2.5i Opensource Tuning

[OhBe1]

Thanks and when do we need to define adjectives on this forum when talking about gasoline? Why would you think 93 is better than 87 if for no other reason that one is 93 and the other is 87? Are you saying 87 and 93 are one in the same?

 

I am merely asking why you think 93 is "better" than 87, in a car not tuned for 93. Indeed, some say it's actually worse.

[andyarmada]

93 and 87 are practically the same thing in our cars. When you tune, higher octane adds a safety to further prevent knock, this is mostly in turbocharged cars because they are much more knock prone (which is why they are supposed to be run on premium only), so in essence, on a non-tuned 2.5i it doesn't matter because the engine is running without any forced induction and is significantly less prone. Running 93 in a non-tuned 2.5i is just taking money out of your wallet, but getting it tuned FOR 93 octane will let you yield much higher power gains than on 87.

[mickeyd2005]

I would encourage all car enthusiasts to get a cable and datalog their car. Even if it is stock, datalogging can be informative.

 

Using gas with a higher octane than what the car is tuned for is a waste of money. HOWEVER, the question is what is the stock car tuned for?

 

It's not 87 octane.

 

All stock normally aspirated Subaru tunes that I have seen will knock like crazy on 87 octane. The ecu eventually learns where to pull timing and uses that.

 

Tuning a NA car is really not that beneficial. Maybe 10 hp all things being equal. If you use a different than stock intake, then the car will benefit from a tune.

 

I would drop the car out of stoichiometric fueling earlier than stock. Run a richer setup. Then lean the car out to AFR 13 in the top end.

 

Pull timing where appropriate for the gas chosen.

[shtbxr22]

well, the ecu could not be communicated with. by the way, while datalogging with the wideband A/F, we noted borderline dangerous lean conditions between 3k-5kRPM. also stock map is very choppy. will be posting results when new cable comes in for canbus communication.

[GEE-OTTO]

93 and 87 are practically the same thing in our cars. When you tune, higher octane adds a safety to further prevent knock, this is mostly in turbocharged cars because they are much more knock prone (which is why they are supposed to be run on premium only), so in essence, on a non-tuned 2.5i it doesn't matter because the engine is running without any forced induction and is significantly less prone. Running 93 in a non-tuned 2.5i is just taking money out of your wallet, but getting it tuned FOR 93 octane will let you yield much higher power gains than on 87.

 

That is my train of thought

[SSpeed]

Higher octane simply means the fuel burns slower, not that it's higher quality gas. Some higher octane gases are a large mix of ethanol, which has less energy than gasoline. In turbo cars and high compression motors higher octane is a safety factor that helps control detonation. In an NA car where it's not needed it can rob power because it burns slower. Running the right octane for your motor is going to produce the best results.

[Pawlwawl06]

So what about 89 octane? Is it of any use to run in our tanks?

[cybonic]

any opensource tuning for 2.0r? only option i have is dastek unichip q. which is universal for all cars.

[cybonic]

and we get 95 or 98 oct here.

[whitetiger]

^octane in your part of the world is calculated differently than in the USA. 98 by you is really 93-94 by USA standards.

[cybonic]

^octane in your part of the world is calculated differently than in the USA. 98 by you is really 93-94 by USA standards.

 

my bad. didn't know that. really interested in opensource. if there is other choices other den dastek. what abt the accessport for the impreza?

[GEE-OTTO]

^octane in your part of the world is calculated differently than in the USA. 98 by you is really 93-94 by USA standards.

 

 

Oh China LOL! Currency as well as Octane are not equal

[theflystyle]

recommended data cable vendors?

[cybonic]

Oh China LOL! Currency as well as Octane are not equal

 

sg currency is also much greater den china

[jdmhatch08]

ive been interested in getting a tune.. so far i added a spectre intake and coated it to protect from the engine heat, gms pulley, and coming monday grimmspeed/group powerpack. throttle body spacer and phenolic spacer.. i want to get it tuned but not interested in spending 500 for a tune at the local subi shop! how much and where can you purchase cables?

[03LegacyWgn]

wish i could tune mine, looks like it may just be a piggy back unit..

[H2Otx]

Higher octane simply means the fuel burns slower, not that it's higher quality gas. Some higher octane gases are a large mix of ethanol, which has less energy than gasoline. In turbo cars and high compression motors higher octane is a safety factor that helps control detonation. In an NA car where it's not needed it can rob power because it burns slower. Running the right octane for your motor is going to produce the best results.

 

Higher octane does not mean the fuel burns slower. Higher octane means the fuel doesn't ignite as easily.

 

It relates to compression and detonation. If you run 87 the fuel requires less energy to ignite but doing that in a high performance motor can cause the fuel to ignite prematurely due to heat and other factors.

