Regular Gas?
 

I think the dealer may have filled up (topped off) the tank with regular gas. Do any of you know first hand how the engine reacts when this is done.

I know what the manual says about regular gas.

What I am trying to figure out is, what the symptoms are to see if they match what I am seeing.

welllll what are your symptoms!??

I don't think one fill-up will hurt you at all. Nissan also requires premium fuel for the Maxima and the 3.5 Altima. Those cars are popular for rental companies. How many people do you know that fill up rental cars with premium?

My 350z takes premium also. I have been putting regular in my car every other fill up for a few years, I don't notice any type of issues.

just keep adding premium into the tank every chance you can get. Im sure if you wanted to you could syphon alot out but idunno doesnt seeem like fun.

on after thought it might actualy be 91 octane but from the cheapest crappyes gas station they could find a discount at.

I had no idea what the dealer put into mine but i can only assume it was crap so i kept putting chevron in it every day hoping to mix the good stuff with what ever they put in.

dont worry about it.

when your car is new, you cant (shouldn't, unless you believe in breaking it in by the dyno) rev it above 4kRPM's or so.

the lower octane gas will not do anything to your motor, as a mater of fact, if you plan on keeping the engine below 4krpm for 500+ miles (break in period?), then you might as well use regular gas for the 500+ miles. (although I wouldn't, the price difference isn't much of anything)

the reason premium is required is because the 370z's engine has high compression which will make low octane gasoline detonate BEFORE it reaches the combustion stroke.
there is an exception to that - which is if the engine is not under stress to put out the power, then the gas will not misfire, thus making 87 octane perfectly fine to use. You just have to remember not to floor it.

on top of that, many new cars have smarter ECU's that will regulate the misfiring to prevent damage. (although not all cars have it, and not always successful)

Probably just my imagination, but it "feels" like it misses in a VERY minor way every once in a while. It is not an obvious miss.

If you look in your manual, because I do recall reading it, it says that if it's an "emergency," you can put 87 octane in. However, don't drive hard i.e. don't get on it.

When I had a CRX with a b16a (modded w/ JDM CTR cams, DC headers, high flow cats and Greddy exhaust), I always put in 89 and it didn't hurt it. My motor had over 100K on it and it still felt like the compression was strong....Hate to say this, but when I first dropped that motor in my CRX HF, I'm confident that it could beat a stock 370Z by a hair to say the least in the 1/4.

104
 

Damn I miss that 104 I used to get in Japan. Those were the good ole days.:shakes head:

When i picked up my 370z at the dealership, they've also filled my Z's tank with 89

octane gas, eventhough the minimum recommendation for octane usage is 91. :mad:

However, i don't think it damaged my engine at all, but i can ensure you that when you

fill your Z's tank with 91 octane, you can feel minor improvement compare to 89.(only if

you are extreamly sensitive person.)Personally, i put premium gas(94octane) everytime i

fill my Z's tank, and i can feel way better power than 89 octane. Occasionally, i put

Lucas octane booster with premium gas(94), which it might be raise the octane number

up to 98(approxi), and it makes me think that i've moded my Z

eventhough it's 100% stock. Just opinion :p

some of you guys are funny.....higher octane does not = higher HP output

The car is built for 91 octane, lower octane will produce knock which will cause the ECU to retard the timing and reduce power. Normally increasing octane does not increase power output as the ECU does not advance timing beyond it's preset.

However in this car it actually might. The engine computer reportedly continues to advance the timing until it detects knock. There's been reports of high octane race gas producing a measurable power boost on the dyno. How true this is I don't know, haven't been able to measure this first hand.

That said I use 93 because they don't have 91 locally.

I know for a fact that the 06 Accord V6 I had recommended regular gas but would advance the timing as much as it could. A Honda Engineer actually stated in an interview that you would gain about 10hp by using premium.

I see no reason why the 370Z can't be doing the same. But thanks for coming in Mr. 14Posts and trying to talk down to everyone.

:iagree: Exactly..

My Corvette had 2 distinct timing maps. When knock was detected it would default to the Low octane Map. It's amazing how many cheapskate Vette owners run regular! Most Import ECU systems are a little more sophisticated and alter timing dynamically, always seeking the most advance possible up to the knock threshold.

BUT more timing does..

Does the manual say 'recommend' or 'require' premium?

Here's what it says:

Recommended specifications:

Unleaded gasoline with an octane rating of at least 91 AKI (RON 96)*1

I looked up 91 AKI and that falls in the category of Premium...at least according to this photo on Wikipedia:

http://en.wikipedia.org/wiki/File:Ga...ne_Ratings.jpg

If it says 'Recommended' then you can fill up with regular and it'll be just fine, but don't make it a habit.

Hmm . . . I think you kinda missed the mark on this one, as hp gains with high octane has already been dyno tested and proven with the 370Z.

