ProCoach

From many years at a dealership, then building Italian racing engines, it's best to avoid steady throttle openings at steady RPM's during the break in period. Periodic lifts or breathing off the throttle, especially on the highway, is a good idea.

I remember picking up a new E36 M3 LTW off the showroom floor at Hendrick and being careful to go through a careful 1200-mile break-in. On the way to Roebling Road a week later...

rkeele66

How do you put that kind of miles on a race car that's not street legal??? I just run one or two sessions taking it easy then I was always told drive it like you stole it after that. I realize that's great for a street car that you want to last 100,000 miles but for a race car??? spending big money to enter an event that you have to keep rpm's below redline what? I do 20 min. at 2000rpm then dyno time and breakin oil change .

gbuff

The OP was referring to running a street car at a DE; having said that, though I've never raced or owned a race car I'd think your engine builder could tell you the proper break-in procedure......

mark kibort

thats all you can do and thats fine. there is NO guarantee that "proper" break in does much of anything. more important is heat cycles than miles and general wear in of the bearing surfaces and rings , if the walls of the cylinders are steel. (if not, they dont need breaking in and there is no need to worry about the types of "RPM" that you run at the start.)
run the engine for about 30 mins. drive it around a parking lot or on the dyno . warm and cool down a few times.... a session on the track at maybe 80% redline. then, have fun.

thats pretty old school now. the materials are better, the surface finish is different than the old days when the hashing on the cylinder walls needed to be gently removed by driving the car at varied engine speeds for 1000 miles. now, many of the cars are "broken in" at the factory, and or do not require such care. 1000 miles of street driving.. thats like a month. 60 heat cycles, average speed of about 35mph, etc. there is no way to do this with a race car and a street car, it helps with getting all the surfaces' wear patterns up to snuff evenly. i dont think ive ever seen how taking a engine to the track after 30mins of driving, effects anything life related.

ProCoach

Yep, get any pro racing engine (and quite a few good club race engine builders do this too) and you'll get recommended ignition timing (if it's not electronically set), target temps and pressures, torque settings for commonly serviced items, valve lash (if not hydraulic), oil recommendations, rev ranges. Also, pretty much all the competition engine builders, for their own knowledge (and protection) conduct dyno tests before the engine (or car, if they reinstall it) is delivered.

I know for many exotics, there's time put on the engines at the factory, too. And they STILL recommend certain procedures within a mileage range.

mark kibort

yeah. most top engine builders will put heat in the engine a few times and do all-out dyno runs for max torque/ power and tuning. interesting that after that, they would want YOU to take it easy. the main thing is driving it for a bit. dyno or parking lot or around town.... change the oil and then you are good.. anything that is left in the engine, when assembled, and any wear in particulate, is captured in the oil filter. change the oil , filter and then you are good to go. its not like the chevy or fords of yesteryear as far as materials, clearances and design. also flat tappets, etc all needed time to wear in... now, many of those concerns and designs are just not present. again, if you have an alusil or nicasil engine, there is no real break in for the rings and cylinders. (however, some slight break in is desired for bearing surfaces )
Many of the porsches have alusil or Nicasil engines. porsche 911 turbos have used nicasil for many years. many bmw, audi, mercedes and VWs use this block design.

rlm328

Mine goes on a dyno for an hour. I have a stand alone ECU and it allows me to tweak the ECU to the variables of the new engine.