Octane Needed? 93? 91? 89? 87?

[rkclub]

I just purchased an 03' G35 coupe. Love it, always wanted one. Question is does it really need the higher octane gas. I have an Acura that also says it needs hi octane but really does not. Any thoughts on this from people who have tried?

[ryan_g35]

truthfuly i dont use 91 that much i can feel a small difference though.nothing major thouh . Some people say it makes a huge difference and all that but i dont think you cars gunna break down if you dont use 91 all the time but someone migh know alittle than lol

[SVTCOBRA]

You might want to search on this subject. Lots of opinions here.I use prem. But, I don't think the middle grade will hurt you if you don't experience knocking.

Welcome to Nico!

[joe603]

The ECU will compensate for lower grades of fuel. If it senses pinging, it will retard timing, and reduce HP. Use premium if your owners manual calls for it...

[rn79870]

I go with following the owners manual. The 08 G manual makes a distinction for the G35 and G37 for fueling in the event premium is not available. For the G35 it states that you can use a tank of less than premium without much problem as long as you do not allow the car to constantly ping. For the G37 it states that if premium fuel is not available, fill with the least amount of non-premium fuel possible to get to another fuel station with the appropriate fuel. The distinction tells me that the G35 has lower compression and is more tolerant to lesser fuels.

[etschell]

use nothing lower than 93. cheap bastard now = F'd in the A later.

[telcoman]

I just purchased an 03' G35 coupe. Love it, always wanted one. Question is does it really need the higher octane gas. I have an Acura that also says it needs hi octane but really does not. Any thoughts on this from people who have tried?

I've owned my G for two years now & have 46k miles on it and have never used premium. I use regular 87 octane usually BP or Hess. Never heard a ping, plenty of power, MPG is usually 22.5 - 23.5 commuting. Best MPG was 28.83 on 1 tank on a trip to Florida.

I'm a cheap old farht that will not spend or waste the extra $$$ on premium.

I didn't use premium on my old 92 Lexus & that ran fine for 14 years & never had a problem. Not much profit in regular. Another 20 or 30 cents a gallon helps someones bottom line but hurts mine. I can beat any Yugo, Ford Pinto, Chevy Vega, or AMC Gremlin using regulat 87 octane:rotflmao

Just my opinion

Telcoman Telcoman

[tollboothwilley]

91 is the highest octane at the pumps here...

Friend who used to work for a fuel company said that the middle grade is going to be very close to the premium octane ratings because of all the mixing that they do.

Also, said if you buy gas early in the morning you will get the most gas for money because it will be more dense.

Sounds right... but I wouldnt go lower than midgrade if you want to keep your engine happy

[telcoman]

91 is the highest octane at the pumps here...

Friend who used to work for a fuel company said that the middle grade is going to be very close to the premium octane ratings because of all the mixing that they do.

Also, said if you buy gas early in the morning you will get the most gas for money because it will be more dense.

Sounds right... but I wouldnt go lower than midgrade if you want to keep your engine happy

Filling up in the early morning when it is cold or cool depending where you live will get you more gas for the money.Gasoline expands as temperature rises. If you fill up during the hottest part of the day, the amount of gasoline in your tank will shrink as the temperature falls in the evening.

Telcoman

[gwoods]

Diesel!!

Seriously though the compression ratio is high enough you need premium fuel....

[Number1gsxxr]

I ran 87 or 89 in mine since I got the car in June and never experienced any knocking or pinging. I switched to 93 the other day since I found a place that had it for $3.05/gal as opposed to $3.31+/gal. What an improvment with the 93! I'm now a firm believer of using at least 91 in it. My car felt totally different. It felt like someone was holding the e-brake up for a while and finally let it go. Feels ways faster with 93.

[smockers83]

The reason behind the gains in power that are felt is because you reach full (or near full) compression at combustion using premium fuel, extracting more of the useful power the engine was designed to produce.

[Tampa G35 Sedan 6MT]

I get over 40-50 miles more per tank with the premium. So the difference in price is worth it because i make it up with the extra mileage... And i get the most power!

I see the difference in the high RPMs on the gas 87 vs 93...

But the difference in the amount of MPG is in the normal use... when the car has to use more Fuel to Keep the normal RPMs of the motor!

It will require a few more drops of fuel per RPM and that is where it adds up.

MY .02

DJ

[J-Owner]

Well I will throw my $0.02 in on this subject yet again. If you cannot afford a luxury car and the maintenance, gas, etc that goes along with it then do not buy one.

Use whatever you want and if you do not plan to keep the vehicle past 100K miles then you have nothing to worry about. If you enjoy driving an expensive car that sounds like an '80 model Chevette then always use regular fuel.

I am on my fourth Infiniti and they always eventually ping like Hell when you use the cheap ****. Then you get to spend $200 having the throttle body cleaned or whatever that things is called from build up.

It is bad enough that we are all losing about 4-5 MPG because they put that Ethynol crap in the fuel, it you want to make it worse with cheap fuel....have at it.

My thought is this.........using premium only costs you at most an extra $20 a month if you really break it down. For those of you that $20 matters, that is one less trip to the dry cleaner per month or shifting your Starbuck's trips from every day to ever other day. Two less nights eating out per month, etc. $20 extra a month means nothing to me and I knew what I was getting myself into when I bought a car that uses premium fuel.

