Jeez, I'm starting to be sorry for opening another can of worms on here...

 

You did say the question is "ever persistent"!

So far, the discussion has been civil, and hopefully it will stay that way.

 

Don't be. I think it's a good topic. Enough people are getting their cars that we've moved on from WTF IS MY F'N CAR OMFG OMFG OMFG to proper break in procedures. It's progress. Really!

My take is that by the time we get the cars, the rings have been mostly seated. In order to really break a car in hard, you'd need to take it as it rolled off of the line.

 

My hope, and I guess it was too much to hope for, was that everyone would not get hysterical over ANOTHER non-issue.

It really isn't going to make any difference whether you break it in by running it hard or going easier on it. The rings will be seated in either way, one way just takes a bit longer than the other more fun way to do it.

 

I don't see anyone getting hysterical here. It's a contentious issue. I for one think it's a really relevant topic for discussion.

 

Okay then, I started this thread and said my piece, y'all argue(discuss) it out as long as you want.

 

I don't think I'd want metal shavings in my oil pump at 7k or scoring the cyl walls.

If you are going to bang on it, put some fresh oil in it first.

 

While I can't speak specifically to his assertion about the ports, did you ever understand the venturi concept in carbs? Some narrowing/funneling of the throat actually speeds up airflow.

Lighten up until you can cite some flow characteristics.

 

Bernoulli's principle.

 

 

It seemed to work for Lockheed and the Air Force.

 

Cool.. what did the Ford guys say to do?

 

Picked my 2006 up right off the rail car in Jackson MS, had 2 miles on it. Broke it in with the whip. Full power run ups in 4th gear from 1500 rpm to rev limiter about 10 times. Runs 13.1 @ 106.7 with a tune and xpipe on the stock Pirellies, and gets 28 mpg at 70 mph, and dosen't need to have oil added between oil changes at 5K miles. The car is at 50K miles currently. Think of every drag car purposly built, they don't get broken in with a gentle run in either, if it made them faster, they would be. I've built a lot of motors, long time ago piston ring boxes actually said to do this on the label.

Very good advice, give it the whip.

 

I agree, but "increasing the speed of the air (ft/s)" and "increasing the volume of air actually passing through the port (cfm)" do not mean the same thing.

Anytime air passes through a smaller area, it must speed up, but the increased pressure in the narrow area (which is causing it to go faster), will cause less air, overall, to move through that opening.

 

He wasn't concerned about running it hard when it was new. you can read more if you check out the first post in the thread I had linked.

 

I don't think anyone is getting hysterical. I appreciate the chance for intelligent discussion about this stuff with other car enthusiasts.. it usually ends up with me learning a thing or two.

I agree that it won't make a huge difference how you break in a modern car, but that "moto man website" does say some extremely controversial things, but I think that's why it's good that we talk about it and see other perspectives..

 

This is true for steady state conditions, but in 2 and 4 stroke engines flow conditions are mainly transient, which is why in certain circumstances smaller = more flow.

 

Another counter-intuitive example has to do with turbulent flow. While turbulence generally would mean more drag (because more energy goes into 'spinning' the air), golf ***** have dimples to create turbulence because it reduces drag.

 

The holy grail of cylinder head ports. Smaller or same cross section and yet more CFM = more power.

 

Ah.. ok, didn't know that.. that makes sense.