Your just wasting money if you don't use premiuim
i have done back to back tests on a few different occasions and noted no difference between 85 (in the mountains) 87, and 91, 92, 93. One of those tests was conducted earlier this month when I drove back from the west coast to chicago. Because of the results of those couple tests, I haven't put premium in my daily driver 4th gens in years except for experimentation purposes.
I also set the stock 4th gen 1/4 mile record multiple times (meaning I set it, VeeTec broke it, I set it again, and then I went and beat the record I already held) running 87 octane...
I also set the stock 4th gen 1/4 mile record multiple times (meaning I set it, VeeTec broke it, I set it again, and then I went and beat the record I already held) running 87 octane...
i am going to give you the benefit of the doubt and assume there is something wrong with your keyboard. typical oem turbo or SC engine is around 5:1 compression? maybe you meant 8.5:1... I hope.
Junior Member
Joined: Feb 2011
Posts: 35
From: Pawtucket RI
octane has nothing to do with better mpgs, it will give a little better performance, i have a 99 5 speed gxe that can get 520 on a tank of 87 with my luggage and tools for work which are prob about 150 pounds, never saw an increase in mpg with premium i did notice it got a little better performance but very little not worth the extra price when i drive almost 800-1000 miles a week,in short you use it or you dont, no need to bust someonelses ***** about the fuel they use worry about you.i got my 12 year old car for 550 dollars and have no desire to pay for premium for no mpg gains, also never had a knock or knock sensor code or any other cel besides the precat code,stupid cali cars
But you already know where I'm gettin at with that.
The mileage gains are not a product of the greater octane, but rather a product of the advanced timing. Your engine doesn't knock (detonate), because you have a functioning knock sensor. Bypass it with a resistor and see how you do on regular pump gas. What you are saying is correct in most cases, however not in the case of the VQ30.
I have a bypass as well, and I can make it knock if I really want it too. Hell mine probably knocks every day at a low enough level I just can't sense it.
Bottom line, its not a myth, but rather a common misconception.
EXACTLY, and it makes that adjustment BEFORE it is audible to the human ear. Thus, the engine doesnt knock running regular AFAYK. The VQ will knock with regular fuel, and retard the timing, thereby losing HP and MPG, and you would never even know it, except by watching your MPG and dyno pulls (which have both been done and proved my ORGers).
I have a bypass as well, and I can make it knock if I really want it too. Hell mine probably knocks every day at a low enough level I just can't sense it.
Bottom line, its not a myth, but rather a common misconception.
I have a bypass as well, and I can make it knock if I really want it too. Hell mine probably knocks every day at a low enough level I just can't sense it.
Bottom line, its not a myth, but rather a common misconception.
my point was to dispute someone's claim that running 87 octane means you are automatically going to get mediocre performance. 93mph in rather average air, and 94.5mph in good air in a stock 4th gen on multiple trips to the track proves that adequately enough for me to be a believer that my cars have run just fine on 87 octane.
my point was to dispute someone's claim that running 87 octane means you are automatically going to get mediocre performance. 93mph in rather average air, and 94.5mph in good air in a stock 4th gen on multiple trips to the track proves that adequately enough for me to be a believer that my cars have run just fine on 87 octane.
But... eh... well I quit, cause yes there are cases/environments/situations where the increased knock protection do not matter, because there's a lovely combination of factors which lead to the air entering your motor where you do not need it... for me on the other hand in my car's two environments (Kansas & Texas) it needs all it can get.
I guess i'll retract and say.
Run what you run, I know I'll always run 93.
Last edited by aackshun; Oct 27, 2011 at 01:53 PM.
Thread Starter
Member
Joined: Mar 2010
Posts: 242
From: Denver From Houston Lived in Boston
For those against using prem gas. One thing you didn't note was that my driving was 100% in the city. A crowed city at that. Stop and go traffic, people crossing the street and getting caught behind those damn buses. Lots of hills too.
Wait, is there some funny math going on? I thought we had 3.0 liters? That says we only have 2.98785338 liters.
Is it like, when I buy a 500 GB harddrive, it's actually 488.28125 GB?
Dr J
ps: how do i turn off sarcasm on .org?
Is it like, when I buy a 500 GB harddrive, it's actually 488.28125 GB?
