sr20 break in

[SMatyac]

Okay I know this is a very controversial topic but I wanna get this right.

I'm building my motor with all new forged internals, and I'm looking up break in techniques and it seems a lot of people have luck with either taking it easy, or running hard from the get go.
There's shops that swear by each technique, but it seems more people recommend running hard from the start.
I know the main thing is not running synthetic oil at first and changing it often.

Ive read this http://www.mototuneusa.com/break_in_secrets.htm and it makes good points, but I wanted to get some input from people who have broken in SR's before.

But I really wanna hear from people that had their motors blow right after their builds. How did you break it in? What was the reason for the failure?

I know there's a lot more to reliability and power than just the break in process, but that's the only thing I have control over, so I at least wanna do that right.
I'm having my motor built by a reputable shop, so I'm relying on that part going correctly.

Also should I get it tuned before or after its broken in?
Its already tuned really well, but its tuned for stock internals with thick HG (about 8:1 CR), now im going to run 9.5:1 comp ratio, so I think ill need a new tune, but I don't wanna mess up the break in trying to tune it. But on the other hand I don't wanna blow the motor breaking it in because of the tune.

Any help and input would be awesome.
I have about a week to figure this out till my motor is done.
Thanks!

[Mikester]

Changing to higher compression, you will DEFINITELY need a new tune. Second, there is really no 'break-in' for an SR... More like a "touch all the right points" geared toward seating the rings for the different rpm ranges. It's not like the old days where you would change the oil to get rid of the metal shavings as things 'broke in'. If you rebuild an SR, run it up, then find metal shavings in the oil- you may as well take it back apart & figure out what went horribly wrong ;)

IMO, have your builder/tuner do the initial start/tune/run-in on the dyno- it will be worth the money if he/she knows what they are doing. This way you will be a bit more confident that all the right points were hit for maximum ring seating- then you can basically drive it however you want. A rule of thumb per a very smart builder I know is that whatever is done in the first 20hrs of engine life will pretty much dictate the rest of the motor's days from there on out. According to him, something like 10-15% of available power is either gained or lost by how it is ran in during those first 20hrs. He doesn't pull factoids out of his ass- his life revolves around having to be smart on everything automotive. The guy is brilliant.

I didn't read the article you posted... but if it's the one I'm thinking of, I believe it also says to use regular, not synthetic oil for like the first 1,500mi. This is also a good rule of thumb that most of the folks I know & trust follow.

Hopefully some of the actual smart guys will chime in.

Best of luck to ya.

[jr_ss]

There are A LOT of ways to do this... Some say baby it for the first 1k miles, some say go beat on it like you would normally, others say just stay out of or use low boost and drive around town. I've also seen guys break their motor in on a dyno. I'm not sure there is one correct way to do it.

I personally held my engine at 2k rpms for 20-30mins with an occasional rev here and there to help seat the rings in. Then I went and drove it around for a few hundred miles getting into boost here and there but never exceeding wastegate pressure, which was 11psi. Is it the right way? I don't know, nor could I tell you it was the wrong way. I can tell you my motor ran and made good power at 13lbs of boost.

Every engine builder/tuner has a particular way they like to do things. I think the biggest consistency I've seen over the years is putting load on the engine while breaking it in. My suggestion would be to put some miles on the motor before throwing big boost at it.