 

 

What they don't tell you is what is in the gasoline that you buy at the pump...(My father has worked in a refinery for over 25 years)

 

First of all every gas station really only has TWO tanks, low grade octane and high grade octane (87 and 93). The middle one just comes as a mixture of the two.

 

Gasonline isn't really made specifically for vehicles. Gasonline is a by-product that refineries just throw together. It is a whole jumble of the left over crap they can't sell on the regular market, mix it and call it gasoline. Now here is where octane comes into play...the lower octane (low grade) has more crap in it that you motor can't really ignite and burn off. Therefore higher octane is also cleaner burning. This leads to cleaner exhaust gases, less resedue in your cats and mufflers, less crap in your motor. Higher octane leads to less maintenance and longevity of your vehicle.

[SSpeed]

I definitely respect the insight you have in to that, I saw this though as well, it could be that they are over simplifying for the lay reader?...

 

http://www.state.mn.us/mn/externalDocs/Commerce/Gasoline_Octane_Facts_102902052227_OctaneFacts.pdf

 

Octane Facts

• Knock occurs when cylinder pressures are high. It is normal for an engine to ping a little at full throttle because cylinder pressures are very high at full throttle. Engine knock, however, should not be ignored since it can result in serious damage to the engine.

• High octane gasoline burns slower than low octane gasoline. The slow burn prevents engine knock when cylinder pressures are high.

• If your engine runs well and does not knock or ping on low octane gasoline, there is no advantage in switching to higher octane gasoline.

• If your engine knocks or pings, it does not necessarily mean something is wrong with the gasoline. It could be a problem with the engine’s electronic control systems, ignition timing or exhaust gas recirculation. On a high mileage engine, a carbon build-up in the cylinders can increase cylinder pressures and cause knock.

 

Octane Myths

• High octane gasoline improves mileage.

In general, if your car is designed to run on 87 octane gasoline, high octane gasoline will not improve mileage. If switching to high octane gasoline does improve mileage, you might find that your engine, or its control systems, need repair.

• High octane gasoline gives quicker starting.

No, it doesn’t.

• High octane gasoline increases power.

If your car is designed to run on 87 octane gasoline, you shouldn’t notice any more power on high octane gasoline. Again, if it does make a noticeable difference, your engine, or the engine’s electronic control systems, may need repair.

• High octane gasoline has been refined more – it is just a better product.

Additional refining steps are used to increase the octane; however, these additional steps do not necessarily make the gasoline a “better” product for all engines. They just yield a different blend of hydrocarbons that burn more slowly. The additional steps also increase the price.

[H2Otx]

SSpeed: I wasn't trying to call you out or anything, you just happened to be the easiest post to quote without going back a few pages.

 

If you take a beaker of 87 octane gasoline....and take a beaker of 93 octance gasoline....and light them....yeah they burn, they both will burn for a while

 

Take that excercise a step farther....put both into two spray bottles and put a lighter in front of each one and squeeze...both will shoot flames

 

Going even farther....spray each type in to two glass cylinders while taking a smaller cylinder and compress the air and fuel mixture....both cyclinders will break

 

To say one burns slower than the other doesn't make much since. On a large scale I could see someone making the arguement that one "might" burn slower than the other. But what we are talking about here are minature controlled explosions. An explosion doesn't care whether one burns slower. The burning, if anything, takes place after the initial explosion inside the cyclinder and just means more things are burning off leaving less un-burned particles in your motor, exhaust and etc.

 

Higher octane: means that with the compression of the A/F mixture, the heat of the motor and friction of the piston rings on the cylinder walls...it will be less likely to ignite prematurely (pre-det) before the spark plug is triggered

 

My only reason of bringing this up is people argue that "High octance burns slower, it leads to better gas mileage, it robs performance..." etc. Which to me they are thinking of the situation entirely wrong. I have seen it on motorcycle forums and my jetski forums. It sounds so obsurd to try an make that type of argument. You are igniting the fuel when it is compress, not burning it as it enters the cylinder.

[thestratomaster]

Spectre like the stuff from pepboys/autozone? You have any pics? I was interested in doing that

 

ive been interested in getting a tune.. so far i added a spectre intake and coated it to protect from the engine heat, gms pulley, and coming monday grimmspeed/group powerpack. throttle body spacer and phenolic spacer.. i want to get it tuned but not interested in spending 500 for a tune at the local subi shop! how much and where can you purchase cables?

[SSpeed]

SSpeed: I wasn't trying to call you out or anything, you just happened to be the easiest post to quote without going back a few pages.

 

No problem at all, I was simply regurgitating what I always hear and didn't mind the extra info...

[H2Otx]

No problem at all, I was simply regurgitating what I always hear and didn't mind the extra info...

 

 

Cool, bro.