Dr J
ps: how do i turn off sarcasm on .org?
for those who are calculating their mpg based on really long road trips you have to be careful with that. for example, for the orger that calculated his mileage based on a trip from fort meyers, florida up to asheville, north carolina on one octance, and then from north carolina back to fort meyers, fl using a different octane, you might have to consider that driving from florida to asheville, north carolina is literally uphill, and downhill on the way back. so that may have some affect. maybe negligible, but im sure it does have a bigger impact on some cross country trips.
either way, i calculated my mpg to be around 22 all highway, so i dont even care anymore. sigh
either way, i calculated my mpg to be around 22 all highway, so i dont even care anymore. sigh
for those who are calculating their mpg based on really long road trips you have to be careful with that. for example, for the orger that calculated his mileage based on a trip from fort meyers, florida up to asheville, north carolina on one octance, and then from north carolina back to fort meyers, fl using a different octane, you might have to consider that driving from florida to asheville, north carolina is literally uphill, and downhill on the way back. so that may have some affect. maybe negligible, but im sure it does have a bigger impact on some cross country trips.
either way, i calculated my mpg to be around 22 all highway, so i dont even care anymore. sigh
either way, i calculated my mpg to be around 22 all highway, so i dont even care anymore. sigh
but when your slow, and you get 20mpg city. it sucks.
Junior Member
Joined: Sep 2011
Posts: 70
Unleaded and premium aren't related, it's the octane that matters, when they say unleaded only, they mean don't use diesel, all regular gasoline for regular cars is unleaded.
People seem to think unleaded only means 87
I suspect Spd85 is going to need a re-tune, because other guys on S/C'ers still get their original highway mileage.
Mo.... Man.... Yeah.... Not even going to attempt that one.
Quoted from another forum:
Our cars aren't made for 87 but they can run on it daily driving. One factor that is a changing variable would be mods and upkeep. It is possible for someone running 87 for awhile to put in 91/93 and say they haven't seen a difference in gas mileage or performance. By my experience and observation knock sensors can be pretty inconsistent vehicle to vehicle, meaning there are knock sensors that work intermittently (when it is on it's way out). Also the install of the sensor, it could be torqued too tight or not tight enough causing inconsistency of performance or mileage.
-The working knock sensor retards the timing, "if" it detects knock. This depends on your driving style and the quality of 87 you use. AM/PM 87 octane vs Chevron 87 octane will probably yield different mileage and performance results.
-Tire pressure is a factor in gas mileage, vehicle loads, drivers, rim and tire weights, air filter element condition, oil condition, engine condition also (carbon build up and spark plug condition) so opinions and results will be all over the map especially using different maximas.
-I say mods because of intakes and exhausts. Mandrel bend exhausts vs crush bends, 2.25" vs 2.5" vs 3".
-Test factors will vary, elevation and ambient air temps. There is a reason gas companies change blends depending on the season.
-Ethanol blends kills gas mileage. It is only added for emission reading benefits. If it takes almost double the amount of e85 to give the same power as gas, you do the math. Some stations say up to 10% ethanol content used. 10% of 10 gal=1 gal. Your combustion was cooler but you lost mpg because we are not tuned for e85.
In short, run what you want to run because you know your car. If your car runs fine on 87 no issues, run it, but if you can tell the performance is down and you are not used to it, run higher octane. I ran 87 once when I was NA. Once was enough for me not to do it again.
You do not get more power from higher octane. Octane is a measure of "how much" octane (vs. heptane) is in a given amount of gasoline. Octane compresses better than heptane, so a gas with more octane will be able to be compressed further before it naturally combusts. The compression allows more power to be utilized from the gas, but since you cannot change the amount of compression in your cylinders, you do not get more power from higher octane gasoline than what your motor is made for.
An exception to this is a tune. If you advance timing, etc for a specific octane level, you will get more power.
I have a hypothesis though: Since octane is resistance to combustion by compression, if you tune your car for 89 or 93 and put 87 in the tank (stupid, but possibly necessary) I think the only detrimental effect will be loss of power. By that I mean you will not get knock, because the engine is built for 87 octane (compression-wise). Your timing just wouldn't be optimized for it.
An exception to this is a tune. If you advance timing, etc for a specific octane level, you will get more power.
I have a hypothesis though: Since octane is resistance to combustion by compression, if you tune your car for 89 or 93 and put 87 in the tank (stupid, but possibly necessary) I think the only detrimental effect will be loss of power. By that I mean you will not get knock, because the engine is built for 87 octane (compression-wise). Your timing just wouldn't be optimized for it.
-The working knock sensor retards the timing, "if" it detects knock. This depends on your driving style and the quality of 87 you use. AM/PM 87 octane vs Chevron 87 octane will probably yield different mileage and performance results.
