87 vs 89 octane?

[HemiLonestar]

Ran low on gas on the interstate and the only gas station for miles didn't have premium..............


.

Ahhh. That'll happen

 

[WulfGang]

Engine Knock Explained



10 bucks hardly even buys lunch these days, when you are buying 100 litres of fuel 10 more or 10 less not much of a difference i think.
Obviously when gas was 1.50$/litre its painfull but like they say, with great power comes great responsibility and high fuel consumption.

There have been at least 3 other threads I have said the same thing.

People...

I'm by NO means "well off" and work hard for every penny I get. Which don't go nearly far enough.

With that said, if you can't afford an extra $10 a tank for 93 then perhaps you should consider a Prius

Or, buy a DS tuner and run the 93 oct HF tune. Problem solved. You gotta run 93 then hehe

 

[xb1230]

10 bucks hardly even buys lunch these days, when you are buying 100 litres of fuel 10 more or 10 less not much of a difference i think.
Obviously when gas was 1.50$/litre its painfull but like they say, with great power comes great responsibility and high fuel consumption.

I'm just a cheap ****... What can I say. Besides I can't say I have great Power with my 4.7L... Next truck if still can't afford a Diesel will be a Hemi... now I know!

Just saying...

 

[hemihustlin]

Me too, i forgot who said it but i love the quote "im so cheap i love myself!"
The other expession i live by is im to broke to buy cheap stuff. Do it right the first time or buy cheap twice.
Thats why i got a ram, best quality for the value. Treat it right and it will last you a long time. I also drive it the way i want and have absolute confidence it will handle whatever i throw at it.

Theres a difference between being cheap and spending wisely.
Cheap is people that dont tip service people like waiters or the people that pump your gas when its -20.

 

[Hemiquad]

I run 89 in my stock hemi. It idles better and has better response than 87. I tried many times and noticed 1 to 2 mpg better with 89. Higher octane didn't show any benefits.So with only a 10 cent/gallon difference in gas & better mpg it's worth it.

 

[smiley]

There have been at least 3 other threads I have said the same thing.

People...

I'm by NO means "well off" and work hard for every penny I get. Which don't go nearly far enough.

With that said, if you can't afford an extra $10 a tank for 93 then perhaps you should consider a Prius

Or, buy a DS tuner and run the 93 oct HF tune. Problem solved. You gotta run 93 then hehe

I agree with this on many things but with fuel there is really no gain from any octane over 89 without tune and both having ethanol. If it makes you feel good by all means enjoy but it only helps with placebo effect not reality from what I have found. 89 works awesome for me I spent the money I saved over the years on the regear and that actually makes a real noticeable difference unlike the couple octane. No reason to get mad at anyone for wanting to save money for other things. $10 extra a fill or more on 100,000 miles of fuel is a lot of money.

 

[justin13703]

I agree with this on many things but with fuel there is really no gain from any octane over 89 without tune and both having ethanol. If it makes you feel good by all means enjoy but it only helps with placebo effect not reality from what I have found. 89 works awesome for me I spent the money I saved over the years on the regear and that actually makes a real noticeable difference unlike the couple octane. No reason to get mad at anyone for wanting to save money for other things. $10 extra a fill or more on 100,000 miles of fuel is a lot of money.

I agree with this. There's no point to put 93 in a stock truck without a tune.

 

[WulfGang]

I agree with this on many things but with fuel there is really no gain from any octane over 89 without tune and both having ethanol. If it makes you feel good by all means enjoy but it only helps with placebo effect not reality from what I have found. 89 works awesome for me I spent the money I saved over the years on the regear and that actually makes a real noticeable difference unlike the couple octane. No reason to get mad at anyone for wanting to save money for other things. $10 extra a fill or more on 100,000 miles of fuel is a lot of money.

Who's mad?

 

[Ramrt1]

It runs better with 89 octane, not sure why you would want to put 87 octane in it? octane effects spark, timing, engine knock. I'm sure you had some engine chatter when using the cheap gas.

 

[justin13703]

It runs better with 89 octane, not sure why you would want to put 87 octane in it? octane effects spark, timing, engine knock. I'm sure you had some engine chatter when using the cheap gas.

