87 octane vs 89 octane, fuel economy differences

[Enve46]

Maybe just the result of a bad 4th grade math teacher?

Those numbers sound awfully low for mixed driving. I'd have to have a lot of local stops, or idling time, to get down to 10.

I wish it was bad math, trust me. My monthly update from Shell tells me otherwise. Im in outskirts of Nashville, lots of little hills but I dont think a PW on 37s is going to do much better than I have even with the fact I drive with my right foot. Ive taken pics of my trip B with the miles driven so really cant screw it up. $620 in fuel in February and Im on track to do about the same here in March. As of the 18th, $372.31

 

[Dave01]

I don't have experience with 37's to know just how badly they cut into mpg, but obviously that's the story. I drive a ton too, put over 25k miles a year on the truck, and even getting 12-14 it's a lot of fuel. Makes me wonder sometimes, but it's the vehicle I wanted/needed and is put to good use.

 

[Enve46]

I don't have experience with 37's to know just how badly they cut into mpg, but obviously that's the story. I drive a ton too, put over 25k miles a year on the truck, and even getting 12-14 it's a lot of fuel. Makes me wonder sometimes, but it's the vehicle I wanted/needed and is put to good use.

I don’t know how much 37s hurt it as I didn’t have it stock long. However my trip home from dealer I was 16-17 highway and now I’m 13-14ish at the speeds I drive. I don’t drive slow and I’m not afraid to let the hemi sing. Several factors. But it all has me considering a diesel again. I know the maintenance and upfront costs but my net costs monthly would be lower per my calculations.

 

[Firebird]

I don’t know how much 37s hurt it as I didn’t have it stock long. However my trip home from dealer I was 16-17 highway and now I’m 13-14ish at the speeds I drive. I don’t drive slow and I’m not afraid to let the hemi sing. Several factors. But it all has me considering a diesel again. I know the maintenance and upfront costs but my net costs monthly would be lower per my calculations.

My 21 Cummins only got about 2 mpg better than my 23 Hemi

 

[gimmie11s]

My 21 Cummins only got about 2 mpg better than my 23 Hemi

Eh, not an apples to apples comparison though... Gas short bed 2500 vs diesel long bed 3500 DRW.

 

[Firebird]

Eh, not an apples to apples comparison though... Gas short bed 2500 vs diesel long bed 3500 DRW.

True, only real comparison was both are 3.73 gears

 

[Enve46]

My 21 Cummins only got about 2 mpg better than my 23 Hemi

Even a marginal increase in fuel economy would save me a good bit. Add in that diesels will depreciate slower when you add miles to them, its hard to justify keeping my PW for the long haul. That said, I just installed a Thuren level to make things worse this am hahaha

 

[Enve46]

Here’s another tank of 89. Again nothing changed, put leveling kit on yesterday, no idle time. Same gas station, Shell. Why I got such a drop in this thank is odd. Maybe anomaly so filled with 89 again.

 

[Enve46]

Thought it would be worth updating those following along… I dumped my PW when it started knocking, I got another tank at 8.9 mpg so I don’t know what was going on. I now have a PXL and averaging 13.9 MPG, at .30 more a gallon I’m still saving, not to mention lower payment, lower insurance etc, miss my PW but something was off for sure

 

[gimmie11s]

Thought it would be worth updating those following along… I dumped my PW when it started knocking, I got another tank at 8.9 mpg so I don’t know what was going on. I now have a PXL and averaging 13.9 MPG, at .30 more a gallon I’m still saving, not to mention lower payment, lower insurance etc, miss my PW but something was off for sure

What is a PXL?

 

[Enve46]

What is a PXL?

Prospector XL

 

[gimmie11s]

Prospector XL

AH sheeit!!

 

[Firebird]

Another update on my 87 vs 89 octane experiment. Been running a few tanks of 87 again, just to triple make sure, and definitely still worse fuel economy. Back to 3 tanks of 89, and I'm consistently getting 1 to 1.5 mpg better on 89. Go figure, but for this particular truck, it's just better mpg on 89.

 

[Enve46]

Another update on my 87 vs 89 octane experiment. Been running a few tanks of 87 again, just to triple make sure, and definitely still worse fuel economy. Back to 3 tanks of 89, and I'm consistently getting 1 to 1.5 mpg better on 89. Go figure, but for this particular truck, it's just better mpg on 89.

I found slightly better on 93, not enough to justify cost though. I think something was wrong with my 6.4 than met the eye and ear hahaha… went from high 9s to high 8s for no apparent reason with an associated knock.

