ran my hemi hard today, she did NOT like it

[MannymanX]

Why do you guys use 91 or 89?
I use regular(87) because that's what it says I need.. sometimes I use 91 and get better fuel efficiency but I don't feel or hear anything different...
I know exactly what the fuel grade is for and that's why I use whats recommended.
can someone clarify?

 

[J-Cooz]

Why do you guys use 91 or 89?
I use regular(87) because that's what it says I need.. sometimes I use 91 and get better fuel efficiency but I don't feel or hear anything different...
I know exactly what the fuel grade is for and that's why I use whats recommended.
can someone clarify?

89 is technically recommended but says 87 is fine.

 

[MannymanX]

89 is technically recommended but says 87 is fine.

Mmmm... Did not know that

 

[Stevenc150]

Mmmm... Did not know that

'20 owner's manual

 

[MannymanX]

'20 owner's manual

View attachment 57671

Thank you! My truck is at the shop for over a week now but i'll check the fuel door when i get it back, i think that's where i got the 87 figure...

 

[SD Rebel]

Thank you! My truck is at the shop for over a week now but i'll check the fuel door when i get it back, i think that's where i got the 87 figure...

The only thing your fuel door will show should be a crossed-out 85 symbol. 87 is fine, your truck is optimized for 89, but your timing will adjust. Also, most 87 is closer to 88-89 anyways due to refineries wanting to pad the octane a bit to avoid going under stated octane by law.

I never noticed a difference when running either 87, 89 or 91.

 

[devildodge]

Could have been it cutting spark if you were near red line too long. My 392 did that to me once and also hasn't happened again as I stay away from red line...or because I haven't been back to that long steep grade since...lol

I had the selector in gear 1 and later learned 1st gear is only good to like 37 mph...why mine did the cutting spark.

My guess is nothing is hurt...keep running it hard. They need that, as the HEMI makes its power high the RPM range...and normal driving hardly brings it to 3 grand...

 

[KcRay]

I never thought he may have hit the rev-limiter, but would have had to had it locked into a low gear. These truck don't even have a red line on the tachometer, they don't need it with a rev-limiter.

 

[BigD]

Sounds like he wants to use ethanol free fuel, maybe 91 is the only way he can get it? As for me, I only use 91, but that's because I use Costco, and they don't have 89. But their 91 is cheaper than everyone else's 87.

I use 87 at Costco exclusively. Truck runs great. No point in putting in 91. It's not a Lamborghini !

 

[Le_Slacker]

89 from big name stations
91 from lower brands - I usually avoid lower brands but can’t always

 

[silver billet]

Thanks everyone for your comments. I ran 91 because the manual says 89 is recommended and I thought I'd "treat" her well since gas prices are so low. I had problems with pinging when using 87 octane at the same pump, the pinging goes away mostly with 89, but everybody fills up with 87 so then the first bit of gas you get is 87 even when you select 91, it's left over in the hose. So the theory is... if you put 89 in, but the first eigth is left over in the hose at 87 octane, then I'm not getting a full tank of true 89. Using 91 should have no trouble reaching 90 to 90.5 octane. Maybe I'm just being stupid with the hose thing, who knows.

I was also under the (apparently mistaken) impression that 0 ethanol was best for our trucks? This pump has been reported on a website to supply 0 ethanol, again, just ran it to help the truck run the best it can.

I was pretty much WOT, but it wasn't hitting the rev limiter. It did it under very hard acceleration, going to say from memory, somewhere between 3000 to 5000 rpms. So it was an entire RPM range that it made the sound under.

Guess there is nothing else to be done but drive it hard for a while, see if I can reproduce.

 

[Scram1500]

I'm kinda worried about the ole girl. I was getting onto the freeway and there was a short onramp and lots of traffic so I leaned into it pretty hard and fast. It revved up and downshifted as normal, but it really made a loud crackling noise for a few seconds while it was at 3000 to 5000 rpms (also I think it might have lost a bit of power while it was crackling away); went away the instant I got off the throttle and it upshifted. Back to smooth hemi sound.

Later in the trip I gave it a bit a few times, but not as hard, and sound didn't come back? Sounded like a well running hemi should.

No codes anywhere on the dash, but I will swear that was NOT normal. It sounded like I lost my exhaust for a few seconds?? But the sound was definitely "out front" under the hood, it was not a sound coming from behind. Freaked me out, never heard that before.

Anybody have any ideas?

Possible that it was a low traction situation and there was wheel spin and or traction control going on?

 

[silver billet]

Possible that it was a low traction situation and there was wheel spin and or traction control going on?

That's a great thought, but no, I was already doing at least city speed, 50+ km/h coming down the short on ramp when I goosed it at that point.

 

[BigD]

Make sure your using Top Tier fuel. I think that's more important than what octane u put in. Speedway & Sam's Club do NOT sell Top Tier fuel. Most other big name gas stations do. Google top tier fuel & they have a list on their website of which gas stations sell it. There should also be a label on the pump. Costco sells Top Tier. So does Holiday.

 

[MannymanX]

I always get 87 at Costco or QT. We have plenty of Gas stations here in Chandler, Az so i don't need to compromise.

 

[User_3336]

At least it wasn't "snap..crackle..pop". LOL

 

[SD Rebel]

I use 87 at Costco exclusively. Truck runs great. No point in putting in 91. It's not a Lamborghini !

Sure, but for best performance and mpg, it states 89 is recommended in the manual. By using 91, I'm within the recommendation by the manufacturer, but using 87 I am not.

Considering 91 at Costco is cheaper than 87 anywhere else, it seems like a good compromise, though again, I can't tell the difference. However, I feel better about staying within manufacturers recommendation.

I am paying about $4 dollars more over the course of a month ($48 a year) by using 91, but doesn't seem like a lot in regards to a $50,000.

 

[Stevenc150]

I am paying about $4 dollars more over the course of a month ($48 a year) by using 91, but doesn't seem like a lot in regards to a $50,000.

$4 a month? Good lord man, what's the price difference between grades?! That sounds super cheap. I fill up at avg once/wk. Heres ours today for a single wk 25 gallon fill up...thats $15 between 87 & 91

 

[SD Rebel]

Wow, is that .60 cents from your 87 to 91? Though we get it in the rears for overall fuel prices here!!!

I should have mentioned I work from home and because I got a sedan as well along with a motorcycle. I average less than a tank per month in the RAM.

California is about .20 - .25 cents from 87 to 91 per gallon. As of right now, local San Diego Costco is $2.59 for regular / $2.75 premium, which is only .16 cents per gallon. This isn't usual, I expect to to jump back to 20 cents per gallon by tomorrow.

I'm about 20 gallons per month in the RAM, which at 20 cents over premium, is $4 bucks a month. I guess I could alternate between 91 and half tank of 87, which would create 89 octane, but I'm too lazy for that.

 

[devildodge]

I buy my gas at our local Sunoco station durimg towing season. I run 87 all winter, but come towing season I like to run 89. The Sunoco is only 13 cents more for 89 over 87