Free Track Day?

[MattR]

No, I wouldn't be concerned, the track will definately heat things up.

[sperry]

Originally Posted by cody

Oh, I have my EGT gauge set to turn the threshold light on at 1575*F. It rarely reaches 1550 normally. Cruising on the freeway is 1450 most of the time.

Yesterday the light came on for the first time ever and the needle just kissed 1600.

I have the probe mounted in the casting button on the passeger side manifold. Cause for concern?

Worry when the temps hit 1600 and don't drop when you're off the throttle.

Or if you're like me, when they hit 1800 and vaporize exhaust gaskets.

[cody]

They dropped when I let off. What does that indicate if they hadn't?

[sperry]

Originally Posted by cody

They dropped when I let off. What does that indicate if they hadn't?

That your pistons are dragging and creating heat from friction instead of heat from combustion... i.e. you're out of oil. Basically, you should expect EGTs to rise at a fairly constant rate as the car goes through a long pull in 3rd or 4th gear (or 4th and 5th gear on a 6MT). If you're peaking out at around 1600-1700 you're running a little hot, but as long as the temps drop off quickly when you get out of the throttle, things are fine.

It's when the temps spike quickly (i.e. the car's running lean and temps ramp up too fast), or when the temps stay up (i.e. the heat is being maintained by something other than the heat of combustion) that you have issues.

[cody]

Oh okay, good to know. The stock coolant gauge never budged so I guess that's a good thing.

[MattR]

Good info

[khail19]

Originally Posted by cody

He came over to Nick and I and was like, "Stupid Subarus!".

Says the moron with his air filter sticking out of the headlight.

[NstyNik]

A great point...Our subaru's (with proper care, oh ya... and oil) ran fantastic all day.

[cody]

I don't know why, but when my motor was freshly broken in, it consumed a quart every thousand miles. Now it consumes a quart every 10k at the most. I guess that's good.

[Nick Koan]

Originally Posted by cody

I don't know why, but when my motor was freshly broken in, it consumed a quart every thousand miles. Now it consumes a quart every 10k at the most. I guess that's good.

Mine did the same thing, from about 5k or so till 15k-20k range. Drank a quart every 1k miles or so. And now it drinks barely any.

FWIW, Subaru says 1 quart per 1k is within a normal range (high, but still within spec).

[cody]

Huh, guess it just takes some punishment to get the rings to mate to the cylinder walls or somthing.

[Nick Koan]

I don't know what it is, but I've heard a lot of people talk about it happening to them too. And it kind of makes sense. The engine is still 'breaking in' after 1k miles, up to 10k-15k or so, its just that the majority of the important parts of break in is pre-1k miles (like keeping it under a certain RPM level and whatnot).

[cody]

Ed tells me he's been getting more power out of STi's when people do the "drive it like you stole it" break-in technique right off the show room floor.

[Nick Koan]

Originally Posted by cody

Ed tells me he's been getting more power out of STi's when people do the "drive it like you stole it" break-in technique right off the show room floor.

Yeah, the race break-in idea is an interesting one. I believe I read somewhere that Mike at Gruppe-S no longer believes in it, after having more then a few bad motors that used the process. I believe Nate told me he believed in race break-in.

Its one of those very controversal topics, and to be honest I don't know where I stand.

[cody]

Yah, I really trust HotRod (Larry)'s opinion on most things, but it seems like my car makes plenty of power and I was pretty careful to keep RPM's varried and below 4K for the first 1k miles.

Here's an interesting write up from Larry:

Break-in how to

One of the subjects most likely to get a heated debate going on a car forum is a discussion about proper break in.

There are generally two points of view:
a. The engineers who designed it know best -- RTFM
b. Drive it like you stole it


Both points of view have their merits, but lets take a moment to look at what the break-in is for, and why the manufactures make specific recommendations.

Before I discribe how I broke in my car, a few comments on how and why.

A new engine (or any other mechanical device) is a little like a new pair of shoes. Everyone knows from experience what would happen if you put on a brand new pair of hiking boots and went for a long run. Big time blisters on your feet. In a mechanical device the same sort of high pressure injury occurs, but an engine or a gear does not blister, and cannot heal. You either break it in correctly or you damage it permanently.

The Break in process is actually a carefully controlled form of wear, like the new shoes, it is a chance for the mating parts to "adjust to each other". In a shoe and your foot, most of the adjustment takes place as the shoe leather stretches and softens from repeated flexing. To a lesser extent your feet will form a callous to protect any area where a pressure point persists.

No engine, bearing, gear or other mechanical device is perfect. If you look at a machined surface under magnification a piece of steel that looks to be smooth and polished is actually as rough as sand paper, only the peaks and valleys are on a very small level. When a machinist turns a shaft to a certain size, he is actually working to an acceptable error called tolerance. The crank shaft main journal may be specified to be 2.5 inches + or - 0.0002 inches and a surface roughness of maybe 50 millionths of an inch. A fine human hair is about 2 thousands of an inch in dia. So the acceptable error in diameter of the bearing is plus or minus 1/10 of the diameter of a human hair, and the acceptable roughness is about 1/40th of the diameter of a human hair.