 

[AH64ID]

Another update on my 87 vs 89 octane experiment. Been running a few tanks of 87 again, just to triple make sure, and definitely still worse fuel economy. Back to 3 tanks of 89, and I'm consistently getting 1 to 1.5 mpg better on 89. Go figure, but for this particular truck, it's just better mpg on 89.

What’s the CPM breakdown?

 

[oppizzippo]

I've been running an experiment, I drive about 200 miles round trip to my office once a month. Previous couple months been running 87 and just looking at the dash and it's been in the 14.3-14.8 range. Finally did a "real" test. Late last month did 87, last week did 89. Totally unscientific, just filling up at the same gas station, driving up and back and filling up again. Hand calc my truck is proud by about 0.5mpg. I got 14.8 on the dash, 14.3 hand calc on 87. I got 15.6 on the dash, 15.2 hand calc on 89. I'm going up again this week, but I've reinstalled my front plastic air dam(been removed since 600miles on truck, now going on 9k) and added a soft bed cover. Going to do 89 again, see how much it gains.

Trip Details: 30miles of 60-65mph, then about 60 miles of interstate running 70-75 mph, then driving through downtown Indy to the office.

 

[gimmie11s]

What’s the CPM breakdown?

This is what matters.


I had an EV moron (Subaru at that) telling me the other day how I must buy an EV because he gets to "literally drive his car for free" since our work has free charging. I told him he does not in fact get to drive around for free. He was adamant he does.

SMH. I guess the $60k he spent on that turd magically doesn't count?

I told him I could drive my $2500 '05 Tahoe that gets 14 mpg for 15 years (250 miles per week @ $4/gallon) for CHEAPER than he is currently paying to drive his magical EV. He laughed and walked away.

 

[Dave01]

This is what matters.


I had an EV moron (Subaru at that) telling me the other day how I must buy an EV because he gets to "literally drive his car for free" since our work has free charging. I told him he does not in fact get to drive around for free. He was adamant he does.

SMH. I guess the $60k he spent on that turd magically doesn't count?

I told him I could drive my $2500 '05 Tahoe that gets 14 mpg for 15 years (250 miles per week @ $4/gallon) for CHEAPER than he is currently paying to drive his magical EV. He laughed and walked away.

I get your argument, but I don't agree with it. It's not like 9 out of 10 people on this forum do some careful financial analysis of what our Rams cost including purchase and maintenance and fuel and then carefully weigh it against other new and used vehicles. I know some may do that, but not many. Instead, we look at what we need for capability, want for comfort or look or performance, and go buy a very expensive Ram.

So your friend, who shouldn't have to be called a moron simply because he likes EV's, bought what he likes, paid what he paid for it. Now he's excited because he charges for free at work. You are right, it isn't free, but if it makes him feel good to drive with zero fuel cost, what's wrong with that?

 

[ollicat]

I get your argument, but I don't agree with it. It's not like 9 out of 10 people on this forum do some careful financial analysis of what our Rams cost including purchase and maintenance and fuel and then carefully weigh it against other new and used vehicles. I know some may do that, but not many. Instead, we look at what we need for capability, want for comfort or look or performance, and go buy a very expensive Ram.

So your friend, who shouldn't have to be called a moron simply because he likes EV's, bought what he likes, paid what he paid for it. Now he's excited because he charges for free at work. You are right, it isn't free, but if it makes him feel good to drive with zero fuel cost, what's wrong with that?

"Free" typically means that taxpayers or other people are paying for stuff that one should be paying for themselves Just my 2 cents - or maybe "Free"

 

[gimmie11s]

I get your argument, but I don't agree with it. It's not like 9 out of 10 people on this forum do some careful financial analysis of what our Rams cost including purchase and maintenance and fuel and then carefully weigh it against other new and used vehicles. I know some may do that, but not many. Instead, we look at what we need for capability, want for comfort or look or performance, and go buy a very expensive Ram.

So your friend, who shouldn't have to be called a moron simply because he likes EV's, bought what he likes, paid what he paid for it. Now he's excited because he charges for free at work. You are right, it isn't free, but if it makes him feel good to drive with zero fuel cost, what's wrong with that?

You don't get to agree or disagree with facts, chief. Feelings aren't facts. Math, however, is.

The facts are I can drive the 05 Tahoe for LESS than he spend on his moronic EV. Go back and re-read my post after you remove yourself from the fetal position that this triggering conversation has apparently placed you into.

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