do a search on 'break in' for more info...most people say 1000 miles...I also heard 55 was just the recommended speed since that used to be the speed limit..? I don't know how you could drive an IS for 1000 miles w/o exceeding 55...vary RMPs, but don't go too high for too long...again, do a search to read all the advice from the past, I remember this topic being hot about 2 months ago
I remember reading about related threads a long time ago, wish I paid more attention. My dealer told me just to drive it the way I would normally drive it but I'm still trying to keep it under 3krpm for now, till someone that really knows their sh*t can gimme an accurate answer.
Well I don't want to go into too much detail, but here's the scoop:
Dealers can not tell you to break the law... so they tell you to not drive about 55 (some will say 65). This is below the speed limit, so they can not be held liable for you breaking any laws.
While you shoul "baby" your car and not over-Rev it, you also need to keep in mind to Rev it hard once in a while. When you do rev the engine high (not more then 5K), do NOT keep a load on the engine (essentially, quickly accelerate, then let off the gas immediate and coast back to "normal" driving speeds).
Also, keep in mind to vary your RPM/speeds all the time... speed up a bit, slow down a bit...
Now I don't want to get too technical, but the reason you don't want to drive slow the entire time is because you are trying to seat the rings in the cylinders. The rings expand with heat and pressure, and this can only happen when you Rev the engine high. However reving the engine high all the time also has adverse effects. So the compromise is drive slowly all the time, with occasional high revs.
Ok enough of that... you can search for more answers if you want.
A member gave a very clear and well-informed answer to this some time ago. Speed is not the issue. You can and should run the engine even up to the redline occasionally during the break in period! The reason is to more evenly seat the pistons and their rings into the cylinders. At redline the pistons may travel minutely further up and down the cylinder and hence "etch" it more evenly. Keeping the revs under some low number means the rings may create a small "lip" in the cylinder, just short of the top and/or bottom. Not a good thing.
So just make sure you drive the engine across the entire rev range, including high revs. Sounds more or less the same as what your dealer said . I have always followed the advice to "break it in the way you plan to drive it". I drive my cars hard, so that's how I break them in. I've an engine last to 120,000 miles (at which point I sold it) with NO problems. Your mileage may vary.
thx for the help everyone... my dealer told me the samething.. to just break it in like how I'd normally drive it... but don't keep it at the same speed for long periods at a time.. but I'm still skeptical... why would all these ppl give false info (strictly less than 3krpm or 55mph)
so in your opinion speed do not matter at all.. just don't keep the same rpm for long periods at a time...