified or industry recognized fuel economy test. Again, not saying anybody is wrong and they can draw their own conclusions on what they have done and make decisions based on what they have done but no manufacturer, big investor, etc... who use that data to make a business decision.
I have a '16 Power Wagon with the 6.4 and have done a couple of "studies" between 87 and 89 octane. Always ran at least 3-4 tanks of either octane in a row. Have never noticed any "seat of the pants" power or performance difference, and there was no obvious fuel economy difference that I could tell....at least not obvious enough to justify spending the extra money for 89 octane. Yes, I agree with previous posts saying that the ECM may be pulling timing out of the engine with the lower octane which would lead to reduced power....you don't know unless you are monitoring the data. But keep in mind you are rarely ever using the full power of the engine. The horsepower rating of the engine is the maximum power it can achieve, and not what you are using the vast majority of the time. It doesn't matter that the engine is rated at 410 HP because it doesn't take anywhere close to the much power to cruise down the freeway at 70 mph.
But hey, if people want to spend their money on 89 octane I don't have any problem with it.

Unless towing serious loads through hilly country. Which is what I do on occasion. Then I use 91.
 

Docwagon1776

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Although I know from all the specs and tests all confirmed that the 95 was faster in all test, my ass was telling me the 91 seemed faster. The low end torque curve of the 91 made it feel faster even though I knew better. Seat of the pants can fool us every time.

Noise levels contribute quite a bit to the human mind's sensation of speed as well. Being closer to fixed objects (including the ground) also contributes to feeling of speed, as does choppiness of ride. The more primitive sections of our brain can't really comprehend the speeds modern technology allows us to obtain with relative ease.
 
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