I wonder...

ColoradoDriver

2014 CX-5 Touring AWD - 132k miles
Contributor
:
Denver, CO
This fuel grade thread got me thinking. I am higher altitude so we have 85 octane as our regular here. Since the manual calls for 87, I've always just used the mid-grade 87 octane, plus you never know when you might be going to a lower elevation.

When I had that loaner 2019 GT, I was struck at just how freaking sluggish to accelerate the damn thing was compared to my 2014 CX-5. Figuring they are putting 85 octane in it, think that could be one of the reasons?

The 85 should act like 87 up here, but I just don't know enough about that stuff and have just always stuck with what the manual said to use.
 
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If you had 85 in it and took it to a lower elevation, which is what I'm guessing is what you're saying, then yes. It would've detected the engine knocking and pulled timing until it stopped which would've decreased the power.
 
I can't remember if I asked the last time this came up, but do you remember how many miles were on the loaner? Maybe it just hadn't been driven enough in those conditions.

Additionally, maybe it only felt sluggish because the Gen2 is more refined (and/or produces less feedback) than the Gen1.
 
I can't remember if I asked the last time this came up, but do you remember how many miles were on the loaner? Maybe it just hadn't been driven enough in those conditions.

Additionally, maybe it only felt sluggish because the Gen2 is more refined (and/or produces less feedback) than the Gen1.

I want to say 3300-3500 miles on the odometer.

See people say this, but I've seen the Gen 1 vs. Gen 2 video accelerate from a stop. Gen 1 wins handily.

I don't know. As a spirited driver, once up to speed sure they felt largely the same, but to get up to that speed, there was a HUGE difference in feeling between my 2014 and the 2019. Besides the fact the 2014 is used to my driving style, and the added weight, "refinement" of the Gen2, just trying to figure out what other variables possibly contributed.

I've always seen these discussion of 87 vs 91 or 93, but I wonder the 85 vs. 87 in a place like Colorado.
 
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This fuel grade thread got me thinking. I am higher altitude so we have 85 octane as our regular here. Since the manual calls for 87, I've always just used the mid-grade 87 octane, plus you never know when you might be going to a lower elevation.

When I had that loaner 2019 GT, I was struck at just how freaking sluggish to accelerate the damn thing was compared to my 2014 CX-5. Figuring they are putting 85 octane in it, think that could be one of the reasons?

The 85 should act like 87 up here, but I just don't know enough about that stuff and have just always stuck with what the manual said to use.

What happens to yours when you put 85 in it?
 
Film a 0-80 run with each! A wrx owner did it with 87 vs 93, and had a 0.8 second repeatable difference! (7 vs 6.2 to 60mph!)

turbo, designed for hi test.

But, that's a better way than "feelings". Video is great; a stop watch is great, too. 0-60 should be plenty. Repeat it several times with each tank to get averages, try to keep environmental factors as close as you can.

Report both raw numbers AND feelings. And have fun stomping it in the name of science. :)
 
I want to say 3300-3500 miles on the odometer. That should be more than enough mileage for the typical driver to establish the typical shift patterns in your area, so I think we can rule that out.

See people say this, but I've seen the Gen 1 vs. Gen 2 video accelerate from a stop. Gen 1 wins handily. No doubt about that, I've seen it as well. I'm just saying that the fact that the Gen1 is slightly faster, paired with the "refinement" of the Gen2, is what makes the difference feel so significant. I'm sure that if you did some timed comparisons, the numbers would be much closer than they feel via butt dyno.

I don't know. As a spirited driver, once up to speed sure they felt largely the same, but to get up to that speed, there was a HUGE difference in feeling between my 2014 and the 2019. Besides the fact the 2014 is used to my driving style, and the added weight, "refinement" of the Gen2, just trying to figure out what other variables possibly contributed.

I've always seen these discussion of 87 vs 91 or 93, but I wonder the 85 vs. 87 in a place like Colorado. I think the use of 85 does play a part. The engine probably accounts for the lower octane by retarding timing.
 
My brother drives a 2016 CX-5 and it definitely feels lighter and spry compared to my vehicle in terms of acceleration and spirited driving. The only downside I had was the noticeable wind noise at 80mph on the freeway.
 
I've always seen these discussion of 87 vs 91 or 93, but I wonder the 85 vs. 87 in a place like Colorado. I think the use of 85 does play a part. The engine probably accounts for the lower octane by retarding timing.

The reason they sell 85 up there is that it's supposed to have the same resistance to preignition as 87 at sea level, right? So there's be no reason to retard the timing, because it shouldn't be pinging.

The ECU doesn't have a clue what octane you put in there, it only knows if combustion is "normal" or not.

Get us some real world Denver data, CD!
 
Not sure how I'd safely video while driving, so don't count on that.

But I'll give my current tank of 87 and a few tanks of 85 a whirl and see what happens.
 
Not sure how I'd safely video while driving, so don't count on that.

But I'll give my current tank of 87 and a few tanks of 85 a whirl and see what happens.

Hire an extra hand from the Home Depot parking lot to film it
 
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