as you may or may not know, i'm building my 2.5, and i want to know everyones opinion on the new motor. some cars these days come with synthetic on their new motors, and am wondering if those cars were broken in at the factory with dino oil, or if they have always had synthetic. i rebuild aircraft engines, and for the first 25 hours of break in we use mineral oil. and until they quit using oil, you stay with it. what i'm asking is, is dino oil necessary, or can i use synthetic. also, what do you guys think of this break in proceedure? http://www.mototuneusa.com/break_in_secrets.htm

Subaru and Honda factory break-in oils usually contain a bit more moly. I would use a good dino with moly ie. Chevron/Havoline, Pennzoil for 1k then change to whatever you wish to use.

as you may or may not know, i'm building my 2.5, and i want to know everyones opinion on the new motor. some cars these days come with synthetic on their new motors, and am wondering if those cars were broken in at the factory with dino oil, or if they have always had synthetic. i rebuild aircraft engines, and for the first 25 hours of break in we use mineral oil. and until they quit using oil, you stay with it. what i'm asking is, is dino oil necessary, or can i use synthetic. also, what do you guys think of this break in proceedure? http://www.mototuneusa.com/break_in_secrets.htm

You should deffinately use Dino for break in - I hate to say it, but its true. After break in you can switch to synthetic.

I also agree with the above break in proceedure - it works, I have used this method on several of my own builds. Especially the immediate changing of oil.
Runing them hard seats the rings the best.

yeah, i think it makes sense

yeah, i think it makes sense

Well the last 2 subie's I have had, I did break in as such and bone stock they made 9-14 whp more than any other stock one on the dyno.

I have also done this with my '76 vette stroker motor - it was one of the fastest strokers out there.

Also - one thing you dont want is all that break in crap cycling through the turbo at high preasure, so change that oil! at 20-30 miles and again at 1200-1500 miles. Then at 3k miles again and start your every 3k change or move to synthetic.

On my second 2.5L block in a my04 sti. First one got destoryed due to those lovely det issues.. anyways the thread is around here somewhere. The second block I broke in with mobil 1 5w-30 full syn. Changed the oil at 30 miles, again at 1000 then one at 3000, with every 3 thousand after that. For the first few miles I ran it at varying load levels, nothing extreme but not taking it terribly easy either. After the first 10 miles I returned to my normal driving. I now have 13k on the new block with no oil consumption issues and the car pulls harder then the first block ever did. Shrug syn seems to have worked for this breakin =)