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This is a discussion on After Break In Period within the General Maintenance, Troubleshooting & Accidents. forums, part of the Tech & Modifying & General Repairs category; My dealer said every 4k was fine. Common sense really. Manual says 7500, but recommends more frequently than that. If ...

  1. #16
    Registered User XRedJar's Avatar
    Join Date
    Oct 2012
    Laurel, Md
    My dealer said every 4k was fine.

    Common sense really. Manual says 7500, but recommends more frequently than that. If I drove it really hard all the time, I'd round down and change between 3 and 3.5k. Since I'm not that hard on it, I think the dealer is right and every 4k is the way to play it.

    2013 Ice Silver Premium 5 door - Stage 1 E-Tune

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  3. #17
    Registered User wrxnguyen's Avatar
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    Jul 2013
    714 Orange County
    just putting this out here.. ive gone WOT like 10 times already and im only at 200 miles LOL :hides behind curtain:

  4. #18
    Registered User
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    Jul 2013
    I'm interested in Subaru's break-in recommendations. I'm driving a new 2013 WRX, just 150 miles so far. I am observing the 4k RPM limit, and will change the oil at 3750 miles.

    It's true there is a fair amount of wear in the first 1000 miles, but those bits of metal are caught in the oil filter, that's what it does best. The reason you need to change oil isn't build up of metal or grit, but build up of combustion products. The oil dissolves them, but can only hold so much. Turbocharged engines are considered extreme duty for two reasons: there is more exposure to combustion products in the cylinders when the boost is on (more fuel/air means more combustion products) and the oil bearing in the turbo is continuously exposed to exhaust gases. They seal as best they can, but the oil is the final barrier, and that exposure occurs anytime the engine is running.

    So I'll stick to 3750 for at least the duration of the powertrain warranty. It's actually 3750 miles or 3.75 months, and since I don't normally put 1,000 miles a month on the car, the time will be the limiting factor. At least I can schedule the oil changes well in advance.

    I also recently broke in an airplane engine. Airplane engines are mostly boxer-type flat-fours. Mine is 6.4 liters (390 cubic inches) and makes 210 HP at 2700 RPM. Not turbocharged, I'd love one, but the engine alone set me back 35 bills for a rebuilt unit. A turbo setup would double that.

    Airplane engines are operated much differently than car engines. They are almost all air-cooled, which means that in fact they get a lot of their cooling from the oil - 8 quarts of it, with an oil cooler/radiator exposed to the slipstream. Throttle and mixture control are manual from the cockpit. Every takeoff is WOT and max HP; after 500 feet you retract the flaps and gear, at 1000 feet throttle back to climb power of 85-90%. During takeoff and climb operations the mixture is run quite rich; the extra fuel provides a lot of cylinder cooling as it evaporates.

    The cylinders are air-cooled by ram air entering the front of the cowl. The cylinders distort and get oval as they reach operating temperature, as the air rushing over the top and bottom provides better cooling than the more or less stalled air at the front and rear of each cylinder. As a result, all airplane engines burn oil, it is a question of how much. Most people don't worry until the oil consumption exceeds 1 quart per hour, although new engines often burn a lot less.

    So there is no RPM or power restriction during break-in. In fact, Lycoming wants you to run at least 75% power for the first 25 hours, and requires one 30-minute WOT run at low altitude where the air is thicker and you get 100% power from the engine. The idea is to provide lots of compression to seat the rings and make sure they wear into the cylinders.

    The WOT run at 190+ MPH was exciting! Airplanes have a speed limit, a green arc on the airspeed indicator. If you get into the yellow then a bump might bend or break something, if you go past the redline speed then flutter will eventually destroy the controls, and you will die. The only time you go to redline is an emergency descent if the airplane is on fire. The redline on my airplane is 198 MPH.

    The engine is shipped with a break-in oil, an ashless dispersant mineral oil with special corrosion inhibitors. Airplane engines tend to spend a lot of time not running. After the 25-hour break-in period is over, switch to synthetic 20W-50. Oil change interval is 100 hours or 6 months, whichever comes first. My mechanic cuts open the oil filter after EVERY oil change, and we both look at it for any signs of distress. I also have a sample sent out for analysis of wear metals.

    Having your WRX engine quite is a PITA, having the airplane engine quit in flight is at best extremely exciting, and at worst fatal. It shouldn't be fatal; all that happens when the engine quits is that I have to land, but I accepted that responsibility when I took off. The airplane continues to fly, and will glide about 2 miles for each 1000 feet of altitude. But emergency landings do kill a few pilots each year.

    The engine runs at 65-75% power for hours at a time. I have an engine monitor instrument that monitors and displays CHT and EGT for each of the four cylinders, oil pressure and temp, manifold pressure, outside air temperature, bus voltage, fuel flow, fuel consumed and remaining. You lean the engine until the EGT peaks on one cylinder, then either run there for max economy or increase the mixture until peak EGT drops by 75 degrees for max power.

    My cruise airspeed is about 163 MPH, and I burn about 10.5 GPH (gallons per hour) after leaning for cruise power (over 25 GPH at take-off). At higher altitudes my fuel burn is less but so is the engine power - there isn't enough air and the manifold pressure falls even with WOT. So my mileage is about 15 MPG. Not bad for 163 MPH in a straight line.

    So what I took away from the airplane engine break-in is that there might be some benefit to getting a bit of boost on the WRX during break-in. The higher combustion chamber pressures may help seat the rings a bit better. So I'm not afraid to goose it a bit, I just have to shift when the needle gets to 4k. Why not? It's a fun car to drive.

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