This is the second time I've seen this. When did "heat cycling" become the break-in process for anything but track tires?

 

Yes!! We have success!!! I'm out the door now for the trip back to Jax. Will post a lot tomorrow, including pics and an initial dyno. Any guesses on RWHP and torque on the break in run? The dyno was run at a little under 6 PSI of boost and only up to 6,000 RPM.

 

280-320whp and 270-300wtq. What turbo are you running? I think I missed that part.

 

360 Rwhp??

 

f*ck guessing, just tell us . I'm dying to know how your car turned out .

 

hahaha,... for real.. and he's going to make us guess...

 

message from the road via my pda at chik fil a - the car is running flawlessly and i'm all smiles. the wolf ems makes the car run like stock - much more though on this tomorrow . i'll post the actual dyno then - come on, guessing is fun! fyi - i'm running the pettit 20b twin turbos in sequential.

 

Sequencial as in the primary turbo transitioning over to the secondary? You mean to tell me that the Wolf ecu is able to run the 20b twins in sequencial mode? If this is true, that will make alot of 20b guys happy with their own DIY projects. Also do you have any cold starting issues?

 

gee, would it be:

3 Rotors
2 Sequential Turbochargers
2.0 Liters
550 HP @ 7500 RPM
460 Lb-Ft @ 5500 RPM

...just a guess

 

6psi at 6000RPM... hmm, I'll guess 310rwhp

 

At 6 psi? And under 6000 rpm?

I'd guess in the low 300's.

 

Oh I'll guess

280 rwhp at around 6000
340 rwtq at around 4500

 

Jim, I was always told "heat cycling" (i.e. short, moderately hard runs, not full throttle) were the best procedure for break-in http://www.mce-racing.com/techtalk/breakin.html
http://www.dragbike.com/news/01-99/drbrock-0199.htm http://www.lubeus.com/convertingtoamsoil.php

this link claims heat cycling is not important http://www.miata-power.com/engine-break-in.htm

I'd be interested to hear what you think and/or expereinces....it is interesting that use of syntheitc oils for break-in is discouraged by most "experts"

 

my guess is 320 at the wheels at 6 psi

 

I've always heard that initial break-in should be done with natural oil vs. synthetic because it allows maximum metal on metal wear at the friction surfaces. However, as far as I know, the Corvette comes from the factory with a gut full of Mobil 1, as do Vipers, Mercedes Benzes, and Cadillacs.

As far as break-in technique, there are probably as many opinions as there are people who have posted in this thread. I've never heard that heat cycling was required for a modern car engine and that initial break-in should consist of varying load/rpm for the first 500-1,000 miles. I can't speak for motorcycles, but they've got different requirements, I'm sure.

If the break-in has to take place on the highway (as it did with my Z06), then varying gears puts different loads on the engine. I varied 4th, 5th, and 6th for the first 500-1,000 miles when on the highway, with some town driving during and after stops, and of course the car cooling completely over night. At ~4,000 miles, my car put down 355.8 RWHP (~419 at the flywheel), which is about or a little above average for an '02-'04 Z06, so there were no problems. I wasn't able to change my oil until after the trip home (~3,200 miles) and a magnet run through the oil picked up nothing.

I think a lot of opinions are based on "the old days". I don't think that modern engines require nearly as much babying, and if modern car engine blocks require heat cycling to stress relieve the casting (per your last link), it's news to me.

 

I think everyone guessing low 300s is right on the money.

A healthy 13B-REW makes ~220 RWHP stock @ 10 psi. With a full open exhaust and intake, the same car @ 10 psi would probably be in the ~280-285 RWHP range. At only 6 psi, you're probably right back to 220 RWHP, if you could get the wastegate to open at 6 psi and not 7 psi.

If Stephen's math theories held true and a 20B made 50% more power than a 13B because it has 50% more displacement, then 220 RWHP * 1.5 = 330 RWHP. Since the extra rotor can't possibly be 100% efficient at producing power, my vote is for 300-320 RWHP.

 

and a magnet run through the oil picked up nothing

why would it? the engine internals are almost all aluminum in the LS6

 

Right... like the um, rings, and the um, cylinder sleeves, and the um, bearings, and the um, rod and crankshaft journals...

 

bearings arent aluminum neither is the crank shaft

 

oops, forgot about the steel cylinder sleeves I'm used to bike engines where the cylinder sleeves are typically ceramic-composite

how long did you let the oil sit before running a magnet through it? the tiny particles take a long time to settle out

 

And all the other friction surfaces in the engine with the exception of the valve guides...

What does settling out have to do with running a magnet through the oil? A magnet won't pick up metal shavings if they haven't settled out first?

 

Jim, I can't speak for the other cars on this list, but I thought Mercedes come "pre-broken in" or so they say?

 

according to this link http://www.miata-power.com/engine-break-in.htm

Several factors make the older information on break-in obsolete.

The biggest factor is that engine manufacturers now use a much finer honing pattern in the cylinders than they once did. This in turn changes the break-in requirements, because as you're about to learn, the window of opportunity for achieving an exceptional ring seal is much smaller with
newer engines than it was with the older "rough honed" engines.

In addition, there is a lot less heat build up in the cylinders from ring friction due to the finer honing pattern used in modern engines.

The other factors that have changed are the vastly improved metal casting and machining technologies which are now used. This means that the "wearing in" of the new parts involves significantly less friction and actual wear than it did in the distant past.

 

ha, yeah I know but the "magnet test" doesn't seem to work too well with freshly dumped oil....I've tried it...in a modern engine I think we are talking about micron size particles

 

Nothing that would evade a magnet from the back of an old 15" subwoofer...