I would follow what is recommended in the owners manual, but that is just my opinion.

[J-Owner]

As a follow up. I just took my CLS in for a detail and was asking my Mercedes tech about this octane question and he agreed that following the manual is recommended.

He said that continued use of low octane fuel in a high output engine WILL eventually damage the engine's cylinder heads and pistons.

Just my $0.02.

[redhed]

Filling up in the early morning when it is cold or cool depending where you live will get you more gas for the money.Gasoline expands as temperature rises. If you fill up during the hottest part of the day, the amount of gasoline in your tank will shrink as the temperature falls in the evening.

Telcoman

but this makes me wonder...since gas is generally stored underground...how much of a temperature change does it go through during the day??
Modified by redhed at 5:11 PM 1/10/2008

[redhed]

As a follow up. I just took my CLS in for a detail and was asking my Mercedes tech about this octane question and he agreed that following the manual is recommended.

He said that continued use of low octane fuel in a high output engine WILL eventually damage the engine's cylinder heads and pistons.

Just my $0.02.

nah, that only happens to mercedes engines!

[J-Owner]

Well had I been taking the G in for its regular detail I am sure the Infiniti tech would agree.

[gwoods]

As a follow up. I just took my CLS in for a detail and was asking my Mercedes tech about this octane question and he agreed that following the manual is recommended.

He said that continued use of low octane fuel in a high output engine WILL eventually damage the engine's cylinder heads and pistons.

Just my $0.02.

Which CLS do you have?

My wife wants one bad!

[SVTCOBRA]

but this makes me wonder...since gas is generally stored underground...how much of a temperature changes does it go through during the day??

probably not much to matter! good point.

[Bullet_35mm]

I do like what J-Owner wrote and I do agree with him from his point of view! Since I work in car dealership and I was always driven cars which require Premium fuel here is my knowledge in this topic:When you open tank cover you will see one of these stickers: 1- PREMIUM FUEL ONLY or2- PREMIUM FUEL RECOMMENDEDAnd believe me there is difference! Everything basicly is about the knocking factor. If you drive the car with sticker 2, you will not do anythind bad to your engine putting lower grade fuel. The engine will work pretty much same way. Engines nowdays are so advanced that besides VERY LITTLE difference performancevise your engine will be in the same condition after 100K miles no matter which fuel did you use.A little bit different story if, just like in G35 (at least mine) there is sticker #1. That means that your engine will not work the same when you will use lower grade fuel. There will be chance that you will start hearing pinging very soon. And whati s most important, motor will be in different condition after putting lots of miles using lower grades than Premium fuel.Anyway that's basically how it is and... THE CHOICE IS YOURS!!!!!!!!!!

[J-Owner]

Jeff,

I have a loaded 2006 White CLS500. It is a very PIMP car. It would be better if it had an Infiniti symbol on the front but what can you do.

[gwoods]

Sweet ride~!

Used they were still in the mid 60k when I bought my G but it was something I can see owning down the road!

I like the E63 too but it isn't as much a luxery car as the CLS!

Nice garage!

[J-Owner]

Jeff

My CLS stickered for $91M but I got it for $82M with some hard negotiation and a walk out. I had sent several referrals to Park Place that purchased vehicles and you would think they would show some appreciation for me sending them some business. They didn't at first but after wearing them down I got a little bit of a break.

One of my friends husband's just got a new company car that is a '07 Lexus LS460 fully loaded. (He is a top salesman for an international company that makes engine belts for large machinery - not bad for a company car). Anyway, that thing is even more luxurious than mine. Had I driven one of those before getting the CLS it would have been a hard choice.

I love luxury cars and the CLS is an AWESOME highway car. I am Infiniti loyal so for me to purchase "outside the family" was big but Infiniti just does not have an Ultra Luxury Flagship and they really need one.

I also have a '95 F-150 for trips to Home Depot. Luckily I have a 3-car garage so my house does not look like a car lot. If I ever decide to part with the Benz, I will keep you in mind.

Brandon

[haloseven]

I don't use less than 93. If you use lower octane, you may or may not hear any knocking, as the computer will alter timing to minimise it. You might lose some HP. I found that Sunoco offers 100 octane here in Western PA. Giddyup!

[lucidd]

Re: Octane... There were many ?'s that has been made on this subject...I've read replies from Road & Track and Motor Trend... and a few references from other sources...goes something like this:

Octane: the higher it is, the more detergents in it... and these detergents are designed to ensure clean burning, and also predetonation. Clean burning is one thing, but more importantly, predetonation [pinging] is and can be detrimental to your engine - both short term and long term.

Predetonation happens when your engine warms up [and in some cases during hot summers] -heats up- it causes the gas to explode-detonate before it is suppose to. When this happens, you get pinging. At high engine speeds = high piston speeds, the predetonation- pinging can be so bad, that the it will cause engine damage [without getting too far into it].

Some articles even go as far as suggesting that you go 2-3 octane higher than recommended - to ensure the engine-combustion chamber, injectors, valves etc - stay clean... I believe this was an older article from R&T.

Luckily, for my 07g35s, I've always put 94 octane in it... highest available... and it really isn't that much more - ... for peace of mind.