-Tire pressure is a factor in gas mileage, vehicle loads, drivers, rim and tire weights, air filter element condition, oil condition, engine condition also (carbon build up and spark plug condition) so opinions and results will be all over the map especially using different maximas.
-I say mods because of intakes and exhausts. Mandrel bend exhausts vs crush bends, 2.25" vs 2.5" vs 3".
-Test factors will vary, elevation and ambient air temps. There is a reason gas companies change blends depending on the season.
-Ethanol blends kills gas mileage. It is only added for emission reading benefits. If it takes almost double the amount of e85 to give the same power as gas, you do the math. Some stations say up to 10% ethanol content used. 10% of 10 gal=1 gal. Your combustion was cooler but you lost mpg because we are not tuned for e85.
In short, run what you want to run because you know your car. If your car runs fine on 87 no issues, run it, but if you can tell the performance is down and you are not used to it, run higher octane. I ran 87 once when I was NA. Once was enough for me not to do it again.
I suspect all those other guys Are lying lol. With 440s, walbro 255, and a 2.62 pulley forcing in so much more air i just dont see it getting any better. My cruising afr on the highway is right at 15.0 too. Eh, ive learned to deal with it.
Quoted from another forum:
Our cars aren't made for 87 but they can run on it daily driving. One factor that is a changing variable would be mods and upkeep. It is possible for someone running 87 for awhile to put in 91/93 and say they haven't seen a difference in gas mileage or performance. By my experience and observation knock sensors can be pretty inconsistent vehicle to vehicle, meaning there are knock sensors that work intermittently (when it is on it's way out). Also the install of the sensor, it could be torqued too tight or not tight enough causing inconsistency of performance or mileage.
-The working knock sensor retards the timing, "if" it detects knock. This depends on your driving style and the quality of 87 you use. AM/PM 87 octane vs Chevron 87 octane will probably yield different mileage and performance results.
-Tire pressure is a factor in gas mileage, vehicle loads, drivers, rim and tire weights, air filter element condition, oil condition, engine condition also (carbon build up and spark plug condition) so opinions and results will be all over the map especially using different maximas.
-I say mods because of intakes and exhausts. Mandrel bend exhausts vs crush bends, 2.25" vs 2.5" vs 3".
-Test factors will vary, elevation and ambient air temps. There is a reason gas companies change blends depending on the season.
-Ethanol blends kills gas mileage. It is only added for emission reading benefits. If it takes almost double the amount of e85 to give the same power as gas, you do the math. Some stations say up to 10% ethanol content used. 10% of 10 gal=1 gal. Your combustion was cooler but you lost mpg because we are not tuned for e85.
In short, run what you want to run because you know your car. If your car runs fine on 87 no issues, run it, but if you can tell the performance is down and you are not used to it, run higher octane. I ran 87 once when I was NA. Once was enough for me not to do it again.
Our cars aren't made for 87 but they can run on it daily driving. One factor that is a changing variable would be mods and upkeep. It is possible for someone running 87 for awhile to put in 91/93 and say they haven't seen a difference in gas mileage or performance. By my experience and observation knock sensors can be pretty inconsistent vehicle to vehicle, meaning there are knock sensors that work intermittently (when it is on it's way out). Also the install of the sensor, it could be torqued too tight or not tight enough causing inconsistency of performance or mileage.
-The working knock sensor retards the timing, "if" it detects knock. This depends on your driving style and the quality of 87 you use. AM/PM 87 octane vs Chevron 87 octane will probably yield different mileage and performance results.
-Tire pressure is a factor in gas mileage, vehicle loads, drivers, rim and tire weights, air filter element condition, oil condition, engine condition also (carbon build up and spark plug condition) so opinions and results will be all over the map especially using different maximas.
-I say mods because of intakes and exhausts. Mandrel bend exhausts vs crush bends, 2.25" vs 2.5" vs 3".
-Test factors will vary, elevation and ambient air temps. There is a reason gas companies change blends depending on the season.
-Ethanol blends kills gas mileage. It is only added for emission reading benefits. If it takes almost double the amount of e85 to give the same power as gas, you do the math. Some stations say up to 10% ethanol content used. 10% of 10 gal=1 gal. Your combustion was cooler but you lost mpg because we are not tuned for e85.
In short, run what you want to run because you know your car. If your car runs fine on 87 no issues, run it, but if you can tell the performance is down and you are not used to it, run higher octane. I ran 87 once when I was NA. Once was enough for me not to do it again.
