What Fuel?
08-12-2010, 03:06 PM
#43
Senior Moderator
i dont know how compression relates to octane, my last motorcycle (sportbike) was pushing 13:1 compression ratio and it was recommended 87 octane...
i will only put premium fuel in my acura, but my mom is driving a tsx that she has had since 06 and only uses 89 octane and has never used premium and the car has 100k miles on it and runs like a champ...i keep telling her to put premium in it and she will get better miliage, but she doesnt care....
i will only put premium fuel in my acura, but my mom is driving a tsx that she has had since 06 and only uses 89 octane and has never used premium and the car has 100k miles on it and runs like a champ...i keep telling her to put premium in it and she will get better miliage, but she doesnt care....
08-12-2010, 04:22 PM
#44
I can't comment on sport bikes since I have almost no knowledge about them, but car engines with high compression, 87 or 89 will ignite before the piston has reached it's top point when the spark ignites the fuel. What this does is put a huge amount of force on the piston, valves, rods, and crankshaft. Over time this force can seriously damage the engine.
a combustion engine is a combustion engine, size wouldnt matter for this comparo...
08-13-2010, 03:12 PM
#45
Senior Moderator
The size of the cylinder and the RPMs of the engine play into the requirement [octane] heavily also. If you think about it rationally, the time for one cylinder of a 600cc 4 cylinder (149cc per cylinder) spinning at 10k RPM to be able to predetonate is pretty short (about 1/320th of a second). It also has a quite small surface area to produce heat concentrations at, with fresh fuel-air charge being crammed in (cooling down the cylinder) every 1/84th of a second at 10k RPM. By comparison, a chevy 350 V-8 running at 3k RPM has a 716.9cc cylinder, and is taking in a fresh charge every 1/25th of a second. That's a lot of difference in heat exposure times, both in terms of how long the detonation product is left in the cylinder to heat the cylinder up, and in terms of how often fresh (cool) charges are sucked in. Thus, in situations where the compression ratio would dictate a nominal 93 octane rating, a much smaller cylinder that cycles at a much higher rate may be able to get away with a few points less, such as a 91 octane rating
08-13-2010, 09:02 PM
#46
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Come on guys, lets kick this thread up a notch! Do you only put name brand gas(Exxon, Mobil, Sunoco) in your car or do you think the generic brands(BJ's, Costco) are good enough? I don't think I've seen this ageless debate in the 4th generation forums yet.
08-14-2010, 07:31 AM
#48
Pro
I would only use gasoline from the list of this website www.toptiergas.com
08-14-2010, 09:20 AM
#49
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I've tried to stick to Shell fuels for all my cars (I've only had 3).
But my last car was an 05 TL Base and I always used V-Power, here it's 93 Octane, if I was on a trip and couldn't get to a Shell I'd use BP as a backup as around here their highest grade (Ultimate) is also 93 Octane with then invigorate stuff. I'm planning to do the same with the 2010 TL SH-AWD, so far I've always used V-Power.
But my last car was an 05 TL Base and I always used V-Power, here it's 93 Octane, if I was on a trip and couldn't get to a Shell I'd use BP as a backup as around here their highest grade (Ultimate) is also 93 Octane with then invigorate stuff. I'm planning to do the same with the 2010 TL SH-AWD, so far I've always used V-Power.
08-14-2010, 10:43 AM
#50
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08-15-2010, 09:21 PM
#52
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Octane measurement refers to a fuels ability to resist knock, nothing more nothing less. The higher the octane the higher the knock resistance. Higher compression engines require a higher octane rating. The scale is set by Iso-octane being equal to 100 and n-Heptane being equal to 0. Octane’s over 100 are obtained by adding things like tetra-ethyl lead (now illegal) or toluene. This standard is common the world over. In the US we use R+M/2. R refers to the research octane which is basically your car at idle. The M refers to the motor octane which simulates the engine under load. Manufactures recommend the best fuel for your car's engine because they design them to run at that octane. Detergent packages are another story. The EPA sets a minimum detergent level for ALL gasoline. Top tier gasolines add their own additives to 'brand' the fuel i.e. Shell, Chevron...etc. If your owner’s manual says 91 octane then run 91 octane. If you want a clean engine then buy name brand fuel NOT Rotten Robbie or some other cheap stuff.