The bearing clearance is the space between the bearing journal and the bearing shell surface where the oil film is supposed to exist. Lets suppose the clearance on this crankshaft is supposed to be 5/10000 of an inch to 7/10000 of an inch. Now suppose you take a bearing that is on the small side with a nominal clearance of 5 ten thousandths and put it on a journal that is at the large limit of 2.5002 inches. You have an actual clearance between those two high points of only 3 ten thousandths of an inch. On another journal in the same engine you might have a large bearing that has a nominal clearance of 7 ten thousands of an inch and a small journal that is only 2.4998 inches in diameter. On this bearing the actual clearance would be 9 ten thousands of an inch. Needless to say the bearing that has a true running clearance of 3 ten thousandths of an inch is going to have much less room to expand if it gets hot than the looser bearing journal that is at 3x the clearance.

In real life the crank shaft journal actually moves around inside the bearing. On average the bearing maintains a thin oil film between the moving parts but from time to time, under high loads or just due to random vibrations and variations in oil pressure and such, the bearing and journal will move into very close contact. Over time this will "burnish" the high spots down so the average surface is much smoother than it was when it came out of the factory. If you imagine the sandpaper like surface it had from the factory on a microscopic level, over time the appearance of the surface roughness will begin to look like a lot of table top mountains, as the upper most points on the the surface get either worn or beaten down by millions upon millions of small impacts.

The break in process is intended to facilitate this "wearing in" process with out giving your engine the mechanical equivalent of a blister.

[ what is a mechanical blister ?? on a fly wheel or a brake disk it is a premanent hard spot created by overheating a small high spot which is rapidly cooled by the metal surrounding it. This portion of the flywheel or brake disk will never wear at the same rate as the rest of the disk and will cause chatter and uneven friction for the life of the part. On a bearing it can be a hot spot on the surface that either hardens or softens the bearing surface or destroys the thin wear resistant coating put on by some manufactures. On a gear tooth it will be change in the hardness of the surface of the gear tooth that will make it wear or break under load. It could also lead to micro-cracking due to the rapid heating which will permanently weaken the gear. On a piston ring it can be scratching or scoring of the cylinder wall so the engine will always use oil to a softening of the piston rings due to over heating that results in poor ring seal and low compression and oil consumption.]

How do you allow controlled wear? You have to create a situation where you have sufficient load to create the brief periods of close contact required, without over heating or damaging the bearing surfaces. The problem is that each mechanical component needs slightly different conditions to allow this to happen.

The RTFM approach to auto break-in will give you a reliable car that does not require any warrantee work due to problems you created by mistreating the car in its first few miles of use. IT DOES NOT necessarily give you the best running car, or the most horsepower from your engine.

The drive it like you stole it approach will MOST of the time, give you a powerful engine, but may lead to various trips to the dealer for things you pushed too hard too soon during the first few miles of driving.

The best break in approach is about half way between these two extremes. The cam shaft and the cam followers are among the most heavily loaded parts on an engine, and need special care during the first hour or so of engine operation to avoid permanent damage. The bearings through out the engine and the gears in the transmission and differentials also need a pattern of alternating load and time to cool starting at low intensity and gradually increasing stress, to avoid permanent changes in gear hardness. The piston rings require brief periods of heavy load (hard acceleration), to seat the rings, followed by time to cool. The brake pads and brake disks as well as the flywheel and clutch need a progressive pattern of bedding in for the friction material and friction surface to get properly conditioned to avoid permanent damage due to over heating or poor performance due to improper bedding.

Most people think of the break-in process as applying to the engine, but it actually applies to the entire car and all its systems.

So what do I recommend for a break-in procedure?

First, cater to the cam shaft and the bearings, piston rings and cylinder walls in the engine. Start the car and hold the engine at a slightly fast idle (about 1500 -2000 rpm), let the engine run at this fast idle with slight variations is speed for about 30 minutes or until the engine is at full operating temperature for a minimum of 10 minutes.

Second, begin the bedding in process for the clutch, brakes, and the break-in process for the gears and piston rings/cylinder walls.

Take the car for a short drive (drive it home). Make a point to not slip the clutch too much, or ride the brakes too much, accelerate briskly up to the recommended rpm limit the manufacture gives in the break in guidelines, but be sure to give plenty of time between the periods of brisk acceleration for the engine to cool any hot spots. After you have several minutes of driving on the car, in a safe location, make some moderately hard stops to begin the bedding process on the brakes, but space them well apart so you never smell hot brakes. By now you should have a feel for the clutch, make a couple moderately hard accelerations which load the clutch a bit, again with plenty of time to cool. By now you should be home. Park the car someplace where you will be able to see any drips, and let it cool completely.

