I've read many posts about how safe it is to NOT use the 93 octane our manuals recommend. Some say it's not that bad, others warn against it with horror stories. I found this on accident on You Tube and thought it did a great job of explaining octane on a chemical level in addition to an engine performance and safety level.
http://youtu.be/UPaUlfKHzUM
OCTANE - EXPLAINED
Re: OCTANE - EXPLAINED
Nice video larz
I use 93 all the time, never had a problem.
I even have the Uprev tune which I can run 89, stock or 93.
I see nothing wrong with using 91 on the M's
I use 93 all the time, never had a problem.
I even have the Uprev tune which I can run 89, stock or 93.
I see nothing wrong with using 91 on the M's
Re: OCTANE - EXPLAINED
If there are three buttons I pick the far right, if there are four I pick second to last on the far right...either way I think that is always 91. But from what this vid states, it looks like I can go to 89 with no issue and save a crap load of money since I'm not driving a porche.
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svard75
- Posts: 1564
- Joined: Mon May 11, 2009 3:26 am
- Car: 06 M35x
- Location: Toronto, Ontario, Canada
Re: OCTANE - EXPLAINED
Our ECU's are intelligent enough to be able to adjust the timing and the Variable Valve Technology to accommodate lower octane fuel, however if you bump the octane up to 91 or higher again the ECU can compensate to create a better, stronger burn by advancing the timing and closing the valves to provide the full 10.3:1 stock compression ratio the VQ35DEs have (10.5:1 for the V8). This would create a detonation condition using Regular fuel, however with knock sensors our ECU can retard the timing so that the valves are still slightly open during combustion therefor lowering the actual effective compression ratio.
Since my uprev was tuned on 91 octane fuel I have been using 94 octane with good results for both fuel economy and performance. Now the fuel economy is not sufficient to compare someone using 87 octane in terms of money economy but I'll blow the pants off an M35 with 87 octane in the performance arena
Since my uprev was tuned on 91 octane fuel I have been using 94 octane with good results for both fuel economy and performance. Now the fuel economy is not sufficient to compare someone using 87 octane in terms of money economy but I'll blow the pants off an M35 with 87 octane in the performance arena
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The00Dustin
- Posts: 1041
- Joined: Mon Jun 29, 2009 4:05 am
- Car: 2006 Infiniti M45
- Location: Bloomington, IN
Re: OCTANE - EXPLAINED
When a vehicle's manual mentions a higher octane, it usually specifies what octane. I had a 94 Chrysler LHS that required 89 octane and a 98 Buick Park Avenue Ultra that required 91 Octane. When a vehicle requires a specific octane, lower octane can cause damage. When a specific octane is recommended, a lower octane will not cause damage, but it also will not provide the advertised performance levels. In the 06 M35, higher octane is recommended (don't know which because I don't have that manual) for better performance, it is not required. In the 06 M45, 91 is required, and the manual specifically states that you should get the minimum amount you need vs filling up and subsequently drive gently so as to not cause damage if the required octane is unavailable and you must get a lower octane to continue your journey.
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szh
- Posts: 15932
- Joined: Tue Jul 23, 2002 12:54 pm
- Car: 2018 Tesla Model 3.
Unfortunately, no longer a Nissan or Infiniti, but continuing here at NICO! - Location: San Jose, CA
Re: OCTANE - EXPLAINED
I can't find 93 here in California, so use 91 Premium in my car. I assume that folks use the 93 in other parts of the country. 
My opinion: if a car requires 91, then stick with that rather than going to 89, or worse yet, 87. For a car that is designed for 87 or 89, then using that lower octane is probably fine.
Yes, in theory, the engine management computer can prevent serious knock and damage when using lower octane, but till the knock sensors kick in, the correction does not happen immediately. So, what often happens is "silent pinging" with reduced gas which we don't hear inside our well-sealed cars. BUT, this silent pinging is damaging the engine in minute ways and reducing its overall longevity.
Since I keep my cars for long periods, I want it to perform mechanically as close to original new as I can keep it.
FWIW, the looks I don't give a darn about ... so dings and scratches are a "shrug" moment after the first few.
Finally, with my miles per month, and the current difference of about 20 cents per gallon difference between 91 and 87, I would only "save" about $15 to $25 per month maximum. Why should I bother using 87 when my car manuals asks for 91? If that amount of money was a concern to me, I would not have bought a semi-luxury car.!
Bottom line: if the manuals says "use premium", do so. If it says "use 87", then stick with 87. Using higher octane than the mftr spec will not really help much from a performance perspective. However, using higher may prevent the occasional bad gas (and those do happen!) situations from hurting your engine.
Z
My opinion: if a car requires 91, then stick with that rather than going to 89, or worse yet, 87. For a car that is designed for 87 or 89, then using that lower octane is probably fine.
Yes, in theory, the engine management computer can prevent serious knock and damage when using lower octane, but till the knock sensors kick in, the correction does not happen immediately. So, what often happens is "silent pinging" with reduced gas which we don't hear inside our well-sealed cars. BUT, this silent pinging is damaging the engine in minute ways and reducing its overall longevity.
Since I keep my cars for long periods, I want it to perform mechanically as close to original new as I can keep it.
FWIW, the looks I don't give a darn about ... so dings and scratches are a "shrug" moment after the first few.
Finally, with my miles per month, and the current difference of about 20 cents per gallon difference between 91 and 87, I would only "save" about $15 to $25 per month maximum. Why should I bother using 87 when my car manuals asks for 91? If that amount of money was a concern to me, I would not have bought a semi-luxury car.
!Bottom line: if the manuals says "use premium", do so. If it says "use 87", then stick with 87. Using higher octane than the mftr spec will not really help much from a performance perspective. However, using higher may prevent the occasional bad gas (and those do happen!) situations from hurting your engine.
Z
