Yeah 4 seconds is poop when compared to my 5 second 5000lb SRT10. J/k
Anyone use more than 87 octane gas?
- Thread starter Armchair Bronco
- Start date
Yeah 4 seconds is poop when compared to my 5 second 5000lb SRT10. J/k
what the hell is 86 and 88 octane? (dunno)
I have never seen that and if you heard pinging then your knock sensors are hosed or the gas you got is pure sh1t.
Armchair Bronco
Member
- :
- 2007 Mazda CX-9 GT AWD
I've never seen those values out in the Pacific Northwest, either. Out here, it's 87, 89, and 92.
You will see 85 or 86 at high altitude. An engine needs less octane at higher elevations. It's not unusual to see 86 in Albuquerque, as we sit 5000' above sea level.
OK, so finally after reading all inputs here are my two cents and experiences.
First off the higher the octane the better your engine runs to an extent. The higher the octane the higher the temperature required to detonate the fuel/air mix. Rocker chatter is due to pre-detonation of fuel due to lower octane.
Pre-det is caused by the fuel/air mix detonating before the pistons reach TDC, thus chatter. High alt conditions require less octane rating because of lesser O2, hence slower burning ignition rate.
To state my point, my 9 runs fine on 87 octane; no chatter. So I began experimenting with fuel in Ohio. They offer 93 ocatne. I ran 5 tanks worth through my 9. This being said I have ran 27,000 mile worth of 87 through before testing.
What I have noticed; There is a big diff in response, with 87 when tromping on the accel the vehicle thinks for a sec than wakes up, ripping my head ove the head rest. Having 93 in my tank the vehicle is much more responsive to throttle input.
I cannot believe otherwise that the 9 has some software that compensated for different octane, not that it tastes the gas but that it measures detonation rate.
First off the higher the octane the better your engine runs to an extent. The higher the octane the higher the temperature required to detonate the fuel/air mix. Rocker chatter is due to pre-detonation of fuel due to lower octane.
Pre-det is caused by the fuel/air mix detonating before the pistons reach TDC, thus chatter. High alt conditions require less octane rating because of lesser O2, hence slower burning ignition rate.
To state my point, my 9 runs fine on 87 octane; no chatter. So I began experimenting with fuel in Ohio. They offer 93 ocatne. I ran 5 tanks worth through my 9. This being said I have ran 27,000 mile worth of 87 through before testing.
What I have noticed; There is a big diff in response, with 87 when tromping on the accel the vehicle thinks for a sec than wakes up, ripping my head ove the head rest. Having 93 in my tank the vehicle is much more responsive to throttle input.
I cannot believe otherwise that the 9 has some software that compensated for different octane, not that it tastes the gas but that it measures detonation rate.
Very interesting test results and findings. Thank you.
The "lag" has always been a bit of a drag (no pun intended) when it comes to me zoom-zooming off an exit ramp. For the past few months, I've corrected the problem by using the auto-stick to manually shift the car. No more lag, and it shifts when I want.
Perhaps I'll try a few tanks of 93 and see what improvements I see here in MA.
I'm sure you know it already, but just incase, the "auto-stick" in the CX-9 is still an automatic. There's no clutch. It uses a torque converter. So, it is not "manually" shifting the car.
Big difference between the real "auto-stick" with clutch that rev match on downshift. And now the newer system has dual clutch for even smoother shifting marketed in different names - DSG being one of them used by Audi.
Both you guys are right.
I don't really eliminate the "lag" of lower octane, but I get the same kick by doing a manual shift.
I didn't realize you were 4K feet above sea level. I'm at sea level here outside Boston, so perhaps the octane change won't make much of a difference (except in my wallet).
And yes, I realize it's not REALLY a standard, but it's the closest thing I have to a stick shift and it feels like I am a bit more in control of the performance when I need to zoom zoom.
(rofl2)(rofl2)(rofl2)(rofl2)
Octane
Interesting thread and commentaries but they're all purely anecdotal.
Whether the CX9 can gain any benefit from higher octane fuel depends on whether the engine computer in the vehicle is programmed to allowed it to provide more timing advance if no knock is detected. Honda does do this so running higher octane does result in more HP on most Honda vehicles recommended to use 87 grade.
I don't know if Mazda does this as well or not. They might but I haven't seen a statement from them saying so on the CX9.
My point about anecdotal is that seat of the pants doesn't mean much, if anything.
The only way to prove if the 9 gets any benefit from higher octane is to put the vehicle on a dyno under controlled conditions and actually test it out using the various octanes under those controlled conditions. To prove it conclusively the test would have to be run at a constant air temperature, atmospheric pressure, and humidity running back to back tests using the different grades of fuel and seeing what the dyno readings say. Does higher octane result in more HP and torque to the wheels?
If the engine can leverage the increased octane then there's a benefit in running the fuel. If it can't then higher octane is just a waste of money.
As for hearing any knocking in a modern vehicle the chances are pretty slim unless the knock sensors have failed (which would likely trigger an engine check light and reduced performance anyway). Most vehicles today are performing millions of adjustments per second and would retard timing before we'd even be aware that the knock occurred. The only indication we'd see is reduced power and then only if it was a significant reduction. Small reductions would likely go unnoticed.