08-17-2010, 11:52 PM
#55
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In California, all the gas stations(Shell, Mobil, Chev, etc.) pretty much have 87, 89, and 91 octanes. I only use Shell V-Power for my car because from my personal experience I "feel" more power from V-Power compared to fuel from Chevron and Mobil.
08-19-2010, 05:56 PM
#56
10-20-2010, 08:04 AM
#58
10-21-2010, 02:32 PM
#59
Instructor
My salesman actually said to use 87...which I immediately ignored. Used 89 for first few fill ups, then switched to 91 (usually Luk-Oil or Exxon) and its been just over 2 years and car's been solid.
10-21-2010, 02:50 PM
#60
Chevron Supreme 91
Same station, same pump, same direction, filled to the brim
I have never had any problems with any of my vehicles but they have also all required 91 or higher. For me personally it is worth the extra couple of bucks per tank to ensure that the engine is running on what it likes.
I was forced to fill up on 87 one time and the difference was noticeable to me. The car felt sluggish and my mpg's went down for that tank.
I know other people though that drive vehicles requiring 91 and they run 87 in them and say that there is no noticeable difference. Perhaps it is just a placebo effect for me but I feel better running the 91 regardless.
Once per year in the spring when the fuel is switched out from winter blend I run 1 can of BG 44K just to help keep her cleaned out and fresh.
Overkill? especially when running 91 all the time. Possibly, but in my mind it is cheap maintenance.
Same station, same pump, same direction, filled to the brim
I have never had any problems with any of my vehicles but they have also all required 91 or higher. For me personally it is worth the extra couple of bucks per tank to ensure that the engine is running on what it likes.
I was forced to fill up on 87 one time and the difference was noticeable to me. The car felt sluggish and my mpg's went down for that tank.
I know other people though that drive vehicles requiring 91 and they run 87 in them and say that there is no noticeable difference. Perhaps it is just a placebo effect for me but I feel better running the 91 regardless.
Once per year in the spring when the fuel is switched out from winter blend I run 1 can of BG 44K just to help keep her cleaned out and fresh.
Overkill? especially when running 91 all the time. Possibly, but in my mind it is cheap maintenance.
10-21-2010, 02:59 PM
#61
Mademoiselle Chanel!!
10-21-2010, 03:30 PM
#62
I've tried to stick to Shell fuels for all my cars (I've only had 3).
But my last car was an 05 TL Base and I always used V-Power, here it's 93 Octane, if I was on a trip and couldn't get to a Shell I'd use BP as a backup as around here their highest grade (Ultimate) is also 93 Octane with then invigorate stuff. I'm planning to do the same with the 2010 TL SH-AWD, so far I've always used V-Power.
But my last car was an 05 TL Base and I always used V-Power, here it's 93 Octane, if I was on a trip and couldn't get to a Shell I'd use BP as a backup as around here their highest grade (Ultimate) is also 93 Octane with then invigorate stuff. I'm planning to do the same with the 2010 TL SH-AWD, so far I've always used V-Power.
10-21-2010, 06:13 PM
#63
Pro
Chevron Supreme 91
Same station, same pump, same direction, filled to the brim
I have never had any problems with any of my vehicles but they have also all required 91 or higher. For me personally it is worth the extra couple of bucks per tank to ensure that the engine is running on what it likes.
I was forced to fill up on 87 one time and the difference was noticeable to me. The car felt sluggish and my mpg's went down for that tank.
I know other people though that drive vehicles requiring 91 and they run 87 in them and say that there is no noticeable difference. Perhaps it is just a placebo effect for me but I feel better running the 91 regardless.
Once per year in the spring when the fuel is switched out from winter blend I run 1 can of BG 44K just to help keep her cleaned out and fresh.
Overkill? especially when running 91 all the time. Possibly, but in my mind it is cheap maintenance.
Same station, same pump, same direction, filled to the brim
I have never had any problems with any of my vehicles but they have also all required 91 or higher. For me personally it is worth the extra couple of bucks per tank to ensure that the engine is running on what it likes.
I was forced to fill up on 87 one time and the difference was noticeable to me. The car felt sluggish and my mpg's went down for that tank.