I used 87 in my truck for 3 months after I bought it because I didn't know 89 was recommended. I saw absolutely no adverse affects when I was using 87 and noticed no difference at all when I started using 89.

In short, if there was any chance of 87 causing damage to a motor, Dodge would not state in the manual that 87 is acceptable. Remember, they had to warranty these motors...

 

[RAM_CRNA]

a little off topic but kinda makes you consider that by using 87 vs 89 for the life of the truck at 20 cents difference per gal where I live x (150k miles/15mpg) = 200000 cents or $2000. More than enough to pay for the lifetime power train warranty. So by this beer logic I would buy the lifetime for the added peace of mind and use the extra to go higher octane on days I want extra performance.

 

[xtremewlr]

a little off topic but kinda makes you consider that by using 87 vs 89 for the life of the truck at 20 cents difference per gal where I live x (150k miles/15mpg) = 200000 cents or $2000. More than enough to pay for the lifetime power train warranty. So by this beer logic I would buy the lifetime for the added peace of mind and use the extra to go higher octane on days I want extra performance.

Higher octane does not equal extra performance.

I've ran 87 for the last year and just switched back to 89 for the last couple months and there was absolutely zero difference in the way the truck ran. Not in performance or in mileage. Only difference was in the wallet.

The only time you NEED higher octane is if the motor is tuned for it.

 

[Graygoose]

If the truck see's detonation due to a lower octane, yes, you can/do lose power. So power can be had with higher octane to keep from PCM pulling timing. But anything OVER 89 for a stock truck IMHO is a waste.

 

[WulfGang]

I gotta run 93oct for my 93oct tune on a stock truck.

Are you saying that I could run an 87oct perf tune on a stock truck instead of the 93 and get the same performance? Because according to what I was told by either Matt or the Hemi Fever man himself that an 87oct perf tune is almost useless. That a perf tune should be ran with 93oct even stock. Loosely quoted.

*I'm not being hostile* - I hate the interwebs.

 

[RamRMK]

I just got a trinity and asked Sean at Hemifever if there was a big diff between the 91 vs 93 tune, he replied a few HP.


Sent from my iPhone using Tapatalk

 

[WulfGang]

So obviously there is something to this 93 vs' 87 octane debate.

Seems to me there are reasons you can't run a High Perf tune on 87oct.
Therefore, you cannot achieve the horse power boost on the 87.

 

[Graygoose]

Timing.

 

[hemihustlin]

Spoonfeeding

Many high-performance engines are designed to operate with a high maximum compression, and thus demand fuels of higher octane. A common misconception is that power output or fuel efficiency can be improved by burning fuel of higher octane than that specified by the engine manufacturer. The power output of an engine depends in part on the energy density of the fuel being burnt. Fuels of different octane ratings may have similar densities, but because switching to a higher octane fuel does not add more hydrocarbon content or oxygen, the engine cannot develop more power.

However, burning fuel with a lower octane rating than that for which the engine is designed often results in a reduction of power output and efficiency. Many modern engines are equipped with a knock sensor (a small piezoelectric microphone), which sends a signal to the engine control unit, which in turn ******* the ignition timing when detonation is detected. Retarding the ignition timing reduces the tendency of the fuel-air mixture to detonate, but also reduces power output and fuel efficiency. Because of this, under conditions of high load and high temperature, a given engine may have a more consistent power output with a higher octane fuel, as such fuels are less prone to detonation. Some modern high performance engines are actually optimized for higher than pump premium (93 AKI in the US). The 2001 - 2007 BMW M3 with the S54 engine is one such car. Car and Driver magazine tested a car using a dynamometer, and found that the power output increased as the AKI was increased up to approximately 96 AKI.

Most fuel filling stations have two storage tanks (even those offering 3 or 4 octane levels): those motorists who purchase intermediate grade fuels are given a mixture of higher and lower octane fuels. "Premium" grade is fuel of higher octane, and the minimum grade sold is fuel of lower octane. Purchasing 91 octane fuel (where offered) simply means that more fuel of higher octane is blended with commensurately less fuel of lower octane, than when purchasing a lower grade. The detergents and other additives in the fuel are often, but not always, identical.

Octane rating - Wikipedia, the free encyclopedia

If any of you found that interesting go read the rest of the article!

 

[Graygoose]

Amen!^^^