Premium Unleaded vs. Regular

[ncuster]

Does anyone have any real evidence to show what the difference in power is using 89 vs. 91 or 93 octane fuel?

[Q45tech]

"The 98-99 Honda Odyessys were actually dual specified depending on what kind of gas was in the tank. 205 HP and 217 TQ on 87 octane, but 210 HP and 229 TQ on premium. The new Accord V6 (03+) also works the same way. The official company rating is 240HP/212TQ on 87 octane, but a Honda engineer interviewed in USA Today said that the engine was good for another 10HP/10TQ on premium. Track times from members at V6Performance.net have backed this up. 15.2 @ 91 on 87, but 15.0 @ 93 on premium under similar conditions and nearly identical 60' times. Dyno evidence has also backed this up, although only indirectly because nobody has done a direct back to back comparison of regular vs premium. Even the brochure for the 2002 Honda Pilot (240HP/242TQ on 87) stated that premium fuel was recommended for towing because the engine produces more torque."

http://www.hotrod.com/techarticles/72498/

[ncuster]

Thanks for the info and the link... the article is informative. I might try regular and see if there is a noticeable difference.

[Q45tech]

The major diiferences are the amount of detergents in in grade with premium usually having more per gallon.

The cost to produce premium over regular is ~~5-6 cents per gallon at the refinery................the rest is progressive retail markups due to limited sales volume [takes up the same space]. I noticed Citgo has started breaking away from the retail industry standard of 20 cents more per gallon......they are using 14-16 cents in ATL .

Another Chavez trick? [Citgo is owned by government of Venzuela].

[myg35ss]

Obviously NOT a G35 owner ! Your engine ECM (especially with variable cam timing) is calibrated for the Octane rating in your owners manuel. Significant power loss, detonation and abnormal combustion temperatures(hello converter meltdown!) are only a few results of a decision to use a derated fuel. However if you insist on Regular there are plenty of Escorts on the lots these days.

[C-Kwik]

Obviously NOT a G35 owner ! Your engine ECM (especially with variable cam timing) is calibrated for the Octane rating in your owners manuel. Significant power loss, detonation and abnormal combustion temperatures(hello converter meltdown!) are only a few results of a decision to use a derated fuel. However if you insist on Regular there are plenty of Escorts on the lots these days.

There is little concern with any OEM car of running on regular grade fuel. OEM's tune the cars to be able to run safely on regular grade fuel. Imagine being stuck in the middle of nowhere with no premium fuel available. Even Porsche engineers will state their motors can run on it. There is a slight degredation in power, but with OEM set-ups, you're probably looking at no more than a few HP. Most cars use knock sensors to back off timing so detonation is probably not going to be a big issue. And combution temperatures aren't somehow going to skyrocket. Consider for a moment that a typical person is not at wide open throttle 100% of the time. At cruising, the amount of energy being spilled out the exhaust are going to be significantly lower than at WOT. And even then, how much do you think combustion temps will actually rise? I'd guess the ECU would have to compensate no more than a couple of degrees of timing retard. This isn't going to be that bad.

[elwesso]

The bottom line is... Under decently normal conditions, the car will never knock itself ot death!! if you have an upgraded ECU, different stories obviously

I run premium because thats whats supposed to be run... thats what I did in my old Q... In my current Q i have to do because if i dont i certainly will ping, as I have a chip.

[elwesso]

to the original poster, we have indianapolis meets all the time..... You should check out the central region meets forum...

zeroforum?id=153

[Tictakman]

man, what a newbie question, jk....this is Zak.

Ya gas prices are a PITA arent they...Actually im not sure if you want to go through the extra work and math but you can mix a type of paint addative to low octane gas and get a higher octane out of it. im not sure if anyone can shed some light on it but you can search for the actual chemical and the equation to mix it in...good luck.

Zak

[szh]

One final point to remember is that the cost difference between 87 and 91 is such that the average user only spends about $10 to $15 extra per month - obviously depending on the miles you drive.

For some folks, every penny counts, yes. But (particularly since I can afford it), my philosophy is that I'd rather spend that extra $10 to $15 and (a) stress the engine less trying to compensate for the lower rating and/or bad gas, and (b) enjoy the end result of better performance!

Now, going higher octane than what is recommended as normal by the mftr for the car is probably a waste.

Z

[myg35ss]

Atta boy !

If their is someone here that is stressing over $10--$15 monthly in fuel costs their momma probably bought the car (so borrow it from her!)

I'm disappointed to see this kind of posting in a group of folks successful and tasteful enough to own one of the most prestigeous automobiles ever produced for the middle income public.

