Not sure if this has been posted before here, but I came across this today; it is a good read and informative on Porsche's philosophy regarding breaking in a new engine.

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Not sure if this has been posted or not before, but a good read from PCA regarding Porsche's philosophy on the 4000 rpm advisement.

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New Engine Break-in Conundrum

By Ken Koop
The Yellowstone Region (Old Faithful Newsletter)

Since I was a young boy, I have always wondered why it takes so long to break-in a new engine–especially those built by Porsche. Most people driving new cars also do not fully understand the real reason for the break-in period. Are you one of them? A good friend of mine just picked up his brand new 911 Turbo and complained about the break-in period taking so long (2,000 miles, not exceeding 4,000 RPM). We have talked about this issue many times over the past few years, always coming up with many scenarios of why such a long break-in period is required. However, we have never agreed on a reasonable answer. Well, you are about to find out the reason Porsche requires the break-in period it has today. The answer comes directly from the engineers at Porsche.

I was on a recent Porsche factory tour and was watching an engine being built and dyno tested. Each engine is built by a single person on a moving production line. Porsche feels that they can obtain better quality control with one person building an individual engine from start to finish. In addition, each engine builder can assemble every type of production engine that Porsche produces and every gasoline engine is still built at the Stuttgart factory. It takes 2-3 ½ hours to assemble each engine, depending on the type. Afterwards, the completed engines are either used in the cars produced at the Zuffenhausen factory or are boxed up and shipped to Leipzig (for the Cayenne and Panamera) or off to Finland (for the Boxster and Cayman).

Before all of the parts are assembled for a particular engine; the pistons, connecting rods and valves are individually weighed and grouped together using similar weights to optimize performance. They are put onto a cart that moves along the assembly line with each engine block. This cart contains every part required to assemble that particular engine which includes each washer, nut, bolt, bearing etc… As a result, if any part is left in the cart at the end of the assembly line, then—Houston, we have a problem!At the end of the assembly line, the engine is filled with Mobil 1 Synthetic Oil. Each engine is then dry run (without fuel), pressure tested and checked for leaks. Every car coming off the production line is also run on a rolling road dyno. This enables all cars and engines to be tested at highway speed before they leave the factory.

Some of the engines are also randomly selected to be tested on a dyno stand before they are installed into the car. The assembly plant has 5 dyno rooms located directly off the production line. The day I was on the tour, there were around 40 engines lined up on dollies. Some of these engines were in the process of being tested for quality control purposes. Once the engine is bolted onto the dyno, warm water is circulated throughout the engine to bring it up to temperature. The operator then starts the engine and checks for the correct pressures and temperature before the actual test begins. Engine speed is then increased in RPM steps to about 80% of its red line (the engine’s maximum RPM). The entire engine run takes around 30 minutes. Since each engine type (Turbo, GT3, Boxster or Carrera…) has a different red line, all of the data is recorded and analyzed after the test is completed.After the engine is turned off, the engine is again checked for seal leaks and its actual HP is compared to its advertised HP. To pass final inspection, the engine has to develop, at a minimum, 100% of what its advertised HP rating is. Also, the engine cannot produce more than 5% over that same advertised rating. If the engine falls out of those parameters, the engine is rejected and then torn down to determine why it did not deliver the anticipated HP.

When the test was completed, a Porsche engineer came over to review the results. I couldn’t resist asking the question that I had been searching to find an answer to for all these years. I asked “why does Porsche feel it is safe for a new engine to run at nearly full throttle in the factory, while the customer must keep the engine speed to no more than 4,000 RPM for a 2,000 mile break-in period?” I thought that was a logical question and if I do say so myself-well stated!

The engineer replied, “Herr Koop, you do not understand (that I already knew). When we do our engine test, the metals inside the engine never reach the temperatures they would when driven on the street since the test session is fairly short. In other words, the bearings, pistons and cylinders never get a chance to thermally expand to their maximum. Therefore, there is little wear on the moving components. But when you drive a car on the street, the engine parts expand considerably more because of the heat being generated from the engine running for an extended period of time. No matter how tight the tolerances are, there is always a slight amount of expansion in the material. The moving parts can wear quickly if exposed to excessive heat and not always in a uniform way. We also constantly vary the speed and allow the engine to run at both high and low RPM’s”.

“Porsche wants the engine to break-in slowly, which means it needs to maintain a lower operating temperature (below 4,000 RPM) and to allow all parts to adjust (wear-in) within their own thermal expansion parameters. This is also the reason why Porsche wants the owner to vary the RPM throughout the break-in period; therefore the engine doesn’t get use to one operating temperature range”.

