MPG's on 89 vs. 91
Joined: Mar 2008
Posts: 486
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From: Glendale,CA
MPG's on 89 vs. 91
I decided to pump a full tank of 89 octane at Chevron last week to test for differences in MPG & performance and compare it to that of 91 octane at Shell. Here are the results in the first 50 miles of driving.
With 89 octane, my average MPH was 27.7 and MPG was 18.8
With 91 octane and the same style driving the average MPH was 16 and MPG was 15.5.
No noticeable loss in performance or "pinging". I knew what I was getting into when I upgrade from my 4cyl. 00' Celica GT to a 6 cyl. 08' G35. But I never expected to see any difference by pumping a mid grade octane compared to a premium octane.
Any opinions fellas?
With 89 octane, my average MPH was 27.7 and MPG was 18.8
With 91 octane and the same style driving the average MPH was 16 and MPG was 15.5.
No noticeable loss in performance or "pinging". I knew what I was getting into when I upgrade from my 4cyl. 00' Celica GT to a 6 cyl. 08' G35. But I never expected to see any difference by pumping a mid grade octane compared to a premium octane.
Any opinions fellas?
The ECU will pull timing with lower grade fuel.
Keep in mind, you ARE losing power and MPG with lower octane, because the engine is not running at maximum efficiency.
The ECU can only do so much, and low grade fuel WILL eventually cause damage to the engine.
Just because you don't hear or feel pinging does not mean it is not happening; it has to occur before the ECU pulls timing. The knock sensor built into the car is MUCH more sensitive than the human ear.
Keep in mind, you ARE losing power and MPG with lower octane, because the engine is not running at maximum efficiency.
The ECU can only do so much, and low grade fuel WILL eventually cause damage to the engine.
Just because you don't hear or feel pinging does not mean it is not happening; it has to occur before the ECU pulls timing. The knock sensor built into the car is MUCH more sensitive than the human ear.
89 grade gas in a 40k car??
I give you credit for even doing this I would NEVER put 89 in my car no matter what I was looking at. The damage that you coiuld cause is not worth it. An yes you would not hear any pining unless you have my old car 04 Max just traded dealer could not fix it 5 times..
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Joined: Aug 2008
Posts: 47
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From: Nashville, TN
So... Here in Nashville gas has been scarce lately and I really needed some. I filled up with 89 since that was all that was available and put an octane booster in it from Advance Auto. I should be OK, right?
Originally Posted by Rizzagt22
I decided to pump a full tank of 89 octane at Chevron last week to test for differences in MPG & performance and compare it to that of 91 octane at Shell. Here are the results in the first 50 miles of driving.
With 89 octane, my average MPH was 27.7 and MPG was 18.8
With 91 octane and the same style driving the average MPH was 16 and MPG was 15.5.
No noticeable loss in performance or "pinging". I knew what I was getting into when I upgrade from my 4cyl. 00' Celica GT to a 6 cyl. 08' G35. But I never expected to see any difference by pumping a mid grade octane compared to a premium octane.
Any opinions fellas?
With 89 octane, my average MPH was 27.7 and MPG was 18.8
With 91 octane and the same style driving the average MPH was 16 and MPG was 15.5.
No noticeable loss in performance or "pinging". I knew what I was getting into when I upgrade from my 4cyl. 00' Celica GT to a 6 cyl. 08' G35. But I never expected to see any difference by pumping a mid grade octane compared to a premium octane.
Any opinions fellas?
your average speed difference gives your test zero credibility. An average of 16MPH indicates a some major stop and go traffic. Do a highway test and report back your results.
Joined: Feb 2006
Posts: 13,068
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From: Southern Cali --> 818
Originally Posted by Mike@RiversideInfiniti
The ECU will pull timing with lower grade fuel.
Keep in mind, you ARE losing power and MPG with lower octane, because the engine is not running at maximum efficiency.
The ECU can only do so much, and low grade fuel WILL eventually cause damage to the engine.
Just because you don't hear or feel pinging does not mean it is not happening; it has to occur before the ECU pulls timing. The knock sensor built into the car is MUCH more sensitive than the human ear.
Keep in mind, you ARE losing power and MPG with lower octane, because the engine is not running at maximum efficiency.
The ECU can only do so much, and low grade fuel WILL eventually cause damage to the engine.
Just because you don't hear or feel pinging does not mean it is not happening; it has to occur before the ECU pulls timing. The knock sensor built into the car is MUCH more sensitive than the human ear.
Originally Posted by twin001
your average speed difference gives your test zero credibility. An average of 16MPH indicates a some major stop and go traffic. Do a highway test and report back your results.
.
I just filled up yesterday at $3.75 (cheapest in my area)
Average for 91 is about $3.9x.
www.gasbuddy.com
Average for 91 is about $3.9x.
www.gasbuddy.com