OCTANE FOR THE TWIN TURBO

[335isGuy]

I always run Sunoco Ultra 94. And maybe try C-16 for a pull :headbang:

[mgarritson]

The fuel quality here in southern California is pretty bad and to get anything higher than 91 you've got to jump thru some hoops. So, 91 for me.

[bimmernet]

Originally Posted by bradford

Sunoco has 94 Ultra.

Also, some gas stations sell 100 octane UNLEADED race fuel, usually Torco brand around here (at Gas City). You can add a gallon or two of that to skew your average octane level up.

At $5 a gallon, it's hardly cheap, but at least the cost of race gas hasn't really increased with the cost of regular gas, making it more of a bargain these days when i costs only 70% more. It used to be about 200% more...

I would do so only in extremely hot weather or if you intend to subject the vehicle to extreme duress (IE track events). It iwll prevent the ECU from retarding timing and keep power levels up.

I buy gas at a station out here in CA (Sunol Super Stop) sells Torco pump gas (104 Octane) for about $5.10 gal alongside their 91 (at $3.39). I'm not conversant with what happens in the N54 if you run the 100 or 104, so what will be the net result besides a guarantee that'll it never knock going up a long grade into the mountains?

[manj]

Only thing to worry about with lower octane as many members have said is loss of power and lower MPG but other then that knock yourself out :> or jus buy a v4 :> lol but the way i see it like most people is why put a lower octane of gas when only 5 dollars will get you the higher octane on the full tank its boggling what people will do to save a penny lol and plus has anyone here realized how much water costs? i explained to my cousin who drinks 4 litres a day and i told him that a 1 litre bottle of water cost him 2.40 us dollars here in the UK and 1 litre of gas cost him 2 US dollars for the lowest octane which is 84 i believe so what is cheaper? you guys be the judge its boggling how expensive watter really is when you break it down to the ml or even L thats just my two cents hope you guys get where im coming from

[manj]

Originally Posted by bimmernet

I buy gas at a station out here in CA (Sunol Super Stop) sells Torco pump gas (104 Octane) for about $5.10 gal alongside their 91 (at $3.39). I'm not conversant with what happens in the N54 if you run the 100 or 104, so what will be the net result besides a guarantee that'll it never knock going up a long grade into the mountains?

if you put 100 octane or even 104 octane in a 1 series that isn't got program for that level is a waiste of money and gas cause your car doens't know how to use it if it isn't programs :> another two cents of mine

[Race 1]

Originally Posted by Boost Junky

I always run Sunoco Ultra 94. And maybe try C-16 for a pull :headbang:

ya, and then you'll be spending a pretty penny for new cats....

i cant believe this thread is 3 pages long...

91 if your state sucks
93 everywhere else in the USA
name brand gas for both (dont be a cheap ass)

/thread

[manj]

SUNOCO THE WAY TO GOOOOOOOO

[Garrett]

Originally Posted by Race 1

ya, and then you'll be spending a pretty penny for new cats....

i cant believe this thread is 3 pages long...

91 if your state sucks
93 everywhere else in the USA
name brand gas for both (dont be a cheap ass)

/thread

LOL


I think the only ones that are confused are the people who live in Cali.

[dna550]

I blend a few gallons of 100 octane [unleaded] with the 91 octane in the Cayman S, which also has an engine management system tuned for 93 octane.

With the richer fuel blend the engine revs more freely, hesitates less in lower RPMs, and pulls stronger to the red line.

My butt dyno says the higher octane blend is just what these California-based, high performance engines need and were designed for.

[WhiteOne]

All gas is fungible only the additives are different. There are only like 3 different additives on the market. They all pass the BMW test for keeping engines clean.
Oh yeah, I pump gas for a living.....

[Scuderia]

I think this would be debatable if we we're talking about a NA car, but IMO any turbo car should use the highest octane fuel you can find. There's a few 76 stations here that sell 100 octane fuel for about $5-6 a gallon. Gonna give that a try when I go to the track.

[ErikB]

There is so much going on inside a combustion chamber that will dictate where pre-ignition will occur. Things like rpm, timing, octane, afr, piston diameter, hot spots, static and dynamic C.R., WOT vs Part throttle, air intake temp...

A BMW is probably like nearly every other modern fuel injected car, in using a knock sensor to sense, well, knock (pre-ignition). Having a faster burning fuel with more "energy" like a lower octane 87 may work fine at certain rpm points, boost levels, etc. But, the higher octane fuels that have a slightly slower flame kernel reduce the chance of knock.

Any MPG differences between octane grades are more from the PCM changing timing and other variables around to keep knock to a minimum. Tq/HP are affected, and usually MPG is changed a bit with that, as the engine would be more or less efficient at a given RPM point.

Just my 2 cents from 20 years of wrenching and modding.

[BMW135iCA]

For this car 91 would be the minumum I would put in. In my Legacy Gt I put 93 everytime. Higher octane is much better for today's turbo cars. I bet BMW even suggests high octane fuel like subaru does with my car.

Chris