For my part I'd stick with running 87 grade unless I had statistical proof or a statement from Mazda saying the engine could make use of the higher octane. This is what Mazda did with the '09 CX7. You can now run them on 87 but will get more horsepower if you run higher octane.
Interesting thread and commentaries but they're all purely anecdotal.
Whether the CX9 can gain any benefit from higher octane fuel depends on whether the engine computer in the vehicle is programmed to allowed it to provide more timing advance if no knock is detected. Honda does do this so running higher octane does result in more HP on most Honda vehicles recommended to use 87 grade.
I don't know if Mazda does this as well or not. They might but I haven't seen a statement from them saying so on the CX9.
My point about anecdotal is that seat of the pants doesn't mean much, if anything.
The only way to prove if the 9 gets any benefit from higher octane is to put the vehicle on a dyno under controlled conditions and actually test it out using the various octanes under those controlled conditions. To prove it conclusively the test would have to be run at a constant air temperature, atmospheric pressure, and humidity running back to back tests using the different grades of fuel and seeing what the dyno readings say. Does higher octane result in more HP and torque to the wheels?
If the engine can leverage the increased octane then there's a benefit in running the fuel. If it can't then higher octane is just a waste of money.
As for hearing any knocking in a modern vehicle the chances are pretty slim unless the knock sensors have failed (which would likely trigger an engine check light and reduced performance anyway). Most vehicles today are performing millions of adjustments per second and would retard timing before we'd even be aware that the knock occurred. The only indication we'd see is reduced power and then only if it was a significant reduction. Small reductions would likely go unnoticed.
For my part I'd stick with running 87 grade unless I had statistical proof or a statement from Mazda saying the engine could make use of the higher octane. This is what Mazda did with the '09 CX7. You can now run them on 87 but will get more horsepower if you run higher octane.
Armchair Bronco
Member
- :
- 2007 Mazda CX-9 GT AWD
When running at idle, is it possible that an engine will run marginaly more smoothly when using gas with higher octane?
not in today's engine that are electronically controlled to the precise hilt especially when new. Down the road with alot of miles on the vehicle and the combustion chamber and valves are carboned up from crap fuel, still no..
You could put 85 octane in your vehicle and at idle see no difference
will your engine run smoother at idle if it gets better gas (regardless of octane level), yes it will. Stick with a brand name fuel and you will do just fine. The speedmarts and pit stops are crap, plain crap and don't let anyone tell you otherwise. I mean you want to buy fuel from a coffee importer (cause that is what you are doing) then be my guest. But I don't think you want that!
Shell, Sunoco, BP, Valero are all excellent.
Have a nice day!
Shell, Sunoco, BP, Valero are all excellent.
Have a nice day!
Armchair Bronco
Member
- :
- 2007 Mazda CX-9 GT AWD
Well, for the last 4 tanks, I've been alternating between 87 and 89 octane. The car *seems* to run ever-so-slightly more smoothly (or at least idle more smoothly) when I'm using 89 octane.
But I can't prove it and my impressions are anecdotal at best...Heck, I'm probably expecting it to run more smoothly, so I've convinced myself that it IS running more smoothly.
Oh well, I'll continue with my informal experiment for a few more tanks. So far, I've spent about $4.00 on this little experiment...
But I can't prove it and my impressions are anecdotal at best...Heck, I'm probably expecting it to run more smoothly, so I've convinced myself that it IS running more smoothly.
Oh well, I'll continue with my informal experiment for a few more tanks. So far, I've spent about $4.00 on this little experiment...
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- 2022 CX-5 Turbo
Just read the news release of 2010 Odyssey. In it, it says that when towing (rated at 3500lbs) premium fuel is recommended. Based on the same reasoning (assuming Honda is not on drugs), when your CX9 is fully loaded or towing, using 89 or 91 may not be a bad idea.
quote:
"Premium unleaded fuel recommended when towing."
quote:
"Premium unleaded fuel recommended when towing."
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- 2022 CX-5 Turbo
If I am not mistaken, you should also take final drive into comparison (from shaft to tire).
Odyssey has a final drive ratio of 4.312 vs CX9's 3.46. When you multiply that numbers with gear ratios, the difference is not as big. Take 1st gear, for example....
CX9: 4.15x3.46 = 14.35.
Odyssey: 2.697x4.312= 11.629
Odyssey has a final drive ratio of 4.312 vs CX9's 3.46. When you multiply that numbers with gear ratios, the difference is not as big. Take 1st gear, for example....
CX9: 4.15x3.46 = 14.35.
Odyssey: 2.697x4.312= 11.629
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- 2022 CX-5 Turbo
In US, AKI is used (R+M)/2. (RON+MON)/2 - see wikipedia for details here
http://en.wikipedia.org/wiki/Octane_rating
In Europe and most Asian countries, RON is used. (usually much migher).
For example, RON 98 ~= AKI 91.
http://en.wikipedia.org/wiki/Octane_rating
In Europe and most Asian countries, RON is used. (usually much migher).
For example, RON 98 ~= AKI 91.