[laclos]

The Infiniti car salesman told me he uses regular in his coupe and doesn't notice a difference. He also said paying for premium is "a waste."I don't understand why a poster would be disappointed when someone asks a logical question, as did the first poster in this thread.

[Tictakman]

Honestly, i dont see why you should be "disappointed" about this post. Its general question as to why the higher octane should/is needed rather than the 89 octane. Dont put yourself on a pedistal because you own a g35, anyone can take a loan out and buy one making it look like they are "successful and tasteful". Maybe thats what you did...

[ncuster]

myg35ss. Looks like years of minimum wage finally catapulted you into a "service manager" position and now you feel important because you tell Paco where to store the shop rags. Congratulations... you must be making the big bucks.

[rydwhite]

Let's get back on track and keep with the discussion here. There is no need for kicking someone because they stated an opinion.

[joe603]

I've heard from people in the "business" that its all BS...comes in the same truck...any truth to this conspiracy theory?

[C-Kwik]

I've heard from people in the "business" that its all BS...comes in the same truck...any truth to this conspiracy theory?

Doubtful. Quite some time ago, I bumped up the timing in a car I owned. It had some light detonation under high loads with regular unleaded. Even a small step to 89 octane from 87 eliminated the detonation.

[ncuster]

I had a 62 Chevy Nova with a stroker 250. I had to run premium, or else power would literally cut out just over 70 mph. The engine would just stop making power... it almost felt like a governer. With premium - no problem - I could hit 120. The G35 is lightyears ahead of my 62 in terms of technology, and not a stroker... so I know that there is a substantial difference in the fuel. I was more or less curious if premium fuel had to be used in this car, and what kind of power loss is expected by using regular. Thanks for the info. I'll be sticking with premium.

[joe603]

I think I'll stick to premium too; maybe I'll use regular after every 2 tanks of premium... I feel like I'm filling an SUV with the G35's 20-gallon tank!

The gas station I use doesn't have 96...only 87/89/93.

[C-Kwik]

Well there was a test done on a Z with 100 octane and it actually made a little bit more power up top. Its not hard to imagine the lower octane might cause a slight loss of power.

[red_emron]

The compression ratio & the DOHC will allow lesser grade without damage or performance issues. I use mid grade every other tank in my G35 coupe.(298hp) Infiniti allows regular in the 280hp but suggests 91 for better performance. If you are a average driver in a city stop & go driving you may never notice the "pinging" that results from lower grade fuels. If you drive hard like me go with the higher octanes. My Infiniti service mgr. worked with Mercedes & pointed out that the Infiniti engine is one of the best built last 10 years.

Red

http://www.wardsauto.com/Micro...ype=1

[Q45tech]

Regular vs Premium may have stated octane differences but the big factor is the level of deposit cleaning detergents added to Premium.Regular should [on a good day] contain the absolute minimum level per government spec, Premium usually contains 2 x the minimum.

It is a lot cheaper to buy the detergent [at 16-20cents per gallon increment] than to pay Chevron $8 for Techron that treats 20 gallons or BG 44K [$15] that might treat 40-60 gallons.

http://www.mobil.com/USA-Engli...2.pdf

"The Alliance for Automobile Manufacturers twice a year takes gasoline samples in 26 U.S. cities — including Kansas City. One of the tests is for “unwashed gum,” which is an indicator of the amount of detergents in gasoline. In the winter following the EPA standard going into effect, according to AAM tests, unwashed gum levels in regular gas dropped more than 20 percent. By 2002, gum levels had declined about 50 percent. Although recent tests show slightly higher levels, they are still low.Joe Colucci, a retired director of research and development at GM who now operates Automotive Fuels Consulting, said reducing detergent additives to the EPA regulation level was seen by some companies as a way to reduce costs.

Although detergents cost only a fraction of a cent per gallon, it adds up to an enormous sum because of the huge volume of gas sold. “They would say to themselves, ‘We'll meet the letter of the law,' and that's what has happened with much of the gasoline,” Colucci said. By 2002, the automakers say repair records suggested that the EPA standard for detergents wasn't high enough. They approached the EPA about increasing gasoline detergents, but say they were reb

[Q45tech]

Not to say that even the finest PREMIUM has enough detergents to keep the injectors, valves, piston tops like brand new after 15,000 miles.....but the system will be cleaner than if Regular was used.http://www.performancechemical...xhtml

Why I use BG44K prior to every oil change [every 90 days] to cleanup what wasn't cleaned by gasoline detergents.

