Author Topic: How many of you run 87 octane fuel? (Read 40815 times)

Cobra Jet · « **on:** May 06, 2008, 10:56:25 AM »

I was just curious as to how many of you w/o chips are running 87 octane w/ no issues? I read some older threads and it seemed that some folks do run 87 octane with no adverse effects.

Are there any pros/cons to running 87 octane as opposed to 91 on a daily driven, well maintained vehicle that only sees normal use highway speeds?

I know if running a chip (Mark D., etc) that one would have to use 91 octane (or better) and of course if having a forced induction application 91+ is also the fuel to use.

nomad · « **Reply #1 on:** May 06, 2008, 11:05:27 AM »

I'm running 91 but if it's overkill I'd love to know. 4.25/gal sucks
I can only get 87, 89 and 91 here.
Should i run 89 and see how it goes? Our cars have no knock protection so I'm cautious.

CePa318IS · « **Reply #2 on:** May 06, 2008, 12:29:02 PM »

I have an airport 2 miles up the road from me where we can buy 103 octane fuel (not e85 ethanol). other than that 93 is the highest I have seen around my way.

I am personally running 93 octane in my 318is, however, I do not use it as my daily so I can afford 93 from time to time. Car is bone stock right now. I did not have any issues at all. Well before my block exploded, I had no issues with 93 octane. But that wasnt because of my fuel. That was because of my piston slap.

RED IS 91 · « **Reply #3 on:** May 06, 2008, 01:15:14 PM »

I run 93 ,sometimes 91 . Never tried 87 .

tjts1 · « **Reply #4 on:** May 06, 2008, 02:18:51 PM »

I use 87 when the air temp is below 70f, 89 above 70f. With cold air intake I've been able to use 87 octane all the way up 85f. It hasn't been hotter than that yet but we'll see at what temperature it will start to ping again. Last tank was 31.5mpg, mostly short trips.

With a completely stock intake, air temperature inside the airbox can spike up to 40f above ambient. Try it. Take the outside temperature sensor and stick it inside the airbox.

oldtimer · « **Reply #5 on:** May 06, 2008, 02:24:18 PM »

I've read using 87 can result in poor performance and low mpg. I use 87 on my car stock no mods aside the COP, exhaust, eliminated PS and K&N filter. I have installed a device that allows me to use the 87 and still feels like I am running high ocatin gas and get 26 mpg for mix driving and 30-32 for highway. This is my daily driver and high rev at 4 in between gears.

91318isguy · « **Reply #6 on:** May 06, 2008, 02:31:15 PM »

I've been using 87 on both of my 18's and I get 30/31 MPG. About the only thing going on right now with mine is that the Cat is clogging up (I still get around 31 though). I only am running a K&N conical, and the car came with a generic aftermarket muffler. I haven't noticed ANYTHING as far as knocking. I am also using Iridium plugs (could be that the plugs are burning the fuel hot enough... dunno), so that could be why.

tjts1 · « **Reply #7 on:** May 06, 2008, 02:34:32 PM »

Quote from: oldtimer;48756

I have installed a device that allows me to use the 87 and still feels like I am running high ocatin gas and get 26 mpg for mix driving and 30-32 for highway.

Don't tease me like that. What is this device?

nomad · « **Reply #8 on:** May 06, 2008, 03:10:34 PM »

maybe I'll move down to 89 and see how it does.

quinn11m20 · « **Reply #9 on:** May 06, 2008, 04:08:29 PM »

I run 93 only, my mods are chip, intake, pulstar plugs, resistorless leads, and a little tuning by me. I tried to run 87 before my mods and my little "Natascha" knocked and pinged oh! it was ungodly. There is a Circle K around the block from me. They have 100 Octane. Natascha runs soooo! nice. And the smell. MMMMM! racing fuel smells soooo! nice. Higher Octane fuel permits less carbon build up. The fuel burns hotter which burns the carbon. Lower octane does not. Once in a while you should add an octane booster to help clean out the carbon build up.

vonkamp · « **Reply #10 on:** May 06, 2008, 04:28:09 PM »

With 10.1 compression I would not run 87. It's more fun to drive with 93 or + anyway. Well worth the few extra $$ IMOHO.

Cobra Jet · « **Reply #11 on:** May 06, 2008, 09:58:45 PM »

Quote from: vonkamp;48769

With 10.1 compression I would not run 87. It's more fun to drive with 93 or + anyway.

Why?

I mean, others have used 87 octane w/o any detrimental affects - meaning those that are using their vehicles normally - not those who race away from every stop light and redline the vehicle through every gear...

It seems as though running 87 octane is pretty safe - and due to the current fuel costs for all grades of fuel, especially 91+ octane, using 87 can be a savings to those who daily drive their 318 and for those who travel an extensive amount of miles per day.

Zilla · « **Reply #12 on:** May 06, 2008, 11:17:50 PM »

I use 89 octane, my gas milage is fart so far. For some odd reason I was getting better gas milage on my m20, it doesn't make any sense. I think it may be my fuel filter. I'm going to try 91 and see if it makes a difference, in milage i'll get back to yall if theres a difference. This should mean a lot to everyone since gas prices are sky high :eek:

batsbats · « **Reply #13 on:** May 07, 2008, 02:44:24 PM »

Interesting stuff

e30Andym42 · « **Reply #14 on:** May 07, 2008, 03:55:52 PM »

I use 89 octane and am wondering myself if this is good enough? I can't seriously give any advice/info on how much of a difference it makes because:

1) After the tickets I got, my 318is sits in the driveway
2) I am on my second tank of gas since February/March? (whichever month I filled it up in), still on F
3) My first tank of gas was an unknown octane (bought it with full tank of gas)
4) I can't say I know much about gas and octanes anyway. All I know is the higher the octane, the higher the $$ :mad: