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Discussion Starter #1
Changing factory boost gauge color?

ok, i'm sure this has been discussed before. i was reading the post on engine break-in and it seems alot of people are confused about the differance between the two. its all a matter of the molecular structure of the oil. with conventional oil the oil molecules are not uniform. they vary in size. with synthetic the oil is engineered to make all of the molecules uniform in size. it was stated that it is best to use conventional oil during break-in. from my understanding this is correct. after 1000 miles switching over to synthetic should'nt be a problem. as a matter of fact most engines will make more power using synthetic. this is because there is less friction in the engine making it run smoother by providing superior lubrication. however once you go synthetic there is no going back. you should never go back to a conventional oil. in the end synthetic oil is far superior to conventional oil.
as for the reason for breaking in a motor at all? well its my undersatnding that it has to do mostly with properly seating the rings. if the rings don't seat you get fuel wash in the cylinders. fuel is a poor lubricant. and it will ultimately lead to a shortened engine life. of course how many of us are expecting to get 100,000 trouble free miles from our STi's. in the end its all a matter of how much money are you willing to spend? sure you could rev your STi to 7grand right out of the lot, but you'll be looking for a rebuild in 20,000 miles. and to some of us that might not be a bad thing.
 

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I don't think taking your car to/near redline "before the end of the breakin period" will cause you to need a rebuild within anything close to 20k miles.

I'll be hoping to get as many trouble-free miles as possible.
 

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Discussion Starter #3
every engine requires a break-in. even when you build a new motor you're supposed to fire it up and let it run at like 2500 rpm for a half hour to get it lubed up. then you change the oil and are supposed to still take it easy. parts need time to wear in to each other. and taking it easy for 1000 miles does'nt seem like alot to ask for a break-in. sure a few trips to redline may not cause catastrophic engine failure but it strikes me as one of those better safe than sorry senarios. i too hope we all have many trouble free miles with our STi's but the truth is higher RPM's equal more wear and stress on an engine. if Subaru says 1000 miles than take it easy for 1000 miles. i just don't think its wise to second guess hundreds of thousands of hours of R&D.
 

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Start looking into the break-in tips for small airplane engines.

I wonder why their manufacturers recommend such a different style.... (IE, most aircraft engines are recommended for a "hard" style break-in from what I have been able to read.)
 

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Discussion Starter #5
are we driving airplanes? i'm not familiar with the break-in procedure for plane engines. at the same time i'm not sure waht you mean by "hard" break-in. i also think that break-in on our STi's refers to the entire powertrain, not just the engine.
i would imagine that the biggest differance between planes and cars is the way thier are used. you can't idle around in the sky with your plane. its a certain rpm or you probably won't stay airborn.
 

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Subaru engine is about as close to a small airplane engine as you can get. Continental and Lycoming both use boxer engines for small airplane applications. And you don't drive an Airplane. You Fly it,
Maynard/Az Silver/Gold STI. Commercial Pilot ASEL, Instrument Airplane, Advanced ground instructor.
 

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The only reason MOST people don't put synthetic in right off the bat is the fact that they know they will be changing it after 1000 miles. It won't hurt a thing to break your engine in with synthetic oil.

Bitablur, I'm not flaming or anything, but if you have documented proof that it isn't a good idea to break-in an engine with synthetic oil. I have my documented proof that it won't hurt anything. I have a friend who is a chemical engineer and has done work for many different petroleum companies through his company.
 

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bitabur said:
Start looking into the break-in tips for small airplane engines.

I wonder why their manufacturers recommend such a different style.... (IE, most aircraft engines are recommended for a "hard" style break-in from what I have been able to read.)
Probably because the engines are totally different...or at least their application and use.

-st
 

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bitabur said:
yxan2 said:
you can put syntehetic oil when ever you want :)

but its not a good idea....
Based on? MANY engines come with synthetic from the factory. For example, just about all the Audi engines that are currently in production. It is absolutely, 100% fine to change to synthetic at the first 3k mile oil change.

-st
 

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To change to synthetic, but not to start with it.

The reason I made the point about small airplane engines is because they are 4 cycle engines, many of them VERY similar to the engine in the STi, and many airplane manufacturers recommend ONLY pure mineral oil during break-in, with its high viscosity. This is because higher friction helps wear the engine parts and break them in faster, allowing for a smoother and better fitting engine.

Even if they come with synthetic from the factory (which i have my doubts about...) that doesn't mean they weren't broken in at the factory with conventional oil to begin with. It is an important step.



Also, chemical engineering and studying the molecular difference between snythetic and conventional oil isn't going to give you any conclusive evidence as to the best treatment of your car engine, it's just going to help determine what chemical differences will yield different results.

"Documented Proof" only means that one person tried it once, and wrote it down on paper.
 

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Here's an important detail that many people don't realize: given the same grade of oil (i.e. 5W-30), synthetic will have the same frictional properties as natural oil. The key difference is the longevity - synthetic won't break down at higher temps (which is really key for our turbo engine). I did try this in the lab - heated a beaker of natural and a beaker of synthetic to 300F for 8 hrs; the synthetic looked the same, natural had turned BLACK. Just to be 'better safe than sorry' I broke in with natural; going to Mobil 1 for change #2.
 

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Discussion Starter #16
the bottom line is that synthetic motor oil is far superior to conventional. there is no reason not to run it in the STi. i had forgotten that synthetic motor oil had a higher resistence to breakdown at high temps. thats just another bonus. check out the company AMSOIL. i believe they are the first company that offered a synthetic motor oil. i would imagine they have a website detailing everything we've been talking about. as far as breaking in a motor with synthetic? i had heard that the new corvette came with synthetic oil and that they were having issues with the rings seating. it does'nt matter anyway, since i don't think the STi came with synthetic to begin with. i however will definately be switching to synthetic in the future.
 

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syntethic motor oil even gives more power, there was a motorcycle article in sport rider where they had dynoed bikes like the gsxr 1000 it gained almost 3.5hp from just an oil change, although a motor cycle engine revs alot higher than a car engine there still are benefits to using synthetic oils, and they can be used when ever one wants to.
 

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Discussion Starter #18
MY 2005 STi production dates

...and they can be used when ever one wants to.
yes, but the truth is once you go synthetic you are NOT supposed to go back to conventional. honestly though, who would? with all of the benefits of using synthetics. we all paid $32000 plus for our Sti's why go cheap on the oil?
 

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Maynard/AZ said:
Subaru engine is about as close to a small airplane engine as you can get. Continental and Lycoming both use boxer engines for small airplane applications. And you don't drive an Airplane. You Fly it,
Maynard/Az Silver/Gold STI. Commercial Pilot ASEL, Instrument Airplane, Advanced ground instructor.
I think you are overestimating the importance of any similarities between the boxer Subaru which is purpose designed for the needs of propelling an awd car across the surface of the earth, and the boxer Continental or Lycoming which are purpose designed for propelling an airplane across the sky.

Following the Subaru recommended procedures might work, huh? They did design the engine after all, and one would assume they MIGHT know what kind of break in their engine needs.
 

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Their suggested break-in procedure is probably designed more to the effect of stopping people from breaking anything within the warranty period than with performance and power longevity of the car in mind.


And I don't think there is any reason to assume that there is a significant engineering difference between the subaru boxter and an airplane boxter. Engines all function in almost the same basic way, and it shouldn't matter if the engine is intended for a different application.
 
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