"Shell Oil estimates that 60 percent of the fuel sold in the United States is at or near the “EPA minimum level of detergency” and says that has caused problems in some cars. “We have measured significant deposit buildup in certain vehicles in as little as 5,000 miles,” Shell stated in one document. Early this year, GM approached Honda, Toyota and BMW to join in an effort to improve gasoline detergent levels. GM believed that an organized group rather than a lone automaker would show the seriousness of the issue."

Polyisobutyleneamine Polyetheramine Polyisobutyleneamine/polyoxyalkylene Polyoxyalkylene

[Q45tech]

Most people can't even name over 3 chemicals that are in gasoline.........there are over 100-155 different ones.And it varies substainally batch by batch day by day from the same refineries depending on which well the base oil comes from not which country which individual well! It all gets sloshed together in the tankers but not mixed 100%.

http://www.faqs.org/faqs/autos/gasoline ... faq/part4/

[C-Kwik]

Most people can't even name over 3 chemicals that are in gasoline.........

Most of us can't even pronounce 3 of them.

[Q45tech]

Those 4 are just some of the possible detergents used........Google them and their patents to understand how they work.

Amazing how trusting people are, just buy gas and use it without chemical analysis.

[1SweetG]

I've always burned premium in my "Sweet G." Here are few things to consider when deciding on which grade and brand of gas to use:

Cost - An average MPG of 20 with 20K per year is 1,000 gallons. At the worst case scenario of a .20 per gallon, you have $200 per year of additional cost.

Quality and cost – Premium generally has 2X the detergent of regular. The cost to have a dealer clean your fouled injectors $200 to $300 (sometimes much more). Is this saving you money?

Performance – Premium will provide the highest level performance for cars like the G35 that were factory tuned for it. The owner’s manual recommends premium doesn’t it? Putting premium in an Escort is a waste, not a performance car.

MPG – My boss and I both have G35’s. He burns regular because his Infiniti sales rep said that is what they burn in the demo cars and they haven’t seen a problem. We both drive similar types of roads, but I drive more aggressively, yet I get 1 or 2 better MPG than he does. Could it be the premium?

RFG – Reformulated Gas. I have this crap gas in most of the area’s I travel and live. They add 10% ethanol for a bogus improvement to the environment. Regular gas with ethanol has caused a massive increase in the number of Fuel Injector service problems in my area. The service mangers and mechanics that I’ve spoken to haven’t heard of anyone having these injector problems when premium gas is always used. I’ve also noticed that some gas stations don’t have the 10% ethanol stickers by the premium stickers. Could it be that the premium doesn’t have ethanol?

Brand of Gas – I never thought the brand of gas made a big difference until my wife’s Chevy Blazer suffered from Fuel Injector problems one day after a fill-up at a local Citgo station. I did some research on it. Read about it in the links provided below. The bottom-line is that the EPA standards for gas additives is inadequate for RFG. Four of the world's top automakers, BMW, General Motors, Honda, and Toyota have banded together to form TOP TIER. The purpose of the group is to help drivers avoid lower quality gasoline which can leave deposits on critical engine parts, which reduces engine performance. That’s something both drivers and automakers want to avoid. This group has identified gasoline retailers that meet their more rigid standards for gas.

TOP TIER recommends you buy gas at:

QuikTripChevronConocoPhillips76ShellEntec StationsMFA Oil CompanyKwik Trip/Kwik StarThe Somerset Refinery, Inc.Chevron-CanadaAloha PetroleumJiffy MartMahaloTri-Par Oil Company

Links:http://www.toptiergas.com/http://www2.j ... s10325.htm

Summary – Your G35 is a performance luxury sedan/coupe that deserves quality gas to do what is was designed to do, go faster than over 90% of the vehicles on the road. Why mess with that to “save” a few bucks?

[Q45tech]

At the local tank farm there are usual only 2 grades available .......sent down the pipeline to service every station in your town.........mid grade is producted by mixing some of each together................don't assume that it is 50/50.

Even US Premiums rarely meet the Japanese Premium MON levels...........some US gasoline has a minimum MON of 82 whereas the EU and Japan require a minimum of 85.

[J-Owner]

Q45tech - Ok I have to play stupid for a minute. Are you saying you use something called BG 44k as a detergent between oil changes?

(Sorry, I am on a boring conference call and apparently I can't multi task at the moment to figure out the lingo in this thread).

Can you tell me more about that. Is the name BG 44K? Who makes it? Where can I get it?

I have just never heard of that. Sorry, if I am asking a stupid question.

Thanks,Brandon

[Q45tech]

BG makes a line of specialty chemical additives/cleaners for automotive shops and dealers.http://www.bgfindashop.com/locator/index.php

http://www.bgfindashop.com/bgservices/fuelair.htm

These sites should explain