“Porsche has been using Mobil 1 Oil since the early 90’s. With its superior lubricating properties, it takes many miles of driving (without getting the engine too hot) before the components actually seat (or break-in). Porsche’s own tests reveal that after 2,000 miles have been driven, all of the moving parts have had a chance to wear into their adjacent surfaces and then an increase in engine RPM is permissible.” I replied, “JA DAS SOUNDS GUT, when you explain it that way, it makes a lot of sense.” I thought to myself “You Dummkopf, why didn’t you think of that”.

The engineer commented that there were many other moving parts other than the engine that needed break-in as well. Wheel bearings, constant velocity joints, tires, brakes and transmission were just some of the other components that were mentioned.

So breaking it down into layman’s terminology, it all comes down to; higher RPM equates to more heat, which leads to greater expansion. For a new engine, that can mean uneven wear on certain parts if excessive heat is allowed to build up. In Porsche’s opinion, the thermal expansion of different parts and various materials need time to adjust to one another. Porsche’s time frame for that to occur is calculated to be 2,000 miles, with the heat restriction being 4,000 RPM. So simple; who woulda thunk.

Many experienced Porsche engine builders and experts on the Flat-6 engine state that the peak power of a Porsche engine is developed around the 20,000 mile mark. This coincides with the principle of what the Porsche engineer was telling me; “Break it in correctly and the engine will last longer and perform better”.

It only took me 45 years to find out the real answer to this puzzling question. After I returned home, I explained this to my friend. As for our ongoing debate, we now feel a solution to this riddle has finally been reached. Neither one of us had the answer to this complex question totally figured out, but we were on the right path! I am finally able to resolve another one of my life’s unanswered mysteries and now it’s been crossed off the list. I hope this helps explain one of your unanswered questions in the car world as well.

 

Thanks indeed for this brilliant and insightful piece. Makes one appreciate the car even more.

 

Interesting that this 4000/4200 rpm limit is directed towards the U.S. buyer. This restriction is not applicable in Europe and in fact the mechanic at my dealership here in Colorado advised that once the car reaches operating temperatures that I simply drive it. He said if anything, the break in period is crucial as to how responsive the engine is now and in the future. He said he always knows which ones are the "grocery getters." I know this is a controversial topic, but I took my mechanic's advise..... I will share this article with my mechanic...thanks

 

I'm leasing my 991. I have 2yrs / 15k miles with her. Can't wait for 2k. Time is ticking. I just hit 1k and I'm going to put my foot in it!

 

I'm going to vary my revs and not routinely run up in any gear but I will do it on occasion when the engine is warmed up. Probably won't do a launch control start for awhile and not often. I don't even buy bananas green so there's no way I'm going to wait a year to get to 2K miles to only THEN begin really enjoying my car.

 

Noooo not this again!!!! It's a car. It will not remember whether or if you exceeded 4000 rpm in the first 2000 miles.

These engines are amazing pieces of engineering and because the girls and guys who designed them told me how to break mine in I listened and did it their way

Have 22000 miles on the engine
It is quick and powerful.

It does not burn oil not a drop and while cruising at 75-85 mph it returns 32-33 mpg with the a/c on

Drive it like you stole it from day one if you want. I didn't

Btw it really lets loose after 20000 miles. Seems to have more power and torque.

 

If it 's leased, proper protocool is when you pick up the car you do a burn out leaving the dealership parking lot followed by a couple of donuts screaming "see you in 2 years! "

 

Thanks a lot for your very informative write up! I will follow this 2000/4000rpm rule after I receive my new GT3 next year!

 

That's a really nice and informative read! Thank You~

 

i just did my first 1K, and i couldn't resist any more, so i stepped on the full throttle was i bad lol?

 

I'm in Europe and I can tell you the break in restrictions ARE applicable in Europe !

 

One solution is to drive the car 2000 miles in the first month, hitting 4000 rpm in each gear as frequently as traffic permits, pay off your tickets and when you get your license back, everything will be nicely broken in and it will still be a low mileage car.

 

I don't understand the preoccupation of many owners (not lessees) with keeping mileage low on these cars. I drive it and I am not manufacturing the best used car for someone else to enjoy

 

With all of the electronics in this car (like rev matching in sport plus!), if it were vital for you to "break it in", I'd think they'd have thrown in a warning light and chime.

My c4s has 7000 miles and it doesn't burn oil (unlike the cpo 996 and 997.1 tt I owned). I don't drive it like a nut when it's cold, but I've never bothered with rev limits.

 

Interestingly enough... there is no break-in period in Germany. You pick up your car at the plant in Zuffenhausen and hammer it home on the Autobahn.

I can guarantee you the engine gets redlined at the factory.

I did the "proper" break-in period since the tech can pull up the shadow memory to check for "over revs" if you have a substantial warranty claim.

It is more important to make sure you let the engine warm up properly before stepping on it.