YouTube - XXX Race Gas gains 14whp on stock 370z



Edit: This was original posted here -> http://www.the370z.com/nissan-370z-g...light=race+gas

Yup....Apparently the Z has a pretty broad ability to adapt timing to available octane.
On my old Audi, the only difference between a 93 octane flash and a 100 octane flash was timing changes, good for 20-30 hp with that alone..

My dealer, I would imagine, used regular for its first tank as well. Think about a lot of dealers... It's all about the almighty dollar. Anyway, I noticed that my first tank of gas, running well within the break-in procedure, I only returned about 19.5-20.5 MPGs. I put in my Shell V-Power (and then made the "V" sign with my fingers to all the people who passed me. he he. JK. Their ad) my MPG's jumped to between 23.5-26.5. Initial few miles? Maybe, but I think it could've been the gas.

I imagine it'll be the same as the 350z - the ECU will adjust itself to to the poorer fuel, meaning you have less power, but your engine won't be damaged.

That said, why buy a greyhound and feed it on slops, if you know what I mean?

Hey how did you know about my wife's cooking? :yum:

Gas cap
 

Doesnt the inside of the trap door for the gas cap say "Premium Fuel Only"? I know mine does......I read it twice a week.

Peeps here can't read the owners manual...You expect them to read the fuel flap door??......:rofl2:

Mine does too. But here's a screenshot of what's actually in the manual:

http://i618.photobucket.com/albums/t...09-20950PM.jpg

Agree. I asked my sales rep what kind of gas he put in the tank (I got Free full tank) and he assured me it was premium. I told him I have a device that I can use to check if it's premium or not (I was just bs'ing around) and if it's not premium, I'm bringing the Z back! His reply, " I swear, I put 93 premium!"... I was just joking anyway...

To the OP, you'll be fine. Just wait till the tank is half or 1/4, then fill it up with 93.

You guys seem to think im saying that 87 octane will do just as well as 91. I did not say that, However, the post above my last post stated that he'd (she'd?) bump their octane up as much as possible to get more and more HP.

most of you must have skipped my original post, I did not state 89 is just as good as 91. I know the difference, I may only have 14 posts here, but I'm not an idiot. And 89 is perfectly fine to use, as long as you dont floor it.

The compression on the 370z's engine is 11:1, having 110 octane is not going to give you more power over 95 octane, the engine is still only compressing the gas to a 11:1 ratio.

The only thing higher octane will do is allow you to compress it to a higher ratio and avoid knocking. as I stated in my last post, octane does NOT = hp gains. other factors = hp gains, not octane, It just allows those other factors to take place safely.


-edit, forgot to mention about that Z with the HP claims for having higher octane.
The race gas from XXX Racing Fuel is highly oxygenated, and that is most likely the cause for the gains. We all know that if you could compress more air into the cylinders, then you get a bigger bang - and thats how the race fuel from XXX Racing Fuel works. Regular gas typically has a oxygen weight of 2% while the XXX Racing Fuel 138 octane claims to contain nearly 20%!

Theres a gas station about 2 miles from were i live that offers 103 octane i believe but at 8 bucks a gallon it can stay there. lol

That's a good point about the oxygenation, Cjanik.

So if I am reading this right, "if" the dealer put in Regular gas, it won't damage anything, but I got confused on one thing? Will the ECU permanently reset the timing or just while that gas is being used to compensate for knock?

Not permanent. It will quickly recover when premium gas is put back in.

:wtf: the cylinder volume does not change when you rev past 4k, the compression is the same at 1k or at 8k. it may not be as detrimental since it's not exploding 8k times per min, but it's still exploding prior to the piston reaching TDC which damages the piston, piston rings, cylinder walls, valves, spark plugs, injectors, if it's in there, it's damaged.

don't put regular in your car unless u have some kind of piggy back or stand alone ecu which will redo the timing.

^^ what does your manual say about regular gas? It's ok :)

Your volume statement is correct, but your conclusion about pre-detonation is incorrect. If the ECU detects pre-detonation, it will retard the timing to alleviate the knock. It's very unlikely to suffer any damage from low octane gas, your performance will just suffer.

All higher octane gas lets you do is advance the timing which can increase the torque generated by starting the combustion process earlier on the compression stroke without detonation.

Essentially, there's no additional energy available in the air/fuel mixture, it's simply how it's being used that results in the generation of more power.

Well, I filled my blue one up today with Premium....93 Octane.....17.5 gallons.....$47.....ouch!

when i had my 350 i 80% of all the fillups i used with unleaded... didnt feel any diverence. my dad who grew up with datsuns and had a 300Z for a long time always used the 'cheap' gas... idk the only gas u should b worried about NOT putting in ur ar is from "THRIFTY"..

Didn't feel any "diverence" between the unleaded and leaded? :confused:

$2.69/gallon?? You get no sympathy from this quarter. 91 octane in Santa Barbara county is well north of $3/gallon.