I know other people though that drive vehicles requiring 91 and they run 87 in them and say that there is no noticeable difference. Perhaps it is just a placebo effect for me but I feel better running the 91 regardless.
Once per year in the spring when the fuel is switched out from winter blend I run 1 can of BG 44K just to help keep her cleaned out and fresh.
Overkill? especially when running 91 all the time. Possibly, but in my mind it is cheap maintenance.
10-21-2010, 11:21 PM
#64
Instructor
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Technically you can get away with 87-89, as the anti-knock sensors will kick in and I believe alter the firing timing (because lower octanes combust at lower compression). This I've been led to believe lowers your fuel efficiency and horsepower, so that in the end the $$ difference is a wash. Meaning that you save $/gallon with 87 gas but you also lose some mpg.
I have not done the experiment myself but the cost difference between 87 and 91 is not enough for me to go against the owners manual's recommendations.
I've been debating whether Shell vs Chevron is better. I was told that the higher octane gas also contain higher concentrations of detergent. The difference is probably minimal though so I usually just pick the cheaper of the two. That being said I find the talking Shell engineer guy somewhat annoying at their newer stations.
I have not done the experiment myself but the cost difference between 87 and 91 is not enough for me to go against the owners manual's recommendations.
I've been debating whether Shell vs Chevron is better. I was told that the higher octane gas also contain higher concentrations of detergent. The difference is probably minimal though so I usually just pick the cheaper of the two. That being said I find the talking Shell engineer guy somewhat annoying at their newer stations.
10-22-2010, 06:23 AM
#67
Technically you can get away with 87-89, as the anti-knock sensors will kick in and I believe alter the firing timing (because lower octanes combust at lower compression). This I've been led to believe lowers your fuel efficiency and horsepower, so that in the end the $$ difference is a wash. Meaning that you save $/gallon with 87 gas but you also lose some mpg.
I have not done the experiment myself but the cost difference between 87 and 91 is not enough for me to go against the owners manual's recommendations.
I've been debating whether Shell vs Chevron is better. I was told that the higher octane gas also contain higher concentrations of detergent. The difference is probably minimal though so I usually just pick the cheaper of the two. That being said I find the talking Shell engineer guy somewhat annoying at their newer stations.
I have not done the experiment myself but the cost difference between 87 and 91 is not enough for me to go against the owners manual's recommendations.
I've been debating whether Shell vs Chevron is better. I was told that the higher octane gas also contain higher concentrations of detergent. The difference is probably minimal though so I usually just pick the cheaper of the two. That being said I find the talking Shell engineer guy somewhat annoying at their newer stations.
Whether Shell or Chevron, both are Tier 1 gasolines, so you can't go wrong. Tier 1 gasolines (Shell, all Exxon/Mobil, Chevron, Phillips 66/Connocco, NOT BP or Sunoco) will always do you right. They have higher detergent standards and lower particulate standards. For those who do not run Tier 1 gasolines in their car, I would recommend a fuel system treatment every oil change and also I believe you run through fuel filters at a faster rate as well.
10-22-2010, 09:48 AM
#70
If you on avg fill up 2x per month or 26 times a year you are only talking an extra $93.60 per year in fuel. X3
Last edited by TLNV; 10-22-2010 at 09:52 AM.
11-03-2010, 05:43 PM
#71
I was cross shopping the g37 before I bought the TL and the Infiniti salesperson mentioned that all their cars (demos) are filled up with the 89 octane gasoline.
11-04-2010, 10:09 AM
#72
Not always true. Not with motors using a knock sensor. 87 octane is the minimum required but for maximum performance you can use premium fuel. With a knock sensor the engine can benifet from higher octane. timing can be advanced or retarded depending on the octane used. The ECU adjusts the timing. The 03-11 Accord V6's gain HP and TQ using premium fuel over regular unleaded. So do the honda odysseys. It states it in the owners manual of my uncles 00 Honda Odyssey. Now my 98 Accord V6 does not have a knock sensor and will not benifet from any higher octane for extra power.
11-04-2010, 10:20 AM
#73
Started using the Shell at a considerable premium, might go back to Costco. However I've noticed the cars (especially the RDX) run better with the V-power.
11-04-2010, 04:18 PM
#74
"As a thank you for patronizing our dealership we are offering a free tank of gas for you new car!" LOL!
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