91 or 95 gas

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peternz, Oct 14, 9:39am
x1
Hi, Have fresh inport . 2005 Nissan Elgrand V6 , 2.5L
Should i use 91 or 95 gas ?
serf407, Oct 14, 10:13am
The Russian recommendation was A-92.
Using the vehicle everyday use 91, if only once a week or less then 95. (not something like gull or others with volatiles)
I assume the vehicle does not have aftermarket engine parts/ tunes that require high octane fuels.
peternz, Oct 14, 10:59am
stock standard .
flack88, Oct 14, 11:00am
That's high compression engine,95 it thank you for it.
intrade, Oct 14, 11:57am
like i said 91 is only 3th world counry fuel not to be used in almost anything including my astra who has a sticker the australian morons put under the bonnet that it can run 91. Thats why all astra shitting them selfs they are not a crap car the fuel nukes the engines.
mber2, Oct 14, 12:10pm
which is probably why fuel companies sell more 91 than any other

I have never heard anyone who is supposed to be a good mechanic (or is that only self praise) talk so much crap
berg, Oct 14, 12:18pm
x1
Lol, I worked on Ashtrays (Astras) for years. They are a shit car
joanie04, Oct 14, 12:27pm
I second and third that.
campbellluke, Oct 14, 2:57pm
Japan has 90Ron for standard and 100Ron for premium. 85% of fuel volume is people buying 90 Octane and I'd say that the Elgrand is tuned for our 91 perfectly fine.
thejazzpianoma, Oct 14, 3:13pm
Never confuse the ignorance of the public with the expertise of the manufacturer who designed the engine.

There are a lot of engines out there designed for 95 or higher octane and why wouldn't you when it's easier to meet emissions and economy guidelines when you design for a high octane fuel?
thejazzpianoma, Oct 14, 3:31pm
The VQ25 that's in your car came in a variety of compression ratio's. You should have the 137kw version which is a high compression version and should run a minimum of 95 octane.

Also, NEVER (in my opinion for legal reasons) run biofuel mixes (as sold at Gull) in your vehicle, not even once.

Lastly, aside from compression ratio issues. There is one other reason to run high octane fuel in your vehicle that is particular to your engine. The VQ25DE has a serious design fault that can cause it to ingest bits of it's exhaust system and destroy the engine. By running a high octane fuel (Ideally BP98) you can keep exhaust gasses cooler which may help with the longevity of the pre cat (part of the exhaust that failes and ends up in your engine).

This reason in my opinion is more than enough to run 98 octane.

Also. at that compression ratio you will get better economy so the fuel price will cover itself.

One last tip. If your vehicle starts to use oil, sell it IMMEDIATELY, ideally trade it back to the same dealer who sold it to you (revenge is sweet). Once they start to use oil it compounds the rate of damage and they tend to disintegrate quite rapidly thereafter.

I also wouldn't tend to own one of those beyond about 120'000km, it's just pushing your luck a bit far in my opinion with the design fault. Although plenty fail before that milage too unfortunately.

Sorry to be the bearer of bad news but better to know this stuff ahead of time in my opinion.

Best of luck with it.
jmma, Oct 14, 4:15pm
Wonders if someone is quoting the correct engine above :oP

Nissan 2.5 L Four Cylinder

The pre-catalytic converter built into the exhaust manifold of Nissan’s 2.5 L four cylinder engine can reportedly disintegrate as it ages. The ceramic material gets sucked back into the motor, causing increased oil and coolant consumption and, eventually, engine self-annihilation.

It’s a big problem among 2002 and 2003 2.5 L four-cylinder Altimas, as well as Sentras with the same motor. Then came word Altimas and Sentra SE-Rs equipped with the same engine built between January and May 2006 may experience unusually high oil consumption. This can lead to premature engine failure and possibly a fire.

Owners of any 2.5 L Nissan engine are advised to check their engine oil level frequently. This motor also reportedly loves to ingest the screws from the butterfly valves in the intake runners, another hazard that can score the cylinder walls.
extrayda, Oct 14, 4:23pm
Interesting exhaust issue, though not an engine design fault.

I sold my VQ25 with just under 200,000ks on the clock, and apart from basic standard maintenance, it required nothing, and was still going strong when I sold it (no oil burning either). VQ's are excellent engines.
From my 5 minutes of google expertise, ideally rip out the front cats, and the problem doesn't happen.

I always ran 95 in mine, was ultimately no more expensive than 91 (more miles per tank).
thejazzpianoma, Oct 14, 4:23pm
Good Spotting!
Yip was having a brain fart, I am sick with tonsillitis and a fever so not quite thinking as normal.
VQ25 is the V6 what's in the Elgrand and it's a pretty good motor.
QR25 is the four cylinder which is the pig.
Elgrand still needs high octane fuel though as I am pretty sure I am right on the compression ratio (but feel free to check that as well, just remember which version as there are three I think)
Probably your most useful post ever jmma, thanks.
thejazzpianoma, Oct 14, 4:23pm
Lost my mind and got mixed up, see above. Agree, good motor.
peternz, Oct 15, 9:12am
Thanks so much guys . info is great . cheers.
ruby2014, Oct 18, 5:46am
We would never put 91 octane into anything we own. We even put 95 into our lawnmower. (91 octane is rubbish fuel and will eventually cause engine damage.) We use 98 when ever we go anywhere that has it.
The thing is, that the higher the octane the fuel is, the more kilometers to the Lire of fuel you will get out of it. So it evens out in the end.
ross1970, Oct 18, 6:44pm
One vehicle is a 96 ef2 falcon, almost 400k on it, about 200k mine.
Has always had 91. Put 95 in it, it idles like a pig. Compression is excellent, burns no oil. When should I expect this engine damage? 500k ?
sharchew, Oct 22, 6:38am
I have run 91 octane in my BMW for 12 years never had a problem there is a lot of bullshit on this site .
sw20, Oct 22, 7:19am
You might not have a problem either.

You might also get more distance per litre off the correct grade of fuel.
sharchew, Oct 22, 8:03am
I think 8.9liters per 100 ks for a 2.5 ltr car is ok.
thejazzpianoma, Oct 22, 5:34pm
Exactly, just because they haven't destroyed it yet doesn't mean it's running as efficiently as it could.
thejazzpianoma, Oct 22, 5:38pm
Have you?

1. Checked the recommended octane rating for your model?

2. Done a test to see which gives you the most fuel milage?
(Hint, if it goes further on higher octane that pretty much means it's compromising ignition timing to avoid damage running on the low octane)

3. Have you ever hooked up a scan tool with the different fuels and compared the ignition timing and knock detection values?

An older BMW is not likely to explode running low octane fuel. (Unlike some other vehicles that may melt pistons etc). However it is more than likely not running as efficiently as it could if it's designed for high octane, which is likely.
thejazzpianoma, Oct 22, 5:39pm
That's not the point. The point is the difference in economy on the different grades of fuel.
thejazzpianoma, Oct 22, 5:41pm
A good tip. When you can, fill you mower can with BP Ultimate 98. Unlike 95 and 91 it actually increases it's octane rating slightly with storage as opposed to losing it significantly. You still don't want to keep it in a sealed can longer than 3 months in my opinion but it does keep much better. Makes for nice easy starts on small motors if nothing else!