Miles

how long did you guys go before really wailing on your srt-4's? i was told by the salesman at the dealership that the engines came broken-in from the factory, but i'm fairly certain he might have been legally retarded, so i don't really know whether to believe him or not. i finally got some 93 octane in the car tonight, and took it up through the top of 3rd gear at near full throttle on a street i had no business doing more than 40 on ( but that's a different story altogether) to get the ecu back on the right fuel map... 15 psi is way more fun than 2... but i've been taking it easy otherwise... should i be driving like my grandmother or should i drive down to orlando speed world right now and beat the shit out of it?

Fast420A

Reset the ECU by disconnecting the battery for a few minutes. This is how I break engines in.

http://www.mototuneusa.com/break_in_secrets.htm

Nice and hard so everything sets in right. I had 4 miles on the car when I got it. Drove it nice and hard. Had 2 races against a WRX with only 320 miles on the car.

Josiah

just to let you know, engines do come "broken in" from the factory...all the cars follow a break in procedure when engines are belt, this is necesary to correctly seat the rings against the cylinder walls...however, a lot of people reccomend at least 500 miles on the motor before starting to drive it hard...however, it all depends on what you want out of your motor...there are multiple theories about how a motor should be broken in...but really, after it has been driven 20 miles there is not much you can do that will make a real difference(within 20 miles is when the rings are still in the process of seating)...and since I am sure it already has 20 on it...just wait till after 500

mpbiv

+1 to what Josiah said.

Personally I pounded mine to full throttle on the test drive. Rings either seat right away or not all. The only thing that is really affected by break in on a new engine is the block and head castings. Because they are brand new castings, it takes a number of heat cycles before they become completely stable. The material properties of the block and head change slightly as it is heat cycled after it is first cast. In the large scope of things this is not terribly important because the engine is over built, and the slight changes in the material property of the block and head do not effect the reliability of the engine.

You might hear from some places that sell race engines that they build their engines with "seasoned blocks" meaning blocks that have already been heat cycled.