After the car has cooled down, check all your fluids to be sure all your levels are good. Look under the car and check for drips.
Take the time to give the car a good visual inspection. Think like a pilot giving a plane a pre-flight. Grab stuff and try to shake it, check tire pressures, oil levels, get out the owners manual and learn where the transmission fill is, where the brake master cylinder is, where the fuse boxes are, how to turn on the 4 way flashers etc.

Now your ready for phase 2. Take the car for another drive, where you have a lot of stop and go driving. Find a residential neighborhood that has lots of stop signs and learn the feel of the clutch. When conditions are safe, make a few brisk accelerations to seat the rings and bed in the clutch, then pull your speed down briskly (about 50% effort) with the brakes to help bed in the brake pads. Again be sure to give the car plenty of time to cool with easy "grandma driving" between these bursts. (be careful your brakes will not grab at full strength until the bedding process is complete - don't put your self in an emergency must stop situation !!)

Find a low traffic highway and make a max effort acceleration up the on ramp to highway speed, revving the engine to the max rpm listed in the manufactures guide lines in each gear (lets not go 140 mph here guys just 1-4 th gear ). cruise for a mile or two, to let everything cool and then find a safe place to make a 75% effort stop or two. Do this several times then take it home and let the car cool over night. Follow this pattern for a couple days, gradually increasing the level of effort on brakes, clutch and acceleration until you have about 200-300 miles on the car. At this point you should be able to make max effort stops and accelerations, but still limit your engine rpm to the max rpm recommendation by the manufacture.

From this point on, drive the car hard (safely!!) and every 100 miles or so, raise your engine rpm limit by 100-200 rpm. By this time you can make long highway trips with no problem, just avoid running on cruise control for extended periods of time. If you do use cruise control, periodically vary both speed setting and/or alternate between 4 th and 5th gear.

Switch to a quality synthetic oil on your first oil change, and by the time your at about 3000 miles you should have finished all the break in that requires special precautions. The engine will continue to gain power for the first 5 - 10 thousand miles as it slowly loosens up.

As an example of how these principles came about, here are some other examples of break in guide lines.

As far as manufactures recommending it, they have, but only to that fraction of their customer base that are likely to understand it. Several manufactures have specifically recommended this sort of high load, with cool down to racers.
The one I'm familiar with is Chrysler Corp when they introduced the Street hemi.

For their racing buyers they told them to follow the following sequence to break in their race engines for drag racing.

Start them up and let them idle at a fast idle 1500 rpm or so for 20 minutes or so. ( most cam shaft manufactures recommend the same for new cam shafts ) Then after checking for leaks etc. let the engine cool down completely.

Next make runs at 1/4 throttle , 1/2 throttle, and 3/4 throttle, each followed by a full cool down. Make a final full throttle pass then go racing.

Carrol Smith one of the most respected racing engineers in the business, goes to great length in his book "Tune to Win", and then bothers to repeat the same advice in a following book about how important this sort of periodic high load, followed by cool down is to proper break in of differential gear sets.

Several major engine builders describe how they dyno break-in an engine and they also use the same pattern. 30 minutes or so of moderate fast idle to warm things up, followed by brief runs up through the engines rpm range under gradually increasing load, followed by cool down cycles.


Mark Donohue the famous race driver describes how he broke-in race engines after rebuilding them in his book "Unfair Advantage". He liked to take the newly rebuilt engine and let it run at a fast idle for an hour or so, with a garden hose running in the cooling system to keep it cool. Then he would put it back in his car and take it to the track. By the time he finished his tuning laps and time trials for qualification, the engine was ready to race.

Graham Bell author of the book "Four Stroke Performance Tuning" gives an example of a dyno run in process he uses on all his race and rally engines. To make it universal I converted the numbers to % of maximum torque.

CODE


rpm Torque min
3500 25% 10
4000 33% 30
4500 45% 30
5000 56% 30
5500 66% 30



Followed by cool down, adjust tappets, and retorque heads then full power runs for tuning purposes.


Larry

http://www.wrxfanatics.com/index.php...=5706&hl=break

[Dean]

I'm with Larry, and the people he references.

You have to let things set, but then you have to make sure you are stretching all the parts, and making sure they seat over their entire range of motion.

I personally believe this is especially true of rings/cylinders. If during break in you only rev to 4K at light load, the pistons will never have reached either of the extremes the would reach at 7K under high load. While this may only be thousandths of an inch, it is enough to leave some sort of ridge/uneveness at those extremes that can cause leakage or even damage to the rings later when the engine is run at those extremes.

[cody]

Pics (round 2)

[tysonK]

If you are going to trash your STi and run $8k suspension why are you running stock wheels, wtf?

[Kevin M]

That STi has to be a salvage title rebuild or something. I hope.

[doubleurx]

Originally Posted by AtomicLabMonkey

You've got to be kidding me with that air filter...

"Colonel Hogan!.................Sirty days in za cooler!"


Sorry I missed it. Looks fun.