/End thread
Junior Member
Joined: Apr 2010
Posts: 86
From: South Florida
I'm also going to chime in and say that local temperate zones make a difference as well. somebody up here said they get 520 or so miles per tank and they're from Rhode Island. My car is running excellently, but I live in disgusting muggy and humid south Florida and it definitely makes a difference. I grew up in NY, have driven my cars to and from, and have ALWAYS noticed way better engine performance in the north.
Just food for thought...
Just food for thought...
-Ethanol blends kills gas mileage. It is only added for emission reading benefits. If it takes almost double the amount of e85 to give the same power as gas, you do the math. Some stations say up to 10% ethanol content used. 10% of 10 gal=1 gal. Your combustion was cooler but you lost mpg because we are not tuned for e85.
Same with e85. It's cheaper at the pump, but there's less stored energy, which makes it cost more in the long run.
Hence, the title of the thread: "Your just wasting money if you don't use premiuim"
Dr J
Senior Member
Joined: May 2010
Posts: 625
From: Connecticut
lol! no they mean don't use "leaded" fuel! look up "Tetraethyllead"
He may be younger and not remember leaded gas at the pump. But since it's been, what, decades? since leaded was available at the pump, his assumption about it keeping people from trying to put diesel in their car may be partly accurate.
Senior Member
Joined: May 2010
Posts: 625
From: Connecticut
lol yeah never thought about that, i guess it still serves a purpose. should be "gasoline" only on our fuel doors.
wait isnt the diesel fuel nozzle much larger and wont fit into "gas" tanks?
Last edited by Br0nz; Oct 29, 2011 at 07:22 AM.
Thread Starter
Member
Joined: Mar 2010
Posts: 242
From: Denver From Houston Lived in Boston
If we are staying true to the original post, this's what this thread is about. You get better performance using Premium, so much better performance that it's actually cheaper to use Premium over regular.
Same with e85. It's cheaper at the pump, but there's less stored energy, which makes it cost more in the long run.
Hence, the title of the thread: "Your just wasting money if you don't use premiuim"
Dr J
Same with e85. It's cheaper at the pump, but there's less stored energy, which makes it cost more in the long run.
Hence, the title of the thread: "Your just wasting money if you don't use premiuim"
Dr J
If we are staying true to the original post, this's what this thread is about. You get better performance using Premium, so much better performance that it's actually cheaper to use Premium over regular.
Same with e85. It's cheaper at the pump, but there's less stored energy, which makes it cost more in the long run.
Hence, the title of the thread: "Your just wasting money if you don't use premiuim"
Dr J
Same with e85. It's cheaper at the pump, but there's less stored energy, which makes it cost more in the long run.
Hence, the title of the thread: "Your just wasting money if you don't use premiuim"
Dr J
The difference between reg gas and prem is around 20 cent. I do 100% city driving and I was getting a little over 18mpg on reg gas. I just moved to a new city and do alot more driving now. I thought using the cheapest gas would save me money but it was actually costing me an extra 5/6 bucks a month. I put in prem last month and filled up today. I got 21.3 MPG would have been higher if I didn't have to use the heat. I think that's pretty wonderful for 100 percent city driving in a place like Denver.
From my calculations in order for it to be worth the extra for prem I would need to get 31 more miles to the tank, with todays fill up I got an extra 55.5 miles to the tank using prem. I had been wasting 5 bucks a month before. Not the mention the restored power. I have a good knock sensor, I replaced it with an ebay one last feb.
From my calculations in order for it to be worth the extra for prem I would need to get 31 more miles to the tank, with todays fill up I got an extra 55.5 miles to the tank using prem. I had been wasting 5 bucks a month before. Not the mention the restored power. I have a good knock sensor, I replaced it with an ebay one last feb.
You're
Newbie - Just Registered
Joined: May 2010
Posts: 1
Question re: your Nissan's and purchasing methods
Thanks for sharing if you are able.
Junior Member
Joined: Jun 2011
Posts: 20
From: Fort Huachuca, Arizona
I bet diesel will clean the motor pretty good......im gonna try that next time I fuel up. Clean motor means great gas mileage. I also think "the man" tries to lie to us so that "unleaded fuel recommended" on the gas filler door is a all just a ruse..... lol 
How do I turn off sarcasm in here?
Oh, and for the OP: I think that you are most likely correct about the grade having an effect on your car. Its hard for numbers to lie...so long as they are calculated correctly.
How do I turn off sarcasm in here?
Oh, and for the OP: I think that you are most likely correct about the grade having an effect on your car. Its hard for numbers to lie...so long as they are calculated correctly.