What Octane do you use?

[sunfighter]

Hey all,
I was just wondering, What Octane fuel do you all use on your 2.0 turbo's?
Is it ok to use 89 or 87 if you turn down the boost?
Thanks all.

 

[crankbender]

92 octane with 10% ethanol is a mix of 90% 92 octane gasoline and 10% entanol. This is often done because alcohol is cheap, burns clean, and is a renewable resource. Running this will cause you to use ~5% less air, so it will lean your mixture out a little. All in all it can make the same power and burn cleaner...make sure you up the fuel about 5% if you want to run it though. If you can get this it may help you pass emissions.

 

[swordfish]

The do actually make 1600cc injectors for DSM's. Aniel (Humble Performance) has them on his 10.0:1, T-78, Alcohol, Haltech E6K FWD.

jeff

 

[IPT]

Thanks crankbender

I have always wondered why my fuel settings always seemed to be higher than most people. I always use the ethanol.

 

[crankbender]

NP if you have any other questions you can im me on msn messenger I work swings for the USAF so I am usually around during the day and late at night.

 

[Mirko]

hello DSM Friends


i germany we can buy at shell 98 Octane.... and the must time i run with that... i never has use <94 Octane!!!

Mirko

 

[larryd]

must be nice.. but then again dont you have to pay like 4.00 a gallon?

 

[Mirko]

yes Gas is very expensive here in germany, but 98 Octane is only some cents more expensive as 92.

1L cost at the moment around $1.05
1Gallon is around 4,5 Liter !!!



i hate the prices here in germany, but we can do nothing against that..... but i can drive 140mph++++ or more ..... how fast your car can drive legal on the most highways!!!

Mirko

 

[larryd]

true.. but DAMN.. how often do you have to fill up yer tank? I can imagine I couldnt afford to drive if i had to pay that much..

 

[Mirko]

I know its unbelievable how expensive gas is here in germany.....

germany is not so tall as usa.... cause that we dont drive so much (and also cause the gas is so expensive).....

i drive only around 500-800 miles in a month

because the gas is so expensive not many people drive here a V8.... you must be rich to can drive a V8..... or V12

but my Eclipse Turbo also takes alot when i drive fast

Mirko

 

[gstspyder1998]

I'm using 91 octane because that's all you can get in California. I also add xylene when I feel the need.

 

[DSMSTYLE]

92 is the lowest. C16 when I have spare cash... yes thats the wallet crying

 

[Bohrn]

my car had been on a steady diet of 89 for years. The lady that had it didnt drive it hard enought to notice, so she saved money at the pump. I put in 94 to dilute the 89. Once the computer was able to adjust to the higher octane fuel, I was back up to factory specs powerwize. After the 94 octane is used up, I will use 91. That is what the factory reccomends.

quick question for crankbender...

Isn't octane just a measure of a fuel's ease of ignition?? the higher the harder it is to ignite? You say that octane is an actual "thing", whereas I was taught that it is more of a concept. Additives increase a fuel's octane for sure, but they aren't octane.

now I'm confused

 

[DSMSTYLE]

to add to the mix what abotu knock? My roomate has a 1G TSi AWD and was getting knock in 2nd gear and up upon higher rpms and couldn't figure it out for ****. The idea was thrown out there to toss in some 110 or higher and see if it goes away... after everything said and done he did this and now no more knock....??? any ideas where this may be related to the octance or just one messed up knock sensor.

 

[crankbender]

Sorry I was gone so long had an issue involving a drunk driver and my car not having suspension on the drivers side....etc you get the idea.

Quick answer (better answers to follow if needed):

DSMSTYLE knock is dependent on many things. one of these is indeed the octane (see below) of the fuel. there are many other factors that need to be addressed tho (110 octane gas is really expensive to drive on daily). If you need i can probably help you on diagnosing your problem. e-mail me some time or drop me a message on messenger.

BOHRN : yes and no. There is an octane. It is a hydrocarbon containing 8 carbon atoms. You could possibly have cyclooctane also. The tendency of a fuel containing only this molecule is used to establish a base octane rating of 100. Then other fuels are checked against this to give them an octane rating. Higher octane at the pump does mean it is less likely to knock but does not mean it has more octane. The rating is actually the average of 2 different ways to measure it in most states (all?). I mentioned the octane about the alcohol because i just basically had a brain fart (mistook rating for content). alcohol has a very high octane rating but no octane content...

Good call on catching it! kudos


Hope that answers your question and once again sorry for the delay

 

[Bohrn]

hey thanx for clearing it up

 

[Mitsu_Racing]

I guess i'm in trouble i have been using 87 octane since i got my car 2 years ago. Just recently i moved up to 89. I've never noticed any problems though. I'm at stock boost, 14LBS. Should i move up to 91 oct. now. What exactly happens to a car like mine that has been using 87 octane? What are the side affects? Also what is detonation? Thanks.

 

[crankbender]

sooo many questions. First off there is no way of knowing if your car was detonating without having logs of the knock sensor. 87 octane didn't necessilarily hurt your car...you would probably know it if it did. If you detonate you can literally melt your pistons...or just pit em either way it is bad. You want to run the lowest octane that works well. That means get a logger and know for sure, or run the highest you can get and be safe. Remember detonation is more likely in warm climates so living in pa is probably helping you. The following is from autolite and explains it well.

What is a detonation?
Spark plug engineers will tell you that detonation is the result of two flame fronts colliding in the combustion chamber. What that means is that the air-fuel mixture has been ignited almost simultaneously in two locations within the combustion chamber of an engine. One flame front was probably ignited by a spark plug, while the second front was ignited spontaneously. The most common causes of detonation are too low octane fuel or over-advanced ignition timing. The result produces the characteristic "knock" or "ping" sound associated with detonation. If left unchecked, it can cause serious engine damage. Expect broken or bent valves and spark plug tips.

What is pre-ignition?
Pre-ignition is similar to detonation, but only one flame front is ignited in advance of the spark. The ignition point can again be a hot spot, but the hot spot will usually be glowing deposits or metal such as the spark plug electrodes or an exhaust valve. A spark plug center wire may start to glow and cause pre-ignition if the spark plug has too hot of heat range for the application. A lean fuel mixture, a defective EGR valve or over-advanced timing may also cause this problem. Sustained pre-ignition will likely melt spark plug electrodes, and it can burn holes in valves and pistons.

 

[dsmnate]

I always try to run 93 octane....I tried 92 from Sheetz but have never gotten as good of gas milage on it. After trying it a couple of time I now only use 93 octane wich is the highest around here unless you go to Sunoco but they cost a hell of alot more than anyone else.